As people, we are all shaped by the neighborhoods we grew up in, whether it was a bustling urban center or the quiet countryside. Objects in distant outer space are no different.
Like you, every supermassive black hole lives in a home – its host galaxy – and a neighborhood – its local group of other galaxies. A supermassive black hole grows by consuming gas already inside its host galaxy, sometimes reaching a billion times heavier than our Sun.
Theoretical physics predicts that black holes should take billions of years to grow into quasars, which are extra bright and powerful objects powered by black holes. Yet astronomers know that many quasars have formed in only a few hundred million years.
I’m fascinated by this peculiar problem of faster-than-expected black hole growth and am working to solve it by zooming out and examining the space around these black holes. Maybe the most massive quasars are city slickers, forming in hubs of tens or hundreds of other galaxies. Or maybe quasars can grow to huge proportions even in the most desolate regions of the universe.
Galaxy protoclusters
The largest object that can form in the universe is a galaxy cluster, containing hundreds of galaxies pulled by gravity to a common center. Before these grouped galaxies collapse into a single object, astronomers call them protoclusters. In these dense galaxy neighborhoods, astronomers see colliding galaxies, growing black holes and great swarms of gas that will eventually become the next generation of stars.
A simulation of a galaxy protocluster forming. In white, clouds of dark matter collapse and merge, while the red shows the motions of gas falling into the gravitational pull of the dark matter halos. TNG Collaboration, CC BY-NC-SA
These protocluster structures grow much faster than we thought, too, so we have a second cosmic problem to solve – how do quasars and protoclusters evolve so quickly? Are they connected?
To look at protoclusters, astronomers ideally obtain images, which show the galaxy’s shape, size and color, and a spectrum, which shows the galaxy’s distance from Earth through specific wavelengths of light, for each galaxy in the protocluster.
With telescopes like the James Webb Space Telescope, astronomers can see galaxies and black holes as they were billions of years ago, since the light emitted from distant objects must travel billions of light-years to reach its detectors. We can then look at protoclusters’ and quasars’ baby pictures to see how they evolved at early times.
An example of a galaxy image and spectrum from the ASPIRE program at the University of Arizona. The inset shows the infrared image of a galaxy 800 million years after the Big Bang. The spectrum shows signatures of hydrogen and oxygen emission lines, whose wavelengths translate mathematically to a 3D location in space. J. Champagne/ASPIRE/University of Arizona
It is only after looking at spectra that astronomers determine whether the galaxies and quasars are actually close together in three-dimensional space. But getting spectra for every galaxy one at a time can take many more hours than any astronomer has, and images can show galaxies that look closer together than they actually are.
So, for a long time, it was only a prediction that massive quasars might be evolving at the centers of vast galactic cities.
An unprecedented view of quasar environments
Now, Webb has completely revolutionized the search for galaxy neighborhoods because of an instrument called a wide-field slitless spectrograph.
This instrument takes spectra of every galaxy in its field of view simultaneously so astronomers can map out an entire cosmic city at once. It encodes the critical information about galaxies’ 3D locations by capturing the light emitted from gas at specific wavelengths – and in only a few hours of observing time.
The first Webb projects are hoping to look at quasar environments focused on a period about 800 million years after the Big Bang. This time period is a sweet spot in which astronomers can view these monster quasars and their neighbors using the light emitted by hydrogen and oxygen. The wavelengths of these light features show where the objects emitting them are along our line of sight, allowing astronomers to complete the census of where galaxies live relative to bright quasars.
One such ongoing project is led by the ASPIRE team at the University of Arizona’s Steward Observatory. In an early paper, they found a protocluster around an extremely bright quasar and confirmed it with 12 galaxies’ spectra.
Another study detected over a hundred galaxies, looking toward the single most luminous quasar known in the early universe. Twenty-four of those galaxies were close to the quasar or in its neighborhood.
The neighborhood of galaxies around J0305-3150, a quasar identified approximately 800 million years after the Big Bang. STScI/NASA
In ongoing work, my team is learning more details about mini galaxy cities like these. We want to figure out if individual galaxies show high rates of new star formation, if they contain large masses of old stars or if they are merging with one another. All these metrics would indicate that these galaxies are still actively evolving but had already formed millions of years before we observed them.
Once my team has a list of the properties of the galaxies in an area, we’ll compare these properties with a control sample of random galaxies in the universe, far away from any quasar. If these metrics are different enough from the control, we’ll have good evidence that quasars do grow up in special neighborhoods – ones developing much faster than the more sparse regions of the universe.
While astronomers still need more than a handful of quasars to prove this hypothesis on a larger scale, Webb has already opened a window into a bright future of discovery in glorious, high-resolution detail.
Comet Nishimura has been taking the world by storm. This icy visitor from our outer solar system is speeding through the sky on its way toward the Sun. Now visible less than an hour before dawn, the next few days are your absolute last chance to glimpse this bright comet before it rounds the Sun and flies off out of our solar system, never to be seen again.
Also cataloged as C/2023 P1, Nishimura was only recently discovered in the constellation Gemini. It has been rapidly traveling east, appearing to “fall” toward the Sun day by day as it approaches perihelion on September 17. Along the way, it’s been brightening dramatically and has developed a long, thin tail as ices sublimate away from its surface in the rising temperatures near the Sun.
How to catch the comet
Nishimura is now 4th magnitude, easily captured with optics even in the brightening sky. But because it’s so close to the Sun, it rises only about 40 minutes before dawn tomorrow (September 12). Some 25 minutes before sunrise tomorrow, Nishimura will be just 5° above the eastern horizon in the constellation Leo the Lion. Because most stars will no longer be visible at that time, look instead for the planet Mercury, also close to the eastern horizon, hanging directly below the delicate crescent Moon and shining at magnitude 2.7. From Mercury, look about 15° east-northeast — that’s within about 2.5 binocular fields to the planet’s left and slightly above its location.
Although 4th magnitude objects are visible to the naked eye, between the growing twilight and the comet’s low altitude, you’ll definitely want binoculars or a telescope to find it. Also try to choose an observing site that gets you above your surroundings — a roof or a hill — and pick a place with a clear eastern horizon devoid of tall trees and buildings.
Look east 25 minutes before sunrise on September 12 to find Comet Nishumura to the left of and just above Mercury. Credit: Alison Klesman (via TheSkyX)
By Wednesday the 13th, Nishimura is just 2° high in the east 25 minutes before sunrise. It will be about the same distance from Mercury (which has faded slightly to magnitude 2.2) but to the lower left, not the upper left. It forms the apex of a downward pointing triangle, with the Moon and Mercury as the base.
On September 13, Comet Nishimura is now to the left of and below Mercury in the eastern sky 25 minutes before sunrise. Credit: Alison Klesman (via TheSkyX)
Wednesday is likely the last time Northern Hemisphere observers will catch Nishimura. By Thursday, the comet rises only 15 minutes or so before the Sun. On Friday, the comet rises with the Sun, and in subsequent days, it will rise after the Sun.
As always, make sure to put away binoculars or telescopes several minutes before sunrise from your location to prevent serious and potentially permanent damage to your eyes.
Comets like Nishimura offer a wonderful opportunity to see the dynamic nature of our solar system right before your eyes — but only if you move fast!
Astronomy can be a lonely activity, with you and your telescope out under the stars. But for decades now, astronomy enthusiasts have also gone out of their way to cluster together at so-called star parties. Observing together under the night sky, sharing enthusiasm and discoveries, listening to talks by experts in the field, and building telescopes, sharing info on cameras, and other equipment has been a big part of the hobby.
In August the oldest and most storied of all American astronomy meet-ups, Stellafane, in Springfield, Vermont, celebrated its 100th anniversary with a wonderful gathering. What is the oldest amateur astronomy meeting doing in southern Vermont? The host town is a very old manufacturing center, and in the late 19th Century came to prominence when James Hartness brought the machining tool company Jones & Lamson to town. By the early 20th Century, talented machinists who were also intellectually alert turned to a new hobby by building telescopes. (In those days premade commercial telescopes did not exist.)
Built in 1923, Stellafane’s legendary pink clubhouse is inscribed with the phrase “The heavens declare the glory of God.” Credit: David Eicher
Historic hilltop
Hartness built a huge estate (that is in more recent times a hotel) before being elected Vermont’s Governor. One of his close friends, Russell W. Porter, was destined to become a great telescope designer. Hartness designed a revolutionary so-called Turret Telescope in which the optics stay outside while the observer can view the heavens inside a heated room. Porter adapted Hartness’s design to a reflector-based instrument, which he and the Springfield club later built on a hilltop outside Springfield.
At the very end of 1923 the telescope making movement in Springfield caught fire, and the Springfield Telescope Makers, the local club, erected a clubhouse on what they called Breezy Hill. The annual meeting sprang up, and came to be called Stellafane, meaning “shrine to the stars.”
This year was special for everyone who attended, the centennial causing a big focus on Stellafane’s storied past. Activities cranked up on Thursday, August 17, and lasted through the weekend, with cleanup and restoration of the site happening on Sunday the 20th. Talks occur underneath a huge tent area at the meeting, and included some special presentations.
A number of Stellafane participants had the great experience of walking along a scale model solar system, with detailed explanations of the planets, put on by astronomy enthusiast Kaitlynn Goulette. She is a 15-year-old who is very active in outreach, publishing notices under the title Starry Scoop. Credit: David Eicher
Sharing stories
An expert on astronomical history, Richard Sanderson presented a talk on an historic telescope in Springfield, Massachusetts, his hometown. Al Takeda spoke on photographic techniques to bear in mind for the upcoming solar eclipses. Astronomy contributor Phil Harrington’s superb talk on the history of Stellafane was a major highlight of the weekend. Alan Ward spoke about optical coatings for telescope mirrors. Clifton Ashcraft described the Local Supercluster of galaxies. On Friday evening, informal talks covered a large range of topics and shared many amazing images to the whole group.
Saturday talks were no less fascinating. Peter Bealo described the opportunities amateur astronomers have in cooperating with professionals to make scientific contributions. Rich Nugent delivered an outstanding talk on breathing new life into vintage refractors, a popular topic among many in the audience. Mario Motta provided another great historical talk with an in-depth biographical presentation on the life of Russell W. Porter. Larry Mitchell wowed the audience with a detailed and highly precise talk on the astrophysical nature of and observing opportunities with planetary nebulae.
An inside view of the Hartness House Turret Telescope shows the primitive workings of the World War I-era creation, at the time a novel pathway to viewing the heavens. Credit: David Eicher
Opportune observing
The weather at this Stellafane centennial looked sketchy. Fortunately, however, we had what turned out to be a magnificent night on Friday, observing countless deep-sky objects for hours. And the wonderful folks who were operating telescopes on the upper field were generous, sharing views of globular clusters, planetary nebulae, emission nebulae, and galaxies. My pal Mike Witkoski and I spent a great deal of time peering through a very fine 25-inch Dobsonian, which had enough heft to show practically anything we could think of very nicely.
Lots of other activities also kept Stellafaners busy. Historical displays on early Springfield club members, telescope making workshops, Stellafane history in videos and pictures, and observing with some of the permanent observatories on Breezy Hill occupied much of the time for many attendees. Late in the meeting, I had the great opportunity to tag along on a scale model solar system walk with several friends, which was led by 15-year-old Kaitlynn Goulette. She publishing a digital newsletter about Astro happenings called Starry Scoop and has already garnered rave reviews from Phil Harrington, Richard Sanderson, and others in the New England region who know her. The walk was great, with wonderful descriptions of the planets provided by Kaitlynn.
After three days of nonstop astronomy talk, I left slightly worn, very pleased and happy, and ready for a little vacation time in Boston. Reliving the Freedom Trail, exploring the Constitution and Lexington and Concord, I thought back to how nicely Stellafane unfolded, and hoped that I will make it back to this great gathering again sometime soon.
Editor’s Note: The original text incorrectly stated that Porter invented the Turret Telescope.
The space shuttle era was a time of many firsts for space exploration. Most prominently, it marked the regular usage of the first reusable spacecraft to carry humans into low Earth orbit. In its 30-year history since beginning in 1981, the Space Shuttle Program’s fleet — Columbia, Challenger, Discovery, Atlantis, and Endeavour — flew 135 missions, clocking in at a total of 1,334 days, 1 hour, 36 minutes, and 44 seconds in space. In that time, astronauts helped build and maintain the International Space Station and deployed laboratories and satellites to space. The shuttle program came to an end when Atlantis touched down at the Kennedy Space Center on July 21, 2011.
Since then, the three remaining space-flown shuttles, Discovery, Endeavour, and Atlantis, have been put on public display in museums across the United States. Each one is curated to showcase its history and as a reminder of each shuttle’s scientific contributions.
Earlier this year, Atlantis celebrated its 10th anniversary since it was welcomed to its permanent home at the Kennedy Space Center Visitor Complex in Florida. And Endeavour is getting an update to its permanent museum home at the California Science Center.
The Space Shuttle Endeavour will be the only shuttle to be displayed in its vertical, stacked configuration when the construction of its new home, the Samuel Oschin Air and Space Center, is completed, depicted here in a rendering. Credit: ZGF
As retired space relics, the orbiters inspire, teach, and astound visitors who venture into their exhibits. Thousands of hours have been spent to ensure that their exhibits tell each orbiter’s story and preserving it for generations. With the shuttles now a decade into retired life, Astronomy spoke to the curators of Endeavour and Atlantis to learn more these historic crafts’ new missions.
Space Shuttle Endeavour (OV-105)
When Endeavour launched on its final mission in May 2011, it brought spare parts to the International Space Station and delivered a the $2-billion astrophysics experiment: the Alpha Magnetic Spectrometer. After Endeavour touched down for the last time June 1, 2011, NASA began preparing to the shuttle for its forever home at the California Science Center in Los Angeles.
The Space Shuttle Endeavour soars over the Golden Gate Bridge atop the Shuttle Carrier Aircraft on Sept. 21, 2012, as it toured California to close out its flight career. Credit: NASA/Carla Thomas
Endeavour was delivered to L.A. atop one of NASA’s Shuttle Carrier Aircraft, a modified Boeing 747. At the Los Angeles International Airport, crowds welcomed the orbiter’s return to its birthplace in California (like every other shuttle, it was constructed in Palmdale by Rockwell International). After landing, the orbiter was removed from the 747 with a crane, placed on a transporter, and began its 12-mile (19 kilometers) trek to the California Science Center.
The streets of Los Angeles were swarming with excitement as onlookers stretched their necks and pulled out their cameras and phones to take photos of the Endeavour orbiter. “Oh my goodness, the entire city was like the largest block party that the city of Los Angeles had ever had,” says Kenneth Phillips, the aerospace science curator at the California Science Center.
On its journey from LAX, Endeavour weaved through neighborhoods with outstretched wings, carefully maneuvering around sidewalk trees and crowds of enthused onlookers at a leisurely 2 mph (3.2 km/h). “Fortunately, we have boulevards that are wide enough to accept the wingspan because you can’t take the orbiter apart,” says Phillips. Processions of cars followed before and behind Endeavour. Astronauts who flew on Endeavour paraded alongside the orbiter and interacted with the crowds.
For nearly 12 years, Endeavour has dazzled visitors on display in a temporary hangar at the Samuel Oschin Pavilion at the California Science Center in the same horizontal position when it rolled in. But the museum is now preparing to move the orbiter into its new home, where Endeavour will be reunited with its rocket stack and shifted into a “ready to launch” position. The stack includes NASA’s last remaining external fuel tank built for flight and two rocket boosters recovered from previous launches, making it the first vertical display of a shuttle.
Phillips says that since Endeavour arrived at the museum in 2012, the plan was always to display the orbiter in an awe-inspiring way and showcase the level of effort required to launch the 160,000-pound (73,000 kilograms) shuttle into space. “It takes the large orange external tank and the two solid rocket boosters strapped to the side of the tank to lift the entire stack,” says Phillips. The new building, dubbed the Samuel Oschin Air and Space Center, will have to be built around the Endeavour orbiter and its accompanying shuttle stack. Once complete, visitors will ascend the gantry tower adjacent to the rockets, just like an astronaut preparing for flight.
Endeavour, built to replace the shuttle Challenger, cost about $1.7 billion and was the last space shuttle ever built. For many scientists, including Phillips, Endeavour represented hope following the Challenger disaster.
The crew of STS-51L, the final flight of Challenger. Front row left: Michael J. Smith, Francis R. “Dick” Scobee, Ronald E. McNair. Back row from left: Ellison S. Onizuka, S. Christa McAuliffe, Gregory B. Jarvis, and Judith A. Resnik. Credit: NASA
“I have a dear friend, a good friend, who was on the Space Shuttle Challenger when we lost it in 1986… So, it kind of makes me think that my buddy, my friend [Dr. Ronald McNair], was beaming when I had the spaceship that replaced the one he was on, which is great,” says Phillips. “It’s nice to have that particular ship.”
Endeavour also was reconfigured in 2014 when, still in its horizontal position, its cargo bay was loaded with the SpaceHAB module, to look as it did during the 2007 STS-118 mission. “SpaceHAB is a pressurized module that connects to the part where the astronauts flew in the front of the shuttle, so you could do laboratory experiments and things like that,” says Phillips.
With the Spacehab laboratory inside the payload bay, the amount of space onboard the shuttle for crew-tended experiments more than doubled. Credit: NASA
On that mission, Barbara Morgan, NASA’s first educator astronaut and original backup astronaut to Challenger’s Christa McAuliffe, flew 5.3 million miles (8.5 million km) in space during the two-week mission to help construct the International Space Station. “We replicated that as closely as possible as a nod to teachers and educators. So, we have what I call ‘The Teacher’s Shuttle,’ which is great,” Phillips says. The California Science Center recently added a replica Orbiter Boom Sensor System (OBSS) — a boom extension to the shuttle’s Canadian-built robotic arm — to the payload bay, adding to the authenticity of what the shuttle looked like during STS-118.
Three weeks after it was installed with tools from NASA and the Smithsonian, the payload doors were closed again. Once the shuttle is attached to its launch stack in the new building, one of the cargo bay doors will be reopened to show off the SpaceHAB payload.
Among other firsts, Endeavour flew Mae Jemison, the first African American woman in space, in 1992 on STS-47. It was the first orbiter to service the Hubble Space Telescope, installing equipment in 1993 on STS-61 to correct the observatory’s flawed mirrors. It delivered to orbit the first American contribution to the International Space Station, a module named Unity, and also carried out the final ISS assembly mission. “It was sort of the bookends, the alpha and the omega of the assembly of the International Space Station,” Phillips says.
Space Shuttle Atlantis (OV-104)
Like Endeavour, the Atlantis orbiter made a trek over ground to its final home — in this case, a 10 mile (16 km) ride on a transporter from the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida to the Kennedy Space Center Visitor Complex, where it was welcomed with dozens of sparkling fireworks. Soon after it arrived, Atlantis was shrink-wrapped in 16,000 square feet of protective plastic like a boat to protect it from the construction as its new building was developed around it.
Atlantis sits on display at the Kennedy Space Center with its payload bay doors open. Credit: Elizabeth Gamillo
The Atlantis orbiter is the only shuttle displayed in an in-flight configuration with its payload doors open. Curators wanted to display Atlantis in this position because it allowed visitors to see it as astronauts would have. “We’ve seen people be floored by their first encounter with Atlantis, coming nose to nose with this vehicle and having an unexpected and powerful reaction,” says Jennifer Mayo, senior manager of project development at the Kennedy Space Center Visitor Complex. “It’s like the shuttle has a personality of its own that touches people.”
The shuttle greets visitors head-on with an outstretched second-generation Canadarm and tilts as if it’s orbiting in space. Currently, there are no plans to remodel the Atlantis exhibit. “The attraction is so well done and has such a lasting impact on guests even a decade after it was put in place,” says Mayo. “Much magic is left in this display for years to come.”
Visitors crowd around Atlantis at the Kennedy Space Center. Credit: Elizabeth Gamillo
Orbiter preservation
Before any orbiter was placed on display, NASA had to “safe the orbiter” for the public —removing fuels from the orbital maneuvering engines, taking out some interior components that were toxic, and preparing each orbiter for their flight on a Boeing 747. The engines were removed and replaced with replicas. Each orbiter’s avionics, lockers, tools, and toilets were removed.
Each shuttle on display was preserved to showcase the miles each shuttle endured and the beating they took as they reentered Earth’s atmosphere at blazing speeds. For the orbiters on display, the goal is to keep them looking as they did on their last flight home. “If you look closely at the tiles and know where to look, you’ll see some of them are damaged,” Phillips says of Endeavour. “That happens almost all the time when a shuttle launches. Normally they would be repaired for re-flight, but we didn’t want to fix we wanted it exactly as it was for its last mission.”
And to keep them looking spiffy, there is always maintenance. “Areas more prone to dust collection are cleaned weekly. There are also quarterly preventive maintenance tasks to address hard-to-reach areas,” Mayo says of Atlantis’ upkeep routine.
The Samuel Oschin Air and Space Center is under construction on the California Science Center’s campus in LA’s Exposition Park. Credit for all images: California Science Center
Completing Endeavour’s new exhibit is expected to take several years. While the new building is built around it, Endeavour will be surrounded by a protective scaffolding of plywood and Kevlar fabric. The orbiter is currently on display in its stacked configuration until December 31, 2023, when construction on the Samuel Oschin Air and Space Center will commence. The shuttle will return to the public eye after the Samuel Oschin Air and Space Center is completed. “It’s going to be quite the experience,” says Phillips.
Fresh on the heels of an inaugural Moon landing at the lunar South Pole last month, the Indian Space Research Organisation (ISRO) has done it again with the successful launch of its Aditya-L1 spacecraft. This mission, specifically designed to study the Sun, seeks to answer some of the most pressing questions about our nearest star.
Aditya-L1 took flight from the Satish Dhawan Space Centre, located on Sriharikota Island, atop ISRO’s Polar Satellite Launch Vehicle (PSLV) on Sept. 2. The spacecraft was deployed into low-Earth orbit roughly an hour after launch. Its remaining journey will see it travel some 93 million miles (150 million kilometers) over the course of around 110 days, ultimately entering a halo orbit at a gravitationally stable position between the Sun and Earth.
Aditya-L1 mission overview
Aditya-L1’s primary objective is a comprehensive examination of the Sun, particularly focusing on its outermost layer (the corona), the Sun’s surface (the photosphere), and the solar wind. Among the many mysteries the mission aims to address is the long-standing question of why the corona is substantially hotter than the photosphere, despite the corona being tenuous and far from the Sun’s core.
The spacecraft’s position at Lagrange point 1 (L1) — a gravitationally stable point some 900,000 miles (1.5 million km) from Earth — offers it a particularly strategic vantage point. This location allows Aditya-L1 to remain stable relative to Earth and the Sun, providing a continuous and uninterrupted view of our star.
The Aditya-L1 mission is expected to last roughly five years.
An illustration showing the various Lagrange points. Credit: ESA
Mission evolution and design
The Aditya-L1 mission has come a long way from its initial concept in 2008. Originally envisioned as a modest 880-pound (400 kilogram) satellite in low-Earth orbit, the mission’s scope has expanded over the past 15 years. For example, the spacecraft recently launched with a mass of nearly 3,300 pounds and its new mission profile sees it venturing far beyond low-Earth orbit.
ISRO’s innovation is evident in Aditya-L1’s design. The cube-shaped craft boasts a honeycomb sandwich structure, and its integrated miniaturized GPS receiver ensures real-time data on position, velocity, and time. When unfolded, two solar panels will help recharge Aditya-L1’s lithium-ion battery, ensuring a steady power supply.
An image of Aditya L1 in the cleanroom prior to its launch on September 2, 2023. Credit: ISRO
Scientific instruments, at a glance
Aditya-L1’s spacecraft’s instrument suite is specially tailored to seek the answers to three primary questions: How do stars like the Sun sustain a superheated outer layer (corona)? How does the Sun’s magnetic field generate powerful solar storms? And how does the Sun’s variable magnetic field affect Earth’s atmosphere?
To help answer these pressing questions, Aditya-L1 comes equipped with seven specialized instruments.
Visible Emission Line Coronagraph (VELC): This instrument will observe the inner corona by looking toward the limb of the Sun. This approach allows it to easily focus on phenomena like CMEs and bursts of plasma from the Sun’s upper atmosphere (coronal loops), which will help researchers better understand the cause or causes of coronal overheating.
High Energy L1 Orbiting x-ray Spectrometer (HEL1OS): Primarily concentrating on hard, or high-energy, X-rays generated during solar flares, this instrument will monitor thermal and non-thermal emissions. The data it collects will provide researchers with insights into how solar flares are generated and evolve.
Solar Low Energy X-ray Spectrometer (SoLEXS): With a focus on soft, or low-energy, X-rays, this instrument will likewise shed light on the nature of solar flares. By measuring X-ray flux, SoLEXs will hopefully help researchers pin down the mechanism or mechanisms that drive coronal heating.
Solar Ultraviolet Imaging Telescope (SUIT): This ultraviolet telescope will capture images of the solar disk in near-ultraviolet wavelengths, with the goal of helping researchers understand how the photosphere and/or chromosphere transfer so much energy to the corona. SUIT was developed in collaboration with India’s Inter-University Centre for Astronomy and Astrophysics.
Magnetometer (MAG): Developed by the Laboratory for Electro Optics Systems, this magnetic sensor measures the strength and direction of the interplanetary magnetic field at the spacecraft’s L1 position. This instrument consists of two sets of sensors mounted on a 20-foot (6 meter) deployable boom, and the data it collects will be key to understanding events like coronal mass ejections (CMEs) and solar plasma waves.
Aditya Solar wind Particle Experiment (ASPEX): Consisting of two sensors and built by the Physical Research Laboratory at Ahmedabad, ASPEX’s focus will be studying the solar wind to better understand where charged particles originate and how they are accelerated. The Solar Wind Ion Spectrometer will measure solar wind particles (such as protons and alpha particles), while the Suprathermal and Energetic Particle Spectrometer will detect particularly high-energy ions.
Plasma Analyser Package for Aditya (PAPA): This plasma analyzer, developed by the Vikram Sarabhai Space Centre’s Space Physics Laboratory, will likewise focus on studying the solar wind. The instrument’s Solar Wind Electron Energy Probe and Solar Wind Ion Composition Anaylser will help create a record of variations in the composition, flux, and density of both electrons and ions in the solar wind over time.
As for the mission’s cost, while ISRO has not disclosed official figures, estimates from Indian media sources suggest a price tag of around $46 million — which is relatively modest when it comes to space exploration.
With the recent successful launch of Aditya-L1, India has now accomplished two impressive feats in just a few short weeks. True, the nation has been ramping up their space program for years, but now, it seems, they have solidified their position as a major player on the global space stage.
Astronomers recently discovered an enormous cosmic bubble packed with galaxies that stretches nearly 1 billion light-years across and seems to be an ancient vestige from the infant universe.
Named Hoʻoleilana, a nod to a Hawaiian creation chant that describes the origin of structure, the massive bubble is thought to be what’s called a baryon acoustic oscillation, or BAO. These fossilized imprints of matter in the early universe date back more than 13 billion years, to the moment the cosmos entered a new transparent phase some 380,000 years after the Big Bang.
Ho’oleilana, which is located just 820 million light-years from the Milky Way, consists of a full spherical shell of galaxies with a supercluster core, as predicted by theory. The massive bubble also displays an enhanced density of galaxies emanating from its center, and it is composed of previously identified structures that themselves are some of the largest known structures in the universe.
The new finding, published Sept. 5 in The Astrophysical Journal, will not only help astronomers untangle the mysteries of early galaxy evolution, but also might hint at subtle issues concerning the expansion rate of the universe.
How BAOs are born
Massive BAOs like Ho’oleilana are predicted based on our current understanding of the Big Bang and how the early universe evolved.
For about 400,000 years following the Big Bang, matter in the universe took the form of a dense, nearly uniform sea of extremely hot plasma, with electrons too energized to settle down with atomic nuclei. Slight density fluctuations (of roughly one part in 100,000) within this sea led to gravity attempting to pull together larger pockets of matter.
However, the universe remained too hot for particles to cling together after colliding, leading to a tug-of-war between the outward pressure of radiation and the inward pull of gravity. This created pressure oscillations similar to sound waves in the plasma sea. BAOs were created when these pressure oscillations rippled outward, leading to slight overdensities of matter.
But then, some 380,000 years after the Big Bang, the universe cooled to the point that the sea of electrons and nuclei combined into neutral atoms, making the cosmos transparent to radiation. At that point, the bubbles became frozen in place, with any matter density peaks eventually manifesting as vast bubbles that are densely populated with galaxies.
By observing and analyzing patterns in galaxy distribution within BAOs, astronomers can learn a great deal about what gave rise to the largest cosmic structures in the universe.
In the illustration the red region shows the shell enclosed by the Baryon Acoustic Oscillation, with individual galaxies depicted as luminous tiny specks. The blue filaments show the greater Cosmic Web, with previously known features like Laniākea highlighted. Credit: Frédéric Durillon, Animea Studio; Daniel Pomarède, IRFU, CEA University Paris-Saclay. This work benefited from a government funding by France 2030 (P2I – Graduate School of Physics) under reference ANR-11-IDEX-0003.
Piecing together a cosmic jigsaw
The first hints of Ho’oleilana were uncovered in 2016 by the Sloan Digital Sky Survey, which captured part of its shell structure. However, that shell was never linked to a BAO, as the true extent of the billion-light-year-wide bubble remained hidden.
“We were not looking for it,” said Brent Tully, an astronomer from the University of Hawai’i and lead author of the new study, in a press release. “It is so huge that it spills to the edges of the sector of the sky that we were analyzing.”
Using data from Cosmicflows-4, the largest-ever compilation of precise galaxy distance, the researchers mapped out the gargantuan bubble in three dimensions, allowing them to discern Ho’oleilana’s full spherical shell, as well as unravel how its many galaxies are clustered together.
“Constructing this map and observing the vast shell structure was an awe-inspiring process,” said co-author Daniel Pomarede of CEA Paris-Saclay University in France, who refers to himself as the cartographer of the group.
“[M]apping Hoʻoleilana in three dimensions helps us understand its content and relationship with its surroundings,” he added. “It was an amazing process to construct this map and see how the giant shell structure of Hoʻoleilana is composed of elements that were identified in the past as being themselves some of the largest structures of the universe.”
Some of the previously identified enormous structures that are now linked to Ho’oleilana include the Sloan Great Wall, the Hercules complex, the Coma Great Wall, the Boötes Supercluster (near the core of the bubble), and the expansive Boötes Void, which is a roughly 400-million-light-year-wide spherical underdensity of galaxies.
In conflict with the Hubble constant?
The discovery of Ho’oleilana might have more profound implications than just a better understanding of the hierarchy of nearby galactic superstructures, too. According to Tully, the enormity and proximity of Hoʻoleilana raises questions about the presumed expansion rate of the universe.
“The very large diameter of one billion light years is beyond theoretical expectations,” said Tully. “If its formation and evolution are in accordance with theory, this BAO is closer than anticipated, implying a high value for the expansion rate of the universe.”
Current estimates peg the universe’s expansion rate (or Hubble constant) between 67 and 74 kilometers per second per megaparsec. But according to the new study’s analysis of Hoʻoleilana as a BAO, the researchers calculated a slightly faster expansion rate of between 74.7 and 76.9 kilometers per second per megaparsec. If confirmed, this result may further complicate the already contentious question of how fast the universe is really expanding.
The discovery of Hoʻoleilana, especially considering its vast size and proximity to the Milky Way, underscores the myriad mysteries that the cosmos still holds. However, as with all discoveries, the researchers say further observations and analysis are needed to fully grasp the true nature of this fossilized bubble from the infant universe.
This near-infrared and visible image shows the galaxy M89 as viewed by the Hubble Space Telescope’s Wide field and Planetary Camera 2. The 2019 image captures M89’s bright central nucleus and was taken to further understand how elliptical galaxies like M89 form, as well as to bolster evidence for a central black hole within these galaxies.
The galaxy is at least 50 million light-years away in the constellation Virgo and appears to be perfectly spherical, which is unusual for elliptical galaxies that tend to be egg shaped. However, researchers think that what might give M89 its seemingly round shape is not a physical characteristic, but rather its orientation toward Earth.
Within the galaxy, which is only slightly smaller than the Milky Way, reside some 100 billion stars and 2,000 globular clusters. At its center sits a supermassive black hole . A huge structure of gas and dust extends 150,000 light-years out, perhaps the remnants of a time when that black hole was more actively feeding. Researchers have also found jets that reach out to 100,000 light years from the galaxy, again suggesting that at one point, M89 may have been more active as a quasar or radio galaxy.
M89 is surrounded by shells and plumes of material, making researchers suspect it has recently undergone mergers with smaller galaxies, implying that M89 formed not long ago.
The deep-sky object was found in 1781 by Charles Messier, who began cataloging faint, fuzzy targets in the sky after he mistook a hazy object for Halley’s Comet. That unclear object instead was the Crab Nebula (M1). To help other stargazers from making the same mistake, Messier created a guide of all bright, deep-sky objects that could be confused for comets. His and others’ careful observations eventually led to the Messier Catalog. M89 is the last giant elliptical Messier found and the most impeccably circular galaxy in his catalog of 109 objects.
Within the constellation Virgo numerous galaxies that comprise the Virgo Cluster, including the potato-shaped elliptical M87, whose supermassive black hole was imaged in 2019.
Scholars across the globe often refer to astronomy as the oldest science, dating back to the ancient Mesopotamians and Babylonians. While that may be true, modern-day amateur astronomy can trace its origins back to Dec. 7, 1923. On that date, the first meeting of a small club known as the Springfield Telescope Makers sparked a movement that continues to this day.
Born in Springfield, Vermont, in 1871, Russell W. Porter exemplified a 20th-century Renaissance man. He was an artist, an architect, an engineer, and an arctic explorer. It was on those excursions around the Arctic Circle that celestial navigation, astronomy, and telescopes began to pique his interest, paving the way for a lifelong hobby.
After his arctic adventures ebbed, Porter moved to Port Clyde, Maine, and got married. He made a living designing new oceanfront cottages and renovating older buildings. But by night, the dark Maine skies beckoned him to learn more about the universe.
Russell Porter’s first telescope-mirror-making class in October 1920 gathered at Jones and Lamson, and was composed of 15 men and one woman. Some would go on to found the Springfield Telescope Makers. Credit: Stellafane Archives
In 1910, Porter’s longtime friend and enthusiastic amateur astronomer James Hartness began introducing him to articles in Scientific American and Popular Astronomy magazines, to fuel his interest in astronomy. One issue included an intriguing article written by Leo Holcomb on speculum (or mirror) making. Although the article was only a general introduction to the subject and did not contain actual instructions on mirror grinding, it was enough to prompt Porter to write to Holcomb, asking for more information.
Holcomb began corresponding with Porter, sending a copy of the book Glass Working by Heat and by Abrasion by Paul Hasluck with one of his letters. This book was just the thing Porter needed to begin crafting his first telescope lens. In a later article in Popular Astronomy, he wrote, “Since that time, I have figured a dozen or more discs for telescopes, and derived so much pleasure from the pastime that I wish to pass on to others, who may enter on this fascinating work, the benefits of my experience.”
Meanwhile, to cope with the intensely cold winter nights in northern New England, Hartness had devised a clever “indoor observatory” that kept the optics of his 10-inch refractor outside in the cold to prevent distortion, while the observer stayed in a heated room.
Inspired by Hartness’ design, Porter created a similar observatory for his home, featuring a reflecting telescope. The excellent quality of his new observatory prompted Porter to write an article about its design for the May 1916 issue of Popular Astronomy. It was the first of many articles to come.
The 1936 Stellafane Convention attendees examine a large mounted telescope. Credit: Stellafane archives
Expanding the scope
In 1915, Porter joined MIT as a professor; he then worked at the National Bureau of Standards during World War I. But in 1919, Porter moved back to Springfield with his wife Alice and young daughter Caroline. He got a job with Hartness at Jones & Lamson Machine Co., a large manufacturer of small mechanical parts.
Porter’s fascination with telescope-making soon proved contagious and by 1920, many fellow townsfolk had become interested in the hobby, prompting Porter to start teaching classes. Eventually the members began hauling their completed telescopes all over town for observing sessions. One favorite spot was land owned by Porter atop Breezy Hill, just outside Springfield.
On Dec. 7, 1923, the Springfield Telescope Makers club was born, with Porter elected as president. Around the same time, members began constructing a clubhouse on the summit of Breezy Hill. The building consisted of a main meeting room and two upstairs bedrooms, and later a kitchen.
In 1924, the club adopted Porter’s proposal that the site be christened Stellar Fane, Latin for “shrine to the stars.” Within months, the name was shortened to Stellafane.
Porter spread the word about Stellafane within the pages of Popular Astronomy. In 1925, after reading Porter’s articles in the magazine, editor Albert Ingalls met with him to learn about the telescope-making process and the Springfield club. Ingalls subsequently visited Stellafane to meet with members.
Ingalls’ article about Porter’s club and their homemade telescopes made the cover story of the November 1925 issue of Scientific American. The response was almost immediate. Readers wanted to know how to build their own instruments. At the time, most commercial telescopes were high-priced refractors, impossible for many amateurs to purchase. Porter’s articles ignited an excitement that the average person could make their own telescope, even on a limited budget.
The popularity of that article helped Ingalls convince Porter to write two articles on amateur telescope-making for Scientific American. They appeared in February and March 1926. Letters from interested readers around the world poured in, and Porter soon became a corresponding editor for the magazine.
Two men inspect a 6-inch telescope in front of the Stellafane Clubhouse at the 1926 convention. Credit: Stellafane archives
The reaction also prompted the club to invite amateur telescope makers to Stellafane for a weekend gathering to exchange ideas and compare their creations. On July 3, 1926, about 20 people ventured up the dirt roads to the summit of Breezy Hill to attend the first Stellafane convention.
Growing interest in amateur telescope-making prompted Ingalls to compile a book with step-by-step instructions, called Amateur Telescope Making. He included Porter’s first two articles from Scientific American, along with several new chapters. Published in 1926, it has since become the amateur telescope maker’s bible.
This continued to fuel a movement that changed the face of the hobby forever. Rather than spending a fortune on a small refractor, the growing field of amateur astronomers preferred to make their own larger Newtonian reflectors for less money. Meanwhile, the Stellafane convention became an annual event.
In 1928, Porter met with astronomer George Ellery Hale, who had read some of his articles. Hale was in the early planning stages of installing a 200-inch (5.1 meters) reflector — the world’s largest telescope at that time — on Palomar Mountain, 61 miles east of San Diego, California. Later that year, Porter received a telegram from Hale, asking him to come to California “to assist in designing the 200-inch telescope.” Porter did not hesitate to accept.
Porter expected his involvement would be brief, but it soon became clear that the move to California was permanent. He relinquished his club presidency but still managed to attend many Stellafane conventions. During a club meeting in 1929, Porter revealed plans to build a telescope on a massive rock on Breezy Hill, just north of the clubhouse. The ingenious design called for a new observatory building surrounding the scope to double as a shelter and telescope mount. A circular opening in the north wall, sloped to match the property’s grade, would be capped with a rotating turretlike dome that would serve as the telescope’s right ascension axis and viewing portal. Incoming light would reflect off a rotatable diagonal mirror to the instrument’s primary mirror, which would direct it back through a hole in the diagonal and into the eyepiece inside the observatory. The partially constructed turret telescope was one of the chief attractions at the fifth annual convention and by the sixth in 1931, the Porter Turret Telescope was complete.
World War II forced the suspension of the Stellafane conventions from 1942 to 1945. The first postwar Stellafane in 1946 drew over 350 people, the largest crowd at the time.
Porter’s failing health kept him from the 1948 convention, but he sent a letter that was read at the event’s Twilight Talks. “You may be sure that I regret not being with you tonight, but the stress of other work has made it impossible,” Porter wrote. “But I am very much with you in spirit.”
On Feb. 22, 1949, while working Porter suffered a major heart attack. Around 11:30 that night, he experienced a second, fatal heart attack. He was 77 years old.
Among the many honors and awards bestowed on Porter, the most unique was the posthumous renaming of a lunar crater in his honor. Today, Porter Crater is located in the southern portion of the Moon, inside Clavius Crater.
The modern era
A 12½-inch ball-mount telescope sits on display at the 1972 convention, with its creator Norman James standing nearby. Credit: Richard Sanderson
Porter’s death left a huge void, but the Stellafane conventions eventually recovered. His spirit lives on to this day in every telescope and other equipment displayed each year. Most of the instruments at Stellafane are Newtonians, though other types of telescopes are also present. Occasionally, a telescope displayed on Breezy Hill features a breakthrough in design.
One such instrument was John Gregory’s 5-inch Maksutov at the 1956 convention. Gregory, an optical designer from Stamford, Connecticut, modified the shape of the corrector plate so that an aluminized spot at its center served as the secondary mirror, rather than requiring a separate mirror. Today, most commercial Maksutovs use his innovative design.
My first year at Stellafane, 1969, featured a solar observatory assembled on Breezy Hill by Walter Scott Houston. Inside the small plywood building, an 18-inch-diameter (45.7 centimeters) image of the Sun appeared on a rear projection screen.
During all those gatherings, I have seen some incredible instruments. Some have been works of art, like the 12.5-inch ball-mount reflector by Norman James in 1972, the monstrous 22-inch reflector by Steve Dodson in 1981, the even larger 32-inch reflector by John Vogt in 1998, and a stunning pair of 6-inch Alvan Clark reproduction refractors by Allen Hall and Dick Parker in 2016. Then, there are the great telescopes made by first timers and juniors, like the award-winning 4.5-inch reflector last year, made by teenage sisters A.K. and Sydney Burke.
Today’s conventions offer something for everyone, including mirror grinding demonstrations, “Observing Olympics,” and a range of talks for all levels of attendees. But what is it about this place that makes so many people return there every year? Is it the excitement of seeing some of the most exquisitely fashioned amateur-made telescopes ever created? Perhaps it’s the sense of walking in the shadows of giants, like Porter and Ingalls. Maybe it’s the swap tables, where bargains in telescopes, optics, and more can be found. It could be the prospect of observing under some of the clearest skies all year. Or is it the camaraderie that one feels as the ever-growing Stellafane family returns for a huge annual reunion?
It’s all this and more. Stellafane is not just a place, it’s a spirit — the same spirit that drove a dozen people up to the same spot a century ago to erect a monument to the heavens. Russell Porter said it best in the letter he sent to the 1948 Stellafane convention, “There will never be another Stellafane.”
Why is Stellafane painted pink?
Today, One of the most common questions people ask is “Why is the Stellafane clubhouse painted pink?” The answer is steeped in legend. One story says that a local merchant donated paint but did not specify the color; the telescope makers later discovered that the paint was pink. Another version claims that Porter wanted to paint the clubhouse spruce-gum pink, which is white with the faintest hint of pink. But club members misunderstood and painted the clubhouse that vibrant “Stellafane pink.” Whichever story is true — if either — is lost to history, but the clubhouse remains the candy-colored shade to this day.
Friday, September 8 Although the heat of summer still lingers, the constellations of winter are starting to rise earlier each night. Within a few hours of sunset, the Pleiades star cluster in Taurus is visible well above the horizon. This naked-eye object has been known since antiquity, and its rising likely marked the changing of the seasons for ancient skywatchers.
Also cataloged as M45, the Pleiades is a young grouping of stars around 100 million years old. The cluster’s visibility can be a great way to test your eyesight and the conditions at your observing site — how many individual stars can you pick out by eye? Most people can easily see six, but nine or more may appear when conditions are excellent and eyesight is at its peak. In truth, there are some 500 stars in the Pleiades. It’s so large — about 110′ across — that it’s best viewed with binoculars or a low-power scope. Too much magnification won’t show many stars at all, as you’ll be zoomed in a little too much.
Many people mistake this cluster when viewed with the naked eye for the Little Dipper asterism; the latter is much larger and always in the north, anchored at the end of its handle by the North Star, Polaris. Nonetheless, the Pleiades might appear to hang in the sky in the shape of a tiny spoon.
Sunrise: 6:34 A.M. Sunset: 7:21 P.M. Moonrise: 12:06 A.M. Moonset: 4:12 P.M. Moon Phase: Waning crescent (33%) *Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
Comet Nishimura moves quickly through Leo. It is visible for about another week in the predawn sky. Credit: Alison Klesman (via TheSkyX)
Saturday, September 9 Now is the time to catch the bright Comet C/2023 P1 (Nishimura). Newly discovered just a few weeks ago, it is quickly approaching perihelion, the closest it will come to the Sun. On September 17 it will reach that point from inside Mercury’s orbit.
By then, the comet will be too close to the Sun for us to see in the sky. So, we need to catch it now, as it’s rising later each morning and tracking quickly eastward through Leo. But it’s also brightening rapidly — on September 6, it was recorded at magnitude 5. By today, it should be roughly magnitude 4. It’s expected to continue brightening through perihelion, perhaps reaching magnitude 3 or even 2 before it disappears from view. You can track its position day by day using the chart above.
You may know that anything brighter than magnitude 5 should be visible to the naked eye — but in this case, there’s a catch. The comet is both fuzzy and close to the horizon, standing less than 10° high in the east an hour before sunrise this morning. So, it’s really best to try searching it out with binoculars, a telescope, or a long-exposure photograph — all of which will show the green glow of the comet’s coma.
This morning, look for Nishumura just less than 2° southeast of 3rd-magnitude Zeta (ζ) Leonis. This star is part of Leo’s Sickle asterism, which also includes Regulus (Alpha [α] Leonis) and Eta (η), Gamma (γ), Mu (μ), and Epsilon (ϵ) Leonis.
The solar system’s most distant planet reaches opposition this month, shortly after passing 5th-magnitude 20 Piscium. Credit: Astronomy: Roen Kelly
Sunday, September 10 Distant Neptune is nearly at opposition, but first it’s making a close pass of the 5th-magnitude star 20 Piscium in Pisces the Fish. The planet sits on the ecliptic between Saturn in the south and Jupiter in the east. Our solar system’s other ice giant, Uranus, lies just a little east of Jupiter, giving a clear view across the outer solar system when you step outside at night (note that Neptune isn’t visible to the naked eye and Uranus is visible without aid only from a clear, dark location).
Some two to three hours after sunset, the region hosting Neptune is rising ever higher in the southeast. Look first for the Circlet of Pisces, a seven-star asterism, or unofficial pattern of stars. The brightest sun in the oval-shaped pattern is Gamma Psc at magnitude 3.7. The rest of the stars in the circlet include 7, Theta (θ), Iota (ι), 19, Lambda (λ), and Kappa (κ) Psc.
From a point roughly in the center of the Circlet, drop your gaze about 7.7° down toward the horizon, or southeast on the sky. That should land you on 20 Psc; Neptune sits just 4′ to the star’s north, making it easy to identify. The planet glows softly at magnitude 7.7 and spans just 2″. It will likely look more like a small, “flat” star that may have a bluish or grayish tint. We’re just about a week from opposition, making now the best time to capture views of the majestic ice giant.
On Sept. 11, brilliant Venus hangs beneath a crescent Moon. The pair sits near the picturesque Beehive Cluster (M44). Credit: Astronomy: Roen Kelly
Monday, September 11 The Moon passes 11° north of Venus at 9 A.M. EDT; a few hours earlier, you can catch Luna hanging with Venus and the Beehive Cluster (M44) in Cancer just as the first hints of dawn are contemplating an appearance. Venus has now reached magnitude –4.8 and is unmissable as a bright morning star. It lies just over 11° south of a delicate 12-percent-lit waning crescent Moon, with the Beehive Cluster buzzing between them. See how long you can study the scene in the brightening sky.
The Beehive is an open cluster of young stars that stretches nearly 100′ across. With a total magnitude of about 3.7, it’s visible to the naked eye while the sky is still dark. Depending on your eyesight, it may look more like a misty or fuzzy patch of light. If you want to study its stars under some magnification, particularly as the sky begins to lighten, binoculars or any low-power scope will do — you can even try looking through your finder scope, which can capture the entire cluster in one view, rather than zooming in on only a portion through the higher-powered eyepiece of your telescope. (Remember how we did the same to study the Pleiades earlier in the week.)
Despite its bright light, Venus too is only a crescent when viewed under magnification. It is just 21 percent lit but spans an impressive 43″ — only 2″ shy of Jupiter’s apparent girth. Venus, of course, is a much smaller, rocky planet. It appears so large in our sky because it’s much closer than the more distant gas giant, which lies beyond the main belt of asteroids outside of Mars’ orbit. Over the course of the month, Venus will slowly fade just a touch to magnitude –4.7, but its size will shrink by 11″ even as its phase increases to 36 percent.
Tuesday, September 12 The Moon reaches apogee, the farthest point from Earth in its orbit, at 11:43 A.M. EDT. Our satellite will then stand 252,457 miles (406,290 kilometers) away. The Moon is now just two days from New. You may recall that the most recent Full Moon was a Super Moon, meaning Luna’s phase reached Full around the time our satellite reached perigee, the closest point to Earth in its orbit, making the Full Moon appear slightly larger and brighter than average. The cycle will continue for one more month, as September’s Full Moon on the 29th will also be a Super Moon that occurs near perigee.
With just a sliver of the Moon still visible in the early-morning sky, now is a great time to try catching the so-called false dawn or zodiacal light. This ethereal glow, which appears before sunrise in the fall, comes from sunlight scattering off dust in the inner solar system. Where did the dust come from? It’s most likely left by comets as they circle the Sun; warming temperatures near our star cause ice to boil off a comet, liberating plenty of surface dust along the way. This dust settles onto the ecliptic plane of the solar system and we see the light it scatters as a cone-shaped glow while the sky is still dark in the hours before dawn begins to appear. Look east from a clear, dark location for a spike of light thrusting upward along the steeply inclined ecliptic, spreading through Leo, Cancer, and Gemini. The bright planet Venus, which we focused on yesterday morning, appears embedded in the glow. The zodiacal light can be quite faint, especially if there’s nearby light pollution, but often shows up nicely in long-exposure photographs.
Viewing conditions for the zodiacal light will remain favorable for at least the next week or two, so don’t worry if you can’t get out this morning or there are clouds obscuring your view.
Wednesday, September 13 Last week, Saturn lay close to a few background stars that could be easily confused for moons. Now it’s Jupiter’s turn. Look east in the hour or two before local midnight to find the gas giant rising higher in the sky along with the stars of Aries. The magnitude –2.7 planet is readily visible to the naked eye, dominating the sparse southern regions of the Ram and far outshining 2nd-magnitude Hamal, the constellation’s alpha star, to its northwest.
Look up with binoculars or a telescope, and you’ll see that tonight Jupiter sits just 10′ east of a star: That’s 6th-magnitude Sigma (σ) Arietis.
Now, look 4′ south of that star — do you see the fainter point of light? That’s Callisto, one of Jupiter’s four Galilean moons. The other three moons are clustered closer to the planet: Around 11 P.M. EDT, Io sits close to Jupiter’s eastern limb, having just reappeared after passing behind the planet. Meanwhile, Europa and Ganymede sit in a nearly vertical line, with Europa about 30″ north of Ganymede. Keep watching to see Europa pull east while Ganymede moves west, approaching Io as the latter moves east away from the planet. Early tomorrow morning just before 3:30 A.M. EDT, Io will pass 30″ due north of Ganymede as well.
Jupiter moves slowly against the background stars in the coming days, gradually slipping southwest relative to Sigma Ari. Overnight on September 17/18, the planet will pass about 5′ south of the star.
Thursday, September 14 Mercury stands stationary against the background stars of Leo at 8 P.M. EDT. The solar system’s smallest planet is visible in the morning sky, rising around 5:30 A.M. local daylight time about 8° almost directly below Regulus, the star that marks the Lion’s heart. Try catching it in the half hour before sunrise.
Mercury spans just 9″ through a telescope and, like Venus, it is roughly 20 percent lit. It now shines at magnitude 1.7, but that brightness is changing quickly as the planet brightens more each day. Within a week, Mercury will reach magnitude 0; by the end of the month, it will be magnitude –1.
Now finished with its retrograde path, Mercury will swing slightly north and then start tracking east, heading right for 4th-magnitude Sigma Leonis. It will pass within 40″ of this star in two weeks, though the appulse will occur when the pair is below the horizon or very low after rising and shortly before or after sunrise for many observers.
New Moon occurs at 9:40 P.M. EDT, leaving the sky dark and conditions great for deep-sky viewing for at least the next several days.
Friday, September 15 Want to take a peek at a dying star? Look to the constellation Lyra tonight, high in the north after dark. You can’t miss the Lyre’s brightest star, Vega, shining at magnitude 0.
From Vega, look about 6.5° south-southeast and you’ll land on two more bright stars: magnitude 3.3 Gamma Lyrae and magnitude 3.5 Beta (β) Lyrae. Draw a line between these two stars and look halfway along it — there you’ll find M57, famously known as the Ring Nebula.
Stretching about 1′ across and glowing at magnitude 8.8, this fuzzy cosmic ring is a planetary nebula composed of gas blown off by an aging red giant star. That star has since evolved into a white dwarf, whose light is still energizing the gas and lighting it up. The white dwarf lies at the very center of the nebula. It takes a large scope to spot the 15th-magnitude stellar corpse, but not so for the nebula itself — you can see the Ring with binoculars, though magnifications of 100x or more are needed to start resolving the fuzzball into a doughnut shape with a darker center and brighter rim.
Although visually the nebula looks gray or perhaps even greenish, composite images taken at different wavelengths show the shell has several layers composed of varying elements such as nitrogen, oxygen, and helium. More advanced astrophotographers can capture these “colors” for themselves by imaging in several filters.
After a record-breaking summer of global weather catastrophes, climate change is a hot topic. But while many look skyward in despair, some astronomers do so with hope. They see the L1 Lagrange point — a distant spot between Earth and the Sun where gravity is perfectly balanced — as a potential ally in fighting climate change.
Two recent papers propose using L1, about 1 million miles (1.6 million kilometers) from Earth, to reduce global warming. Both proposals, although completely theoretical, are space-based ideas for what is called solar geoengineering, a family of technologies that would artificially limit how much the Sun heats our planet. One paper proposes a giant sail in space while the other uses lunar dust, but both depend on a gravitational balancing act to hold shielding in place.
The concept of geoengineering has long been controversial, and solutions involving spaceborne hardware are especially grandiose. Critics say space-based geoengineering is a distraction from reducing carbon emissions and won’t be technologically feasible for many years — too long to wait for climate action. But space-based solutions also carry several advantages compared to Earth-based geoengineering proposals, at least in principle. And as drought, wildfires, and floods ravage regions around the world, some scientists are more willing to consider the premise.
István Szapudi of the University of Hawai’I in Honolulu and author of one of the papers, says that radical solutions are needed. Just one week after his paper published in late July, a tragic wildfire tore through West Maui and obliterated the town of Lahaina.
“These are the extreme things climate scientists keep warning us will happen that are otherwise very unlikely,” says Szapudi. “Lahaina strengthens my resolve to continue with this research and try to contribute however I can toward a solution.”
Flashing a shield
Szapudi’s solution involves an asteroid, space tethers, and a huge graphene sail. The asteroid would be positioned closer to the Sun than the L1 point and tied across a vast distance to the shield, which would be positioned closer to Earth, on the other side of L1.
The tug-of-war between the two — the asteroid falling toward the Sun and the sail being pushed toward Earth by solar winds — would balance and hold the pair between Earth and the Sun. Szapudi’s paper notes that the closer to Earth the shield sits, the smaller it needs to be, since its shadow would become larger. That would allow for a lighter payload, but require longer tethers stretching between asteroid and shield.
Some critics of space-based geoenginering say that reducing carbon emissions remains the surest means of keeping climate change below the internationally agreed target of 1.5 degrees Celsius. Credit: Anna Jiménez/Unsplash
As a purely conceptual paper, Szapudi’s equations do not specify the surface area of the shield nor the mass of the asteroid, but his other numbers are daunting.
He proposes various tethers, as long as 1 million miles (1.6 million km), four times the distance between Earth and the Moon, and a shield-tether payload of 35,000 tons. Since the heaviest lift rocket available, SpaceX’s Starship, carries a maximum of 166 tons, more than 200 launches would be required to assemble the system.
“SpaceX is already launching every four days,” says Szapudi, “and they are increasing their frequency. For a year, you would be putting up one payload a day.”
As for selecting and moving the asteroid, his ideas have a Hawaiian bent: He would alter the asteroid’s trajectory using the shield itself as a sail, like any good surfer. “First we find the best asteroid,” Szapudi explains, “and then maneuver it into place like a kite surfer by pulling on the tethers like strings.”
Gathering clouds
Planning and assembling the shield system could take decades, but climate scientists say there is no time to spare. Another team of astronomers has a lower-tech solution that could take off once NASA’s moon program lands. They propose using lunar dust to shade the Earth, and their paper includes a number of innovations and surprises.
“You don’t necessarily have to use L1 as the place to park your stuff,” says Benjamin Bromley of the University of Utah, first author of the paper, which was published earlier this year in PLOS Climate.
“One strategy is finding orbits that actually intercept the Earth-Sun line of sight. You can tune them so that dust persists for days on these special orbits on its way toward L1. It wasn’t obvious to us when we started that such orbits existed, where you could keep something between Earth and Sun that wasn’t actually on L1.”
With a background studying exoplanet-forming dust rings that orbit stars — called protoplanetary disks — Bromley and his team borrowed from their knowledge of how these debris rings obscure starlight. They analyzed a variety of materials that would provide the best solar shading in terms of grain size, mass, and light scatter.
The perfect material, it turned out, is the abundant silica regolith that covers the Moon. Launching it into space would only require solar energy, another abundant lunar resource. The team proposes using solar-powered electromagnetic rail guns to eject dust from the surface of the Moon toward the L1 Lagrange point. Momentum and gravity would do the rest.
Lunar dust launched from the Moon’s surface could create streams that temporarily block some sunlight from reaching Earth, as shown in this image from a simulation. Credit: Ben Bromley/University of Utah
He emphasizes that the system is easily reversible. As the Earth moves through space, the lunar dust patch dissipates and harmlessly trails behind us, gone with the solar wind.
“That’s an advantage and disadvantage,” says Bromley, noting that the dust shield would require constant replenishment of its 11 million tons of lunar regolith. “But if you want to return to where you were before you started, all you have to do is nothing.”
Earth versus space
Such reversibility is a major issue for those fundamentally opposed to geoengineering. Some climatologists worry that Earth-based geoengineering ideas — like pumping aerosols into the stratosphere to deflect solar radiation or pouring iron into the oceans to increase carbon dioxide uptake — could have unequal and unintended consequences that cascade out of control.
Over 400 academics have signed a letter petitioning the United Nations and others to “prevent the normalization of solar geoengineering as a climate policy option.” This debate has created a schism in the climate science community and led entities like Bill Gates and the National Academy of Sciences, Engineering, and Medicine to entertain space-based solutions as possibly more benign. Harvard University’s Solar Engineering Research Program website counters that space-based proposals are too far off, if not too far out.
Meanwhile, the U.N. says that to meet their ideal target of a maximum end-of-century global temperature rise of 1.5 degrees Celsius (as measured against pre-Industrial Age levels), we must dramatically cut planet-warming carbon emissions by the end of this decade.
“The solution to global warming is to rapidly move to an economy powered by the wind and Sun, and leave the fossil fuels in the ground,” climatologist Alan Robock of Rutgers University told Astronomy in an email. “We need to do research on the impacts of various proposed climate intervention schemes … but there is [presently] no technology for solar radiation modification, and will not be for at least a decade.”
With temperatures already 1.1 degrees Celsius above pre-1800 levels, nearly all scientists agree that whatever the cost, something must be done much sooner than later.
“Our proposal would be horrifically expensive,” says Bromley, “and it would require collaboration that I think, it’s fair to say, we should put into keeping carbon in the ground instead. Maybe it will become a necessity, but I really hope not.”
The night sky is a captivating canvas of celestial wonders, with the Moon serving as one of its most enchanting features. Luna’s gentle glow has inspired poets, guided sailors, and piqued the curiosity of humanity for countless generations. And as our closest celestial neighbor, the Moon also holds secrets that can help us better understand our own planet and solar system.
So, let’s learn more about our familiar yet alien Moon, exploring its size, composition, distance from Earth, and the reason behind its ever-changing phases.
How big is the Moon?
The Moon is Earth’s only permanent natural satellite, and it’s the fifth-largest satellite in our solar system. The Moon’s diameter is approximately 2,160 miles (3,475 kilometers), or about the distance via airplane from New York City to Las Vegas. That makes the Moon roughly one-fourth the width of Earth, which itself has a diameter of some 7,920 miles (12,750 km).
Despite its modest size compared to Earth, the Moon is still quite expansive, boasting a surface area that could easily contain all of North and South America combined.
This image illustrates the topography on the far side of the Moon. Credit: NASA/GSFC/DLR/Arizona State Univ./Lunar Reconnaissance Orbiter
What is the Moon made of?
The Moon’s outer layer is a thin, rocky crust made up of oxygen, silicon, magnesium, iron, calcium, aluminum, and trace elements like potassium, titanium, and uranium. Beneath the lunar surface lies the Moon’s mantle, which is made up of minerals like olivine and pyroxene. The Moon’s core, which is much smaller and less dense than Earth’s core, consists primarily of iron. However, the Moon lacks a global magnetic field, which suggests that its core is solid instead of molten like Earth’s.
The lunar surface largely consists of rocky terrain punctuated by dark, flat plains known as maria, which are ancient asteroid impact basins that filled with molten rock when the Moon’s interior burst through its crust, cooled, and solidified a few billion years ago. While the maria are dark and smooth, the Moon’s older highlands are lighter in color and marked by particularly rugged terrain, which is the result of countless impacts over time. The entire lunar surface is also covered with a layer of fine, charcoal-colored dust called regolith, which formed through billions of years of sustained meteorite and micrometeorite impacts.
Over the years, scientists have even discovered traces of water ice on the Moon, especially at the bottom of permanently shadowed craters at its south pole. In fact, the existence of water ice at this location is a large reason why NASA seeks to send astronauts to Luna’s south pole during the upcoming Artemis missions. Because, after all, readily available water is going to be essential to the establishment and success of any future human settlements on the Moon.
ESA’s Mars Express spacecraft took this photo July 3, 2003 of the Earth and Moon on its way to Mars. Credit: ESA/DLR/Freie Universität Berlin
How far is the Moon from Earth?
The Moon’s average distance from Earth is about 238,900 miles (384,400 km). However, this distance is not constant, as the Moon follows an elliptical orbit around Earth. When the Moon is closest to Earth, or at perigee, the Moon is about 226,000 miles (363,000 km) away. During apogee, when the Moon reaches its farthest point from Earth, the Moon is around 252,000 miles (405,000 km) away.
The varying distance of the Moon from Earth is also why we sometimes see a supermoon. A supermoon occurs when a Full Moon coincides with the Moon being at perigee, which makes it appear slightly larger and brighter in the sky. However, though this size difference is noticeable, it is not particularly obvious: A supermoon will only appear about 7 percent larger than a regular Full Moon.
Why does the Moon have phases?
The ever-changing appearance of the Moon, known as its phases, is one of the most prominent features of our neighboring celestial body. The Moon’s phases are a result of the changing orbital geometry of the Sun, Moon, and Earth. And there are eight primary phases of the Moon, which occur in a regular cycle approximately every 29.5 days:
New Moon: The Moon is on the Sun-side of Earth, so the Earth-facing side of the Moon is not illuminated and appears dark. Solar eclipses can only occur during a New Moon.
Waxing Crescent: A small sliver of the Moon’s surface is illuminated. This sliver is gradually increasing in size as more and more of the Moon reflects sunlight toward Earth.
First Quarter: Half of the Moon’s nearside – the side that faces Earth – is now illuminated, making it resemble a pock-marked half-circle.
Waxing Gibbous: More than half of the Moon’s nearside is now illuminated, and the percentage visible keeps increasing until Full Moon.
Full Moon: The Moon is now on the opposite side of Earth than the Sun, so the entire side of the Moon facing Earth is illuminated. Lunar eclipses can only occur during a Full Moon.
Waning Gibbous: The illuminated portion of the Moon begins to decrease in size immediately following a Full Moon.
Last Quarter: Half of the Moon’s nearside is now illuminated, but it’s the opposite half compared to First Quarter.
Waning Crescent: A small sliver of the Moon’s surface is still illuminated, but it gradually continues to decrease in size until New Moon arrives.
The Moon, our nearest neighbor
The Moon has been Earth’s trusty companion for billions of years. Its size, distance from Earth, and phases have all played a role in shaping our planet’s history and daily life, and the Moon remains a source of fascination for both amateur astronomers and curious minds alike.
Studying and understanding the Moon offers valuable insights into the cosmos and our place within it. So, the next time you look up at the Moon, remember that it’s more than just meets the eye.
There’s a lot of trash on the Moon right now – including nearly 100 bags of human waste – and with countries around the globe traveling to the Moon, there’s going to be a lot more, both on the lunar surface and in Earth’s orbit.
In August 2023, Russia’s Luna-25 probe crashed into the Moon’s surface, while India’s Chandrayann-3 mission successfully landed in the southern polar region, making India the fourth country to land on the Moon.
With more countries landing on the Moon, people back on Earth will have to think about what happens to all the landers, waste and miscellaneous debris left on the lunar surface and in orbit.
India’s Chandrayaan-3 lander successfully touched down on the south pole of the Moon, sparking celebrations across the country. AP Photo/Rajanish Kakade
Space is getting crowded
People think of space as vast and empty, but the near-Earth environment is starting to get crowded. As many as 100 lunar missions are planned over the next decade by governments and private companies like SpaceX and Blue Origin.
Near-Earth orbit is even more congested than the space between Earth and the Moon. It’s from 100 to 500 miles straight up, compared with 240,000 miles to the Moon. Currently there are nearly 7,700 satellites within a few hundred miles of the Earth. That number could grow to several hundred thousand by 2027. Many of these satellites will be used to deliver internet to developing countries or to monitor agriculture and climate on Earth. Companies like SpaceX have dramatically lowered launch costs, driving this wave of activity.
“It’s going to be like an interstate highway, at rush hour in a snowstorm, with everyone driving much too fast,” space launch expert Johnathan McDowelltold Space.com.
The problem of space junk
All this activity creates hazards and debris. Humans have left a lot of junk on the Moon, including spacecraft remains like rocket boosters from over 50 crashed landings, nearly 100 bags of human waste and miscellaneous objects like a feather, golf balls and boots. It adds up to around 200 tons of our trash.
The clutter in Earth’s orbit includes defunct spacecraft, spent rocket boosters and items discarded by astronauts such as a glove, a wrench and a toothbrush. It also includes tiny pieces of debris like paint flecks.
There are around 23,000 objects larger than 10 cm (4 inches) and about 100 million pieces of debris larger than 1 mm (0.04 inches). Tiny pieces of junk might not seem like a big issue, but that debris is moving at 15,000 mph (24,140 kph), 10 times faster than a bullet. At that speed, even a fleck of paint can puncture a spacesuit or destroy a sensitive piece of electronics. https://www.youtube.com/embed/0Aj2lmQBSAg?wmode=transparent&start=0 The amount of debris in orbit has increased dramatically since the 1960s.
In 1978, NASA scientist Donald Kessler described a scenario where collisions between orbiting pieces of debris create more debris, and the amount of debris grows exponentially, potentially rendering near-Earth orbit unusable. Experts call this the “Kessler syndrome.”
Nobody is in charge up there
The United Nations Outer Space Treaty of 1967 says that no country can “own” the Moon or any part of it, and that celestial bodies should only be used for peaceful purposes. But the treaty is mute about companies and individuals, and it says nothing about how space resources can and can’t be used.
The United Nations Moon Agreement of 1979 held that the Moon and its natural resources are the common heritage of humanity. However, the United States, Russia and China never signed it, and in 2016 the U.S. Congress created a law that unleashed the American commercial space industry with very few restrictions.
Because of its lack of regulation, space junk is an example of a “tragedy of the commons,” where many interests have access to a common resource, and it may become depleted and unusable to everyone, because no interest can stop another from overexploiting the resource.
The author and his research collaborators argued that U.S. environmental regulations should apply to the licensing of space launches. However, the court declined to rule on the environmental issue because it said the group lacked standing. https://www.youtube.com/embed/jSuETYEgY68?wmode=transparent&start=0 The tragedy of the commons asserts that if everyone has unlimited access to a resource, then in the long run it may become depleted and unusable.
National geopolitical and commercial interests will likely take precedence over interplanetary conservation efforts unless the United Nations acts. A new treaty may emerge from the work of the U.N. Office for Outer Space Affairs, which in May 2023 generated a policy document to address the sustainable development of activities in space.
The U.N. can regulate the activities of only its member states, but it has a project to help member states craft national-level policies that advance the goals of sustainable development.
NASA has created and signed the Artemis Accords, broad but nonbinding principles for cooperating peacefully in space. They have been signed by 28 countries, but the list does not include China or Russia. Private companies are not party to the accords either, and some space entrepreneurs have deep pockets and big ambitions.
The lack of regulation and the current gold rush approach to space exploration mean that space junk and waste will continue to accumulate, as will the related problems and dangers.
