Page 55 | Astronomy Magazine

Binocular Universe: Searching for the Cygni 100

In his 1948 book, The Stars in Our Heaven, Peter Lum wrote: “The Swan of Heaven is a long-necked bird in full flight down the Milky Way. He is … by far the most magnificent of the feathered creatures of the star world. There is no other constellation that has such a feeling of outstretched wings, no other which so successfully suggests the movement of flying.”

Cygnus, to which Lum refers, is indeed a magnificent constellation. One of my favorite things to do on late summer evenings is to sit back in a chaise lounge and scan its features with binoculars as it soars across the sky. It has so much to offer.

A few years ago, the Swan’s wide array of double and multiple stars captured the attention of Kansas amateur astronomer Fiske Miles. In a letter he expressed that like me, he believes that “binoculars are often thought of as supplements to telescopic observing, good as a finding aid or for quick views, but if one delves deep with a binocular, an amazing amount can be seen. Honestly, there’s enough to keep an observer occupied for a lifetime.”

Miles enjoys viewing double stars through his collection of binoculars. “For observers who view most frequently from light polluted locations,” he writes, “double stars are fantastic objects. Thousands can be seen.”

To share his enthusiasm with the community of like-minded amateurs in the Binocular forum on www.cloudynights.com, Miles created a thread called “Adventures With Binocular Double Stars.” He posted that he had drawn up a list of 100 double and multiple stars within Cygnus that are visible through binoculars, calling it the “Cygni 100 Challenge.” All are within reach of 20×80 binoculars, and many are visible in far smaller models.

Here are some of my favorites.

Albireo (Beta [β] Cygni) is always on everyone’s list. The 5th-magnitude azure secondary is separated from the 3rd-magnitude golden primary by 35″. That’s wide enough to resolve through 10x binoculars, although bracing the instrument against a tree or fencepost may be required. Defocusing the view slightly also helps accentuate the colors.

A tighter pair is 61 Cygni, famously nicknamed Piazzi’s Flying Star. It lies 9° east of Sadr (Gamma [γ] Cygni). The system’s 5th-magnitude primary is accompanied by a 6th-magnitude companion to the southeast. These orange K-type dwarfs are separated by 31″, which is very close, but doable at 10x. My 16x70s resolve them nicely.

Italian astronomer Giovanni Piazzi bestowed the “Flying Star” nickname in 1792. He noticed that the pair’s position had shifted against the surrounding star field when compared to earlier observations by British astronomer James Bradley in 1753. We now recognize that 61 Cyg has one of the highest proper motions of any star in the sky.

Lastly, there is 79 Cygni, about a binocular field east of 61 Cyg. Viewing through his 70mm binocular telescope at 19.5x, Miles describes the pair as “a bright white primary with a lemon-yellow secondary, generously spaced” by 150″. That makes them easy targets for 6x and 7x binoculars. But wait, there’s more. The carbon star RV Cygni, which Miles calls “fantastically red,” lies just to their south. RV Cyg only shines at 11th magnitude, however, so seeing the color contrast may require 50mm or larger binoculars.

After you’ve begun your personal exploration of the Swan with three of my favorite double stars, next expand your viewing to a related list on the Cloudynights forum by Miles called the Cygni Sweet 16, considered the best of the flock.

And once you view these, why not take a deep dive into the full list? You can download the entire Cygni 100 file for yourself by going to bit.ly/cygni100.

I would enjoy hearing of your success with the Cygni 100. Contact me through my website, philharrington.net. Until next month, remember that two eyes are better than one.

Galaxies in JWST’s mirror are closer than they appear

Recent announcements from the James Webb Space Telescope (JWST) team have shown galaxies in the very early universe are far more advanced, mature, and evolved than they ought to be. But that might be because we’ve been systematically overestimating the distances of those galaxies, as new research demonstrates.

Measuring distances in space is a tricky business. It’s not always easy to discern whether a bright and/or large galaxy is relatively close, or whether it’s physically large and bright. Over the decades, astronomers have developed a plethora of techniques to get around this issue. The majority of those techniques provide reliable results most precisely in the relatively local universe. For very distant galaxies, like the ones JWST targets, we are forced to use much less precise methods.

Instead of directly measuring distances to extremely distant galaxies, astronomers try to determine their redshifts. A redshift represents the change in a galaxy’s light spectrum due to its movement away from us because of the expansion of the universe. While it’s possible to convert a redshift into a distance, astronomers need to assume a cosmological model to do it. In other words, assume a certain amount of dark energy, dark matter, or other parameters that affect the expansion rate of the universe.

So, astronomers usually just report the redshift and move on. In general, the greater the redshift, the more distant a galaxy is from us, which is what we really care about anyway.

JWST has been able to discover galaxies with redshifts of 9 to 14, representing some of the most distant galaxies ever found, floating very far away in the infant cosmos.

Redshift measurement methods

No matter how you count it, these galaxies are among the first to ever appear on the cosmic scene. So it’s puzzling that some of their structures appear to be surprisingly mature for their young ages. Some of the extremely distant galaxies are large, contain lots of stars, and have lots of heavy elements that require multiple generations of stars to produce.

But those surprising results were based on one particular method for measuring the redshift — a method that isn’t all that accurate. The method, known as photometric redshift measurement, takes the light from a galaxy and sorts it into bins. Astronomers then compare the light in those bins to the same light from nearby galaxies to get a rough estimate of a redshift.

While rather uncertain, this method has the advantage of being quick and easy to do, so astronomers can easily gather a large sample of redshift measurements without having to do a lot of extra work.

In a follow-up paper submitted for publication and appearing on the preprint arXiv, a pair of astronomers compared two dozen photometric redshifts with the redshifts obtained by a more accurate method: spectroscopy. Spectroscopic redshifts involve gathering a galaxy’s detailed spectrum first and then using it to measure redshift. While longer and more complicated, the process yields incredibly accurate redshift measurements.

Evidence of inflated redshift

The researchers found that in their sample almost all photometric redshifts were biased to be higher than the spectroscopic ones. In other words, the rough estimate produced a redshift that was almost always higher than the true redshift. For some galaxies the difference was small, but for others it was huge. In one case, the photometric estimate of the redshift yielded 11.5, while the true redshift was less than 9. This is a difference of billions of light-years.

Overall, the researchers found that the photometric redshifts had to be toned down by roughly one standard deviation. This means that when the photometric redshifts were reported along with their uncertainties, the true redshift lies near the lower end of that uncertainty range, not the middle, as we would expect with a bunch of random uncertainties.

This is not a new phenomenon, researchers pointed out. In fact, it’s something the great astronomer Sir Arthur Eddington first pointed out in 1913 in the context of surveys of distant stars. We expect photometric measurements to be imprecise, but in a random way; roughly half the galaxies should show a redshift that’s too large, and the other half too low.

But since JWST is probing the extremely early universe and the first generation of galaxies to appear on the cosmic scene, more galaxies exist closer to us than farther away. This means more chances exist in which galaxies could be biased high rather than low, and so our overall samples will tend to be biased.

It’s unclear at this stage how these more refined redshift measurements will change our understanding of the early universe, and especially how it will impact our view of those young yet mature galaxies. But, this result shows exactly how science is supposed to work. Over time, it’s always careful, always cross-checking, and always refining.

Marilyn Lillie Lovell, wife of astronaut Jim Lovell, dies at 93

On August 27, 2023, Marilyn Lillie Lovell, wife of Captain James A. Lovell, Jr., American astronaut in the Gemini and Apollo programs, died peacefully in Lake Forest, Illinois, surrounded by her husband and family.

Marilyn Lovell, born July 11, 1930, in Milwaukee, Wisconsin, was the youngest of five children. She attended Juneau High School in Milwaukee, where she would meet her future husband and partner of 71 years.

Originally attending Wisconsin State Teachers College in Milwaukee after high school, Marilyn later transferred to George Washington University to be closer to Jim as he attended the U.S. Naval Academy. The high school sweethearts married shortly after Jim Lovell’s graduation in 1952.

As an active member of the Astronaut Wives Club, Marilyn Lovell promoted her husband’s NASA career and provided support to other astronaut wives.

Marilyn Lovell talks with Apollo 13 flight surgeon Charles Berry in a viewing area behind Mission Control on April 14, 1970, just hours before an onboard oxygen tank exploded and imperiled the mission. Credit: NASA

A tribute on the lunar surface

A triangular mountain on the Moon was named Mount Marilyn by Astronaut Lovell during the Apollo 8 mission. The 4,600-foot-tall (1,400 meters) peak sits between the dark lunar lava plains of Mare Tranquillitatis (Sea of Tranquility) and Mare Fecunditatis (Sea of Fertility). Astronaut Lovell first named the feature from lunar orbit as he mapped potential landing sites for the upcoming Apollo 11 mission.

After scanning the Sea of Tranquility’s coast, Jim Lovell spotted the mountain and its distinctive pyramid shape, which would be recognizable to future crews. He quickly checked with his fellow crew members to see if anyone had spotted it before him; they answered in the negative.

“Then I found it, and I’m going to name it,” Lovell said, as he recounted in his 1994 book Lost Moon: The Perilous Voyage of Apollo 13. “What do you guys think of ‘Mount Marilyn’?”

Mount Marilyn, with its distinctive triangular appearance, is at the upper left of this photograph taken on the Apollo 10. Credit: NASA

Mount Marilyn served as an important landmark for the Apollo 11 astronauts as they descended to the surface, and the name appeared on many Apollo-era technical maps and reports. For decades, it was an informal designation. But on July 26, 2017, the peak was officially recognized as Mount Marilyn by the International Astronomical Union.

Marilyn is survived by her husband; her children, Barbara Harrison, James Lovell III, Susan Lovell, and Jeffery Lovell; and 11 grandchildren and seven great-grandchildren.

Will humans ever go to Mars?

Mars has called to us since ancient times. To humans across the eons, the red-tinted speck glinting in the night sky has garnered special attention, with myths and legends wound around its possible ties to Earth. As we observed Mars with telescopes, this fondness graduated into a scientific fascination.

Within only about the last half century, as science has continued to advance, we gained the ability to land scientific instruments on the Red Planet. Beginning with the Viking probes in 1976 and continuing through the Perseverance rover and its flying companion, the Ingenuity helicopter drone, this robotic exploration has allowed humans to discover complex secrets of Mars.

But this is far from the end of our ambitions. Indeed, humans have planned crewed missions to Mars since at least as far back as the 1950s. Scientists and CEOs alike have crafted intricate ideas to establish a presence on the Red Planet, ranging from small-scale research outposts to major settlements. Elon Musk’s plans to put a million people on Mars stand as a particularly bold example.

Yet even with all the money and influence being poured into the goal of putting boot prints in the Martian regolith, there remain considerable doubts that we will ever actually get there. Between economic and ecological problems mounting here on Earth and the major challenges facing even the most basic mission to send humans to Mars, the impetus to spend the money necessary to fund such an initiative has ebbed with the political tides perhaps more so than any other space mission.

Viking 1 orbiter and lander mapped Mars and collected about close-up images of the Martian surface. Credit: NASA

The right equipment

Whether it be the dangers of deep-space radiation or the possibility of failure in the equipment that keeps them alive, the astronauts who travel to Mars will have to overcome dangers before, during, and after their trip to the Red Planet. But as the thousands of applications submitted to the now-defunct Mars One enterprise clearly show, plenty of people would gladly sign up.

What is it about Mars that draws people with such gravitas? It is a barren, desolate place, after all. That much has been clear from the earliest flybys in the 1960s. The days in which dreamers like Percival Lowell and Edgar Rice Burroughs imagined Mars as a flawed but still inviting destination are long gone, replaced by an era in which futurists argue over whether it makes sense to terraform Mars, thereby altering the Red Planet into something more closely resembling Earth. (And essentially no one realistically addresses whether such a thing is actually possible.)

But the fascination remains, and the call of Mars is still as loud as it was to the futurists of the past. There seems to be something of a destiny in this call that makes it all but inevitable that humans will one day step down onto the surface of Mars, much as we once first stepped onto the surface of the Moon.

This history itself is instructive. In the earliest days of the Space Race, many people thought it inevitable that humans would one day set foot on the lunar surface, even if it took decades as opposed to the scant few years promised by visionaries like John F. Kennedy. But the illusion of inevitability is not proof of its existence in fact, as many failed predictions through history have shown.

Even the Moon landings were subject to faulty predictions. The New York Times’ 1920 declaration that rockets could not fly through space due to the lack of air comes readily to mind. Yet on July 21, 1969, two men from Earth stepped onto the surface of the Moon, proving all but the most determined doubters wrong. Will their spiritual successors at NASA and other space agencies one day follow suit on Mars? The first person to step on Mars likely walks among us now, and their moment in history may be coming soon.

The first step

Let’s look at things as they are now. Earlier in 2023, NASA and DARPA announced a partnership to design nuclear rockets, which some attest could be the first step toward a Mars mission. Elsewhere, analog habitats funded by organizations like the Mars Society simulate missions to Mars to prepare potential travelers for the journey. And futurists like Robert Zubrin and Elon Musk draw up plans to send people to Mars by as soon as the late 2020s, with Musk claiming he can establish a colony of one million people by 2100.

But does any of this mean that Mars pulls us toward its shores any more intensely now than at the height of Space Age optimism, when visions of grand cities on Mars seemed near to fulfillment? The basic fact is that, when humans set our minds to do something, we see it done much more often than not. The South Pole, the summit of Everest, and of course, the Sea of Tranquility are all evidence of that.

So while the exact details of a future Mars mission are unclear—where it will take place, who will be the first to step out of the spacecraft, what flag they will bear (if any), and perhaps most importantly, when it will happen?— the possibility that it does happen is much larger than the chance we will never set foot on Mars. It may take decades, but even if it takes another century, it seems likely that someone will one day become the “Neil Armstrong” on the Red Planet. When that one small step takes place is anyone’s guess, but the high probability that it will happen seems undeniable.

Where is the edge of the universe?

Jay Smith

When Galileo Galilei pointed his first telescope to the heavens in 1610, he discovered “congeries of innumerable stars” hidden in the band of light called the Milky Way. Our cosmos grew exponentially that day. Roughly three centuries later, the cosmic bounds exploded once again when astronomers built telescopes big enough to show the Milky Way is just one of many “island universes.” Soon they learned the universe was expanding, too, with galaxies retreating from each other at ever-accelerating speeds.Since then, ever-larger telescopes have shown the observable universe spans an incomprehensible 92 billion light-years across and contains perhaps 2 trillion galaxies. And yet, astronomers are still left wondering how much more universe is out there, beyond what they observe.

“The universe has always been slightly larger than what we can see,” says Virginia Trimble of the University of California, Irvine, an astronomer and expert in the field’s history.

Building bigger telescopes won’t help extend the cosmos anymore. “Telescopes only observe the observable. You can’t see back in time further than the age of the universe,” explains Nobel Prize-winning cosmologist John Mather of NASA’s Goddard Space Flight Center, who’s also chief scientist for the James Webb Space Telescope. “So we are totally limited. We’ve already seen as far as you could possibly imagine.” At the edge, we see the leftover glow from the Big Bang — the so-called cosmic microwave background radiation (CMB). But this isn’t some magical edge of the universe. Our cosmos keeps going. We just may never know how far.

In recent decades, cosmologists have tried to solve this mystery by first determining the universe’s shape, like the ancient Greek mathematician Eratosthenes calculating Earth’s size using simple trigonometry. In theory, our universe can have one of three possible shapes, each one dependent on the curvature of space itself: saddle shaped (negative curvature), spherical (positive curvature) or flat (no curvature).

Few have championed a saddle-shaped universe, but a spherical cosmos makes sense to us earthlings. Earth is round, as are the sun and planets. A spherical universe would let you sail into the cosmos in any direction and end up back where you started, like Ferdinand Magellan’s crew circumnavigating the globe. Einstein called this model a “finite yet unbounded universe.”

But starting in the late 1980s, a series of orbiting observatories built to study the CMB made increasingly precise measurements showing that space has no curvature at all. It’s flat to the limits of what astronomers can measure — if it is a sphere, it’s a sphere so huge that even our entire observable universe doesn’t register any curvature.

“The universe is flat like an [endless] sheet of paper,” says Mather. “According to this, you could continue infinitely far in any direction and the universe would be just the same, more or less.” You’d never come to an edge of this flat universe; you’d only find more and more galaxies.

That’s all well and good with most astronomers. A flat universe agrees with both observation and theory, so the idea now sits at the heart of modern cosmology.

The problem is that, unlike a spherical universe, a flat one can be infinite — or not. And there’s no real way to tell the difference. “What could you look for to see whether there’s an infinite universe?” Trimble says. “Nobody quite knows.”

So instead, astronomers hope an answer can come from theory — a model that could offer indirect proof one way or the other. For example, the Standard Model of physics predicted the existence of numerous particles, like the Higgs Boson, years before they were actually discovered. Yet physicists still presumed those particles were real.

“If you have a good description of everything you’ve observed so far and it predicts something is true, then you expect it is,” Trimble says. “That’s how most scientists think about how science works.”

Continue reading “Where is the edge of the universe?”

Understanding the phases of the Moon

The Moon, Earth’s nearest celestial neighbor, has fascinated humanity for ages with its ever-changing phases. Each month, the Moon transitions through a series of distinct visual stages, providing a captivating and evolving spectacle in the night sky.

But why do these phases occur, and how do specific phases of the Moon contribute to rare phenomena such as eclipses? Let’s explore the science behind the Moon’s phases, each of their unique characteristics, and the critical role the Moon plays in lunar and solar eclipses.

Why does the Moon have phases?

The phases of the Moon are a result of the geometric interplay between the Sun, the Moon, and Earth. As the Moon orbits Earth, the nearside of the Moon always faces Earth. So as the Moon circles our planet, the amount of the Sun’s light striking the Moon’s nearside changes, causing varying portions of its face to be illuminated from our point of view.

It’s essential to remember the Moon does not emit its own light; instead, it reflects the light from the Sun. And the phases that we see are a consequence of the relative positions of the Sun, Moon, and Earth, which determine which parts of the Moon’s surface are simultaneously illuminated by sunlight and visible from Earth.

This graphic depicts the location of the Earth, Sun and Moon during the lunar phases throughout each month. Credit: Credit: NASA/JPL-Caltech

What are the Moon’s Phases?

The Moon’s phases represent the changing appearance of the lunar disk from Earth’s perspective. There are eight distinct phases the Moon goes through. Beginning with New Moon, they are:

New Moon: The New Moon phase marks the beginning of the lunar cycle. During this phase, the Moon is positioned between the Earth and the Sun, leaving the side of the Moon facing Earth completely in shadow.
Waxing Crescent: Following a New Moon, the waxing crescent phase first emerges as a thin crescent of light visible on the Sun-facing edge of the Moon.
First Quarter: The First Quarter Moon is characterized by half of the Moon’s nearside being illuminated, forming a perfect half-circle when viewed from Earth.
Waxing Gibbous: In the waxing gibbous phase, the Moon is past First Quarter but not yet Full. Most of the Moon’s face appears illuminated at this stage, with only a small crescent-shaped portion remaining in shadow.
Full Moon: A Full Moon occurs when the Moon and Sun are positioned on opposite sides of Earth. This causes the entire face of the Moon to be illuminated by sunlight.
Waning Gibbous: During this phase, the Moon is past Full but not yet at Third Quarter. Most of the Moon appears illuminated, with a small portion gradually darkening as the phase progresses.
Third Quarter: The Third Quarter Moon is the opposite of the First Quarter Moon. Half of the Moon’s nearside is illuminated, forming a bright half-circle on the opposite side of the Moon as during First Quarter.
Waning Crescent: As the Moon approaches the end of its repeating cycle, the waning crescent phase sees the Sun-facing edge of the Moon shrinking to a thin sliver of illumination.

The terms “waxing” and “waning” indicate the direction of change in the Moon’s phases. Waxing phases occur as the Moon progresses from a New Moon to a Full Moon, with the illuminated portion increasing. Waning phases occur as the Moon moves from a Full Moon to a New Moon, with the illuminated portion decreasing.

The Moon’s role in lunar and solar eclipses

The Moon plays a crucial role in the phenomenon of eclipses, both lunar and solar.

A lunar eclipse occurs when Earth is directly between the Moon and Sun, which only occurs during the Full Moon phase. If the alignment is just right during a Full Moon, the Moon will pass right through Earth’s shadow in space caused by sunlight washing over it. Such lunar eclipses can be spectacular (and hours-long) events, but even a temporary rust-colored Moon during a lunar eclipse fails to compare to the glory of a solar eclipse.

A solar eclipse occurs when the Moon passes precisely between Earth and the Sun, casting the Moon’s shadow on Earth’s surface. These awe-inspiring events can only happen during a New Moon phase, and all three celestial bodies must be in particularly perfect celestial alignment.

There are three types of solar eclipses: partial, annular, and total. In a partial eclipse, only a part of the Sun is obscured by the Moon. During an annular eclipse, the Moon covers the center of the Sun, leaving a bright ring of sunlight visible around the edges. In a total eclipse, however, the Moon entirely covers the Sun, casting a shadow that plunges a small portion of Earth into temporary darkness.

On April 8, 2024, North America will witness a total solar eclipse. During this event, the Moon will completely block the Sun, casting a narrow shadow path that treks its way up across the continent. This upcoming eclipse will provide a unique and unforgettable experience for the tens of millions of people living within the path of totality, offering a rare opportunity to witness firsthand the Moon’s role in this stunning celestial phenomenon.

The phases of the Moon and their role in solar eclipses showcase the intricate relationships between Earth, the Moon, and the Sun. Observing the Moon’s changing appearance and experiencing the spectacle of a solar eclipse serve as powerful reminders of the beauty and wonder of the cosmos. And the upcoming total solar eclipse in 2024 will provide an especially unique opportunity to appreciate the Moon’s vital role in creating one of nature’s most awe-inspiring events.

Mystery of strobing pulsar may be solved

An international group of scientists and a massive observing campaign may have uncovered the reason behind a distant pulsar’s flashy behavior. This pulsar, dubbed PSR J1023+0038, has two different modes of brightness — and switches between them almost constantly, which may be due to sudden ejections of matter.

“We have discovered that the mode switching stems from an intricate interplay between the pulsar wind, a flow of high-energy particles blowing away from the pulsar, and matter flowing towards the pulsar,” Francesco Coti Zelati, an observational astrophysicist and study author at the Institute of Space Sciences in Barcelona, said in a statement. Researchers published details on the pulsar today in the journal Astronomy and Astrophysics.

Beacons of the cosmos

Pulsars are the dead remnants of massive stars that exploded in a supernova. Though they produce no internal nuclear fusion, they spin quickly, generate strong magnetic fields, and emit beams of light into space. When such a beam sweeps across Earth, its star appears to pulse in brightness in radio waves.

The most rapidly rotating pulsars have revolution periods of less than 30 milliseconds — spinning hundreds of times per second — and are called milliseconds pulsars (MSPs). Scientists think they achieve these rotation rates by periodically pulling in material from a nearby companion star, which falls onto the pulsar and spins them up. In total, there are about 3,000 known MSPs.

Located around 4,500 light-years away within the constellation Sextans, the millisecond pulsar PSR J1023+0038 closely orbits a companion star. When it was identified in 2007, it appeared to be a normal radio pulsar. But archival data showed that it was the same object as one that astronomers had previously identified as an X-ray binary system — a pair of stars where one is stealing matter from the other, forming a hot accretion disk capable of emitting X-rays. Follow-up observations showed that by 2007, that accretion disk was gone.

This earned J1023 the distinction of one of the first known transitional millisecond pulsars (tMSPs) — an object that can switch between a radio pulsar state and an active low-luminosity X-ray disk. tMSPs represent a key period in the lives of MSPs. The X-ray emission is evidence that these pulsars indeed spin themselves by occasionally accreting matter from their host star, which forms a hot disk around the pulsar and emits X-rays.

In 2013, astronomers noticed that J1023’s behavior abruptly changed again: The pulsar’s sweeping beam vanished and the star began showing erratic changes in brightness, seeming to have two modes of emission. When the pulsar shines brightly in what astronomers came to call its high mode, it emits X-rays, ultraviolet, and visible light. When the pulsar dims to its low mode, it instead releases more radio waves. PSR J1023+0038 usually stays in either mode for no longer than several minutes and then changes between the two in seconds.

The X-rays emitted during the high mode suggested that J1023 had regained an accretion disk. But how the pulsar switched between the two modes puzzled astrophysicists — until now.

What’s in a pulsar?

Scientists sought to decipher PSR J1023+0038’s mercurial behavior with a coordinated observing campaign using 12 telescopes, both in space and on Earth. These observations spanned the electromagnetic spectrum, from X-rays to radio waves. Over two nights in June 2021, they captured over 280 switches between its high and low modes. The team then used models of the pulsar and its accretion disk to reverse engineer their observations. This modelling showed that the changes in brightness were coming from the innermost portion of the accretion disk.

Another piece of the puzzle came from a flare observed at radio wavelengths by the Atacama Large Millimeter/submillimeter Array in Chile, one of the 12 facilities involved. This burst of emission came right as the object switched from its high to low mode.

This led the team to conclude that when the pulsar dims, it expels the hottest material around it in a jet perpendicular to the disk. Within minutes, accreting matter is once again heated by the wind coming from the pulsar, generating bright X-rays. This is the pulsar’s bright mode; it switches back to its dim mode after the jet ejects this hot matter from the inner region.

Researchers hope to learn more about J1023 with the European Southern Observatory’s Extremely Large Telescope (ELT). The telescope is under construction in Chile, recently passing the 50-percent completion mark and scheduled to begin scientific observations in 2028. “The ELT will allow us to gain key insights into how the abundance, distribution, dynamics, and energetics of the inflowing matter around the pulsar are affected by the mode switching behavior,” said Sergio Campana, coauthor of the study and research director at the Italian National Institute for Astrophysics’ Brera Observatory in Merate.

Get ready for Wednesday’s Blue Super Moon

On August 30, a cosmic confluence of events will impact the Full Moon. Step outside after sunset and you’ll notice a big, bright Blue Super Moon.

What do all those terms mean? Let’s break it down.

First, the Moon reaches perigee at 11:54 A.M. EDT Wednesday morning. Perigee is a term for the closest point to Earth in our satellite’s orbit, which is not perfectly circular. So, it sometimes sits closer to Earth than others. (Apogee is the opposite term, for the farthest the Moon is from Earth each orbit.) At that time, Luna will sit just 221,942 miles (357,181 kilometers) away — nearly 17,000 miles (2,736 km) closer than its average distance of 238,855 miles (384,400 km).

Then, just a few hours later, the Moon reaches Full at 9:36 P.M. EDT. This is the crucial moment, as this Full Moon is special for two reasons.

First, because the Full phase occurs so closely after the Moon reaches perigee, it is considered a Super Moon. By “closely,” astronomers require the Full Moon to occur within 90 percent of perigee, so a Super Moon can be either shortly before or shortly after perigee.

And second, because this is the second Full Moon within a single month — the last Full Moon occurred August 1, called a Sturgeon Moon — this Full Moon is called a Blue Moon. This term is used for any second Full Moon to take place in a calendar month.

What will the Super Moon look like?

In astronomy, distance affects how large something appears in the sky. The average Full Moon subtends about 31′, or roughly half a degree. But when the Moon is closer or farther than average, it naturally appears — very slightly — larger or smaller than average as well, respectively. As it’s rising on the 30th, the Moon will appear roughly 33.5′ across, or 8 percent larger than average. To the human eye, that small difference indistinguishable, so the Moon won’t appear any bigger than usual.

What you may notice is something often seen with any given Full Moon, which always rises from the horizon around the time of sunset: The rising Moon can appear huge while near the horizon, then seems to shrink as it gets higher in the sky! This is often called the Moon illusion and is due in part to the fact that your brain has objects of known size to compare the Moon with while it is near the horizon. Once the Moon climbs high enough, it sits alone in the sky and thus appears smaller. Be on the lookout around sunset to see if you notice the big, bright face of the Full Moon on your eastern horizon.

Distance and angular size play a role in how bright the Super Moon will appear. Because it is marginally larger and closer, a Super Moon’s light (remember, the Moon doesn’t generate light and instead simply reflects incident sunlight) can appear slightly brighter. A Super Moon can look some 14 to 16 percent brighter than a normal Full Moon and several times beyond even that than a Full Moon at apogee, when our satellite appears smallest and is farthest away. That change in brightness is still small, but it might be enough to ping your awareness that something is slightly different about the Moon as it traverses the sky this week.

Child looking through telescope International Observe the Moon Night — You can choose to use a telescope, but you don’t need any equipment to see and enjoy the Blue Super Moon. Credit: NASA/GSFC/Debbie Mccallum

How to view the Blue Super Moon

Looking at the Full Moon is one of the easiest astronomical observations you can undertake — you don’t need anything but your eyes! Anyone can look out the window or step outside to enjoy the bigger, brighter Full Moon on Wednesday.

If you’re in a dark location with minimal artificial lighting, notice how the Moon’s light is bright enough to cast shadows (this is true of any Full Moon, so you can observe this effect any time one is in the sky). Looking at Luna’s bright face, you’ll notice big, round darker patches — these are lunar seas, or maria, which were not filled with water but are composed of cooled lava from our satellite’s formative past.

More advanced observers may want to turn binoculars or a telescope on the Moon. Note that it will appear exceptionally bright under magnification — your eyes may water and it will definitely ruin your night vision, so only turn to the Moon after you’ve done any observing that requires better dark adaptation. To cut down on the glare, you can increase the magnification (which gives you a smaller field of view, and thus less area to reflect light), use a Moon filter, or even wear sunglasses while sitting at your scope.

Below are the approximate times of sunrise, sunset, moonrise, and moonset — note these times will differ slightly by location.

Sunrise: 6:26 A.M.
Sunset: 7:35 P.M.
Moonrise: 7:49 P.M.
Moonset: 5:35 A.M.
Moon Phase: Full
*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.

2023’s spate of Super Moons

You may have noticed the term Super Moon has popped up a lot this year. That’s because 2023 has now hosted three Super Moons so far — and there’s one more still to come! The next Full Moon on the morning of September 29 is also a Super Moon, coming soon after our satellite reaches perigee late in the evening on the 27th.

2023’s Super Moons occurred in July, August (twice!), and September. This run of Super Moons is due to the fact that the Moon’s orbital or sideral period of 27.3 days happens to have lined up with its synodic period, or the time it takes to go from New Moon to Full Moon to New Moon again, which is 29.5 days. Essentially, the two periods have fallen briefly in sync, but will diverge enough after September’s Full Moon that the Full phase won’t occur near perigee again for another year and a half or so.

How does this work? Think of sitting in your car in the turn lane, waiting for the light to change. If you watch your blinker light on the dash and the rear blinker of the car in front of you, you’ll notice that sometimes they blink at exactly the same time for a short while, then slowly start to flash at different times until one turns on when the other is turning off. This is what’s happening with the two lunar periods as well.

That lunar month of 29.5 days also affects how often a Blue Moon occurs in much the same way. These events are much rarer — this is 2023’s only Blue Moon, as every other month of the year hosts only a single Full Moon. The next Blue Moon won’t occur until May 2026.

So, get out there and enjoy the moonlight!

Caroline Herschel was England’s first female professional astronomer, but still lacks name recognition two centuries later

Caroline Herschel, the first English professional female astronomer, made contributions to astronomy that are still important to the field today. But even many astronomers may not recognize her name.

Most scientists care about the newest techniques, data and theories in their field, but they often know very little about the history of their discipline. Astronomers, like me, are no exception.

It wasn’t until I taught an intro to astronomy class that I learned about Caroline. Now, thanks to a new display of her papers at the Herschel Museum in Bath, England, others will get to learn about her too. Her story reflects not only the priorities of astronomy but also how credit is assigned in the field.

Her path to astronomy

Caroline Herschel, born in 1750, did not have an easy childhood. After a bout with typhus left her scarred at a young age, her family assumed that she would never marry and treated her as an unpaid servant. She was forced to complete household chores, despite showing a keen interest in learning from a young age. She eventually escaped her family to follow her older brother William Herschel, whom she adored, to Bath.

Caroline Herschel worked with her brother William on many pursuits. A. Diethe/Wellcome Images via Wikimedia Commons, CC BY-SA

Caroline was a somewhat unwilling astronomer at first. She didn’t become interested in astronomy until William was already thoroughly engrossed in the subject. Although she spoke somewhat disparagingly about how she followed her brother to different interests, including music and astronomy, Caroline eventually acknowledged her real interest in studying astronomical bodies.

Astronomers at the time were mainly interested in finding new objects and mapping out the heavens with precision. Using telescopes to look for new comets and nebulae was also popular. William Herschel became famous after his discovery of Uranus in 1781, though he mistook the planet for a comet at first.

At the beginning of her career, Caroline worked as William’s assistant. She focused mostly on astronomical instrumentation tasks, like polishing telescope mirrors. She also helped copy catalogs and took careful notes about William’s observations. But then she began to make her own observations.

Searching the skies

Caroline Herschel (1750−1848) was the first woman to receive a salary as a scientist. ETH Library via Wikimedia Commons

In 1782, Caroline began recording the positions of new objects in her own logbook. It was through this work that she discovered several comets and nebulae. On Aug. 1, 1782, she discovered a comet – meaning she was the first to see it in a telescope with her own eyes. This was the first comet discovery attributed to a woman. She went on to discover seven more comets over the next 11 years.

At the time of the Herschels’ work, it was the actual observation of an object that warranted public recognition, so Caroline was given credit only for the comets she saw through the telescope herself. For all of her other work, like recording and organizing all the data from William’s observations, she received less credit than William.

For instance, when Caroline took all of William’s observations and compiled them into a catalog, it was published under William’s name. Caroline is mentioned only as an “assistant” in the paper.

Nonetheless, in recognition of her discoveries and her work as William’s assistant, King George III of England granted Caroline a salary, making her the first professional female astronomer.

Later in life, Caroline reorganized the same catalog in a more efficient way, according to how practicing astronomers interested in looking for comets actually observed the night sky. This updated catalog was later used as the basis of the New General Catalogue, which astronomers still use today to organize the stars.

The Herschels also created the first – though not quite correct – map of our galaxy, the Milky Way.

Who gets the credit in astronomy?

Recognition for scientific work within the astronomical community is pretty different now than it was in the Herschels’ day. In fact, most of the astronomers who receive credit today are those whose work looks a lot like Caroline’s – recording and organizing data about astronomical observations.

Astronomers seldom put their eyeballs up to a telescope eyepiece anymore, and many of the most important discoveries are made by telescopes in space. But astronomers still need to be able to make sense of all the data from these telescopes. Catalogs like the ones Caroline made are important tools for doing so.

Most people today haven’t heard of Caroline Herschel. Despite having several astronomical objects – and even a satellite – named after her, she doesn’t have the same name recognition as the other astronomers of her time. Some of the lack of recognition is probably because her brother received all the credit for her catalog. Today, astronomers would give them both credit.

The cluster of stars NGC 7789 is unofficially nicknamed ‘Caroline’s Rose’ in honor of Caroline Herschel. Anton Vakulenko via Wikimedia Commons, CC BY-SA

Herschel is just one in a long line of female astronomers who did not receive the credit they were due and whose work was used to justify prizes for male scientists instead. These issues aren’t just restricted to 18th-century science, but persist through modern astronomy as well. Jocelyn Bell Burnell, who discovered the first radio pulsar, was left off the 1974 Nobel Prize, and the award was instead granted to her Ph.D. adviser.

Although astronomy has come a long way since the 18th century, astronomers still need to think carefully about how to fairly recognize the people who participate in scientific discoveries. Acknowledging the contributions of astronomers like Caroline Herschel is a small step toward giving credit where credit is due.

This article has been updated to acknowledge other women astronomers who preceded Herschel.

Kris Pardo, Assistant Professor of Physics and Astronomy, USC Dornsife College of Letters, Arts and Sciences

This article is republished from The Conversation under a Creative Commons license. Read the original article.

New Horizons’ Kuiper Belt mission may be changing

The New Horizons mission needs your help. This highly successful endeavor, which has sent home unprecedented views of the most distant worlds we’ve ever seen, is currently slated for a big change. At the end of September 2024, NASA is planning to restructure the mission and its team, adjusting its scientific goals and effectively ending its exploration of the outer solar system. To protect New Horizons’ current function and staff, the National Space Society is asking the public to show their support by signing their petition by the end of August.

New Horizons’ new view

New Horizons is the mission that brought humanity its first up-close images of Pluto during its historic flyby in 2015. The groundbreaking mission showed us Pluto’s heart — literally — and revealed the distant dwarf planet as a vibrant, active world that likely harbors a liquid ocean under its surface, catapulting it from a historical oddity into the coveted list of potentially habitable worlds in our solar system. Pluto is now known as a complex and intriguing world that is nothing like the dead, distant rock researchers might have once envisaged.

But the mission didn’t end there. New Horizons flew on and just a few years later, zipped past 2014 MU₆₉, then also known as Ultima Thule and today officially named Arrokoth. The encounter, which occurred 4 billion miles (6.6 billion kilometers) from the Sun, is the most distant encounter with a solar system object to date. Here, too, New Horizons showed planetary scientists a strange new world, showing a flattened, two-lobed body hosting organic molecules called tholins on its ruddy surface.

Since then, New Horizons has ventured ever deeper into the Kuiper Belt of icy, ancient objects beyond the orbit of Neptune. So far from the Sun, these worlds represent pristine pieces of the building blocks that created the worlds of our solar system. Studying them offers a unique window into the past. The spacecraft itself remains fully operational and has been on the lookout for new worlds it might closely fly past, all the while making observations of several dozen other Kuiper Belt objects even from afar.

New Horizons sent us this iconic image of Pluto in false color, showing its “heart.” Credit: NASA/JHUAPL/SwRI

A big change

Currently New Horizons carries out several functions, one of which is exploring the worlds of the Kuiper Belt. The mission also has a heliophysics bent, taking valuable measurement of our Sun’s outer heliosphere that were not achieved with other spacecraft such as Voyager or Pioneer. New Horizons data is also used in collaboration with other heliophysics missions to study our Sun and the makeup of the outer solar system.

The proposed restructuring would bring its Kuiper Belt exploration to an end, according to Alan Stern, the mission’s current principal investigator. NASA would refocus the spacecraft’s efforts — and that of its team — entirely on the Sun. So, New Horizons would stop observing Kuiper Belt objects and its outer solar system experts would be dismissed from the team, leaving only the heliophysics staff.

To prevent this change, the National Space Society has set up an online petition and is asking the public to sign it by the end of August to show their support for continuing the spacecraft’s mission of Kuiper Belt discovery. You can find the petition and additional details on the society’s change.org page.

The mystery of dark matter: This Week in Astronomy with Dave Eicher

Dark matter is an invisible and mysterious form of matter that has enormous implications for the ultimate fate of our universe.

Dark matter was posited by Dutch astronomer Jan Oort in the 1930 when he studied star motions in the Sun’s neighborhood. Because the galaxy was not flying apart, he reasoned, there must be more matter in the disk to keep the stars from moving away from the galaxy’s center. Oort postulated that in the Sun’s neighborhood, three times as much dark matter existed as bright matter.

Also in the 1930s, American astronomer Fritz Zwicky deduced that much larger clouds of dark matter exist in the Coma cluster of galaxies, about 300 million light-years from Earth. By looking at the Doppler shifts of individual galaxies in the cluster, Zwicky concluded that 10 times more mass than was detected via visible light must be present to keep the galaxies gravitationally bound.

Then in the 1970s, Vera Rubin, working with instrument-maker Kent Ford, began examining the luminous disks and halos of other galaxies and discovered that the outer regions were moving faster than expected. This also implied that there was more matter than was visible, and that this dark matter was widespread in galaxies.

One of the great scientific mysteries of recent decade remains: What exactly is dark matter? Over the years, scientists have proposed many different possibilities. These include massive numbers of normal neutrinos; MACHOs (massive compact halo objects) such as brown dwarfs, neutron stars, and black holes; and WIMPs (weakly interacting massive particles) such as exotic particles, massive neutrinos, and photinos.

In recent years, the leading candidate has been the axion — a hypothetical particle with very small masses. However, separate multimillion-dollar experiments based at the University of Washington and the Institute for Basic Science in Daejeon, South Korea, have not yet found such a particle.

Whatever it is, dark matter carries enormous implications for the structure and future of the cosmos, as it accounts for 26 percent of the universe’s total mass-energy.

For more on Vera Rubin’s groundbreaking work — and the widespread disappointment that she was never recognized with a Nobel Prize — check out this 2016 feature by Sarah Scoles.

How Vera Rubin confirmed dark matter

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In With a Bang, Out With Ammonia: Saturn’s Strange, 100-Year Storms

This article was originally published on DiscoverMagazine.com

Jupiter’s Great Red Spot is an anomaly with no known equal in our solar system. The powerful anticyclone churns beneath the planet’s equator, where it produces winds estimated at between 270 and 425 mph. While it has shrunk in recent decades (to just a bit wider than Earth), it’s probably not going anywhere soon.

The spot has marked Jupiter since at least 1831, when amateur astronomer Samuel Heinrich Schwabe first observed the storm.

Saturn, by contrast, is a bit dull in appearance and lacks in a persistent spot. But a recent study revealed new details about the atmosphere’s surprisingly varied inner life. Just like Jupiter, storms have left their mark on Saturn, altering chemical compositions for years afterward.

Saturnian Storms

While Saturn’s major storms are not as persistent as the Great Red Spot, they splash across the ringed planet in dramatic fashion. Every 20 to 30 years, they spin up like massive hurricanes and swirl their way around the planet, though no one knows for sure what causes them. The last such megastorm broke out in 2010 and persisted for more than six months, long enough for the Cassini probe to study it.

The next storm will hit in 10 to 20 years, scientists predict. In the meantime, astronomers from two institutions – the University of California, Berkeley and the University of Michigan – are studying the long-last effects of these powerful storms. Like the Great Red Spot, they make lasting changes to their world, though you need special equipment to detect them.

The new study relied on observations from the Karl G. Jansky Very Large Array radio telescope back in 2015, about four years after the megastorm. The results were revelatory and allowed the researchers to look deep into Saturn’s cloud layers, which appeared disturbed. The storm had caused ammonia vapor to precipitate down to lower levels, perhaps for hundreds of years to come.

The team also identified a number of smaller storms that have raged around Saturn’s equator for potentially hundreds of years.

Two Worlds

The astronomers say Saturn’s epic storms are unique in their own way, though they lack the Red Spot’s special rouge. The ringed planet’s storms are true storms, unlike Jupiter’s “tropospheric anomalies,” which manifest in dark- and light-colored atmospheric bands.

Scientists have yet to explain why disturbances on each gas giant play out so differently.

Future study may rely further on radio telescopes, which reveal variations in Saturn’s atmosphere not seen in visible light.

“Despite bland looking at the visible wavelengths, different latitudes on Saturn show dramatic contrast in the radio emission,” the new paper says.

Radio waves help to reveal “heat transport, cloud formation and convection in the atmospheres of giant planets on both global and local scales,” said Imke de Pater, a University of California at Berkeley professor of astronomy and earth and planetary sciences, in a statement.