From the July 2014 issue

Cosmic food fights

Disputes in astronomy don't exist only in ancient history.
By | Published: July 28, 2014 | Last updated on May 18, 2023
Surely astronomers are too courteous to get worked up over celestial arguments.

Think again.

Scientists on the “wrong side” of a dispute, like the dark matter versus Modified Newtonian Dynamics controversy I explored in the April Astronomy cover story, sometimes find themselves shunned. Tempers can flare. Well, there’s an old journalism adage that “controversy sells.” It’s juicy. So let’s review some famous standout astro-squabbles.

We’ll ignore many of the high-blood-pressure incidents of earlier centuries, such as when Galileo Galilei and Christoph Scheiner spent decades during the 1600s putting each other down in print, each claiming to be the first to discover sunspots and having different theories on their origins. The seemingly endless arguments about these solar blemishes continued in the 19th century. Some said sunspots were islands in a sea of glowing liquid on the Sun’s surface. Others perceived them as holes in white-hot clouds, through which we can glimpse a comfortable dark surface complete with meadows and Sun-people.

The debates were not always polite. Just as former world chess champion Aron Nimzowitsch once jumped on a table and yelled, “Why must I lose to this idiot?” some astronomers had a personal stake in the debate — a situation that still can exist.

In the memories of grandparents and great-grandparents, the most famous debate happened at the Smithsonian’s Museum of Natural History in 1920. Astronomer Harlow Shapley believed the Milky Way Galaxy was the entire universe. Spiral nebulae like Andromeda, he and many others insisted, were small structures inside it, near Earth. If those spirals lay beyond the Milky Way, he argued, they’d have to dwell at “impossible” distances of millions of light-years. The universe just couldn’t be that big. Moreover, a respected astronomer had just claimed to observe the spiral galaxy M101 spinning — proof it must lurk nearby.

On the other side of the debate stood Heber Curtis. He said that all those spirals were separate “island universes” lying at staggering distances. After all, if Andromeda was a nearby gas cloud, why were we seeing novae popping off within its boundaries?


Shapely won the debate, the audience agreed. He was a better speaker. He was more famous and arguably better looking. He had the energy of youth, while Curtis appeared much older than his 48 years. He was an old fogey.

Curtis lost, yet he was right! The new 100-inch Hooker Telescope at Mount Wilson in California settled the matter within six years.

Soon another debate raged — and lasted decades. Starting in the late 1920s, British astronomers James Jeans and later Fred Hoyle argued that the universe eternally appears as it does now, a condition they called the “steady state.” As galaxies fly off into the distance, new material pops into empty space to take their place. A single atom per century materializing in each parcel of space the size of a football stadium would do the trick. Who would notice such a thing? How could the steady state theory ever be disproved?

In the other camp was the notion of a sudden birth of everything from a kind of cosmic egg. Edgar Allen Poe mentioned this idea in an 1848 essay but was disregarded. The concept finally gained traction in 1927 after Belgian physicist and Catholic priest George Lemaître wrote of the cosmos expanding from what he soon called a “primeval atom.” Twenty-two years later, after Hoyle started to dismissively characterize the idea as “a big bang,” the term caught fire. For the next 14 years, the two radically different cosmologies had roughly equal followers. The steady state theory abruptly fell into fringe status only with the discovery of the cosmic microwave background in 1964. (In modified form, though, it still has a few adherents.)

In recent times, the biggest controversy involved a celestial body smaller than our Moon. Nothing has generated more heat than the 2006 International Astronomical Union “demotion” of Pluto.

That year, the astronomical community grew hotly divided over how the community should define a planet. In the end, Pluto’s tiny mass, just 4 percent that of Mercury, and the continued discovery of more Pluto-ish bodies like Haumea, Makemake, Sedna, Quaoar, and Eris carried the day. Nonetheless, some professionals still simmer over the decision.

For the largely pro-Pluto public, familiarity played a big role. Most folks have little astronomy knowledge. Relatively few could name Earth’s diameter or even a single moon beyond ours in the solar system. Yet everyone could recite the nine planets. Their sole morsel of astro-knowledge was being messed with.

Moreover, “Pluto” has a cute familiarity. In 1931, a year after that world’s discovery, Walt Disney abruptly gave the name to his only non-speaking character, reportedly to exploit its sudden topical fame. (In an earlier cartoon, Pluto simply had been called Rover.)

Oh, well. Celestial food fights always quiet down with time.

Undoubtedly, so will the demotion of poor Pluto.

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