Scientists studying a distant region of the solar system near Pluto have discovered the unexpected: a minuscule object with its own atmosphere. It was previously believed that such small celestial bodies located that far from the sun are incapable of having their own atmospheres. Now, the new finding could unlock insights into planets in our solar system millions of miles away.
What did scientists discover?
The 310-mile-wide celestial body, officially named 2002 XV93, is classified as a trans-Neptunian object (TNO) because its distance from the sun, approximately 3.5 billion miles, lies beyond the outermost planet, Neptune, according to Japanese astronomers in a study published in the journal Nature Astronomy. And though the icy body was identified many years ago, only now has it been observed to be “swaddled in a layer of air,” said The New York Times.
The TNO is “thought to be the solar system’s smallest object yet with a clearly detected global atmosphere bound by gravity,” said lead study researcher Ko Arimatsu, the head of Japan’s National Astronomical Observatory, to The Associated Press. The discovery of the thin atmosphere is surprising because the “gravitational pull of such a small celestial body is weak, and any air surrounding it should have long ago floated away into space.”
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The highly fragile atmosphere appears to be “roughly 5 million to 10 million times thinner than Earth’s robust atmosphere and about 50 to 100 times thinner than Pluto's tenuous atmosphere,” said Reuters. Scientists believe this atmosphere may have formed due to “cryovolcanoes on the small, icy body, which release internal gas such as methane, nitrogen or carbon monoxide from beneath its surface” — a previously unknown phenomenon, said CNN.
At the edge of the solar system, temperatures “are so cold that most of the molecules that exist as gases in Earth’s atmosphere freeze solid,” said the Times. And any air that does “not float away would be expected to turn into ice and fall to the surface,” not become an atmosphere.
Why is this so significant?
Because a TNO shouldn’t have one, the discovery of the atmosphere could offer an “unprecedented glimpse” into how one “forms and remains around a small object,” as well as “change how astronomers think about objects,” said CNN. And it suggests that “some small icy bodies in the outer solar system may not be completely inactive or unchanging, as previously assumed,” said Arimatsu to Reuters. “Even in a distant, cold world, there are dynamisms we haven’t imagined,” said study co-author Junichi Watanabe, the director of Japan’s Koyama Space Science Institute, to the outlet.
Others say more information needs to be gathered. This is an “amazing development, but it sorely needs independent verification,” said Alan Stern, the scientist behind NASA’s New Horizons mission to Pluto, to the AP. The “implications are profound if verified.” But the researchers who made the discovery are optimistic. “It changes our view of small worlds in the solar system, not only beyond Neptune,” said Arimatsu to the AP. The finding is “genuinely surprising.”
