© Vincent et al., Nature Publishing GroupThis close-up image shows the most active pit, known as Seth_01, observed on the surface of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft. A new study suggests that this pit and others like it could be sinkholes, formed by a surface collapse process similar to the way these features form on Earth.
The European Space Agency's Rosetta spacecraft first began orbiting comet 67P/Churyumov-Gerasimenko in August 2014. Almost immediately,
scientists began to wonder about several surprisingly deep, almost perfectly circular pits on the comet's surface. Now, a new study based on close-up imagery taken by Rosetta suggests that these pits are sinkholes, formed when ices beneath the comet's surface sublimate, or turn directly to gas.
The study, which appears in the July 2, 2015 issue of the journal
Nature, reveals that the surface of 67P/Churyumov-Gerasimenko is variable and dynamic, undergoing rapid structural changes as it approaches the sun. Far from simple balls of ice and dust, comets have their own life cycles. The latest findings are among the first to show, in detail, how comets change over time.
"These strange, circular pits are just as deep as they are wide. Rosetta can peer right into them," said Dennis Bodewits, an assistant research scientist in astronomy at the University of Maryland who is a co-author on the study. The pits are large, ranging from tens of meters in diameter up to several hundred meters across.
"We propose that they are sinkholes, formed by a surface collapse process very similar to the way sinkholes form here on Earth," Bodewits added. Sinkholes occur on Earth when subsurface erosion removes a large amount of material beneath the surface, creating a cavern. Eventually the ceiling of the cavern will collapse under its own weight, leaving a sinkhole behind. "So we already have a library of information to help us understand how this process works, which allows us to use these pits to study what lies under the comet's surface," Bodewits said.
Comment: The Rosetta mission scientists have already admitted, based on new information, that what they "have discovered is already starting to transform our understanding of Rosetta's target comet, 67P/Churyumov-Gerasimenko (C-G for short), and cometary science."
Wheres the ice 3 surprising comet facts we've already learned from Rosetta
Perhaps if they considered the electrical nature of comets, as Wallace Thornhill states in this video, these sinkholes and other phenomena, such as the "increasingly stormy" conditions on Uranus, increased volcanic activity on Jupiters moon Io, scientists have been puzzled by the wobble of Saturn's moon Mimas and a major increase in asteroid activity has seen MIT astronomers upgrade the solar system from stable to dynamic would seem to indicate solar system-wide 'climate change'.
For more information read: Earth Changes and the Human Cosmic Connection