- The Rosetta spacecraft, currently orbiting Comet 67P/Churyumov–Gerasimenko, spotted 120 bright, reflective spots on the surface of the comet that were at least a few meters (about 6 feet) in size. While their composition is still being examined, the spots tend to appear in areas that are shaded by the sun, scientists noted.
- The spots are up to 10 times brighter than the average surface brightness of the comet, as measured by Rosetta. Sometimes they appear together, particularly when they are at the bottom of cliffs. The research team speculates this is because the cliff wall recently eroded or collapsed, revealing material below the dusty surface.
- It’s not clear when the ice patches formed, but the team has two hypotheses. The first suggests that when 67P was closest to the sun, 6.5 years ago. Alternatively, perhaps carbon monoxide and carbon dioxide beneath the surface pushed the ice around while the comet was farther from the sun.
Rosetta Sees Signs of Water Ice on Comet Surface
6. 29. 15 by Martin Ross