Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 June 29
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Ice Volcanoes on Mars?
Credit: Peter Lanagan (LPL, U. Arizona) et al., MOC, MGS, NASA

Explanation: What causes these unusual cone-shaped features on Mars? Spanning an average of only 100 metres at the base, these small cones appear near massive Martian volcanoes such as Olympus Mons. Near the cones are also dry channels and eroded banks. Given these clues, some scientists speculate that the cones were formed by lava heating ice lying just below the Martian surface. Lava heated ice would vapourize and expand, punching holes in the cooling lava flow as it escaped. Interestingly, nearby volcanoes may have erupted as recently as 10 million years ago, indicating the equatorial near-ground ice existed in the recent past, and therefore may also exist there today.

Tomorrow's picture: Stars Of M10

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
& Michigan Tech. U.