Astronomy Picture of the Day 8-08-02

NASA ^ | 8-08-02 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

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.

2002 August 8

Ancient Volcanos of Mars
Credit: Malin Space Science Systems, MOC, MGS, JPL, NASA

Explanation: Findings of ancient martian microbial fossils in meteorites and liquid water related features on Mars' surface are currently controversial issues. But one thing long established by space-based observations of the Red Planet is the presence of volcanos, as Mars supports some of the largest volcanos in the solar system. This synthetic color picture recorded in March by the Mars Global Surveyor spacecraft shows two of them, Ceraunius Tholus (leftmost) and Uranius Tholus. Found north of the Tharsis region of truly large martian volcanos, these are actually two relatively small volcanos, Ceraunius Tholus being only about the size of the Big Island of Hawaii on planet Earth. Impact craters which overlay the volcanic martian terrain indicate that these volcanos are themselves ancient and inactive. North is to the right and the scene is illuminated by sunlight from the top left. A light region of dust deposited by recent global dust storms lies on the lower left flank of Ceraunius Tholus, whose summit crater is about 25 kilometers across.

[petuniasevan]

Astronomy Fun Fact:

Mars is home to the biggest volcano in the Solar System: Olympus Mons.
Olympus Mons is 15 miles tall and is almost 350 miles wide.

Get on the APOD PING list!

[petuniasevan]

APOD PING!

[foolish-one]

Any idea what trickled down the right side of Ceraunius Tholus and pooled at the bottom?

[MozartLover]

bump

[2Trievers]

[dansangel]

That is a really neat picture! It lends a lot of character to the "Red Planet."

Have a blessed day!

[BossyRoofer]

WOW what a picture!

[petuniasevan]

The only reference I can find for the phenomenon is this one at http://www.solarviews.com/cap/mars/ceraun.htm :

A major impact crater, just above Ceranius Tholus, postdates the plains material and volcano. However, a prominent delta of probable volcanic material was emplaced within the impact crater at the mouth of a sinuous channel that extends up the flank of Cerauius Tholous to the summit crater.


The theory is that the volcano was dormant when an impact occurred by it, which "awoke" the volcano. It then erupted material which ran down into the impact crater.