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Opportunity Finds Another Big Meteorite

by Nancy Atkinson on October 2, 2009

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Another Mars meteorite seen by Opportunity. Image Credit: NASA/JPL-Caltech

Another Mars meteorite seen by Opportunity. Image Credit: NASA/JPL-Caltech



It’s amazing what a rover can find laying by the side of the road. The Mars Exploration Rover Opportunity has found a rock that apparently is another meteorite. Less than three weeks ago, Opportunity drove away from a larger meteorite called “Block Island” that the rover examined for six weeks. Now, this new meteorite, dubbed “Shelter Island,” is another fairly big rock, about 47 centimeters (18.8 inches) long, that fell from the skies. Block Island is about 60 centimeters (2 feet) across and was just 700 meters (about 2,300 feet) away from this latest meteorite find. At first look, the two meteorites look to be of a similar makeup; Opportunity found that Block Island was is made of nickel and iron.

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This image was taken during Oppy’s 2,022nd Martian day, or sol, (Oct. 1, 2009).

See below for a 3-D version of this image created by Stu Atkinson.

Shelter Island in 3-D. Dimensionalized by Stu Atkinson

Shelter Island in 3-D. Dimensionalized by Stu Atkinson

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About

Nancy Atkinson is Universe Today's Senior Editor. She also is the host of the NASA Lunar Science Institute podcast and works with the Astronomy Cast and 365 Days of Astronomy podcasts. Nancy is also a NASA/JPL Solar System Ambassador.

Tagged as: Mars Rovers, Meteorites

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  • Lawrence B. Crowell

    There is enough atmosphere to slow down the spacecraft we send to Mars, Most meteroids we observe are brought to subsonic speeds in the stratosphere with pressures similar to the atmosphere of Mars on the surface. A chunk of rock this size could be slowed enough so a crater does not form.

    LC

  • ND

    So there are several variables with a meteorite impact. The initial speed before reaching the atmosphere, the atmosphere itself, planet’s gravity, the angle relative to the planet, surface area, density, composition (rocky vs iron/nickel), final speed on reaching the surface and surface composition. These are top the head.

    I believe the smaller the object is the greater the role of terminal velocity on the final speed.

    Corrections are welcome. Again these are just reasonable guesses.

  • IVAN3MAN

    davesmith_au:

    Logical thinking… so we have enough “air” on Mars to cool and slow down this rock… that’s news to me.

    I wish that there was Comic Sans text facility here for the above quote. *Sigh*

    Dude, what you are overlooking is the fact that Mars once had a much thicker atmosphere a billion or so years ago — which was probably when that meteorite landed; it did not drop down out of Mars’ sky like, er… last bloody Xmas! — and its atmosphere, being composed chiefly of carbon dioxide from volcanic activity, would probably have been several times denser than even Earth’s atmosphere is today, so the meteorite would have been slowed down sufficiently to just drop onto the ground without causing a big crater.

    I suggest that you read this: Meteorite Found On Mars Yields Clues About Planet’s Past

    Furthermore, there is evidence that Mars once had shallow seas, as well a thick atmosphere, so if the meteorite had landed into one, it would have absorbed even more of the meteorite’s kinetic energy and it would have just settled at the bottom of the sea, which has since evaporated and the water is now locked up as permafrost at Mars’ poles.

  • IVAN3MAN
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