After seeing Phobos imaged from the surface of the Red Planet by Mars Curiosity, now we’re lucky to get a close-up treat: here’s a video showing Mars Express images of the Martian moon over the last 10 years. The images reveal mysterious grooves running through the small moon, which is 13.5-miles (22 kilometers) in diameter, and scientists still aren’t sure what’s going on.
“The moon’s parallel sets of grooves are perhaps the most striking feature, along with the giant 9 km-wide Stickney impact crater that dominates one face,” the European Space Agency wrote.
“The origin of the moon’s grooves is a subject of much debate. One idea assumes that the crater chains are associated with impact events on the moon itself. Another idea suggests they result from Phobos moving through streams of debris thrown up from impacts 6000 km away on the surface of Mars, with each ‘family’ of grooves corresponding to a different impact event.”
For more about amazing discoveries from Mars Express, check out our top 10 list from the summer!
There are grooves on Vesta too, I can’t help thinking there is some special significance to these features. They remind me of the way water streaks on a windshield at high speed, almost as if these bodies had been through something something like water vapor.
In order to give that theory even a small amount of credence, I would have to ignore the fact that Vesta rotates and tumbles in its orbit. Phobos is of course tidally locked, which would give it a “leading face”. It’s not clear from the article if the grooves emanate from that face however.
Artificially made by some intelligent beings
I ignored that fact because i didn’t assume that the grooves are the same age or younger than the current spin/orbit of an object that has clearly had a few impacts in its sojourn in the asteroid belt. We need some clever person to work out how to date the grooves.
Phobos is a prime goal for a sample return – because it is thought to have 0.05% of its surface consists of material from ancient Mars. Perhaps a rover on Phobos could also pick up meteorites from Mars – which would be uncontaminated by Earth. If life on ancient Mars was prevalent enough might have evidence of it on Phobos, maybe more easily than from the surface of Mars.
Also has much less planetary protection issues. Lots of issues returning a sample from the Mars surface that might have life on it that has evolved independently from Earth for billions of years. Studies by the National Space Foundation and the European Space Foundation both advocate extreme caution with Mars surface samples – and I think a new study if carried out now would advocate even more caution bearing in mind recent work on synthetic XNA different from Earth DNA and the hazards those might pose if we were to reconstruct a microbe base on XNA and released into the environment of Earth.
With Phobos, then it would probably be sterilized for at least some hundreds of thousands of years (date of most recent impact on Mars thought to be able to send material into space at least for the Earth meteorites from Mars) – and most would be sterilized for billions of years. You could as an extra precaution subject the capsule to say a million years worth of cosmic radiation dose equivalent before you open it – not going to harm it as it’s been subject to millions of years most likely anyway – and make totally sure there is no chance that there is any reproducing life in the first sample you open before you know what is there.