If mars has an atmosphere, why does it have so many craters like the moon?

Question

http://www.google.com/mars/

Ok, thinner atmosphere.. now got it - swiss cheese - haha ha; ok, I mean aren't astorides supposed to burn to dust b4 hitting the surface, and if that is such a problem - how on earth are ppl safe after a mars landing (if at all) and colonizing it would be totally out I suppost ( at least science fictinally) without hugely considering asteroid impacts?

Answer 1

It is smaller than earth, therefore lower gravity, therefore thin atmosphere, therefore more objects get through.

Answer 2

The equivalent pressure of Mars' atmosphere can be found at a height of 35 km above the Earth's surface. The scale height of the atmosphere is about 11 km; higher than Earth's 6 km due to the lower gravity.
Meteorites coming through the Martian atmosphere would not be slowed down because of the thinness of the atmosphere and because of this the outer layers of the meteorite would not vapourise due to the atmospheric friction on the meteorite.
Mars appears to have no tectonic activity but the martian sandstorms appear to have softened the edges of the craters and these craters may have a dense layer of sand in the bottom.

Answer 3

THESE POINTS MIGHT ANSWER YOUR QUESTION

1.There is strong evidence to support that there did exist a smaller planet between earth and Mars and was very close to a Mars. And this intermediate Planet was destroyed by a meteorite.

2.And a majority of those broken pieces bombarded the southern hemisphere of Mars. This tilted the Axis(that is why there are chunks of ice at both the pole).

3.That is another reason why the Northern Hemisphere is more of leveled land comparing to the southern part which has lots of craters. Also this constant bombardment over thousands of years has torn away the already-thin atmosphere since the chunks of falling rocks were extremely huge.

4.And also since the atmosphere was very thin, it did not provide friction for the meteor showers. that is the reason why these rocks didn't burn on entry and crashed as whole.

Answer 4

The atmosphere of Mars is much thinner than that of the Earth, therefore more objects get through.

Mars is closer to the Asteroid Belt, at present we know of about 4 times as many objects that cross the orbit of Mars than cross the orbit of the Earth.

Mars seems to have very little active geology, unlike the Earth with its tectonic plates. Craters on Mars are thus much more likely to survive for a long period of time than on the Earth.

Answer 5

This answer is just for additional details.

The craters are there from millions of years. Mars is assumed to have earth like atmosphere millions years ago, but it subsequently due to unknown reason (armagedon??) lost 90% of it's atmosphere.

I would say the chance of crater impact on mars for a perticular location for 1000 continuous years will still be significant smaller. Also any colonozation effort will require space radars for the obvious reasons. The space radars will be accompanied by many space missiles (big ones) to minimize/neutralize larger asteroids. small or very small asteroids has limited damage capacity and those kinds strike earth continuously without much damage. (of course on mars the damage will be 9-10 times more, but will still be not that riskier)

I have thought about the whole scenario many times in past. It has given me ideas about underground colonies, land based radar/missiles combo as a supplement to space radar/missile combo. lightweight high density roof material (multiple layers) to minimize impact. early warning message based on space radar signals and subsequent shelters with ~20 inch hardened steel or other highly resistent and dense material roof tops.

Basically combination of such measures can reduce the risk to similar to that of car accidents.

Answer 6

The Mars atmosphere is a lot thinner that its Terran counterpart. If an asteroid want to hit earth it have to goes through 100km atmosphere with average pressure of 0.25 Pascal. In case of Mars it is only have average pressure of 0.0075 Pascal.
It is like comparing hitting a banana tree board to hitting a Redwood tree with your hand.

Answer 7

Three reasons:

1. Its atompshere is a hell of a lot thinner
2. Its moons aren't as good at protecting it as ours.
3. Most are very old, from when there were a lot of asteroids roling around. Earth used to have a lot, but plate tectonics removed them. Mars doesn't have plate tectonics.

3 is the most important.

Answer 8

To answer your follow up, the solar system is much less volatile and dangerous than it was in it's youth. There are far fewer impacts now. We have been kind of "cleaned up" over time by the larger gas giants and even the smaller ones.

Answer 9

earth doesnt have that many asteroids that you can see- in geologically inactive places.
see, over time tectonic plates move and thn the craters get hidden or cracked, so much that you cant see it anymore.

Answer 10

from asteroid impacts
or, if you really think so, it's made from swiss cheese, just like the moon