Ian
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Is it possible that some asteriod could have hit the Earth's surface millions of years ago and then pieces of it could have landed on Mars or any other planet in the solar system?
Asteroid
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Possible, yes. More likely the other way around- Mars has lower surface gravity and so ejecta from an impact there are more likely to reach escape velocity. At least one of the Antarctic meteorites is thought to be Martian in origin. Also, Earth's atmosphere acts as a shield, burning up the small stufff. Not that this makes much difference in the case of an asteroid.
I can't see any reason why it would be impossible though.
You thinking of terrestrial life getting to Mars by meteor?
I can't see any reason why it would be impossible though.
You thinking of terrestrial life getting to Mars by meteor?
Ian
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Meteor
You thinking of terrestrial life getting to Mars by meteor?
I was thinking of a Martian Meteroite getting to the Earth. I wasn't thinking about life on a meteor getting to Mars from Earth or the other way around. I was thinking that this may have happened when the earth was being impacted by lots of Asteroids and Meteors in the early history of this planet.
You thinking of terrestrial life getting to Mars by meteor?
I was thinking of a Martian Meteroite getting to the Earth. I wasn't thinking about life on a meteor getting to Mars from Earth or the other way around. I was thinking that this may have happened when the earth was being impacted by lots of Asteroids and Meteors in the early history of this planet.
Ian
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Meteor
Yes. I was thinking of a meteor going from the Earth to Mars, but I wasn't thinking of life getting there that way. I suppose that that is possible.
Yes. I was thinking of a meteor going from the Earth to Mars, but I wasn't thinking of life getting there that way. I suppose that that is possible.
wollery
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It's possible, but extremely unlikely. Earth's atmosphere has three very important effects on such events.
Firstly it heats up anything entering the atmosphere, the smallest objects burn up without ever reaching the surface, whilst larger ones often fragment or, depending on what they're composed of, explode.
The second effect (related to the first) is to slow down incoming objects by friction.
Lastly, assuming that the asteroid hits the surface and throws off ejecta, the atmosphere will do exactly the same to the ejecta leaving the surface as it did to the asteroid coming in, i.e. heat it and slow it down.
Escape velocity for the Earth is 40200 km/h (25000 mph), ignoring atmospheric resistance. That's about mach 33 (depending on air temp)!
If it acheives all that then it still has to get from the Earth to Mars, something that NASA doesn't always get right!
Going the other way is a lot easier, Mars has no atmosphere to speak of, and its escape velocity is a lot lower (about 18090 km/h or 11250mph, with little atmospheric resistance).
Firstly it heats up anything entering the atmosphere, the smallest objects burn up without ever reaching the surface, whilst larger ones often fragment or, depending on what they're composed of, explode.
The second effect (related to the first) is to slow down incoming objects by friction.
Lastly, assuming that the asteroid hits the surface and throws off ejecta, the atmosphere will do exactly the same to the ejecta leaving the surface as it did to the asteroid coming in, i.e. heat it and slow it down.
Escape velocity for the Earth is 40200 km/h (25000 mph), ignoring atmospheric resistance. That's about mach 33 (depending on air temp)!
If it acheives all that then it still has to get from the Earth to Mars, something that NASA doesn't always get right!
Going the other way is a lot easier, Mars has no atmosphere to speak of, and its escape velocity is a lot lower (about 18090 km/h or 11250mph, with little atmospheric resistance).
CurtC
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Just to be clear, I think it's possible that pieces of a meteorite could have broken off on impact with Mars, been ejected by the impact, and later come down on Earth. But how would we tell that it hit Mars first, and that this wasn't just a smaller meteorite that fell to Earth directly?
What *has* happened is that impacts on Mars have ejected Martian material, and those have ended up on Earth. We can tell with these because the composition of the rocks matches the composition of Mars. This is a little different from what you were asking.
What *has* happened is that impacts on Mars have ejected Martian material, and those have ended up on Earth. We can tell with these because the composition of the rocks matches the composition of Mars. This is a little different from what you were asking.
Ian
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Is it possible that a huge asteroid could have hit the earth when the atmosphere was first forming before it got so thick and impacted and then had some asteroid ejected from it at an extremely high speed and then impact mars and leave some Asteroid there?
wollery
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As I understand it the current theories of planetary formation suggest that the Earth's atmosphere was thicker in the early stage of its history.Ian said:
Edited to add Bear in mind that I didn't say that it couldn't happen, just that I don't think it's very likely.
Ian
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Could a huge asteroid hit the Earth traveling so fast that it penetrated the early Earth's thick atmosphere and then made large asteroids travel to space because of the impact and then go to mars? There are theories that say that life could have originated in space because some meteors have organic materials in it and also, could a comet impact make a Meteor from Earth go to mars if the comet was big enough and large enough?
CurtC
Illuminator
Back in the olden days, the Earth was hit by a giant chunk of material, which ejected lots and lots of stuff into space. Much of this ended up in orbit around the Earth, and eventually coalesced to form the Moon. But I'm sure some of it must have been ejected past escape velocity, and some of that must have gone to Mars.
What are you getting at?
What are you getting at?
Ian
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Back in the olden days, the Earth was hit by a giant chunk of material, which ejected lots and lots of stuff into space. Much of this ended up in orbit around the Earth, and eventually coalesced to form the Moon. But I'm sure some of it must have been ejected past escape velocity, and some of that must have gone to Mars.
If future astronauts go to Mars and land there, then they could try to find some meteoites that came from the Earth. They could analyze the geology or chemical composition of the meteorites or meteorite and then try to find out whether or not they came from the Earth.
If future astronauts go to Mars and land there, then they could try to find some meteoites that came from the Earth. They could analyze the geology or chemical composition of the meteorites or meteorite and then try to find out whether or not they came from the Earth.
Let's exercise caution here. The "Old Days " CurtC mentions are very long ago indeed. Pre life on Earth. Or at least pre anything we are apt to recognise as "life".
An asteroid is a big object. It will spend only seconds in the Earth's atmosphere and won't lose much mass to ablation. The vapourised mass is still infalling anyway. This would have been so during the early days, irrespective of atmospheric thickness or composition.
Also asteroids and comets is beasts of different natures. A big comet will still get through, but being a lot more volatile will lose far more mass to ablation during entry than an asteroid.
Finding terrestrial material on Mars may be possible, but how would we identify it? The isotopic composition of the Earth's crust has changed due to outgassing and radiation throughout it's existence. (My suspicion is that Mars' has too). It would be very hard to say for sure something came from Earth, unless it had "NASA" stamped on it. Say a meteorite contained gas bubbles. How do we know that gas mix is identical to what would have been ejected from the Earth's atmosphere , under high pressure and temperature impact conditions , say 1 billion years ago? How do we age date the rock in the first place? (We can't assume it had Earthlike isotope ratios to start with. That's begging the question.)
Gravitationally, Mars is uphill from here- away from the Sun. Anything leaving here for there must be accelerated into a "higher" orbit. Anything thrown from the surface of Mars into space, with insufficient velocity to maintain a Martian orbit, will fall sunwards. Towards us.
(It's a lot more complicated than that, but statistically, it's easier to go downhill).
An asteroid is a big object. It will spend only seconds in the Earth's atmosphere and won't lose much mass to ablation. The vapourised mass is still infalling anyway. This would have been so during the early days, irrespective of atmospheric thickness or composition.
Also asteroids and comets is beasts of different natures. A big comet will still get through, but being a lot more volatile will lose far more mass to ablation during entry than an asteroid.
Finding terrestrial material on Mars may be possible, but how would we identify it? The isotopic composition of the Earth's crust has changed due to outgassing and radiation throughout it's existence. (My suspicion is that Mars' has too). It would be very hard to say for sure something came from Earth, unless it had "NASA" stamped on it. Say a meteorite contained gas bubbles. How do we know that gas mix is identical to what would have been ejected from the Earth's atmosphere , under high pressure and temperature impact conditions , say 1 billion years ago? How do we age date the rock in the first place? (We can't assume it had Earthlike isotope ratios to start with. That's begging the question.)
Gravitationally, Mars is uphill from here- away from the Sun. Anything leaving here for there must be accelerated into a "higher" orbit. Anything thrown from the surface of Mars into space, with insufficient velocity to maintain a Martian orbit, will fall sunwards. Towards us.
(It's a lot more complicated than that, but statistically, it's easier to go downhill).
I suppose they could but what would be the point?
It is entirely likely that there are asteroids from Earth on Mars (after all there are asteroids from Mars on Earth).
But what would they tell us?
Going all the way to Mars to analyse rocks from Earth seems a bit pointless.
We already have rocks from Earth's past right here on Earth.
Soapy, surely the Sun's gravitational effect on us here isn't really that strong. If a meteorite hit Earth the debris would go in lots of directions, not just towards the sun.
I can't believe that would be much of a factor in the relative amounts of meteorites.
I would have thought Mars' relative small size would be more relevant.
And would it be particularly hard to identify a chunk of rock as a meteorite from earth? Identifying a rock as a meteorite isn't too hard. Once we know it's a meteorite surely identifying it as conforming to an Earth type wouldn't be particularly difficult.
If we can identify meteorites from Mars surely we can identify meteorites from Earth.
FYI the Opportunity Rover found a meteorite on the martian surface : Martian Meteorite
As to your OP question, I'll throw my hat into the possible but very unlikely ring. Ejecta from Mars only has to fall toward the sun to reach Earth. Going the other way takes considerably more energy...
As to your OP question, I'll throw my hat into the possible but very unlikely ring. Ejecta from Mars only has to fall toward the sun to reach Earth. Going the other way takes considerably more energy...
"Soapy, surely the Sun's gravitational effect on us here isn't really that strong. If a meteorite hit Earth the debris would go in lots of directions, not just towards the sun."- Ashles.
Yes, but it would all leave with the same velocity, more or less, relative to Earth. Depending where and when it hit, debris might be flung backward along Earth's orbital path.
All that material will have a lower solar orbital velocity than Earth. It's headed sunward.
We have to be hit at the right velocity, angle and time, for debris to be thrown on the proper course and with at least a 6.5km/sec delta V to get to Mars. Statistically, only a very small fraction of debris from an Earth strike has the right flight characteristics to cross the orbit of Mars- and most of it will miss. Conversely, most of anything flung from Mars into space is headed sunwards, and will cross the orbit of Earth, which is a far bigger target gravitationally.
The stuff going sunwards is headed downhill, in potential energy terms. Anything headed for Mars is headed uphill. Statistically, (as I said) downhill is more probable. I don't deny the possibility of it reaching Mars. Just stressing that it's a lot easier going the other way.
Yes, but it would all leave with the same velocity, more or less, relative to Earth. Depending where and when it hit, debris might be flung backward along Earth's orbital path.
All that material will have a lower solar orbital velocity than Earth. It's headed sunward.
We have to be hit at the right velocity, angle and time, for debris to be thrown on the proper course and with at least a 6.5km/sec delta V to get to Mars. Statistically, only a very small fraction of debris from an Earth strike has the right flight characteristics to cross the orbit of Mars- and most of it will miss. Conversely, most of anything flung from Mars into space is headed sunwards, and will cross the orbit of Earth, which is a far bigger target gravitationally.
The stuff going sunwards is headed downhill, in potential energy terms. Anything headed for Mars is headed uphill. Statistically, (as I said) downhill is more probable. I don't deny the possibility of it reaching Mars. Just stressing that it's a lot easier going the other way.