Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: guest39538 on 27/06/2016 09:28:16
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Throughout the layers of the earth shows dinosaurs existed before our time and then were covered up by millions years of space dust or other.
How do we know that humans did not exist on the moon or likewise on other planets and have been covered up in the same way as the dinosaurs?
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Not many planets have, or ever had, sufficient oxygen and water to sustain animal life of any sort. Possibly Mars but certainly no other in the solar system. And even if Mars did sustain animal life, the probability of it evolving into a recognisable ape is very small - you need to evolve jungle and savannah conditions first!
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Humans have existed on the moon in the past but it was for a very short duration. They did leave some evidence behind.
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Not many planets have, or ever had, sufficient oxygen and water to sustain animal life of any sort. Possibly Mars but certainly no other in the solar system. And even if Mars did sustain animal life, the probability of it evolving into a recognisable ape is very small - you need to evolve jungle and savannah conditions first!
How on earth would we know that other planets never had an atmosphere or plant life before our time of existence?
We would have never known dinosaurs were real if we never dug the ground, so I think maybe there could be some buried secrets on other planets also maybe?
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How on earth would we know that other planets never had an atmosphere .... before our time of existence?
The hotter a planet gets in the daytime, the more energy is pumped into any gas molecules on the surface, and the faster they move.
If a significant fraction of the molecules of gas exceed the escape velocity of the planet, then the gas will eventually escape into space. and the planet will lose its atmosphere.
So the larger the mass of a planet, the more easily it holds onto an atmosphere.
The Earth and Moon are at roughly the same average distance from the Sun, so they have roughly the same average temperature. But the Moon's surface gravity is about 1/6 of Earth gravity. Coupled with the Moon's higher daytime temperature, the Moon lost any original atmosphere quite rapidly, compared to the Earth.
How on earth would we know that other planets never had .... plant life before our time of existence?
The only plant life we know depends on photosynthesis to convert CO2 into sugars dissolved in liquid water.
The other planets are too hot or too cold, too big or too small, or the pressure is too low or too high to have liquid water on their surface.
If the planets haven't shuffled their positions too extensively in the history of the Solar System, then conditions would have been similar in the past.
It may be different under the surface (eg on Mars or Europa), but there is no sunlight there.
There are other ways of gaining energy, eg near hydrothermal vents, or from the decay of radioisotopes. These are the main hopes for finding life-as-we-know-it in our Solar System.
...but there is always the possibility (or likelihood?) of life-but-not-as-we-know-it!
I think maybe there could be some buried secrets on other planets also maybe?
I agree with you - we need to do some more detailed exploration of other planets and moons in the Solar System. Initially with robots (like Mars Curiosity Rover and Philae lander), but people are more interested in people...
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How do we know that humans did not exist on the moon or likewise on other planets and have been covered up in the same way as the dinosaurs?
If you check with the appropriate government agency, you will find no building permits issued prior to the space program.