How do scientist know for sure Mars has no molten core?

i thought the atmosphere is just there becuase it's just there but i think theres probebly more to it then that

excuse me ignorance

Originally posted by mrwupy

Mars has gravity.

Yes it does, it also has an atmosphere...

The atmosphere comes from the magnetic field that a molten core generates. Mars does not have a molten core because it is a dead planet. It has no atmosphere because it is a dead planet.

Mars has an atmosphere...

Yes, Mars has gravity. So does Earth. Earth has a thick atmosphere, Mars does not. Gravity has nothing to do with it.

The electromagnetic field holds our atmosphere in place.

I've yet to hear a better argument on the question at hand.

If that argument was true, then Venus would not have an atmosphere.

Gravity keeps the atmosphere in place, Earths magnetic field helps protect it from being stripped away, and various agents on the planet (volcanoes for example) replenish it. Venus's magnetic field is weaker than Mars (even weaker size vs strength) but it's atmospheric pressure is over 90 times that of Earth. This information can be verified at various web sites (NASA, astronomy web sites) and planetariums or libraries.

Gravity holds earth's atmosphere in place. Earth's magnetic field (magnetosphere) protects our atmosphere from the solar wind. If earth had no magnetic field earth would still have an atmosphere but it would be much thinner than it is.

Gravity holds Mars' atmosphere in place. Mars has essentially no magnetic field so its atmosphere is not protected from the solar wind. Because of this much of Mars' atmosphere has been swept away by the solar wind. Because of this and because Mars' gravity is less than earth's, Mars has a very thin atmosphere.

Gravity holds Venus's atmosphere in place. Venus has essentially no planetary magnetic field but it has a very strong ionosphere, a layer of charged particles in the outer atmosphere. This ionosphere is what protects Venus's atmosphere from the solar wind. It does not work as well as earth's magnetosphere though, and it does allow lighter gases to be stripped from the atmosphere. Water vapor is a light gas, oxygen is a light gas, carbon dioxide is a heavy gas and composes 95% of the atmosphere of Venus.

[edit on 24-10-2008 by Phage]

Magic, clearly.

That, or maybe gravity.

The atmosphere is electrically held to Earth.
There is an electric field of considerable size at ever meter above ground level.
Tesla found microwaves emanating from earth but I hardly know how
that would hold the atmosphere to Earth.
Ask the FBI to take a peek at Tesla's notes they locked up since 1943.
Electrical force is way stronger than gravity.

Originally posted by TeslaandLyne

Electrical force is way stronger than gravity.

The electric universe is still a new theory and pretty much considered quack science.

In time it may hold up though.

Today's mighty oak is yesterdays nut who held it's ground.

Gravity holds it in place.
Although they have not found gravity yet, all eyes are on the massive particle smasher they just finished building to find it.

Have a related question:

IF you took a cross section of the atmosphere would the density of air from bottom to top be a gradient ? or would it be semi constant all the way through ?

Originally posted by R3KR
Gravity holds it in place.
Although they have not found gravity yet, all eyes are on the massive particle smasher they just finished building to find it.

Have a related question:

IF you took a cross section of the atmosphere would the density of air from bottom to top be a gradient ? or would it be semi constant all the way through ?

There is an altitude pressure formula derived from the gas law using
some calculus but never could find the equation or derivation.

So if pressure varied the air density should vary.
(Which beings up and ether question which I'll skip.)

So PV = NRT where a volume is given one of the dimensions of altitude.
That must be way to find the formula.

(The inverse densities of air to ether (sqrt of) is the ratio of
light to sound velocities giving a very very fine ether.)

The Erath's gravity does indeed keep the amtosphere 'in.

The mistake you are making is believing that a vacuum sucks. A vacuum doens't suck. Vacuum is a void, a nothing, it has no properties beyond non-existence. The reason a vaccum appears to suck on Earth is because there is atmosphere all around it trying to push into the void created. The apparent suction isn't caused by the vacuum itself sucking, it's caused by the atmosphere blowing into that vacuum to try to equalise the drop in pressure.

Of course in space there is no atmophere, which is precisely why the vacuum of space has no sucking power. Whether it's a vacuum cleaner or a perfectly evacuated jar if you operate them in space there woudl be absoluetly no effect on anthything around them because there si no presuure difference inside the vacuum and outside.

You are astually better off thinking of the atmophere pushing dust into a vaccum cleaner rather than imagining it being sucked in. It is far closer to reality.