Dust by the Tons.

Dust falls by the tons every day on earth.
I was just wondering, if thats true then wouldn't it be true that a long time ago the atmosphere used to be thicker. Also, Less land for Humans.

If the atmosphere was thicker, then wouldn't it be possible for humans to have lived longer and look younger. Its a known source that gravity and Cosmic rays cause humans to live less than they used to, if nutrition and health remains in good condition.

Ancient cities are covered. I know a couple of tons of dirt doesn't seem like a lot, but millions and billions of years of gathering dust.

The reason I post this is because couldn't the same have happened on mars??

Their could be cities burried deep in mars. Same as on earth.

It is true that tons of dust does enter the atmosphere on a continuous basis, and you do raise a valid point about the effects of the continuous addition of mass to the planet.

However, keep in mind that even millions of tons is a drop in the bucket compared to the total mass of the planet already.

As far as the addition of space dust resulting in less atmosphere, there is no apparent correlation to this effect. To my knowledge, the earths atmosphere has always been approximately equal to its current pressure. It is true that during the carboniferrous period (from 360 to 290 million years ago) the atmospheric concentration of Oxygen was significantly higher (some estimates as high as 30-35%) which did result in very large creatures (my favorite example is the dragonfly with a 12 foot wingspan... such creatures could not live today as the O2 concentration would not support them).

It is also true that the atmosphere outgasses at the upper edge of outer space, but such outgassing is minor compared to the overall volume of the atmosphere. What volume of gas is lost into space is often made up from other sources, such as during volcanic eruptions.

As far as the loss atmosphere from Mars, that is a very interesting subject: It is estimated that approximately 1 billion years in the past, Mars had an atmosphere approximately 1/2 to 1/3 the surface pressure of the earth (currently Mars holds 1/100 surface pressure of earth). A very interesting theory is that a comet or asteroid may have impacted Mars at a very oblique angle, larger than 45 degrees. The impact shock wave, because it was at such a large angle, may have blasted a large amount of atmosphere beyond escape velocity, essentially blowing it off the planet.

Incidentally, this may also explain the presence of Phobos and Diemos, as remnants of either the bedrock blown up into orbit from the impact, or possibly, remnants of the original impactor which skipped off the surface and back up into orbit.

You make a lot of valid points.

The only reason I put that the atmoshpere was greater was that I've read quite a few old, old, old stories that depict humans living a very long time, and the sky was described to look very differently. Doesn't exactly give me much to work with but I was able to understand that many people lived in an environment with no pullution in the air. Colors are described with weird details. The best one is that the grass is so green that it was black, or something like that, have to look at the old story again.

Could you give some examples of what you mean, FoxStriker (about odd colors and so forth)? I collect legends and folklore and don't recall anything of this sort... but I confess I don't know all the legends and tales, of course.

Imagine this senario, A person can see a green color, but another person see's blue. How can this senerio exist, it exist on the fact that we may all see different colors and not know it.

For example, if a Color blind dog see's the color green as described by humans, he would only see a different shade of gray.

Byrd - what I was tring to say is that maybe their are different definitions of what colors used to be. Like colors like green. How do we know its green, because of the reflected light. What if the light had changed, or if the medium which light travels through is not the same, the medium has probably evolved to a point where the original color is now different. Its all theory, but could be true. Im still looking for that story.