[X] My Assistant

[Jinju]

Earth?

I thought I'd share a thought with the GTS since we all seemed to recently taken an interest in outer space physics.

As we all know the sun is a star, and like many stars, they go through a series of color changes which indicate it's heat. When a star is born, it starts off with a distinct blue color and at this stage, the star is in it's hottest state. As it grows older, it starts to lose temperature, and goes from blue, to blue-white, to white, to yellowish white, to yellow, to orange, and lastly red, then death + cool 'splosion.

Now our Sun was born at one point in time, which means it used to be a searing hot young blue fireball. During this time, Earth and the other close-by planets where either not formed yet, or smoldering piles of superheated rock...except for maybe one distant planet, which was probably heated just right for life requirements, but as the sun grew older and cooler, the planet began to wither, and eventually turn into a wasteland like today's Mars. Then the next planet in line was given the gift of life and creation, until it met the same fate, and so forth and so forth...

So, does that seem plausible or am I missing something?

Reply and Discuss.

This post has been edited by Jinju: Jul 30 2010, 02:17 PM

[Phovos]

I honestly don't think so.

When Mars was formed, it was too small to hang on to any atmosphere it had, unlike Earth and Venus, which had sufficient mass to hold on to the oxygen, carbon dioxide and other gasses necessary for life.

All the planets were formed when the Sun was very young, and there was a huge cloud of gas that swirled around it. The particles of dust, over time, gathered and collected together to form pebbles, then rocks, then boulders, etc. until they formed planets. These planets now had enough mass to 'create' enough gravity to create an atmosphere. But Mars was and always has been too small to create a thick enough atmosphere to support life as we know it. Although Mars has many similarities with Earth, its size and mass aren't among them.

As for life as we don't know it, well, I don't know.

[Annakyoyama358]

The outer planets were all gas, so no life there that would be comparable to earth life
Mars can't hold atmosphere.
So I think no.

[Crystal Shards]

Do I think Mars ever had life like ours? As in carbon-based? No. Probably not. But it's possible there are life forms that aren't carbon-based, and well, we can't really know what kind of environment would be necessary for life to be on there.

But your actual question is whether I think Mars was ever like Earth. My answer is no.

[Cinderella Amber]

I've heard that a few millions to billions of years ago that our inner planets could have, but their atmospheres deteriorated and they were ultimately made incapable of holding life.

[Xal]

There is a huge amount more than just temperature that determines what a planet will be like. Mars used to be somewhat similar to Earth, but you have to remember this is talking in relation to other planets. They're a similar size (again, this is still in comparison to other planets. Judged on their own, they're quite different sizes), have/had liquid water and a few other things. However, Earth and the old Mars aren't alike in any way that you seem to be thinking of. Comparing them just to each other instead of to the wide variety of types of planet, they're incredibly different.

Unless I'm mistaken (as I may well be, it's been quite a while since I've read up on this stuff so I wouldn't be surprised if this post is full of nonsense) the Sun is actually getting hotter as time goes on, not cooler. Mars has cooled down because it doesn't have a magnetic field protecting it from solar winds like Earth does, meaning that a lot of its atmosphere gets stripped away, meaning that there's less insulation for the heat. However, some planets could never be like Earth at all. The gas giants (such as Jupiter and Neptune) are right out.

[darkdude]

scientist believe mars had life on it before ours but its distence from the sun destroyed the life

[Reyo]

I feel it's plausible that life was once rooted on Mars, but chances are it would not have have been ended by the natural lifespan of the sun. If it were, we would be on the otherside of mars in relation to the sun which would account for the sun getting bigger. It would be:

SUN ------> Mars -------> Earth

It makes more sense to say that the small belt that can support life expanded outwards away from the sun as it grew older rathor than it started off farther away from the sun and has been getting closer and closer to the edge.

In fact, scientists have been talking about moving from Earth to Mars sometime in the future (not NEAR future but future nontheless) since that belt of life is moving away as the sun grows bigger.

This post has been edited by Reyo: Sep 2 2010, 12:55 PM