Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: hoki on 21/05/2012 01:04:15
-
Was watching The Universe earlier today and got to wondering, would it be possible to determine if certain life-sustaining properties of the earth happened naturally, or if they were terraformed?
An example would be the earth's molten core. Would it be possible to determine if it occurred due to planets colliding like is currently believed, or if it were melted through other means like technology?
Or perhaps materials like water. If the water here came from comets and such, or by more deliberate means?
-
Things like the molten core could be modelled with computers with respect to the condensation of a cloud of debris, as well ongoing nuclear decay, and perhaps other effects. I don't think there would be anything to indicate an outside force.
A lot of what we observe in Earth today is the result of biologic activity. So, without that early seed of life, there would not be an oxygen rich atmosphere, topsoil, and whatnot.
So, that seeding of Earth with prokaryotes and eukaryotes terraformed Earth. And, people will argue for all of eternity on whether life developed on Earth, or elsewhere.
As far as the origin of water, perhaps comets, although, one should be able to calculate the rate at which comets impact the planets now, (it may have been different earlier). Careful observations should help.
-
... would it be possible to determine if certain life-sustaining properties of the earth happened naturally ...
Yes ... https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
[ the case for exogenesis is not good ... https://en.wikipedia.org/wiki/Panspermia#Objections_to_panspermia_and_exogenesis ]
-
Don't we have ideas today for how we might terraform mars? The equipment required, the techniques. Assuming a highly powered civilization capable of this, you could start by trying to find archeological evidence for such equipment and techniques having been used.
-
Both Mars and Venus lie either on the border, or outside of the Goldilocks zone, with Earth in the middle of it.
Terraforming Earth would simply mean making sure that life started, then waiting 4 billion years for Humans to come along. Noting, of course, that much more drastic changes occurred in the last billion years or so.
Mars may not have strong enough of gravity to support an earth-like atmosphere, so it may not ever be able to be fully terraformed. Rather, it is likely that life would be confined to biospheres.
Venus is too hot, and would require some kind of a sun-shield After which, the atmospheric CO2 would have to be converted to something more useful.
Earth needs neither biospheres or sunshields.
4 Billion year old "equipment" would be difficult to locate and identify as Earth has gone through significant changes during that period. Consider the 100 million year old oil deposits under a mile of soil deposition.
So far, there has been no evidence for complex equipment on Earth that hasn't been made by humans.
-
Thanks for replies guys. I'm not suggesting that technology would have been left behind to discover as evidence, I think that would be unlikely, especially in the case of the planet being melted.
It could be technology that doesn't leave something behind, like giant thermal grenades that get so hot that they melt everything around them, sink to the core, and cook it from the inside.
Or if ice was deposited on earth by hurling giant blocks of it at earth. Its really the same way it would have happened naturally, only if it was deliberately hurled there, what evidence might one search for that would suggest so?
-
Water on Earth should not be seen as a mystery. Hydrogen is the most abundant element in the solar system, and oxygen is probably third most abundant (there is a minority view among scientists that iron might be). Water is a particularly strong-bonded and low energy compound of hydrogen and oxygen, involving the union of three particles. It is therefore almost certainly the most abundant compound in the solar system, and is demonstrably abundant in the outer solar system. The two outermost Galilean moons of Jupiter, Ganymede and Callisto, have compositions that I have heard described as "like frozen muddy puddles", and it is widely believed that Europa has a thin ice shell over a "mantle" of liquid water.
In the inner solar system, any water that gets into the atmosphere may be subject to photochemical decomposition from high energy solar radiation followed by loss of hydrogen from the planet. The Earth alone is protected from this process by the oxygen content of its atmosphere, so that water which is still escaping from the rocks is fairly effectively trapped and retained on the planet.