Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Pe-Pe on 19/12/2008 08:35:51

Title: How do we know that another planet collided with Earth?
Post by: Pe-Pe on 19/12/2008 08:35:51
peter Robinson asked the Naked Scientists:

A TV programme stated that during Earth's evolution another planet, Theia?, smashed into it. How do they know this, how do they know when and how do you name a (now) non-existent thing?

What do you think?
Title: How do we know that another planet collided with Earth?
Post by: LeeE on 19/12/2008 14:16:05
We don't know it because there was no one there to witness and record it.  However, the consequences of it are apparent today and these form a record of evidence for which the planetoid collision scenario is by far the best fit solution.
Title: How do we know that another planet collided with Earth?
Post by: TECHFACTOR on 19/12/2008 16:50:18
LeeE: Is correct;too see this evidence you simply have to look up.The answer to this question;began with another question.Where did the moon come from? Not only do we have our own moon but we only see one side of it the reason for this is in its early stages of formation the moon was molten like lava in fact it was lava. The liquid moon began to cool at the same time as it orbited our planet the gravitational pull of the moon on the earth so close to our planet in its original orbit slowed the rotation of the earth. The way this works is through the tidal forces that still pull at the earth today;Kind of slowing the planet like dragging A boat paddle throw the water to slow A canoe. At the same time the earth is doing the same thing to the moon;as the moon cooled it became more solid and eventually locked its rotation to its orbit around our planet. Soil samples from the moon have been studied and are known to be made up of mostly the same material as found on our planet.So Either some thing come along and sliced A moon size chunk off A much bigger earth;(man that's A big knife!)or A smaller earth collided with A smaller planet that was moving in just the right trajectory to hit the planet not dead on;that would have resulted in A situation where the material would have globbed together into A single planet;but at an angle that could leave enough molten material in orbit after gravity and friction had it out;too form our moon... Hope this helps TECHFACTOR:OUT
Title: How do we know that another planet collided with Earth?
Post by: thedoc on 24/02/2009 16:42:24
Listen to the answer to this question on our podcast. (http://www.thenakedscientists.com/HTML/podcasts/show/2009.02.22/)
Title: None
Post by: DR on 23/12/2009 16:36:17
You can find all the evidence of Thea in a book called; the cataclysmic impact/planet earth's most violent intersect. It clearly provides an abundance of evidence, concentrating on Earth's biggest and most profound impact crater.

Vredefort, Barringer, and Chicxulub craters combined, would not equal a quarter of this impact's enormity.
Title: None
Post by: Wells on 12/01/2010 18:29:58
OK, seems logical- but then where did the rest of Thea go to??
Title: None
Post by: Carl on 20/01/2010 23:39:09
The Earth is believed to have absorbed the other planet which had been in the same orbit as Earth. It slowly caught up to the Earth. It was a Mars sized planet.  They collided at small angle instead of a direct collision.  This allowed the Earth to absorb the other planet.  Most of it is believed to have gone into the core of the Earth making it just right for us today.  The entire planet was molten for quite awhile.  The collision is also believed to have blew off excess water into space so we ended up with the perfect amount for us today.  The collision also threw out a lot of rocky type debris which eventually setteled into the large moon we now have that is so essential to keep Earth on a perfect axis as well as regulate tides and other things.  Personally, I give The Creator credit for such a fine tuning event that made it possible for us to have intelligent life on Earth today.  There is an abundance of other fine tuning facts that make the chances of this all accidentally happening numerically so small that it equals zero.
Title: None
Post by: Bones on 25/05/2010 04:04:57
We do not know... The idea that the Moon was made by a glancing strike on this planet makes no sense. The reason Moon Rocks are like Earth rocks is because they are Earth Rocks. Man has not set foot on the moon. Probes, Yes.. Buzz and the boys did not pick up rocks and bring them back to Earth.

Remember back in the 90's when they claimed the found a Mars rock on Earth? Well would it not be more likely be a Rock from Theia? or Thea... the "Mars size" planet that struck this world? Nope.. they said that rock came all they way from Mars... Such Junk Science.

Our Moon is more likely to be a planet that was formed between Earth and Mars and drifted toward the bigger planet and had its orbit around the orrery captured the bigger Earth...

Any theory that requires you to believe man walked on the moon 11 times is junk.
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Post by: CB on 14/02/2011 00:06:38
Bones, you're an imbecile!
Title: None
Post by: lol on 22/10/2011 14:38:27
Bones, what an idiot! Does he live in a cave? Muppet