Astronomy/the iron

Advertisement

Expert: - 1/6/2010


Question
some people are saying the iron is not originally from earth!
is it true??

Answer
I've never heard of such a thing, so I don't know why they would say that. But there is no doubt that the vast majority of iron in the Earth was in it, right from the start. Rocky bodies, such as the Terrestrial planets, formed in a very hot environment, close to the Sun. As a result, they were made almost entirely of metal oxides, such as silicon and iron oxide, which could survive as solids at very high temperatures. So they naturally ended up about half oxygen (the "oxide" in the metal oxides), a quarter silicon, and around a quarter iron. Mercury appears to have a greater percentage of iron than the Earth, and the Earth a greater percentage than Mars, because they formed at different temperatures. But there is no reason to suppose that the iron in them wasn't there, right from the start.

So I'd have to say absolutely, unequivocally, no, that is not true.

Astronomy

All Answers

Answers by Expert:

Ask Experts

Volunteer

Courtney Seligman

Expertise

I can answer almost any question about astronomy and related sciences, such as physics and geology. I will not answer questions about astrology and similar pseudo-scientific rubbish.

Experience

I have been a professor of astronomy for over 40 years, and am working on an online text/encyclopedia of astronomy.

Publications
Astronomical Journal, Publications of the Astronomical Society of the Pacific (too long ago to be really relevant, but you could search for Courtney Seligman on Google Scholar)

Education/Credentials
I received a BA in astronomy and physics and a MA in astronomy, both from UCLA. I was working on my doctoral dissertation when I started teaching, and discovered that I preferred teaching to research.

Awards and Honors
(too long ago to be relevant, but Phi Beta Kappa and Sigma Xi still keep trying to get me to become a paying member)

©2012 About.com, a part of The New York Times Company. All rights reserved.