Ask Ethan #71: Heavy planets, light Sun? (Synopsis)

“The single most powerful element of youth is our inability to know what’s impossible.” -Adam Braun

"I'm going to be a star," says every clump of matter in a molecular cloud, as it prepares to collapse under the tremendous pull of gravitation. But try as they might, only a small fraction of that gas and of those clumps -- the largest and earliest, preferentially -- will ever get there.

This week's Ask Ethan question is one of the shortest and sweetest out there, and comes from Greg Rogers:

If the Sun (and all stars) are mostly Hydrogen and Helium, why don’t planets have about the same distribution of stuff?

They formed from the same things, so why not?

Image credit: © 1998–2015 Lynette R. Cook. Image credit: © 1998–2015 Lynette R. Cook.

The answer is an incredible story of gravity, heat, and mass.


More like this

“You do not become good by trying to be good, but by finding the goodness that is already within you, and allowing that goodness to emerge.” -Eckhart Tolle It's been an amazing week here at Starts With A Bang, and you've been given plenty to think about. In particular, here's what the past seven…
“I think if I had to choose, I would rather have gravity instead of zero gravity. It’s fun for a while, but I’d rather live on Earth.” -Kevin A. Ford By now, you've probably had a lot of opportunities to think about what holds our Universe together: the incredible force of gravitation. Although it'…
"Truth is more valuable if it takes you a few years to find it." -Jules Renard Of all the star-forming nebulae in our galaxy, the Trifid Nebula -- Messier 20 -- is thought to be the newest and youngest. Named "Trifid" for its threefold appearance, the blue reflection nebula, the red emission nebula…
“Hundreds or thousands of years from now, when people look back at our generation, they will remember us for being the first people who found the Earth-like worlds.” -Sara Seager Just a scant 25 years ago, we had never yet found and confirmed another planet orbiting a star other than our own. Fast…

I presume the first stars had no rocky planets?
How many generations did it take to achieve earth like planets?

By david hurn (not verified) on 22 Jan 2015 #permalink