PDA

View Full Version : Carbon planets



Padawan
2005-Mar-08, 12:38 PM
Hello :)


From this article (http://www.space.com/scienceastronomy/diamond_planets_050208.html) among others, you can read about how carbon planets might look. Below are a few quotes from that article:


The rich-sounding worlds are modeled after a certain type of space rock, known as the carbonaceous chondrite, which are thought to be broken bits of asteroids. Many of them have been collected on Earth.

"These meteorites contain large quantities of carbon compounds such as carbides, organics, and graphite, and even the occasional tiny diamond," Marc Kuchner of Princeton University said in a teleconference with reporters Monday evening from an extrasolar planet conference in Aspen.

And..


Carbon planets might have smoggy atmospheres laden with carbon dioxide, and a surface covered with tar-like precipitation. "A little bit like Los Angeles," Kuchner said.

So, my questions are:

What do these "carbides, organics, and graphite" look like?
What color would the "smoggy atmospheres laden with carbon dioxide" look like? Brownish?
What colors could you expect the planets to have? From what I know carbonites are mostly dark/black. But I need more information about this.

antoniseb
2005-Mar-08, 01:38 PM
Hi Fahad,

Let's imagine that there is a planet which is about the size of Earth, has an atmosphere, but is mostly Carbon, Hydrogen, Oxygen, and Nitrogen. It might look a lot like the images we saw on Titan, which is all of these things.

A Carbon Planet would be colder than ours, so I don't think you'd see a lot of runny bubbly tar on the surface. You might see some areas that are much darker than the orange creamy ice chips we saw in the Huygens images, but who can say.

If there were a lot of organics, you might get some shiny dark irridescent effect on a lot of surfaces. I suspect that on Titan, these get regularly washed away by the Methane rain.

Padawan
2005-Mar-08, 03:19 PM
Thanks for your insight so far :)


Imagine that we have a carbon planet orbiting very close to the star (these planets are capable of withstanding much heat), hence you have little or none atmosphere. What do you think the surface would look like? Would it be very dark? Also, could these carbon planets have a similar geology as the earth has (mountains for example)?

If a carbon planet would be a bit further away, do you think it could have some sort of rivers flowing on the surface? What would they consist of and what colours might these liquids have?


Hehe, those are tons of questions.

John L
2005-Mar-08, 05:42 PM
The plate tectonics that are responsible for the mountain building on Earth are powered by internal heat and the movement of the Earth's techtonic plates over the molten mantel. There is no reason why a large carbon planet would not also have this, too. As long as it has a hot dense core it, like the Earth, could power techtonics for billions of years. If, however, it only had a tiny core like Mars, then it would slow and stop and eventually end up a dead, unchanging world.

As for whay the surface would look like, that all depends on the chemistry. Calcium Carbonate, a common carbon compound on Earth, is white. Most compounds tend toward the browns and blacks, though. I'd think it would be a dark colored surface with streaks of whites. It could have oceans of carbon compounds like methane.

antoniseb
2005-Mar-08, 07:28 PM
Originally posted by Fahad@Mar 8 2005, 03:19 PM
Imagine that we have a carbon planet orbiting very close to the star (these planets are capable of withstanding much heat), hence you have little or none atmosphere. What do you think the surface would look like? Would it be very dark? Also, could these carbon planets have a similar geology as the earth has (mountains for example)?
I'm having trouble imagining how a hot Carbon planet could form, since I suspect that the protoplanetary disk would get its carbon blown out to the deeper solar system before any major accreting could occur. The only exception I can imagine to this is if there is a hot Jupiter type gas giant already partially formed before the star gets hot, This object might be able to accrete a lot of Carbon before it is blown away, but then it will just be floating arouns in gaseous forms.

astromark
2005-Mar-08, 08:04 PM
:huh: As to what a planet might look like has more to do with its history of impacting material, proximaty to a star, and atmosphearic conditions. . Dont you think.? what lays beneth its serface is only part of the story. I think iron or hydrogen content would be of more consaquence, and then methain and nitrogen and oxygen and. . . . carbon. What is it you want to know?

eburacum45
2005-Mar-11, 03:03 AM
So carbon tends to be blown into the outer system, eh? If it was abundant, then enough may be retained to build a planet or two in the inner system.

Imagine a carbon-rich planet in the same sort of orbit as the Earth.
We have to envisage a thick protoplantary cloud, but deficient in iron. This world would probably have a thick CO2 atmosphere, which would lead to a runaway greenhouse effect and loss of water. This sort of planet would be too hot for most organic compounds on the surface; even tar would become vapour.
Carbonates are unlikely without water, I believe.

Perhaps a carbon-rich world in the same orbit as Mars would be cool enough to retain water- you might get a carbonated sea, like a huge ocean of salty soda-water. Carbonic acid would erode the landscape, and there may well be organic chemicals on the surface or in the atmosphere;
a brown, oily, fizzy kind of world.