The 10th planet theory.

[chris]

I read in last month discover magazine about how scientists can only explain the odd orbit of the planet neptune and pluto, is that there is a very large planet out there that distorts them. Now, for some time I have accepted this theory. But in this months, it describes a galaxy on the collapse 50 billion light years away. Now, it makes me wonder. Pluto is no where near 50 billion light years. It's not even a billion, So, if this theroy was to be true, This planet would have to be big enough to attract them. But, if we can see 50 billion light years away, and we havent found this 10th planet, it would have to be hard to fathom the size of this planet.

[Guest Unregistered]

We can't see 50,000,000,000 light years away, the current universe is estimated between 12 and 15 billion years old :/

[fafalone]

Depends on the theory. Farthest galaxy we've seen so far is 14 billion light years away. There could be more, certainly if a galaxy is that far away and we saw it already formed, the universe is at least a couple billion older. And of course the latest theory says the universe is trillions of years old.

[chris]

Ok, i found the discover magazine, (March 2002). its not 50. that was a guess cause i was to lazy to look for it. but for who ever signed up. heres the real distance. (4.2 billion light years) k? happy. there

[Halogen Fisk]

Originally posted by chris

But, if we can see 50 billion light years away, and we havent found this 10th planet, it would have to be hard to fathom the size of this planet.

 

 

The big factor here is stars (hence galaxies) generate lots of light.

 

Any planet beyond the orbit of Pluto would only reflect light, & not much out there to reflect.

 

As a metaphor:

It's easier to find someone at night if they're holding a torch!

[blike]

Very good point, Halogen Fisk

[Sayonara]

Originally posted by chris

Now, it makes me wonder. Pluto is no where near 50 billion light years. It's not even a billion.

Significantly less than one, in fact.

 

But everyone else already answered the question.

[Radical Edward]

I can't see the link between a planet just outside the orbit of pluto, and a galaxy 50 billion light years away... or however far it is.

[blike]

I think he was saying if we can see that, why can't we see the planet.

[Sayonara]

Originally posted by Radical Edward

I can't see the link between a planet just outside the orbit of pluto, and a galaxy 50 billion light years away... or however far it is.

He wanted to know why we can see the galaxy but not the planet.

[Radical Edward]

>_< .. oh heh, I get it now, thanks

[chris]

yes thats it! but fisk did bring up a good point. But wouldn't we be able to see the outline of one if we are looking at it with bright objects behind it?

[Radical Edward]

you mean an eclipse... yes you would, be able to see it's shadow if it passed infront of, say, a star (this is one of the methods being used to look for planets, and other large objects like brown dwarves, black holes etc) but you would have to be looking in the right direction at the right time though....

[chris]

very true. But still thats a way. And black holes move? i thought they were stationary.. interesting.

[Radical Edward]

oh black holes move, spin and allsorts - they would, since they are a prediction of general relativity, which in it's simple form - ignoring gravity and acceleration (Special Relativity) relies on the fact that there is no absolute motion - all motion is relative.

[chris]

can a black hole destroy matter?

[Radical Edward]

not exactly. they are information sinks, afaik destroying all information except charge, mass and angular momentum. there may be a couple of other quantum numbers that remain. I can't think of them off hand though if they are conserved, but I doubt it (things like boson number, lepton number etc)

[chris]

so what happens to the matter?

[Radical Edward]

in what way?