A rock bigger than Pluto found...

[Cube Inmate]

Anothing big round thingy has been found in the outer solar system...estimated to be "at least" as large as Pluto, and probably larger -- the first one bigger than Pluto. It's re-igniting the debate over what to call these big round things. If it's not the 10th planet, then how can Pluto be a planet? If it is a planet, then we'd better be prepared for our solar system to expand from 9 planets to accomodate dozens of these things expected to be found in the coming years.

Linky

BTW: I can't believe this didn't show up on CP last week! How am I supposed to follow all the off-topic news when everyone's focusing on hockey!?!

[arsenal]

Another interesting thing that I read about that, was that a hacker got into the computer, and found the data. Then basically said to the team that discovered it.. "Release the info, or I will".

I think I found it on the Register, but other than that.. I haven't heard anyone else confirm the hacker story.

[evman150]

Talk persists about there being a brown dwarf out there in a viciously eccentric orbit with a period of around 30 million years. This would be a companion "star" of the sun and would have caused all of the major extinctions in history.

A brown dwarf is a loosely called a star but it actually just a really big ass planet. An object is a brown dwarf if it is between 0.002 and 0.08 solar masses (Mass of Sun is 2E30kg). Anything bigger than that is a star and anything smaller is a planet/asteroid/comet/whatever.

They are born from the same gravitational collapse and contraction of protostellar nebulae but don't have enough mass to start nuclear reactions in the core. Hence the lack of luminosity.

So the Kuiper Belt could hold more than just a few Pluto size planets/planetessimals.

[Mr. Ski]

Originally posted by evman150@Aug 5 2005, 08:52 PM
Talk persists about there being a brown dwarf out there in a viciously eccentric orbit with a period of around 30 million years. This would be a companion "star" of the sun and would have caused all of the major extinctions in history.

Sounds like a cool theory... what's the connection though?

[evman150]

Originally posted by Mr. Ski+Aug 5 2005, 01:21 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Mr. Ski @ Aug 5 2005, 01:21 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-evman150@Aug 5 2005, 08:52 PM
Talk persists about there being a brown dwarf out there in a viciously eccentric orbit with a period of around 30 million years. This would be a companion "star" of the sun and would have caused all of the major extinctions in history.

Sounds like a cool theory... what's the connection though? [/b][/quote]
The connection to what?

This discovery of a Pluto sized object? Extinction?

[Mr. Ski]

Originally posted by evman150+Aug 5 2005, 09:24 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (evman150 @ Aug 5 2005, 09:24 PM)</td></tr><tr><td id='QUOTE'>

Sounds like a cool theory... what's the connection though?

The connection to what?

This discovery of a Pluto sized object? Extinction? [/b][/quote]
The connection of the brown dwarf's existence to the extinctions on earth (sorry, should have made that more clear).

[Mike F]

Originally posted by Mr. Ski+Aug 5 2005, 01:21 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Mr. Ski @ Aug 5 2005, 01:21 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-evman150@Aug 5 2005, 08:52 PM
Talk persists about there being a brown dwarf out there in a viciously eccentric orbit with a period of around 30 million years. This would be a companion "star" of the sun and would have caused all of the major extinctions in history.

Sounds like a cool theory... what's the connection though? [/b][/quote]
The Nemesis Hypothesis

[Cube Inmate]

Originally posted by evman150@Aug 5 2005, 02:52 PM
Talk persists about there being a brown dwarf out there in a viciously eccentric orbit with a period of around 30 million years. This would be a companion "star" of the sun and would have caused all of the major extinctions in history.

A brown dwarf is a loosely called a star but it actually just a really big ass planet. An object is a brown dwarf if it is between 0.002 and 0.08 solar masses (Mass of Sun is 2E30kg). Anything bigger than that is a star and anything smaller is a planet/asteroid/comet/whatever.

They are born from the same gravitational collapse and contraction of protostellar nebulae but don't have enough mass to start nuclear reactions in the core. Hence the lack of luminosity.

So the Kuiper Belt could hold more than just a few Pluto size planets/planetessimals.

IIRC, there's still some debate on what to call the super-massive planets found orbiting other stars...between the mass of Jupiter and what's normally called a brown dwarf. It's not a clean division between planet and brown dwarf, because nobody's ever seen these things close enough to know for sure!

As for the companion star of which you speak:

Nemesis

Interesting theory. Pretty tough to prove or disprove though, considering the purported orbital period. Even if you can find a small star within 1-3 light years, it would take some work to determine its velocity precisely enough to say whether it was in orbit or not.

Then again, I ain't an astronomer, and they can do some pretty wacky things.

[evman150]

In the wikipedia entry it says it is likely a red dwarf between 50,000 AU and 100,000AU from the Sun and that it is probably a known star with an unknown distance.

I just don't see how that is possible. A red dwarf has enough intrinsic brightness to be visible by the naked eye on a clear night if it was as close as the entry says.

A red dwarf like Barnard's Star (~2pc away) has an apparent magnitude of 9.56 and therefore an absolute magnitude of about 13. If we assume this "red dwarf" that they say Nemesis is is 50 to 100 thousand AU away, and we assume it to be a similar spectral type to Barnard's Star (M4V), then its visual magnitude will be between 5.0 and 6.5 - visible to the naked eye. And it would have one hell of a parallax angle. It's parallax would be betwen two arcseconds and four arcseconds. Most near stars have a parallax along the order of 0.1-0.3 arcseconds. In other words, relatively speaking, in two different observations of the sky six months apart a 5th or 6th magnitude star would appear to shift positions quite noticably in the sky. Guys like Kepler and Galileo and Brahe would have noticed this.

Obviously this is not the case.

It is very obviously a brown dwarf if it is anything because brown dwarfs are not luminous because they are not fusing hydrogen into helium or helium into carbon or whatever.

And yes there is no "clean division", but the numbers I gave are astronomical guidelines.

[Reggie Dunlop]

Does anyone here still giggle when someone says "Uranus?"

[FireFly]

Originally posted by Reggie Dunlop@Aug 5 2005, 10:35 PM
Does anyone here still giggle when someone says "Uranus?"

I love you man. And I love Uranus too. Yes, I'm drunk. However, I can still spell and punctuate properly.

[Cube Inmate]

Originally posted by FireFly@Aug 6 2005, 12:08 AM
Yes, I'm drunk. However, I can still spell and punctuate properly.

Now there's a girl who could sweep me off my feet.