The Dedly Blog

So long, Pluto

The Pluto haters have won. It's now a "dwarf planet", along with everything else that's been discovered beyond its orbit in recent years. Ceres still makes out as its being upgraded from asteroid to dwarf planet.

I'm wondering if the Pluto-is-not-a-planet crowd did it because they're worried that they've run out of names or because they fear having too many planets will make their heads hurt. Well, the protests will certainly make their heads hurt and they'll have to hear this all over again in 2015 when we get our first close up of Pluto.

Astronomers have known for years that Neptune has a bit of a wobble to its motion around the sun. It's been hypothesized that there must be a massive object out there causing it to happen. Pluto and Charon are too small to cause this effect. This leaves open the possiblity of a mysterious "Planet X" floating out in the Kuiper Belt. But if astronomers find it, will they call it a planet or something else?

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DED

posted by DED at 12:06 PM

 Alan P. said...

I always get disoriented when I think about the solar system. If we are in the Milky Way galaxy then how did they get the pictures of it I saw in grade school? Is the plane of the solar system in line with the plane of the galaxy? If not, why aren't we getting smacked more often by stuff passing through? Worse, what if we collide with a black hole or some of this "dark matter" the scientists keep talking about? Maybe we are part of a binary star system and don't even know it. Could the sun have a dark, evil twin?

8/25/2006 7:32 PM

 DED said...

What type of picture of the Milky Way did you see? Edge on or a view of the whole thing, like Andromeda and other spiral galaxies? If it was the whole spiral, then it had to be an illustration. We haven't sent out anything far enough to take a picture. If it was edge on, then you were just looking from within. Like someone standing on your liver and looking down through the intestines. Not the greatest analogy, sorry.

Yes, the plane of the solar system lies within the galaxy.

We generally don't get smacked with stuff bcause galaxies are mostly empty space, like the atom. You have to remember that galaxies are typically hundreds of thousands, if not millions, of light years wide.

If we collide with a black hole, unless it's a theoretical microscopic one, then we're all dead. The black hole's gravity would tear our planet to shreds. But don't worry about it. You're more likely to die from an asteroid impact.

"Dark matter" is the theoretical stuff of the universe that makes up the "missing mass." From what we can see out there, the universe doesn't have enough mass to it to hold it together. So scientists dubbed this missing mass that isn't visible to us, "dark matter". As astronomers use other parts of the spectrum (IR, UV, radio, x-ray) they've been able to see the universe in, literally, a completely different light. But the problem of dark matter is far from solved. Don't worry about colliding with it. If it was big enough to hurt us, we'd see it.

No, we're not part of a binary star system. The sun can't have a darker twin. The gravitational pull of said invisible twin would clearly be noticeable on our bright yellow friend. :)

\_/
DED

8/29/2006 10:14 AM

 Alan P. said...

I say if it is round, and it goes 'round, it's a planet. [/silly]

8/30/2006 10:59 AM