Ten things you don’t know about the Milky Way Galaxy

[laconicsax]

[div class="excerpt" style="border-left: 1px solid #bfbfbf; border-top: 1px solid #bfbfbf; border-right: 1px solid #bfbfbf; border-radius: 0.3077em 0.3077em 0em 0em; box-shadow: 2px 2px 6px #bfbfbf;"]Ten things you don’t know about the Milky Way Galaxy[div class="excerpt" style="border-left: 1px solid #bfbfbf; border-bottom: 1px solid #bfbfbf; border-right: 1px solid #bfbfbf; border-radius: 0em 0em 0.3077em 0.3077em; background-color: #f4f4f4; box-shadow: 2px 2px 6px #bfbfbf;"]So you’ve lived here all your life — in fact, everyone has — but what do you really know about the Milky Way galaxy? Sure, you know it’s a spiral, and it’s 100,000 light years across. And of course, BABloggees are smarter, more well-read, and better looking than the average population, but be honest: do you know all ten of these things? Really?

Liar.

So let’s see if these really are Ten Things You Don’t Know About the Milky Way Galaxy.

...

8) Spiral arms are an illusion.

Well, they’re not an illusion per se, but the number of stars in the spiral arms of our galaxy isn’t really very different than the number between the arms! The arms are like cosmic traffic jams, regions where the local density is enhanced. Like a traffic jam on a highway, cars enter and leave the jam, but the jam itself stays. The arms have stars entering and leaving, but the arms themselves persist (that’s why they don’t wind up like twine on a spindle).

Just like on highways, too, there are fender benders. Giant gas clouds can collide in the arms, which makes them collapse and form stars. The vast majority of these stars are faint, low mass, and very long-lived, so they eventually wander out of the arms. But some rare stars are very massive, hot, and bright, and they illuminate the surrounding gas. These stars don’t live very long, and they die (bang!) before they can move out of the arms. Since the gas clouds in the arms light up this way, it makes the spiral arms more obvious.

We see the arms because the light is better there, not because that’s where all the stars are.
Read the whole piece here: http://blogs.discovermagazine.com/badastronomy/2008/03/12/ten-things-you-dont-know-about-the-milky-way-galaxy/

[Gore1FL]

1. Sigh: I knew all of those things. But still a fun read. Thanks! n/t

[Phoonzang]

3. 95 percent of people don't even know what a galaxy is

or that we're in one. Even otherwise intelligent, and educated people. It's depressing.

[Gore1FL]

4. That is a sad truth! n/t

[Ratty]

5. I knew most of them

Didn't know about the warping. Also I thought Andromeda was bigger than us. I guess that's true in a way, but it's less massive which I didn't know.

[Gore1FL]

6. I hang on every word of Neil deGrasse Tyson.

I watch every video and am hoping to finish every book the guy writes.

[longship]

2. R&K for the Bad Astronomer

Phil Plait is doing great things to bring science, and yes especially astronomy, to the public's mind. If you're not yet a big fan of Dr. Plait you should pick up a copy of his book, Death from the Skies! These are the ways the world will end.

As you can tell I'm a big fan.

[HopeHoops]

7. And the NUMBER ONE thing you don't know about the Milky Way... It is actually made of milk.

[laconicsax]

8. Oh, pshaw. Everyone knows that.

How else could the moon be made of cheese?

[HopeHoops]

9. Exactly.