10 January 2006

Milky Way Warped

We all knew everything was warped, but now we've got some proof, according to a press release from a group at the yearly American Astronomical Society meeting. It always amuses me how early January there's a rash of astronomy articles after or during the conference.

One mode is like a bowl, with the galactic plane bending up all around; another is like a saddle, and the third is like the brim of a fedora hat, bent up in the back and down in the front, Blitz said at a briefing.

The various modes of warping correlate closely with the orbit of two satellite galaxies, known as the Large and Small Magellanic Clouds, that make a looping orbit around the Milky Way. As they go, they plow through a halo of dark matter that encircles the Milky Way, scientists said at a meeting of the American Astronomical Society.
Scientists have known about the Milky Way's warped nature for half a century, but they never knew the cause. The Magellanic Clouds were previously dismissed as suspects because they lacked the mass to influence our galaxy in their 1.5 billion year trip around it.

While the Magellanic Clouds' mass is small, they pass through the dark matter like ships going through an ocean, creating a cosmic wake powerful enough to make our galaxy bend and flap, Blitz said.


So the LMC and SMC aren't directly disturbing the gas disk that is warped, but they're disturbing the dark matter, which in turn affects everything else. I find that to be really elegant, as it is yet another example of how direct evidence isn't required, only indirect evidence and a solid chain of logic, just as with evolution. :)

I gave a talk for 7th graders lately about galaxies. This would've been nice info for the talk, if there were any pictures. One kid asked me, after I mentioned the Big Bang, what existed before the Universe. I at first took it as a creationist argument, but then I realized he probably just really wanted to know. My personal theory is that logarithmic time is more important than linear time, so there wasn't ever a "before," or even a time 0. I'm slightly on the fringe though, and I know it, and I'm definitely not a cosmologist (hence my calling it a "belief" and not even a "hypothesis"). They'd tell you that either there was nothing, or a previous universe, or maybe multiple hyper-universes (branes) collided to create our universe. But, and here's the key thing, we've got no way of knowing currently, so it's still just theory hypothetical, just math, all of which I told the student, and he seemed quite interested.


Candace said...

I love your mind, Z. I especially love that you're influencing kids with your sense and brilliance. They so need that in this repressive climate. Rock on.

zandperl said...

Thanks Candace! :) Hm, technically I misspoke in my original post - scientific speculation about what was before the Big Bang is actually still hypothetical. To be called a "theory," we need supporting evidence. :-P

Kavin Watson said...

I was really touched by your post. I think it's extremely important to get children interested in science. The number of those graduating with degrees in the scientific disciplines in America are dropping compared with the rest of the world. It's people like you who really help scientific awareness in this country. Without you we'd have a lot more ignorance in this country.

Candace said...

Z, I have a question for ya, and, like the 7th grader you mention, I just really would like to know. We hear about the "life force." Is it a force, like gravity? What is it? Do we know? Whatever it is, it's impressive! We keep finding life in the most unexpected places (and will continue to do so on other planets and moons, I'm sure.) Oh, and um, I'm not even sure what a "force" is, either. I'd love to see what you have to say about this!

zandperl said...


Good question! The word "force" as used in common English isn't the same as the science/physics word force. Scientifically, there is no such thing as a "life force." There are four major forces: gravity, electromagnetism, strong nuclear force, and weak nuclear force.

Gravity is that everything with mass attracts everything else with mass, though it gets weaker the further away you go. You and your fridge gravitationally attract each other, but less so than you and the Earth. Electromagnetism (E&M) is everything having to do with both electricity and charges (current, molecular bonds) and magnetism (Earth's magnetic field, compasses). E&M is actually the real force we experience when we touch a surface with our hands. The strong and weak nuclear forces have to do with nuclear reactions, like fission and fusion.

The closest we get to a "life force" in science would be the guiding power of natural selection and evolution, in which every individual struggles to survive and subsequently the species improves.

Candace said...

Thank you! "Life force," then, is more poetical than scientific.
I'm wondering what to call "it" that "causes" or makes possible cell division. Germination of a seed does a something to the seed (or the DNA inside) to make it start growing into whatever it is programmed to become. I'm thinking of that something as a life force.