and if yes, how does a spiral galaxy maintain its shape?
or does it?
2007-10-19 15:20:57 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Astronomers have measured the motion of stars in other spiral galaxies, and all of them show something that a few years ago would have been astounding.
The stars in the outer edges of most spiral galaxies orbit at the same speed as the ones close to the centres.
The visible mass of these galaxies isn't enough to cause this.
Common wisdom was that the farther a star was from the galactic centre the slower it moved (like the planets in our solar system - the farther a planet is from the sun the slower it moves).
Additional observations of distant galaxy clusters at a lot of different wavelengths have revealed the presence of what they now call "dark matter". Galaxies and clusters appear to be embedded in huge halos of this dark matter, and the gravitiational force of this matter is what keeps the outer stars orbiting as fast as they do.
And it also appears to keep the spiral galaxies from spinning apart from centrifugal force.
2007-10-19 15:28:01 · answer #1 · answered by Anonymous · 4⤊ 0⤋
404 blunders places a great spin on the the question and he's nice to a component. The palms of a galaxy are locked in line with the galactic midsection,yet a galaxy isn't a satellite tv for pc gadget like a image voltaic gadget. dark be counted exchange into invented to maintain the integrity of a satellite tv for pc gadget that appeared to be in misery. The galactic midsection has each and every of the ingredients to administration a galaxy without dark be counted. A diminishing area is the making use of mechanism,this holds the palms and additionally produces a crimson shift to the gentle emitted by making use of the galaxy. closer to the galactic midsection stellar collisions start to take place and at last attain huge proportions. Stellar collisions any the place else is amazingly unlikely.
2016-11-08 23:39:48 · answer #2 · answered by Anonymous · 0⤊ 0⤋
yes...the shape of the spiral galaxy is consists of millions of stars n so the stars then orbit together in a group causing the shape of spiral to appear!!=]
2007-10-19 16:09:57 · answer #3 · answered by Pye-par 2 · 0⤊ 0⤋
Yes...everything obey's Kepler's Laws. It's this differential rotation that _causes_ a spiral galaxy's shape, just like cream swirling in a coffee cup.
2007-10-19 15:25:31 · answer #4 · answered by GeoffG 7 · 0⤊ 0⤋
No. They all move at about the same speed. They think htat it's due to dark matter interactions, but nobody knows for sure yet.
Doug
2007-10-19 16:08:03 · answer #5 · answered by doug_donaghue 7 · 0⤊ 0⤋
no, they move as if they were a frozen SOLID disk.
2007-10-19 15:39:44 · answer #6 · answered by ------- 2 · 0⤊ 1⤋