We live in a spiral galaxy of about 300 billion stars
and is about 100,000 light years across.
what is the driving force behind the spiral galaxy's motion..?
2007-09-05 14:29:38 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
I think it is the "space cleaners"
They thought it best to sweep the galaxy into a heap before shovelling it up and putting it all in the "universal wheelie bin"
2007-09-05 18:14:36 · answer #1 · answered by stephen b 2 · 0⤊ 1⤋
In short it is true it is all down to gravity, even you have gravity, although it be very small, everything from a rock, to a planet attracts each other according to the force of gravity.
If you start from earth, the moon orbits the earth, the earth orbits the sun. All the planets in our solar system orbit the sun and then our sun is also in spinning around the Milky Way.
All of the 300 billion starts you mention are also spinning around the milky way.
Most scientists believe there is a black hole at the centre of the the Milky Way. Black holes do not emit light, it is a massive gravitational force which you can feel its effect but is not visible. It doesn't always have to be a black hole though, consider a dance partner, you stand stationary in the centre of the room and she/he moves towards you with speed and grabs and pulls on your hand, the immediate effect is you'll rotate and if your fast enough you swing around. Now imagine it is not a partner but two planets, or 2 solar system each exerting gravity coming into each others path. You can see how the rotation can come about without the need for a black hole.
2007-09-05 21:59:54 · answer #2 · answered by Bear F 3 · 1⤊ 0⤋
A galaxy only becomes spiral once it passes through another galaxy, before that it is usually kind of sphere shaped. Since there are suddenly more stars than before, some of which are moving in different directions, the gravitational pull of other stars forces them into a spiral shape, which cant be seen until it comes out the other end, back into two separate galaxys.
2007-09-06 05:12:59 · answer #3 · answered by Hehe 2 · 0⤊ 0⤋
The centripetal force required to keep the various stars in orbit is supplied by the bulk mass of our galaxy, possibly with a super-massive black hole at the centre. The mechanism is complicated by a number of factors including the radiation pressure from the stars themselves. So perhaps a 'catherine wheel' firework in slow-mo would be an appropriate image here. Also even taking into account the max poss mass of all the visible matter in most galaxies, there is insufficient gravitational force to account for the average rotational momentum of the stars. Evidence for 'dark matter'? (ie GMm/R^2< mw^2R where w=ang vel, R=rad, M=galactic mass and m= ave stellar mass)
2007-09-05 15:58:58 · answer #4 · answered by azteccameron1 4 · 2⤊ 0⤋
... the force and pressure exerted by the "Big Bang".......
think if you took something and blew it up .... the pieces would be pushed outwards by the force of the expolsion thrusting everything into motion.
time and space are interwined .... like fabric not empty space....... and bend in the presence of matter... warping around the objects...... the existence of gravity is what holds the solar system (and universes) together though the 'space between' certain objects does get slightly further apart.....
Light is the fastest moving force in the universe..... 186,292.397 miles per second. I beleive light helps the expanse of the universe... by travelling through the vaccumn and pushing everything outward. Since space is a vaccum the speed of light does not slow as it does when passing through something. So the two work together to expand the universe.................... i'm pretty certain, but double check.
2007-09-05 18:59:13 · answer #5 · answered by Anonymous · 0⤊ 1⤋
There are two (at least) forces at work. One is that the stars, dust etc want to move at their own speed and in their own direction. But they are captured by the mass of the galaxy and tend to circle around it. That the existing mass already has some rotational component, draws the matter in the same direction. This very simplistic but a general idea of the forces at work.
2007-09-05 14:35:39 · answer #6 · answered by tfloto 6 · 1⤊ 1⤋
We are swirling around and towards the big plughole that is a black hole at the centre of our galaxy. The driving force is gravity and the celestial hand that pulled the plug out.
2007-09-05 16:09:07 · answer #7 · answered by Anonymous · 2⤊ 0⤋
The driving force is the speed of travel given to objects in space by the original Big Bang explosion throwing everything outwards. At least that is the theory.
2007-09-05 15:19:11 · answer #8 · answered by zahbudar 6 · 1⤊ 1⤋
Orbits! Everything in the galaxy is orbiting the center of the galaxy. When doing the calculations, you consider the "center" to be everything that is inside the orbit of the orbiting object. So our Sun is orbiting all the mass that is in the galaxy that is inside the Sun's orbit. Got it?
2007-09-05 14:34:12 · answer #9 · answered by luvlaketahoe 4 · 0⤊ 1⤋
The motion is not a spiral.
That is the shape of the visible star mass.
The motion is almost circular orbiting around
a common center.
2007-09-06 07:44:51 · answer #10 · answered by Irv S 7 · 0⤊ 1⤋