I was reading a book, that said that the center of a galaxy might be a black hole. But wouldnt that mean that we're movin closer to the core? So when we take measurements of how far away the next galaxy is it would look like its getting farther, when we're just going closer to the center.
Also if the galaxy is spinning, then wouldn't that also contribute to things lookin farther away over time? Because it would look like the other galaxys are movin away when the galaxy turns and our earth moves to the other side of the galaxy.
Or did they take this all into account when they made up the thoery that the universe was expanding?
2007-09-23 03:27:05 · 11 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
I think that you are picturing the black hole in the center of our galaxy as a vacuum that continues to suck in everything around it so you imagine that our galaxy should be shrinking in. You should, however, imagine a black hole like a hole. Only when something goes near it and goes beyhond a certain point, the event horizon, it is sucked in.
2007-09-23 07:57:26 · answer #1 · answered by azianshrimp 2 · 1⤊ 1⤋
1. The black hole at the center of our galaxy has essentially no effect on the Sun's orbit. It is too small and too far away. The Sun's orbit is determined by the collective mass of the entire galaxy, of which the central black hole comprises about 1%.
2. We are in a (very roughly) circular orbit around the galaxy; we are not falling in.
3. The orbit has no significant effect on what we see through telescopes. It takes 100 million years to go around, so waiting until the "earth moves to the other side of the galaxy" would be an extremely long time.
4. We do not say the universe is expanding because we look at a galaxy, and then look again a little while later and see that it is farther. We directly measure its recession the first time using Doppler shift. Distance is extremely difficult to measure, but velocity is easy. And yes, when we make these measurements, we correct for the Sun's motion around the galaxy.
2007-09-23 10:49:29 · answer #2 · answered by ZikZak 6 · 4⤊ 0⤋
We didn't 'make up a theory' that the universe is expanding. It is based on decades of direct observation. It's a fact.
The universe is expanding - but the galaxy is not. The space between galaxies is expanding, but the local gravitational forces within a galaxy keep it from expanding. Imagine putting stickers on a balloon and then blowing it up. The stickers move away from each other as the balloon expands, but they don't get bigger.
No, we've accounted for the fact that galaxies are spinning. It's quite easy to observe using the Doppler effect.
2007-09-23 10:39:55 · answer #3 · answered by eri 7 · 3⤊ 0⤋
they say it is expanding somewhere in the order of about 1,000,000 mph. and that it is speeding up.they know this by looking at the light spectrum , it works like the doppler effect . Things moving away from us go toward the red end and things moving closer are toward the blue end.They do see shifts of this effect as the earth orbits the sun effectively changing direction.The same effect would be true as we orbit the galaxy.There is a theory that the center of the galaxy is a massive black hole , something like 300,000,000 solor masses - they see this in other galaxies as well.They can tell this by observing stars orbiting the center and calculating the mass from that motion
2007-09-23 11:03:25 · answer #4 · answered by lmndrp44 3 · 1⤊ 1⤋
Yes the Universe is expanding. It has been doing it for 15 billion years.
Our solar system orbits the Milky Way galaxy, once every 250,000,000 years.
2007-09-23 11:19:59 · answer #5 · answered by Anonymous · 1⤊ 0⤋
our universe it's expanding and we are getting further of the center of our universe and we are probably getting closer to our galaxy center. i mean you know that our sun it's relove around our galactic center --->
(2.2 x 10 exp 8 years ) so it could exist an orbit tat it's getting closer or further.
but that we are getting closer to a black hole it's a little strange because in a galaxy center they aren't too much posibilities that could exist a black hole because that galaxy it wouldn't exist at the moment XD .
ja ne ^^
2007-09-23 10:52:43 · answer #6 · answered by Anonymous · 1⤊ 1⤋
you ever hear of the big bang? basically the effects of it caused everything in the universe to be pushed outward away from the center of the universe that force is still pushing us outwards today. The only thing keeping us toward the center is gravity which the farther outward us and everyone else travels the less force it has to pull us inward. Meaning that as we continue to get farther from the center of the universe we are actually accelerating away from it.
The universe is really complicated and we haven't proven for sure what's going on to date.
2007-09-23 10:38:51 · answer #7 · answered by icpooreman 6 · 2⤊ 2⤋
Yes.The universe is expanding.
Edwin Hubble,famous American astronomer,discovered it
in 1924.
The galaxy is also spinning.A spin is completed every
200 million years.
2007-09-23 14:28:37 · answer #8 · answered by najj 2 · 0⤊ 0⤋
If the Galaxy has a black Hole(a singularity at its center)then the Universe should be imploding(contrating) and not expanding(exploding out).
However if the Universe is expanding it could always use more room.
Nevertheless, If the Universe is finite then it cannot expand beyond those limits of constrains in its contaiment.
2007-09-23 10:42:52 · answer #9 · answered by goring 6 · 1⤊ 4⤋
yes there is a black hole in every galaxy watch the latest video here in this link: *watch the episode on super massive black holes.*
http://www.tv-links.co.uk/listings/9/4657
it is very interesting.
2007-09-23 13:10:09 · answer #10 · answered by ★→Damian←★ 4 · 1⤊ 0⤋