Register to reply

Is the Milky Way galactic blackhole slowly sucking us in?

by arabianights
Tags: blackhole, galactic, milky, slowly, sucking
Share this thread:
arabianights
#1
Dec14-11, 04:46 PM
P: 25
with the newest discovery of biggest black holes in the universe, i suddenly had this weird thought: what if they're a draining hole of the galaxy, the spiraled arms and the shape, all looks awfully similar to a whirlpool, with black holes at the center of nearly all galaxies
Phys.Org News Partner Science news on Phys.org
Bees able to spot which flowers offer best rewards before landing
Classic Lewis Carroll character inspires new ecological model
When cooperation counts: Researchers find sperm benefit from grouping together in mice
Drakkith
#2
Dec14-11, 04:57 PM
Mentor
Drakkith's Avatar
P: 11,596
Don't be afraid, this is NOT how black holes work. They are not literal "holes" in space that devour everything nearby. A black hole of 2 times the mass of the sun behaves EXACTLY like a normal star of that mass as long as objects stay outside a distance equal to the radius of the normal star.

For example, if the radius of the star was 1 million km, then as long as you stayed at a distance of at least 1 million km from an equal mass black hole, the gravitational pull is exactly the same. It is only once you get closer to the black hole that the gravity increases, since it is compacted into a much smaller volume of space.

If you compressed the Earth to 1/2 it's size, it would have no impact on how the Moon orbited, but the surface gravity would be somewhere on the order of 4 times as much as it is now. Make sense?
nhmllr
#3
Dec14-11, 07:08 PM
P: 184
Black holes aren't cosmic vacuums. If a black hole the mass of the Sun (which wouldn't normally occur in nature, but can in principal) were to replace the Sun, we would continue to orbit around it at the same rate. This back hole is really heavy, but REALLY far away.

Don't lose sleep over it.

nitsuj
#4
Dec14-11, 09:06 PM
P: 1,097
Is the Milky Way galactic blackhole slowly sucking us in?

Quote Quote by Drakkith View Post

.... if the radius of the star was 1 million km, then as long as you stayed at a distance of at least 1 million km from an equal mass black hole, the gravitational pull is exactly the same. It is only once you get closer to the black hole that the gravity increases, since it is compacted into a much smaller volume of space.

If you compressed the Earth to 1/2 it's size, it would have no impact on how the Moon orbited, but the surface gravity would be somewhere on the order of 4 times as much as it is now. Make sense?
Awesome example of gravity. Imo as easy to absorb as the "rubber sheet" analogy, but much much more descriptive of the physics.


Register to reply

Related Discussions
When I was little I loved thumb sucking. It was so comforting. But, General Discussion 17
Can a blackhole suck in another blackhole? Astronomy & Astrophysics 50
Scientists sue to stop 'black hole' from sucking up Earth General Discussion 2
What happens when an anitmatter blackhole collides with a matter blackhole? Astronomy & Astrophysics 6
Sucking water from vacuum! Introductory Physics Homework 9