If the center of our galaxy is a black hole, does that mean we can never go to another galaxy?

Question

If we are past the event horizon, which we probably are (our galaxy just isn't that big), then we can never escape the gravitational force of the black hole. It seems logical that not only can we never leave our galaxy, but signals sent out will never leave, and no one outside our galaxy would ever see us. Even light gets sucked into a black hole.

Answer 1

It is only inside the event horizon that the gravity of a black hole is inescapable. Gravity decreases rapidly according to the inverse square law (it is the inverse of the square of the distance from the black hole). If you are far enough outside the event horizon, the gravity of a black hole is indeed escapable. And the gravity of the hole is limited by the mass, which Chandra proved had an upper limit. In other words, it's not like the hole just keeps getting more massive as it sucks in other stuff. It gives off a special kind of radiation by creating pairs of particles from the quantum "foam" (Higgs field) near the event horizon. The negative mass half of the pair falls back into the black hole and reduces its mass, while the positive mass part is allowed to exist outside the hole (I am not sure how -- but I suspect it leaves at a very high velocity, given the kind of radiation seen around neutron stars). This is so-called Hawking radiation (first theorized by Stephen Hawking).

That's all I know, and I am sure some of it is wrong. You might check out Hawking's book, Black Holes and Baby Universes.

Answer 2

1. The approximate circumference of the central black hole is probably less than a light-year. Our star is at least 10,000 ly away. Thus the central black hole is subsumed in the total mass of the galaxy.
2. Since we would be heading out from our galaxy, the central black hole should have no effect other than contributing to the general galactic gravitational field and that contribution will still be a meager one.
3. As pointed out earlier, the escape velocity at our location within the galaxy is about 0.004c. So it is physically possible to escape. However, our current technology makes it massively difficult to achieve that speed. We would need a major breakthrough in propulsion science to achieve that velocity.
4. Even if we could get to, say, 0.01c, unless life-extension technology advanced way beyond what we have now, there is no way currently for humans to leave the galaxy. 0.01c gets you to Alpha Centauri in about 430 years if you don't plan on stopping. Considering that the human longevity record is on the order of 110 years, welll....

Answer 3

Of course we are past the event horizon of the supermassive blackhole in the center of the galaxy. There are plenty of other black holes around as well - and we're not in their event horizons either.

Yes, we CAN get away from it. The further you are from a massive object, the smaller it's gravitational pull is. The way you're talking, it sounds like you think every probe we send up gets sucked in. Not true. It wouldn't take much to overcome the pull from the galactic center out here - we're pretty far away from it already. It will not impede our leaving the galaxy, if we ever progress that far.

Answer 4

The force from the 3 million solar mass black hole is just a tiny fraction of the force we feel from the trillion other stars in the Milky Way galaxy. The event horizon of the 3 million mass black hole is about the size of the orbit of Venus. A lightyear away from that Black Hole, you would not be able to distinguish its gravitational pull from that of a very dense star cluster with 3 million stars in it.

Answer 5

Well, we already dified the black hole, the sunlight reaches Earth without being sucked away. Plus, if the all powerful black hole was there than, we would be sucked towards it and eventually swallowed up, right? If not, than why would it affect a small space ship or message when it can't even pull the Earth into it as big as the Earth is?

Answer 6

impossible. A universe present interior a black hollow might have distorted mild waves, the solar may be set out of order, and our galaxy may be offset inflicting temperature transformations too dramatic to proceed helping life in the international. Time might additionally be affected and can ought to continuously as much as date via differentiations in the revolutions and orbits of the earth's circulation. I even have heard yet am no longer specific that still, matter can not exist in a black hollow which might mean we could no longer exist in a black hollow. exciting theory although.

Answer 7

No.

A black hole is simply a quantity of mass that is so dense that it's escape speed is the speed of light. This is bad news for objects that are very close to the black hole (especially if they are inside the "event horizon", the distance at which even light can not move outwards).

However, from a distance, it is for us simply a mass that counts in the total mass of the Galaxy. We would have to count it (as well as the rest of the mass in the Galaxy) when we figure out the speed we need to reach another galaxy.

From our position, the Galactic escape speed is much less than the speed of light (we are well outside the event horizon of our Galaxy's black hole -- tens of light-years outside -- no problemo).

According to Wiki, the Galactic escape speed, at our position, is approximately 1,000 km/s. In comparison, speed of light is close to 300,000 km/s. We only need to go at 0.4% the speed of light to escape to another galaxy.

Of course, we'd want to go faster, if only to get there sooner...
At 0.4% of speed of light, we'd need over 600 million years to get to Andromeda galaxy.

Answer 8

Yes, but how do you know that you are in a black hole, though? Wouldn't everything get sucked up already?

Answer 9

No, you are wrong.