Mastermold Posted February 1, 2003 Posted February 1, 2003 Seriously, black holes are the coolest things out there. Basically, a little background before my question, a black hole is a body of matter that has an escape speed greater than light speed, which means that not even light can escape. And usually these are formed from stars too massive to go nova, and instead collapse on themselves and more and more gravitational force propagates from all of the mass, until it is so massive that a black hole forms. And escape speed is just the speed necessary to completely escape the gravitational pull of a body.. such as Earth, which has an escape velocity of 11km/s. An escape speed is proportional to a body's mass divided by its volume. So if you could throw a ball straight up with an initial velocity of 11km/s, then it would continue upward forever, until is encounters another gravitational body.. of hits the international space station. (Bush would say, "We have no doubt Al Quieda was involved and have decided to bomb Russia, because they might be there.") Talk about off-topic! Anyway, with all of that knowledge of black holes.. my questions are: If black holes exist, then won't ALL matter eventually enter existing black holes because nothing can be travelling at the speed of light? (What a dismal future!) I mean, technically we are all just orbitting black holes then... similar to our galaxy's contents that are orbitting the black hole in the center. And second, if our universe has a certain amount of mass (which has been roughly estimated), and a certain volume (which is infinitely large) the escape speed would be a number less than the speed of light... but how is that possible considering we are all trapped by the pull of black holes? In other words, you cannot escape a black hole, but the same equation says that you CAN escape the universe??? Is the equation for escape speed wrong? Any other ideas?
Mastermold Posted February 1, 2003 Author Posted February 1, 2003 And just one thing to comment on how cool black holes are... we did a Physics problem where you have the calculate the force on one person's head if they are near a black hole... and you basically calculate that the force would rip them in half.. hahaha:)
PogoC7 Posted February 1, 2003 Posted February 1, 2003 http://www.scienceforums.net/forums/showthread.php?s=&threadid=546&highlight=Black+holes Good thread about black hole.
Piccolo Posted February 2, 2003 Posted February 2, 2003 I heard that their was a black hole forming near us isthat true? and if it is What could happen?
PogoC7 Posted February 2, 2003 Posted February 2, 2003 It is believed that there is a Black Hole in the center of our galaxy. Only thing is the Black hole isn't active (eating) at this point. The think it is just off now and my become active again. This was thought to be true until good proof came: http://story.news.yahoo.com/news?tmpl=story&u=/nm/20030107/od_nm/space_hole_dc_2 Super-massive Black Hole. Good artical.
Piccolo Posted February 2, 2003 Posted February 2, 2003 What if it became active could it mean the end for us? Is there nothing that could withstandthe power of the blackhole?
PogoC7 Posted February 2, 2003 Posted February 2, 2003 If it became active, Im not sure what would happen. I think wouldn't be able to tell. If the galaxy moved faster our solar system would still be routating around the sun. But the question, "How long until it ate us"? Don't know that etheir, but I doubt it would be less then half a million years.
fafalone Posted February 2, 2003 Posted February 2, 2003 The influence of gravity decreases proportional to distance; most objects are so far away from black holes that their velocity makes the pull of a black hole negligible. (Why doesn't the moon crash into Earth because of Earth's gravitational field? same thing.)
PogoC7 Posted February 2, 2003 Posted February 2, 2003 Plus, if we are expanding. We must be getting farther away from this Black Hole.
Piccolo Posted February 2, 2003 Posted February 2, 2003 Does anyone know what could be on the other side of ablack hole?
PogoC7 Posted February 3, 2003 Posted February 3, 2003 We don't know much about Black Holes. We only know about them by studying what happens around them.
Piccolo Posted February 3, 2003 Posted February 3, 2003 Maybe there is nothing on the other side of the black hole. Maybe their is adifferent dimention on the other side like the old scify tv show sliders.:scratch:
Mastermold Posted February 3, 2003 Author Posted February 3, 2003 Two things I just have to reply to... first it is a misconception to think of a black hole as "sucking us in," because as Fafalone explained, it is just a super dense area of gravity, so we are always being pulled in.. but we are orbitting the body. The only reason we orbit is because of the black hole's pull. You need to understand centripetal acceleration to really grasp it, but basically we are going in circles because we are being accelerated toward the center. If you shoot water through a curved hose, the water comes out in a straight line, it does not curve all the way in circles as it's falling to the ground. It must have a centripetal force applied to change direction into a circular path. When you spin something around your head on the end of a string.. you must continually pull on the string to keep it moving. Same situation in the way the moon orbits us, we orbit the sun, the galaxy's contents orbit the black hole... etc. Note: (For the true Physicist out there, let me just mention that the centripetal 'force' is not ACTUALLY a force, it is simply the component of the force that is perpendicular to the diretion of the velocity. I lost major points on a test for that.. and it is important to note... I didn't want to get yelled out if anyone noticed.)
Mastermold Posted February 3, 2003 Author Posted February 3, 2003 The other thing is, black holes do not have 'another end' because they are a point singularity... a super massive area that does not allow even light to escape its gravity. Now, it is possible, but not known, if the singularity creates some sort of 'tunnel' (like a wormhole) because of the power of such a singularity. Physicists do not know enough about the medium of the Universe to understand the nature of the interaction.. and what it would do to the 'fabric' of space.
Guest malco94 Posted March 2, 2003 Posted March 2, 2003 Mastermold, I think the reason that we are not all pulled in by Black Holes is because of inflation.
Radical Edward Posted March 2, 2003 Posted March 2, 2003 try not to focus too much on the word 'hole' as a hole implies that it goes somewhere... a black hole does not have to go anywhere.
fafalone Posted March 2, 2003 Posted March 2, 2003 You don't know where it goes, it's not impossible that it goes somewhere.
Radical Edward Posted March 2, 2003 Posted March 2, 2003 I am just saying it does not have to. the concept of 'hole' isn't really an accurate one due to the limitations of language in this respect.
Guest malco94 Posted March 7, 2003 Posted March 7, 2003 Radical Edward, What exactly do you mean? I thoughtthat since a "black hole" is infinitely dense it rips a hole in space-time. This is where the theory of wormholes comes from. Imagine the universe like a pulled out blanket, when you drop objects onto it it creates sort of craters, isn't this the effect of gravity?
Radical Edward Posted March 24, 2003 Posted March 24, 2003 the wormhole thing is a topological argument like bending a rubber sheet over, poking a hole in it, and then connecting it to the sheet underneath. the same can also be done for a 3D space bent in 4D. my point was that the hole doesn't nescessarily go anywhere, though in fact, it does. it ends at the singularity.
atinymonkey Posted March 24, 2003 Posted March 24, 2003 It's more like a black inverted sphere. Not really that catchy a title I suppose.
fafalone Posted March 24, 2003 Posted March 24, 2003 Originally posted by Radical Edward the wormhole thing is a topological argument like bending a rubber sheet over, poking a hole in it, and then connecting it to the sheet underneath. the same can also be done for a 3D space bent in 4D. my point was that the hole doesn't nescessarily go anywhere, though in fact, it does. it ends at the singularity. If the universe is indeed shaped like a doughnut, could it emerge at another point? I don't think we know enough to say it ends at the singularity, because we lack the laws to explain the workings of physics on that scale.
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