Black Holes

cheerfulgreek · #1 05-20-2008, 11:36 AM

Quote:

Originally Posted by RU OX Alum

do you think it would be possible to travel through them? Do they go some place? Or is it just a collection of collapsed gasses that are breaking down, and isn't really a "hole" in that sense.

I don't know that much about them. I do know they move through space though. Right now I don't think it would be possible to travel through one, because we would be stretched and ripped apart, atom by atom.

Well, it really is a hole in space. Gas clouds that collapse under gravity form a star, but if the gas cloud falls too quickly into the star that was created, it creates some sort of shock wave that heats the star, which causes it to expand. The gas envelope traps the heat and squeezes the star making it even hotter. Like I was saying earlier, I think the extreme heat causes some kind of reaction inside the star, and then it starts to cool down. I guess I star needs heat in order to keep from falling in on itself because of the extreme gravity. I think once it cools down to the point where it can't resist the gravity, it collapses in on itself which forms into a small black hole from the start. It only gets larger by consuming gas and other objects around it. If two black holes collide then the new black hole becomes one huge behemoth.

What I don't understand is what's the difference between a black hole star and a star? I guess if our Sun were to die, it would expand, and then turn into a white dwarf star and die. I don't know if it would form a black hole or not.

RU OX Alum · #2 05-20-2008, 11:53 AM

I've wondered about that too. Our Sun being a black hole that is.

This is very intriqueing to me, because I always imagined space to be empty, i.e. the Hole would be made of the same nothing as the space that surouned it.

Tom Earp · #3 05-20-2008, 02:27 PM

I think a black hole is an absorbtion of all in its path!

Like a big vacum sweeper, oops, it is sucked in and gone!

cheerfulgreek · #4 05-21-2008, 07:39 AM

Quote:

Originally Posted by Tom Earp

I think a black hole is an absorbtion of all in its path!

Like a big vacum sweeper, oops, it is sucked in and gone!

Black holes are just regions of space where the gravity is so high that it causes space and time to curve back on itself taking any and all exits with it. In other words no escape.

Another way to look at it is all objects have escape speeds. For example let's say Earth's escape speed is 100 mph, then to escape Earth's gravity an object would have to travel faster than 100 mph to leave the planet entirely. The difference between a black hole and Earth is, a black hole doesn't have any escape speeds. Not even the speed of light can escape.

Tom Earp · #5 05-21-2008, 03:30 PM

Quote:

Originally Posted by cheerfulgreek

Black holes are just regions of space where the gravity is so high that it causes space and time to curve back on itself taking any and all exits with it. In other words no escape.

Another way to look at it is all objects have escape speeds. For example let's say Earth's escape speed is 100 mph, then to escape Earth's gravity an object would have to travel faster than 100 mph to leave the planet entirely. The difference between a black hole and Earth is, a black hole doesn't have any escape speeds. Not even the speed of light can escape.

Wow, I am impressed! So a Black Hole is just a sponge but on a bigger level!

It is not a slingshot to the future is it!

DaemonSeid · #6 05-21-2008, 03:38 PM

Initially, I read the title and was expecting porn...o well...AHEM

errrmmm...yeah... so...black holes...won't be a problem in our puny lifetime

cheerfulgreek · #7 05-21-2008, 06:38 PM

Quote:

Originally Posted by DaemonSeid

Initially, I read the title and was expecting porn...o well...AHEM

omg!! lol lol lol lol

I guess it depends on how you want to look at it.

cheerfulgreek · #8 05-21-2008, 06:35 PM

Quote:

Originally Posted by Tom Earp

Wow, I am impressed! So a Black Hole is just a sponge but on a bigger level!

It is not a slingshot to the future is it!

lol. I don't know Tom. I guess if you want to look at it that way. I always thought sponges did more of an absorbing thing, where as black holes routinely dine upon wayward stars and unsuspecting gas clouds in a different way. A sponge is a great comparisson though.

With black holes, as a cloud approaches it, it hardly ever falls straight in, like water absorbing into a sponge. A gas cloud is typically drawn into orbit before it spirals into the hole. When I took physics we had to learn a bunch of terms and one of them was "Differential Rotation". In this case, if the laws of physics apply to black holes which I'm guessing they do, the parts of the cloud that are closer to the black hole will orbit faster than the parts that are farther away.

Is it a slingshot to the future? I don't know. I've heard that they could be time warps. We would never know, unless we can develop some kind of machine that can withstand being ripped to shreads by its strong gravity.

Tom Earp · #9 05-21-2008, 05:07 PM

Quote:

Originally Posted by DSTCHAOS

hehe

Not as far as they can tell but how would they know that? That's food for thought. Hmmm.

True that!

But there are not ETs or UFOs either.

epchick · #10 05-20-2008, 03:18 PM

Quote:

Originally Posted by cheerfulgreek

What I don't understand is what's the difference between a black hole star and a star? I guess if our Sun were to die, it would expand, and then turn into a white dwarf star and die. I don't know if it would form a black hole or not.

According to the shows on the Discovery Channel that i've watched, then yes our sun would become a black hole. Once our sun exploded it would start to form a small black hole. As the black hole continues to suck everything in to its center it would get bigger.

Quote:

I wonder what kind of effects it would have on Earth and our solar system if a huge one developed within our galaxy or slightly outside of our galaxy. I wonder if we would be able to see it with the naked eye?

If I remember the show correctly, we wouldn't be able to see the black hole w/ our naked eye, but the flares that shoot off from teh center would be able to be seen (depending on how far away our Earth is from the black hole). Our Earth would eventually be sucked into the outskirts of the black hole.

Also on this episode, scientists said that a black hole in our galaxy is going to form as well as a bigger black hole in Andromeda (the galaxy closest to ours). Since our galaxies are moving closer to each other, the black holes would attract each other until Andromeda's black holes consumes ours making a giant black hole (i believe they had a special name for it, but i dont remember) and then our galaxies would crash and it would creat one big galaxy.

AKA_Monet · #11 05-20-2008, 07:24 PM

What makes me confused is the difference with a galaxy, quasars and solar system.

I have seen bunches of stars in a telescope together in one part of our galaxy, the Milky Way. Then I have seen stars of many colors. I have seen the gas rings and dot on Jupiter and I have seen the general Milky Way clouds at night at Mauna Loa.

What is amazing about all of this is they astrophysicists think big, and the microscopists think small...

There are also "white holes"... Don't ask me how to calculate their existence--but they do exist--at least mathematically.

cheerfulgreek · #12 05-21-2008, 08:22 AM

Quote:

Originally Posted by AKA_Monet

What makes me confused is the difference with a galaxy, quasars and solar system.

There are also "white holes"... Don't ask me how to calculate their existence--but they do exist--at least mathematically.

Good question. I guess a galaxy would represent the whole thing, in regards to the planets and the solar system itself. I think quasars are apart of new galaxies that are really far away from us. I've read that we can see the light from them, but since it takes so many light years to reach us it's billions of years old by then, and a solar system is a system of planets and a sun(s). I say sun(s), because who knows, some solar systems could have two suns.

I've heard that white holes are the opposite of black holes. Don't they push matter out rather than taking it in? Maybe white holes are on the other side of black holes.

cheerfulgreek · #13 05-21-2008, 08:01 AM

Quote:

Originally Posted by epchick

According to the shows on the Discovery Channel that i've watched, then yes our sun would become a black hole. Once our sun exploded it would start to form a small black hole. As the black hole continues to suck everything in to its center it would get bigger.

If I remember the show correctly, we wouldn't be able to see the black hole w/ our naked eye, but the flares that shoot off from teh center would be able to be seen (depending on how far away our Earth is from the black hole). Our Earth would eventually be sucked into the outskirts of the black hole.

Also on this episode, scientists said that a black hole in our galaxy is going to form as well as a bigger black hole in Andromeda (the galaxy closest to ours). Since our galaxies are moving closer to each other, the black holes would attract each other until Andromeda's black holes consumes ours making a giant black hole (i believe they had a special name for it, but i dont remember) and then our galaxies would crash and it would creat one big galaxy.

This is really good. I always wondered if we would be able to see it from here. I've heard about two different studies on the sun. I heard that it would form a black hole too, but I also heard that it would just turn into a white dwarf. It is true that not every star forms into a black hole though. I just don't know how scientist know which ones are, and which ones are not.

Yep, this is so true. As a black hole eats, it's diameter grows in direct proportion to it's mass. So, for this reason they can be almost any size, but not all of them will spaghettify you before you cross the event horizon.

Did you ever have physics in undergrad? If you did, do you remember Tidal Force? It's kind of related to black holes I guess. I would think the smaller black holes would really do most of the ripping apart, because the tidal force would seem to be greater if the size of the object going in is large compared with the distance to the center of the object. Like for example. Let's say a 6 foot man falls feet 1st toward a 6 foot black hole (this is just an example not real size), then at the event horizon, his head is twice as far away from the black hole's center as his feet. Here, the difference in the force of gravity from his feet to his head would be pretty large...wouldn't it? But let's say the hole were 6,000 feet across, then wouldn't the same guy's feet be only 1/10th of 1% closer to the center than his head? I'm thinking the difference in gravity (the tidal force) would be correspondingly small..wouldn't it?

I dunno. It just seems logical.

epchick · #14 05-21-2008, 04:07 PM

Quote:

Originally Posted by cheerfulgreek

This is really good. I always wondered if we would be able to see it from here. I've heard about two different studies on the sun. I heard that it would form a black hole too, but I also heard that it would just turn into a white dwarf. It is true that not every star forms into a black hole though. I just don't know how scientist know which ones are, and which ones are not.

Wouldn't a dwarf star eventually turn into a black hole? Ehhh who knows, i'm not a scientist.

No I didn't take physics, I dropped it after like the 2nd day cause i didn't wanna be a biology major anymore.

cheerfulgreek · #15 05-21-2008, 06:59 PM

Quote:

Originally Posted by epchick

Wouldn't a dwarf star eventually turn into a black hole? Ehhh who knows, i'm not a scientist.

No I didn't take physics, I dropped it after like the 2nd day cause i didn't wanna be a biology major anymore.

Not necessarily. A white dwarf is the final phase in the evolution of stars like our Sun. They go through what scientist call the Red Giant phase before they turn into a dwarf star. If our Sun were to turn into a black hole, Earth along with Mercury, Venus and possibly Mars would be toast during the Red Giant phase, long before a black hole develops. They only form black holes if they collapse in on themselves from heat leaving the star. As the star cools, it gradually becomes more dense, until eventually when the core is around the size of Earth, some kind of chemical electron reaction takes place. I'm not sure what kind but it's something to that effect. Anyway, when this takes place, in some stars the pressure prevents the electrons from getting too close together which prevents any further collapse. If it doesn't turn into a black hole it just won't give off anymore energy.

Lucky you. I had a dual major. Zoology and biology with a minor in chemistry. Unfortunately physics was required for me. I hated it.

What you said about Andromeda M31 was right on though.