Black Holes What are they?

[Dave]

Nice explanation.

[7hor]

Sorry if I'm posting in the wrong place...very noob =P

 

Anyways, saw a tv show about supernovas, hypernovas, and black holes, and it talked about "jet streams" that can shoot out of black holes. I've just been curious about what exactly it is and how it happens, couldn't find a clear explanation for my small little mind. Also, will all black holes have them? Thanks

[admiral_ju00]

you sure they said 'jet streams can be shot out from black holes'?

other bodies(example: Sun) can and do, do it, but not black holes.

[PerpetualYnquisitive]

Anyways, saw a tv show about supernovas, hypernovas, and black holes, and it talked about "jet streams" that can shoot out of black holes. I've just been curious about what exactly it is and how it happens, couldn't find a clear explanation for my small little mind. Also, will all black holes have them? Thanks

 

Seems to me that you want information on Pair-ElectroMagnetic pulses or Gamma-Ray bursts that may eminate from black holes, can't say that I have ever heard the term ' jet streams' used for either of these phenomenons before though.

 

BTW these bursts are considered more deadly than a meteor impact as direct exposure would annihilate ALL known life in the solar system.

 

Try doing a search for PEM + black holes or GRB + black holes.

[admiral_ju00]

found something of interest. but even this does not say that jet streams can shoot out of the black hole. merely, they 'think' these jet streams can be caused by black holes. big difference from the coming out of, obviously.

 

There was also a recent discovery of a black hole merger in a distant galaxy though this was discovered by observing the jet streams caused by the black holes. You should note that those results are still preliminary and unconfirmed.

 

and

 

The strange shape could be mostly a function of the shape of the host galaxy. For example, such X-shaped jets appear only in highly elliptical galaxies.

 

and finally, a linky.......

 

http://edition.cnn.com/2002/TECH/space/08/29/black.holes/

 

PY, your search parameters, yield the same info.

[Aeschylus]

The high energy streams that come from supermassive black holes which are active galactic nuclei come from their accretion disc (i.e. the matter outside the event horizon).

[PerpetualYnquisitive]

A team of astronomers have found a colossal black hole so ancient, they're not sure how it had enough time to grow to its current size, about 10 billion times the mass of the Sun.

 

Sitting at the heart of a distant galaxy, the black hole appears to be about 12.7 billion years old, which means it formed just one billion years after the universe began and is one of the oldest supermassive black holes ever known.

 

The black hole, researchers said, is big enough to hold 1,000 of our own Solar Systems and weighs about as much as all the stars in the Milky Way.

 

"The universe was awfully young at the time this was formed," said astronomer Roger Romani, a Stanford University associate professor whose team found the object. "It's a bit of a challenge to understand how this black hole got enough mass to reach its size."

 

Full article: http://www.space.com/scienceastronomy/heavy_blazar_040628.html

[[Tycho?]]

A team of astronomers have found a colossal black hole so ancient' date=' they're not sure how it had enough time to grow to its current size, about 10 billion times the mass of the Sun.

 

Sitting at the heart of a distant galaxy, the black hole appears to be about 12.7 billion years old, which means it formed just one billion years after the universe began and is one of the oldest supermassive black holes ever known.

 

The black hole, researchers said, is big enough to hold 1,000 of our own Solar Systems and weighs about as much as all the stars in the Milky Way.

 

"The universe was awfully young at the time this was formed," said astronomer Roger Romani, a Stanford University associate professor whose team found the object. "It's a bit of a challenge to understand how this black hole got enough mass to reach its size."

 

Full article: http://www.space.com/scienceastronomy/heavy_blazar_040628.html[/quote']

 

 

 

That is a big black hole.

[Martin]

'']That is a big black hole.

 

it is indeed, if it is as old as they say: 12.7 billion years

(only had a billion years to accumulate)

 

for some masses to compare with

I happened to find this----dates from 2002 and

last modified 2004, so it isnt obsolete information

http://curious.astro.cornell.edu/milkyway.php

 

says estimated mass of milkyway is a trillion solar masses

and the mass of the visible stars is roughly a tenth of that

that is the mass in stars is roughly 100 billion solar masses

(but I have also heard 200)

 

the rest of the mass of the MW would be gas, dust, dark matter

we also have a black hole at center of MW but it is only some 10 million

solar masses IIRC. It has been observed swallowing stuff and stars swinging fast around it. But unless stuff just happens to be falling in you cant see it. Anyway it is small: a few million solar masses.

 

so the puzzle here is they have found a youngish hole with a mass

of 10 billion.

it is not a real difficult paradox but it does make you wonder how such a size

hole could accumulate so fast.

[Martin]

it is indeed, if it is as old as they say: 12.7 billion years

(only had a billion years to accumulate)

 

.

 

the popularization article refers to this technical article by Romani and others:

http://arxiv.org/abs/astro-ph/0406252

 

this is what was just published in Astrophysical J. Letters

 

it says the redshift is z = 5.47

 

this is not the highest redshift for a galaxy

a team in france has observed a galaxy with redshift z = 10

that would be even farther and older

and just as massive

BUT it is not a black hole

[Sayonara]

Doesn't the latest information put the age of the universe at 14.5 and not 13.5 BY?

[JaKiri]

Doesn't the latest information put the age of the universe at 14.5 and not 13.5 BY?

 

Perhaps it just aged a lot between the two measurements.

[Martin]

the popularization article refers to this technical article by Romani and others:

http://arxiv.org/abs/astro-ph/0406252

 

this is what was just published in Astrophysical J. Letters

 

it says the redshift is z = 5.47

 

 

just to check the popular article quoted here, I used Siobahn's calculator and it said indeed the signal we are getting from the black hole is 12.7 billion years old and that the black hole was 1.06 billion years from the beginning

 

http://www.earth.uni.edu/~morgan/ajjar/Cosmology/cosmos.html

 

I just put z = 5.47 into the calculator

(also H = 71, and Omega = 0.27, and Lambda = 0.73, which are the latest parameters i've seen)

 

Sayonara I have not seen any new estimates which would lead to an age of the universe like you say.

Everybody is using the WMAP data, that I know of, that came out this year and it leads to age-estimate of 13.7 billion years.

 

If you see that other estimate on the web somewhere, please give us a link! It would be very surprising and I would like to see it.

[Martin]

Perhaps it just aged a lot between the two measurements.

 

actually I just checked at Ned Wright's site

he has something on latest research he calls "News of the Universe"

 

http://www.astro.ucla.edu/~wright/cosmolog.htm#News

 

which I see he has updated as recently as 22 June

but he is still going with the estimate of 13.7 billion years

that actually came out last year

 

I dont think there'v been any more recent measurements that challenge

this, but if anyone finds any please report them!

anything more reliable and accurate than the WMAP (wilkinson microwave anisotropy probe) would be a welcome surprise

[DarthDooku]

About an hour ago i was watching The Science Channel. I just found out about it tonight. It seems they have programs about space every Tuesday at 8pm. I havent had a chance to look it up on the net, so i dont know anything about the channel. In New Jersey its on channel 72 or something.

 

Anyway, they were talking about black holes for a while, until they went into the eventual collision of our galaxy with another. It was really interesting. Now, there explanation on what a black hole is, was pretty simple. When a star collapses, it turns into a tiny particle of dust. But this tiny particle contains all the mass off the star. So you have a tiny particle of dust that has an enormous mass. With this enormous mass comes an enormous amount of gravity. The gravity is so strong that it sucks everything into it. As it sucks in, the tiny particle gets bigger, making the black hole bigger and its gravity. It said that if a person was sucked in, he would explode, or be torn apart into millions of atoms.

 

Im not sure if i explained everything exactly right, but thats pretty much what i remember. So to me, it seems that a black hole is just a tiny piece of matter, that has an enormous mass condensed into it. The gravity sucks stuff in, making it bigger.

 

As for a black hole being a doorway to a wormhole or some way to travel through time, i would have to say no. I would say a black hole is just a piece of dust with a powerful field of gravity. When something goes into it, it gets torn apart into atoms and is collected into the original piece of dust, adding to the growth of the black hole.

 

Whats really amazing about a black hole is how a huge star can collapse on itself and create a tiny piece of dust, with all the mass and more, that the original star possessed. Imagine if we could discover and harness the power and process that caused this. We could turn the worlds biggest landfills into a marble.

[[Tycho?]]

About an hour ago i was watching The Science Channel. I just found out about it tonight. It seems they have programs about space every Tuesday at 8pm. I havent had a chance to look it up on the net' date=' so i dont know anything about the channel. In New Jersey its on channel 72 or something.

 

Anyway, they were talking about black holes for a while, until they went into the eventual collision of our galaxy with another. It was really interesting. Now, there explanation on what a black hole is, was pretty simple. When a star collapses, it turns into a tiny particle of dust. But this tiny particle contains all the mass off the star. So you have a tiny particle of dust that has an enormous mass. With this enormous mass comes an enormous amount of gravity. The gravity is so strong that it sucks everything into it. As it sucks in, the tiny particle gets bigger, making the black hole bigger and its gravity. It said that if a person was sucked in, he would explode, or be torn apart into millions of atoms.

 

Im not sure if i explained everything exactly right, but thats pretty much what i remember. So to me, it seems that a black hole is just a tiny piece of matter, that has an enormous mass condensed into it. The gravity sucks stuff in, making it bigger.

 

As for a black hole being a doorway to a wormhole or some way to travel through time, i would have to say no. I would say a black hole is just a piece of dust with a powerful field of gravity. When something goes into it, it gets torn apart into atoms and is collected into the original piece of dust, adding to the growth of the black hole.

 

Whats really amazing about a black hole is how a huge star can collapse on itself and create a tiny piece of dust, with all the mass and more, that the original star possessed. Imagine if we could discover and harness the power and process that caused this. We could turn the worlds biggest landfills into a marble.[/quote']

 

 

Umm, you are off on a few parts here. A black hole is not a particle of dust, it collapses into a point of zero volume. Zero, it doesn't have a size, so its not like a grain of sand, its not even like an atom or a single proton, its a geometric point with infinite density. It does however have an event horizon, the point at which nothing can escape. This event horizon has bigger than zero size, and will indeed grow as more mass is put in, as gravity would then increase.

 

You say : "a huge star can collapse on itself and create a tiny piece of dust, with all the mass and more" its all the mass of the star, not more. No mass is added, unless something else happens to fall into it. And as for harnessing the power that does it, well, its all gravity, pure and simple.

 

And wormholes and possibilites for time travel have been theorized with black holes that are rotating, and have instead of being a point are a ring. So, maybe possible, but this could easily be proved wrong and really its anybody's guess if its possible or not. But you were right, you certianly wouldn't be going anywhere by just falling into a black hole, no sir.

[ed84c]

simple answer to your question READ BLACK HOLES A TRAVELLERS GUIDE, if there is a simpler way about explaining black holes i would like to hear it.

[ed84c]

500 years ago, everyone didn't believe the world was unflat challenged. There were still people. (and other beings we don't account for) who believed the world was roundish.

 

People didnt actually think the world was flat at all, its an urban myth. One american journalist suggested it was, and people mostly think that people at that time believed it was, they thought it was round like the rest of us, otherwise wouldnt chris columbus and magellan think against sailing off? And why did a ship's sail apear before the rest of it?. Infact [l] gallileo [/i] proved the world was round.

 

Anyway so u dont get misinformed about extra-universal travel regarding black holes, remember space time is not ripped, that is a mathmaticians expression and is not real!, I have seen many people make that mistake before. It is just like any other star except is infinately dence and possibley spining or charged (all though if a black hole 'has no hair' and therefore no charged particles I dont see how it can be). However much I would like it to be; a black hole isnt quantised either. Its density has no value it is infinite so bear that in mind as well.

[Martin]

... However much I would like it to be; a black hole isnt quantised either. Its density has no value it is infinite so bear that in mind as well.

 

Martin Bojowald (Berlin) is preparing to quantize the standard black hole model and get rid of the infinite density business. (but he and colleagues have not accomplished this yet, as you point out it is not yet done)

 

His track record is good, in 2001 Bojowald quantized the big bang singularity and got rid of the infinite density there, his 2001 paper

was "Absence of singularity in Loop Quantum Cosmology"

 

the work has been confirmed and extended by a lot of other people by now----a recent paper (with references to earlier work) is online

http://arxiv.org/gr-qc/0407074

 

Bojowald's two most recent papers were setting up the machinery to quantize gravity in the context of black holes. You can find them online at arxiv.org. Or if you want ask me and I can easily get the links.

[Martin]

People didnt actually think the world was flat at all, its an urban myth...

 

Right, many of the classical mediterannean people were well aware of earth being round and the greek mathematician Eratosthenes even calculated its circumference---and got the right answer within a few percent (if one allows for the weird oldfashione units of measurement he used).

 

Dante was circa 1300, that is before Galileo (circa 1600) and Dante was merely a poet---but he used a spherical Earth, not a flat one, in his poem.

 

Round earth has been a normal view for literate people since at least as far back as 200 BC (Archimedes, Eratosthenes time) in the Mediterranean and European cultures------about other places like Chinese and Mayan and Hindu and Inca and all that stuff I do not know maybe they also had round earth concept.

 

Even Snorri the Icelander who wrote around 1200 referred to the "circle" of the earth, but those vikings up there were just barely literate so it is hard to be sure about what they thought.

 

Tho far from being an expert in history and such questions, I strongly agree with you Mr. Ed 84, that it is a big mistake to suppose old people all thought earth was flat. (but some old maps look as if it was flat or maybe just a patch on a sphere, not the whole ball)

[ed84c]

thankyou, it is a rarety that people agree with me

[JaKiri]

thankyou, it is a rarety that people agree with me

 

Except you're wrong, the 'flat earth' 'theory' was widespread in historical times; look at the 'standard' model of the heavens and the earth, with water above and below.

[ydoaPs]

It depends on when you are talking about. The Greeks and Romans knew it. The Europeans didn't until they rediscovered the ancient classical Greek and Roman text.

[unknow force]

I think that the russians calls that stuffs like cold stars???, so the black hole is an black body, that gravitional distortion sucks the space???, there theorys about other universes inside the cold stars (i like that name) in fact this universe could be an cold star, but thats only speculation (like almost all the cosmology), the nature of the black hole depends if the universe is an open or close thermodynamical system????, the cold stars born in the big bang or in nova-gigant stars collapse????

[ydoaPs]

cosmology is speculation?