Would crossing the event horizon of a black hole be instantly fatal?

[pantheory]

.....I've heard several times that if a person were to fall into a supermassive black hole, that they would survive quite comfortably for a while even after they've crossed the event horizon due to the lack of significant tidal forces. But there's one thing I don't understand. From what I've read about black holes, the event horizon is the absolute point of no return; it's the point at which outward movement becomes impossible....

I've read such things also. But you probably realize that ideas of what is happening near, at, or inside a black hole's event horizon is theory at best, and often just speculation. Near the event horizon where a accretion disc and torus can be observed, speeds can approach 10% the speed of light by observational calculations. It is thought by many or most theorists that at these speed within a torus that molecular and atomic ionization will first occur. Following this friction would bring about molecular disintegration. Following this the resultant atoms would probably remain ionized and the tidal forces at or inside the event horizon are thought to be able to cause spaghettification, being the linear stripping of atoms down to primarily nuclei and electrons (pasma). In active galaxy nuclei (AGN) of galactic black holes, even the atomic nuclei could be further fissioned down by the heat and compression into the lightest nuclei providing the energy for polar galactic jets in such galaxies. This is one proposed model. There are few theoretically passive models like the one you read, to my recollection, that would allow a passive transition of a spaceship, for instance, through the event horizon unscathed.

//

Edited April 19, 2012 by pantheory

[MigL]

There seems to be some confusing of the event horizon with the possible singularity as Penrose diagrams

for spinning black holes may allow passage from one 'universe' to another without exceeding the speed of

light. The 'theory' of black holes is just normal GR, which works quite well for all space=time except at the

possible singularity. Arguments made against black hole 'theory' are arguments against GR, which by 2019

will have a century of verified predictions... Hardly speculation !!!

 

I repeat, read Kip Thorne's book, It is easy enough to follow and will settle a lot of this discussion.

He is , along with Hawking and Penrose, one of the world's leading experts on black hole theory.

 

You may continue your arguments with him if you so wish.

[John Baskin]

The force would stretch and crush the persons body if they were to enter the event horizion

[imatfaal]

John - locally the event horizon is not that special. Additionally for a very large black hole the gravitational gradient and tidal forces would not be quite as extreme as often expected. I included a link in a post above to a calculation one of our posters made in another thread

[pantheory]

eh no... there is evidence.. for super massive... super dense things.. which are dark.

 

THAT.. DOES NOT PROVE THEY ARE HOLES IN SPACE... it does not... not prove black holes exist as proposed.

 

For you to say it does, is nothing but an assumption YOU HAVE BEEN TAUGHT.

IF YOU BELIEVE THINGS... just because others tell you its true... YOU GET MISLED.

 

Sorry.

There is more that one model for black holes. The most accepted definition of a black hole is a small volume where gravity is so strong that matter or light cannot escape from it or pass through it, and therefore it would appear as a black hole in space.

 

The most common definition: A region of space having a gravitational field so intense that no matter or radiation can escape.

 

A mathematical model of a singularity is only one of the hypothetical models concerning a black hole. Dense conventional matter is another model concerning galactic black holes. A third model is a very dense volume of matter like a theoretical neutron star or another more dense form of matter. Some have proposed quark stars, graviton black holes, Higg's black holes, dark matter black holes, and the list goes on.

 

The point is that there is almost a mountain of observational evidence to support the concept of a black hole of stellar size and central galactic black holes of some kind

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Edited May 3, 2012 by pantheory

[space noob]

It depends on whether you could survive being crushed, I don't think survival is likely, or better put, I don't think it's even possible, the black hole would contain so much mass that anything anyone in the universe could create a craft strong enough to withstand that amount of pressure, black holes destroy stars, stars contain unbelievable amounts of energy that we could never even begin to recreate, I think I read that it was something like 1,000,000 nukes per second, it could possibly be more, if a star can't push against the pressure from the black hole and defeat it by exerting more energy than the black hole could crush then I don't think anything could, the black hole at the centre of our galaxy is about the swallow many stars and gas clouds, however some energy will escape but it would not have passed through the event horizon at this point, the black hole in the centre of the milky way is a super massive black hole, we can't compare this to the standard black hole, for the record for someone who said black holes are dark things in space, your wrong, black holes are actually the brightest objects in space, their unbelievable mass can pull in light

[zapatos]

It depends on whether you could survive being crushed, I don't think survival is likely, or better put, I don't think it's even possible, the black hole would contain so much mass that anything anyone in the universe could create a craft strong enough to withstand that amount of pressure, black holes destroy stars, stars contain unbelievable amounts of energy that we could never even begin to recreate, I think I read that it was something like 1,000,000 nukes per second, it could possibly be more, if a star can't push against the pressure from the black hole and defeat it by exerting more energy than the black hole could crush then I don't think anything could, the black hole at the centre of our galaxy is about the swallow many stars and gas clouds, however some energy will escape but it would not have passed through the event horizon at this point, the black hole in the centre of the milky way is a super massive black hole, we can't compare this to the standard black hole, for the record for someone who said black holes are dark things in space, your wrong, black holes are actually the brightest objects in space, their unbelievable mass can pull in light

Can you expand on this please?

[Airbrush]

If you are in free fall through the event horizon of a massive black hole like the ones found in the centres of galaxies, your body and space ship would undergo the same acceleration until very close to the possible singularity, well inside the event horizon.

 

I thought I heard that matter falling into any-sized black hole will be accelerated at light speed (or very near light speed), after crossing the event horizon, towards the singularity. Extreme acceleration would begin far outside the event horizon of any-sized black hole. This acceleration would be so extreme that you would be dead before you crossed the event horizon of any-sized black hole, including supermassive ones.

 

How long would a spaceship survive after getting caught by a supermassive black hole, when the escape velocity exceeds the spaceships top speed? I think the time would be very tiny.

Edited May 8, 2012 by Airbrush

[space noob]

Can you expand on this please?

 

Straight off a website

 

 the material closest to the event horizon hits other materials so often that there is a great deal of friction, and with friction comes heat. The hottest parts of the disk can become really hot, millions of degrees hot. Until all of the material heats up into a plasma which forms a second superheated ring inside the accretion disk. This plasma disk, being so hot, is also very bright because when objects heat up they give off light.

 

As well as being powerful, they are bright. In fact these kinds of black holes, active black holes, are the brightest continuously emitting objects in the whole universe. So there you go, the brightest things in the universes are black holes. That greatly confuses and pleases me, the perfect case of not judging a book by its cover.

[zapatos]

Straight off a website

 

 the material closest to the event horizon hits other materials so often that there is a great deal of friction, and with friction comes heat. The hottest parts of the disk can become really hot, millions of degrees hot. Until all of the material heats up into a plasma which forms a second superheated ring inside the accretion disk. This plasma disk, being so hot, is also very bright because when objects heat up they give off light.

 

As well as being powerful, they are bright. In fact these kinds of black holes, active black holes, are the brightest continuously emitting objects in the whole universe. So there you go, the brightest things in the universes are black holes. That greatly confuses and pleases me, the perfect case of not judging a book by its cover.

Can you please provide a link to that website? It sounds like you are describing a quasar.

[Airbrush]

Can you please provide a link to that website? It sounds like you are describing a quasar.

 

That is obviously a quasar, which is a supermassive black hole that is active.

[MigL]

Given a gravitating mass and a radius you should be able to determine the acceleration due to gravity, Airbrush. Its simple Newtonian gravity and it does not change as you approach, reach or pass through the event horizon. Work it out for youself, I believe the absent DrR worked it out in another thread.

 

The energy to accelerate a given mass is supplied by the gravitating body ( conservation laws remember ? ). The infinite energy needed to accelerate a body with mass to light speed would have to be supplied by an infinite sized black hole. Do you see where your argument falls apart ?

 

 

[zapatos]

That is obviously a quasar, which is a supermassive black hole that is active.

I thought a quasar was a galaxy or galaxy core that was active. I know a black hole is involved with quasars but I thought quasars were outside the accretion disk. Is that incorrect?

[space noob]

Can you please provide a link to that website? It sounds like you are describing a quasar.

 

http://mostodd.wordpress.com/2011/04/30/bright-black-holes/

 

This website does mention quasars but speaks over all of the black hole, the next is from Stanford university,

 

http://oso.stanford.edu/lectures/73-black-holes-the-brightest-objects-in-the-universe

 

Information about a lecture

 

The next is from NASA

 

http://science.nasa.gov/science-news/science-at-nasa/2000/ast15may_1m/

 

please forgive me for not using links, I only use my smart phone now instead of a computer, I didn't know how to copy and paste URL's

 

i'm 20 but I didn't get into my gadgets like the rest of my generation

Edited May 8, 2012 by space noob

[zapatos]

http://mostodd.wordpress.com/2011/04/30/bright-black-holes/

 

This website does mention quasars but speaks over all of the black hole, the next is from Stanford university,

 

http://oso.stanford.edu/lectures/73-black-holes-the-brightest-objects-in-the-universe

 

Information about a lecture

 

The next is from NASA

 

http://science.nasa.gov/science-news/science-at-nasa/2000/ast15may_1m/

 

please forgive me for not using links, I only use my smart phone now instead of a computer, I didn't know how to copy and paste URL's

 

i'm 20 but I didn't get into my gadgets like the rest of my generation

Cool. I didn't know black holes were described that way. Now I need to do more research to try to understand these active black holes versus quasars. They sound very similar. Unless of course they are the same event just described two different ways.

[Airbrush]

I thought a quasar was a galaxy or galaxy core that was active. I know a black hole is involved with quasars but I thought quasars were outside the accretion disk. Is that incorrect?

 

A quasar is the bright result of a supermassive black hole at the center of an active galaxy. A quasar is a kind of active galactic nucleus.

 

http://en.wikipedia.org/wiki/Active_galactic_nucleus

[space noob]

A quasar is the bright result of a supermassive black hole at the center of an active galaxy. A quasar is a kind of active galactic nucleus.

http://en.wikipedia.org/wiki/Active_galactic_nucleus

 

galaxy core that is active or an active galaxy nucleus, pretty close nevertheless,

I don't think that the black hole is part of the quasar though, the black hole is said to power the quasar and even bring the quasar into being

[Airbrush]

galaxy core that is active or an active galaxy nucleus, pretty close nevertheless,

I don't think that the black hole is part of the quasar though, the black hole is said to power the quasar and even bring the quasar into being

 

A quasar is the energy output of an active supermasssive black hole. How is a black hole not part of a quasar? The power souce is the black hole, which is feeding on gas, dust, and other stars. After it gobbles up all matter in the vicinity, it goes black and silent.

 

Here is my question, do all quasars have polar jets?

Edited May 9, 2012 by Airbrush

[MigL]

The quasar IS the black hole's polar jets.

Only 'active' black holes have accretion discs, which is mass spiralling and infalling along the black hole's plane of rotation. This superheated ionized plasma generates elecromagnetic radiation, usually very energetic gamma rays, at angles perpendicular to the plane of rotation ( along spin axis ). Galactic core black holes, when active, generate tremendous amounts of energy by this method, rivalling the intensity of billions of stars and outshining galaxies. Active galactic cores were more common billions of yrs ago, they have mostly settled down in current times.

Neutron stars have similar effects, but because of the lower energies involved, produce x-ray polar jets and we call them pulsars.

Edited May 9, 2012 by MigL