Black Holes and Time

originally posted by: kykweer
Hi everyone,

My goal is to set out whether if you pass the event horizon of a black hole does the universe end?

You might find this site interesting:
Journey into a Schwarzschild black hole

you will be torn apart by a black hole approximately a tenth of a second before you hit the singularity, independent of the mass of the black hole.

a reply to: FamCore
Thanks, pretty cool, but difficult to comprehend the way he answered it was similar to how I took on some papers in varsity, give enough information just to get it done so in astrological terms a black hole would die in a puff of dust after emitting most of its energy?

I like this quote on LHC micro black holes:

There is actually experimental evidence that these kinds of black holes could not have gobbled up the Earth - the fact that the Earth has not yet been gobbled up!

What a relief

originally posted by: Saint Exupery

originally posted by: kykweer
Hi everyone,

My goal is to set out whether if you pass the event horizon of a black hole does the universe end?

I've been pondering this for some years (and have posted elsewhere), and I believe the short answer is, yes - As you fall through the event horizon of a black hole, you watch the universe die.

One of the side-effects of this concerns mass distribution in and around a black hole. Generally, it has been assumed that all of the mass will be in the singularity at the heart of a black hole. However, for outside observers, I do not think this would be the case.

As the star collapses, at the moment the density increases to the point where the event horizon forms, the material will be divided into that which is within the event horizon and that which is not. That which is within the event horizon falls into the singularity. For us intrepid observers observing from a safe distance, the collapsing material outside the event horizon cannot (under General Relativity) ever fall through the horizon within the lifetime of the universe. Thus all of the mass of material falling into a black hole would appear to plate itself around the outside of the event horizon. However, observing this monatomic shell would be very difficult, since the light from it would be drastically red-shifted into the far radio spectrum.

Well like I explained, that if escape velocity is equal to the speed of light is equal to eachother then time is infinite, because you cant actually time relative to us inside a black hole.

After thinking about it though maybe time inside the black hole is finate but it is isolated on that specific spot in the universe, so you might not experience the death of the universe as well, you will only experience the birth of that black hole AND the death of it at the same time... how you will conceive that is a whole other story.

For now we can probably assume that IF we actually saw a black hole we would be seeing its birth and only its birth untill we can actually observe the death of a black hole.

originally posted by: lostbook
a reply to: kykweer

I have my own crazy ideas about Black Holes. I think they contain the history of the universe until it gets recycled.

Maybe if a black hole contains all possibilities then it does contain a whole universe as well

a reply to: Soylent Green Is People

The observer outside the black hole will see you approaching the event horizon forever, while from your perspective you fall through it towards the black hole being violently ripped apart

I don't know, well lets assume you survive, and this is one problem I found while reasearching this, given I may have been sloppy, but few people actually question what the person falling in observers of the outside universe.

The rest of the universe must then be changing drastically, at what speeds will you see solar systems rotating and exploding around you. Or do you only see a bright light surrounding you will all the information in the universe from the birth of the black hole till its death bombarding you at the same time... for one of those instants you ARE still at the event horizon so forever and ever there will be a moment in time where you (falling into the black hole) and the observer will stare at each other till the black hole dies.

originally posted by: dragonridr
a reply to: kykweer

Well let me start by saying our view of blackholes had changed a lot with quantum mechanics. The idea of an event horizon is gone. It's been replaced by what's called an apparent horizon. Meanin an area where things are slowed down but this is O KY temporary. Things can indeed escape a black hole it just tends to garbled up the information fitst. For example the beeps from her ship would be redshifed but also intermixed with a lot of other frequencies bouncing around inside. As far as time time can't stop never happen you can't have motion without time. So even in a black hole things will still move in fact falling into a super blackholes you wouldn't even notice. an apparent horizon suspends matter and energy from trying to escape — and when it does escape due to the wild fluctuations within a black hole. Quantum mechanics tells us yes particall can escape

The difficulty is that there is not a lot of consensus on this seeing as its pretty much Hawking vs the rest on the matter, it sounds like an explanation to plug some holes in earlier theories?

However, this idea doesn't seem to address the firewall paradox at all, said Raphael Bousso, a theoretical physicist at the University of California, Berkeley. "It's not possible to have both of those things, to have no drama at the apparent horizon and to have the information come out," Bousso told SPACE.com. "Stephen just doesn't discuss this argument, so it's unclear how he means to address it." Don Page, physicist at the University of Alberta in Canada, agreed. "I do not think that eliminating event horizons by itself solves the firewall problem, which is a subtle problem," he wrote in an email. - See more at: www.space.com...

This is another new theory

Fuzzballs (yes, fuzzballs) are the new black holes Samir Mathur, a professor of physics at The Ohio State University and sole author of the paper, says as you approach the fuzzball, your body will be destroyed but, oddly enough, you will not die. Rather, you'll be transformed into a copy of yourself, in the form of a hologram, that is forever embedded onto the surface of the fuzzball.

www.businessinsider.com...

It is similar to how I feel, from the outside observer you will see the mass of the particles being conserved at the event horizon as it does not disappear.

originally posted by: Rosinitiate
Here's my take.

When dealing with electricity, depending on what you need to power, determines what amperage and/or voltage that device/machine needs.


Think about your home and the electricity it receives in both Amps and Volts (amps being volume and volts being current). When you have a circuit receiving 120v but your device only needs 24v to operate, what you need than is a "step-down" transformer, let's call that the sun. Now conversely, let's say you need to send power a very long distance. To do that you need to "step up" the voltage because you lose it over distance. We shall call that a black hole.

haha I know as little about electricity as I do about Astrophysics.

originally posted by: carewemust
Are there geyser eruptions of material visible which are the output from a black hole that's present in another timeline, or universe? I mean, if something goes in, it comes out someplace...doesn't it?

It has to come out, but it is not only a matter of where, it is also a matter of when. We can only observe 1 timeline (although it technically is in the past) when looking at the center of a galaxy... which we cant even see because its so bright.

I suppose you have gamma ray bursts that expel energy, maybe this is expelled when the BH dies and time goes back to normal?

Pretty good video

originally posted by: Elementalist
I think you have me head spins and I don't like it

For myself personally, I care not of this black hole thing as it doesn't 'matter' (heh) to me regardless.

I'll never see one, experience one, or understand its nature whatever that maybe.

I'm more concerned why someone like yourself, OP, and those other minds alike, spin your minds with this redundant stuff?

I don't mean this in a condescending way, truely I can't understand why it actually means anything to such people, if meaning is even involved with such a mental pursuit.

It's interesting for sure, but to myself, very redundant.

"Black Holes", just are what they are. A galactic construct, a very nature created within the impossible.

It just is! I leave it at that and save the headache, heh.

Cheers

No problem with that, it is about what floats your boat.

I guess my interest (and frustration) was born at the fact that most of what i read and watch, black holes are often viewed in 2 ways. Either it is an outside observer who watches time stand still at the event horizon, or if you pass the event horizon you will be torn apart by gravitational forces etc... very few information or theories exist about what the few of the outside universe is like when you are observing from inside a black hole.

Sure it does not really matter in the bigger scheme of things, but I am already surrounded by other things that influence me directly such as politics that have my interest, but I am just as powerless there as I am in explaining the mysteries of the universe.

originally posted by: Gothmog
Susskind and Hossenfelder have just about laid Hawking's Radiation to rest. The problem that Hawking injected Hawking's Radiation for did not exist in the first place.

And , Einstein added time dilation because he was "stuck" and didnt know what to do . Took him over 2 years to add something he still wasnt sure about.

Thanks Hossenfender gives a pretty good lay explanation of black holes



This appears do raise more questions though, but it does appear to help steer people away from the wrong direction.

originally posted by: wildespace

originally posted by: Soylent Green Is People
a reply to: kykweer
...I mean, when did it happen? It didn't happen during the infinite period that the outside observer was watching. So when?

What am I missing here?

Well, since time is relative to any frame of reference, the infalling person will experience time flowing normally. If they know their distance from the black hole, and that black hole's size, as well as their rate of acceleration towards it, they can calculate the moment they'd be going through the event horizon, just like you'd calculate the moment you'd hit the Earth's atmosphere when reentering from orbit.

I've read that, in reality, the traveller will never see themselves getting "immersed" into the blackness of the event horizon; it will seem to recede in front of them all the way to the singularity. A black hole isn't like a giant drop of ink into which you could dive, it's just a volume of spacetime curved by gravity to an extreme degree.

And to answer the OP, the traveller will see the universe speed up and blue-shift as they approach the event horizon. So yeah, by the strange application of the time-dilation working in the opposite way, the traveller at the event horizon will get blasted by huge amounts of X-rays and gamma rays from all that blue-shifted light coming from the universe, and actually see all of its future history unfold in an instant.

Mind. Blown.

YES

originally posted by: wildespace

originally posted by: Soylent Green Is People
a reply to: kykweer
...I mean, when did it happen? It didn't happen during the infinite period that the outside observer was watching. So when?

What am I missing here?

Well, since time is relative to any frame of reference, the infalling person will experience time flowing normally. If they know their distance from the black hole, and that black hole's size, as well as their rate of acceleration towards it, they can calculate the moment they'd be going through the event horizon, just like you'd calculate the moment you'd hit the Earth's atmosphere when reentering from orbit.

I've read that, in reality, the traveller will never see themselves getting "immersed" into the blackness of the event horizon; it will seem to recede in front of them all the way to the singularity. A black hole isn't like a giant drop of ink into which you could dive, it's just a volume of spacetime curved by gravity to an extreme degree.

And to answer the OP, the traveller will see the universe speed up and blue-shift as they approach the event horizon. So yeah, by the strange application of the time-dilation working in the opposite way, the traveller at the event horizon will get blasted by huge amounts of X-rays and gamma rays from all that blue-shifted light coming from the universe, and actually see all of its future history unfold in an instant.

Mind. Blown.

Quite (the "Mind. Blown." part).

I'm still having an issue with the idea that the traveler (or anything) can actually fall through the event horizon. If the outside observer can watch FOREVER and NEVER see that person or object fall past the event horizon, then when exactly does that person or object fall past the event horizon?

If the answer is "never", then does any additional mass actually ever make it past the event horizon? How does a black hole gain mass?

originally posted by: Soylent Green Is People
If the answer is "never", then does any additional mass actually ever make it past the event horizon? How does a black hole gain mass?

Ah, but the question "when?" doesn't quite work the way you'd think it would when Relativism is concerned. Things that happen simultaneously as seen from one frame of reference, will appear to happen at separate times from a different frame of reference. en.wikipedia.org...

Thus, it's perfectly valid to say that the external observer will never see event whereas the person participating in the event will see it happen.

a reply to: wildespace

I get that time dilation would make time move a different speeds for different points of view, but what I can't grasp is if the BH traveler really does (at some point during his perception of the passage of time) cross past the event horizon, then why can't the outside observer, who is watching forever, ever see that happening?

I mean, forever is a long time

originally posted by: Soylent Green Is People
a reply to: wildespace

I get that time dilation would make time move a different speeds for different points of view, but what I can't grasp is if the BH traveler really does (at some point during his perception of the passage of time) cross past the event horizon, then why can't the outside observer, who is watching forever, ever see that happening?

I mean, forever is a long time

But since time has been stretched infinitely long, the event can never be observed happen. It's like trying to get to the end of an infinitely long corridor. For an outsider, time at the event horizon slows down to a halt.

originally posted by: wildespace

originally posted by: Soylent Green Is People
a reply to: wildespace

I get that time dilation would make time move a different speeds for different points of view, but what I can't grasp is if the BH traveler really does (at some point during his perception of the passage of time) cross past the event horizon, then why can't the outside observer, who is watching forever, ever see that happening?

I mean, forever is a long time

But since time has been stretched infinitely long, the event can never be observed happen. It's like trying to get to the end of an infinitely long corridor. For an outsider, time at the event horizon slows down to a halt.

But is there a point in time that the black hole traveler (or any matter) "experiences" crossing that event horizon -- i.e., does the traveler ever experience getting to "the end of the corridor"?

originally posted by: Soylent Green Is People

originally posted by: wildespace

originally posted by: Soylent Green Is People
a reply to: wildespace

I get that time dilation would make time move a different speeds for different points of view, but what I can't grasp is if the BH traveler really does (at some point during his perception of the passage of time) cross past the event horizon, then why can't the outside observer, who is watching forever, ever see that happening?

I mean, forever is a long time

But since time has been stretched infinitely long, the event can never be observed happen. It's like trying to get to the end of an infinitely long corridor. For an outsider, time at the event horizon slows down to a halt.

But is there a point in time that the black hole traveler (or any matter) "experiences" crossing that event horizon -- i.e., does the traveler ever experience getting to "the end of the corridor"?

Yes, for the traveller the corridor is normal length.. I'm puzzled as to how you can't grasp this notion. For the traveller, time procedes normally, but for an outside observer, the black hole stretched time to infinity.

originally posted by: wildespace

originally posted by: Soylent Green Is People

originally posted by: wildespace

originally posted by: Soylent Green Is People
a reply to: wildespace

I get that time dilation would make time move a different speeds for different points of view, but what I can't grasp is if the BH traveler really does (at some point during his perception of the passage of time) cross past the event horizon, then why can't the outside observer, who is watching forever, ever see that happening?

I mean, forever is a long time

But since time has been stretched infinitely long, the event can never be observed happen. It's like trying to get to the end of an infinitely long corridor. For an outsider, time at the event horizon slows down to a halt.

But is there a point in time that the black hole traveler (or any matter) "experiences" crossing that event horizon -- i.e., does the traveler ever experience getting to "the end of the corridor"?

Yes, for the traveller the corridor is normal length.. I'm puzzled as to how you can't grasp this notion. For the traveller, time procedes normally, but for an outside observer, the black hole stretched time to infinity.

So if an event (such as crossing that threshold demarking the event horizon) happens for the traveler, then it is an event that happens; the event has an end that the traveler can point to AFTER THE EVENT HAPPENED and say "yep -- that event happened to me".

If it is an event that happens (and there was a time "after" the event), then that means it happens during a finite time. If it happens during a finite time, then why can't the outside observer (who is watching for an infinite amount of time) ever see that happening? The outside observer is watching the entire life of that black hole during the black hole's entire existence, so you would think that they would know everything that ever happens with that black hole.

My logic tells me that if the outside observer can see the entire life of the black hole until the black hole ceases to exist, then they would see the moment in time that the traveler crosses the event horizon -- because that is an event that happens (and the fact that it happens is proven by the fact that the traveler experiences it happening). I understand that my logic is probably wrong, but I just don't get why.


I can reconcile this with my logic this way (sort of):

Perhaps the event does not "happen" (end) in a finite amount of time, and an infinite amount of time outside the black hole passes before the traveler actually falls into the event horizon. If that's the implication, then suppose that means that the traveler's experience is actually happening forever (literally). It takes forever (from my outside point of view) for the traveler to cross the event horizon ("forever" meaning it NEVER happens for me) but from the traveler's point of view, it DOES happen.

But aren't we both experiencing the same "forever", but from different points of view? If so, why does his forever seem different than mine? In his forever (which happens in a normal amount of time to him), he crosses the event horizon, but in my forever he doesn't...

...and that's the part I can't wrap my head around.

a reply to: Soylent Green Is People

In case my post above was tl;dr , here it is in a nutshell:

If events in the universe are unfolding from two different points of view, both points of view are watching those same events unfold, albeit the time it takes for that those events to unfold may differ.

But even if the time differs from the two viewpoints (when observing each others viewpoint), it still seems to me the events that unfold for each viewpoint should not differ. If the traveler experiences crossing the event horizon and can look back at the event and know it happened in his recent past, then it seems the outside observer should be able to know (eventually) that it happened, too.