Escape Velocity From A Black Hole

Joe,

When you get back, let us know how it was.

186,282,000.1 miles per second. That's all you need.

Speed of light is supposed to be exactly 1,86,282 miles, 698 yards, 2 feet, and 5²¹⁄₁₂₇ inches per second in vaccum.

So you need 1,86,282 miles, 698 yards, 2 feet and 5 ^{21.00000...001}/₁₂₇ inches per second to escape.

But there is a flaw. Near the black hole the time space continuum is curved, so the above calculation will not hold good.

Let us wait for some one to escape and then we will ask him/it.

DVader listening? respond.

Hyperspace travel is basically traveling through the space-time continuum, so I'm not sure if it actually qualifies as faster-than-light travel, even though for all intents and purposes it works out to be the same.

The one everyone should really be asking is Vulcan; he's an intellectual, whereas I'm a warrior.

c= 299792458.0000000... m/s exactly. It is the only physical constant which is a whole number. (in meters per second)

Hi NSS, you pondered: "How could the big bang even explode and spew all this matter out when it would have to exceed the speed of light by and incredible amount? Yes? No?

Hmmmm?"

Good question. Next... :)

The current state of thinking is that something called 'inflation' caused space itself to expand ('explode'), taking whatever matter/energy there was with it. The matter did not have to move through space at all, so no problem with superluminal travel.

At about 400 thousand years after the BB, the present observable cosmos was still expanding at around 66 times the speed of light! You can calculate these things with a variety of cosmological calculators on the web. I have one on my website.

-J

Infact as I understood (not in the area, being a mere engineer) just interested in these - assumin the bigbang model as true, the space itself was created at the istant of the bigbang, and after that the things (results of the bigbang) moved mostly along the edge of the universe (ie the space fabric) and within it.

Still the fabric is expanding, and outside it again the space and time do not exist.

So the things actually didn't move at the speed of light or faster, since the space itself was not so much that they could move that fast.

(Correct me if I misunderstood, since not my area of expertise, just interest)

Very good thinking, Guest! The huge difference between a black hole and the "Cosmic Egg" (that is, the universe before the Bang) is that we know what's outside a black hole. A black hole is defined by the boundary between it and the rest of the universe. We have no similar reference for the Cosmic Egg!

(How could all the mass of the Universe, concentrated into a "black hole" or a "singularity" escape to form the Universe as we know it?) ' Also, Jorrie, I point out that back "at the beginning" of everything, the laws of physics, cosmology etc as we know them did not exist, so it's meaningless to say that the Universe was concentarted "at a singularity" at then exploded. Similarly, we have no concept of the "Inflationary" period in our today's physics. It's sort of like saying: I have a big balloon filled with hydrogen, but there never seems to be any helium formed. Why?

Hi Cardio07, you said: "Also, Jorrie, I point out that back "at the beginning" of everything, the laws of physics, cosmology etc as we know them did not exist..."

How would you know?

There is more evidence pointing in the mainstream direction than there is there is pointing the other way...

-J

Hi Jorrie,

Long time no c!

[The following is paraphrased from a post I wrote in 2007:]

One problem with current inflationary theories that I've not seen addressed satisfactorily has to do with the interval between the first spontaneous symmetry breaking where gravity makes it debut at t = t_Planck (≈10^-43 seconds), and the beginning of the Inflationary Epoch at t ≈ 10^-36 seconds.

Prior to Inflation the Universe was smaller than a proton, had a QM-limited density of roughly 10⁹⁴ grams of mass-energy per cubic centimeter, the other three fundamental interactions were still unified, the Universe was small and still expanding slowly enough (< c) where all parts of it could "communicate" with all other parts at the speed of light (meaning that what happened in one part was soon felt everywhere), and yet, for some inexplicable reason, the Universe did not undergo total gravitational collapse. Certainly all the makings of a BH were there - remember, gravity was present (in considerable abundance, I might add) but inflation had not yet begun! Between the appearance of gravity and the beginning of inflation there were roughly 10⁷ Planck times. That's a lot of time for the Universe not to collapse under those conditions! Something must have been holding it back. That or we simply don't understand symmetry-breaking quite as well as we think we do or perhaps should.

Some offer that the Universe was so hot and energetic at that point that it would naturally expand against any tendency to form a black hole. But the enormous energies present are themselves the problem! And this cannot be true as the "escape velocity" was already well beyond the speed of light. Those were ideal - more than ideal - conditions that would otherwise lead to the formation of a black hole. Mass-energy might want to expand, yes, but it would have to expand at a rate much faster than the speed of light (as distinct from the superluminal expansion of space-time itself, which is not subject to this constraint). No, something else was preventing collapse. But what?

While I was working at the MacDonald Observatory I collared cosmologist Dr. Eiichiru Komatsu* and asked him what might have prevented the Universe from undergoing gravitational collapse during that relatively-lengthy epoch. "We really don't know," he said. "Some researchers, in fact, never even ask the question! One possibility is that black holes formed but then instantly vanished, forming 'other universes' and taking bits of our Universe's mass-energy with them. Or, it is possible that there was no delay between the appearance of gravity and the beginning of inflation. This would be the easiest solution, but there's no testing of it one way or another."

Why, then, does the Standard Model peg the beginning of the Inflationary Epoch at 10^-36 seconds? And why aren't Inflation's proponents asking these questions themselves?

Current theory, apparently, traces back to some point at or near the beginning of Inflation, but it doesn't have much to say about the Universe prior to that time, other than to estimate approximately when gravity appeared. Nor do current theories lead to a unique solution. There is a lot of latitude, Eiichiru told me, in exactly when the inflationary period began and almost nothing characterizing the physical nature of the Universe - such as the distribution of mass-energy - prior to that time. Even the WMAP images do not imply with any certainty the homogeneity of the Universe prior to Inflation, as the relaxation of the scalar field "flattened" the Universe to one part in 10⁶⁰ long before the fireball became transparent to photons. It is quite possible that the distribution of mass-energy in the nascent Universe was quite granular and "chunky" prior to Inflation, and that some of the denser pieces winked out of existence, having been swallowed-up by primordial holes that, at that scale of space-time, would have been smaller than one Planck length. For my part I don't see why "denser" pieces should be singled out for this honor when the average density of all mass-energy present at that time was many times greater than that which would quickly lead to wholesale black hole formation.

Inflation does address the Horizon and Flatness problems rather well, but in so doing it creates another problem of comparable magnitude: the Universe did not collapse prior to the Inflationary Epoch. Why not?

Cheers,

-e

_{* Steven Weinberg, who worked three floors below mine and is the author of The First Three Minutes, was at a conference and so I hen-pecked his very nice colleague instead.}

Hi europium,

Many years ago there were 3 theories competing on the universe. Fred Hoyle with the steady state and 1 by Hannes Alfven (I forgot the name). Since you have brought up these problems with the BB, you might want to read about the 3rd one in the following thread. You never participated, so you might not have seen it.

http://cr4.globalspec.com/thread/20974

I would appreciate your response to it one way or the other.

regards,

-S

Hi Europium.

As Dr. Eiichiru Komatsu said: "We really don't know" what the universe was up to prior to inflation.

To me, the simplest understanding is that there was some form of cosmological constant at work, more or less balancing the immense gravitational field. This is an unstable situation and had to go one way or the other (rapid collapse or rapid inflation). Our universe happened to be one which inflated...

To my 'engineering mind', this is not too far-fetched. In it's simplest form, inflation theory postulates [Peebles 1993] that the time varying Hubble constant H(t) may actually have been constant in the extremely early universe, i.e.,

H(t) = 1/a da/dt = constant.

Now, this may look innocent enough, but it has a solution:

r = be^αt,

which, with the correct choice of parameters looks like the log-log plot on the right.^[1] The constant b is just a scale factor and α = √[8/3 πGρ_Λ], where ρ_Λ is a function of the cosmological constant (energy density of the vacuum). The axes are in terms of Planck length (r_P) and Planck time (t_P).

More than this, I don't know.

-J

[1] Discussed in more detail in the Cosmic Inflation chapter of Relativity-4-Engineers.

There are a few problems I have about black holes, First that gravity is so strong that it prevents light from escaping? I am under the impression that gravity bends light not stop it, as illustrated in fig 1. And depending on the angle that light enters it will re-emerge, and only relative time will have altered. The amount of light remerging being a very small percentage? The entrapped light one would think would react with the neutrons to create a hydrogen atmosphere around the central mass and this in turn give off a halo of light due to the excessive number of photons entrapped in the system. Just some of my thoughts about black holes.

Rgards JD.

Hi JD.

No, theoretically there is no way out for a photon that ventured too close to a black hole, because inside the event horizon, it will have to move faster than the speed of light to get out again. It will just spiral towards the central singularity and vanish there...

-J

Gravity doesn't so much bend light as it warps the space time in a manner that at some point all paths that can be traveled will lead towards the center, i.e. space in not flat or nearly flat near a gravitational well, so the 2-D paths you draw must be fitted to a curved surface.

i was reading once a book by Pr. Stephen Hawking (not sure which one, most probably a brief history of time), and i remember reading that black holes can be considered to emit particles, in fact it's some particle on the boundary that gets split, one part gets inside, the other bounces back. And plz don't ask further questions, i barley understand what i just wrote...

Actually called "Hawking Radiation"....

Hi NSS. Jorrie said it well. Whatever is inside space (mass or energy) cannot travel faster than the speed of light (c). But there is not the same restriction for the space itself. Space can be "moved" (expanded or contracted) faster c.

As an example, the stars beyond the observable horizon are already moving away from us in a speed faster than light, so we cannot observe them (their light will never reach us). And some stars that are already on the borders of the observable universe will soon get out of our sight (as they will be departed from us at a speed higher than c). And -as the universe continues to be expanded in this accelerated way- in the far future will be able to see only a few galaxies around us (and the rest of them will have disappeared for ever). We could say that the observable horizon is like the event horizon of a Black Hole (BH): everything that passes this horizon is lost for ever.

Concerning the BH: everything that enters the event horizon cannot escape because -in order to do so- this should get a speed higher than c. And this is impossible because -in order to do so- this should get infinite amount of energy.

However, there are hypothetical cases where sth could have speed higher than c. For example, the (hypothetical) tachyons or a pair of objects one having (normal) possitive mass and the other having (hypothetical) negative mass. These exotic objects (if they exist) could enter the event horizon of a BH and get out succesfully. They could get informations from the inside of a BH and get them out. Even so, we (probably) could not be able to retrieve these infos, as there must be a "mechanism" that forbids us to do so (and that's because we postulate that infos cannot travel faster than c). And -maybe- this "mechanism" is the fact that these weird objects (e.g. tachyons) must move in the opposite direction of time (i.e. from the future to the past).

Joe:

There isn't really any point in trying to apply the laws of physics, as we know them, to your question. The best we can do is speculate wildly. Have you calculated the radius of curvature that would be imposed on space near a mass of the magnitude you're contemplating?

I haven't either, but it's bound to be waaay smaller than the Planck length (l_p = (h_bar G / c³)^1/2 ≈ 1.6×10^-35 m), which is the scale at which most physicists expect quantum effects to forget their toilet training and wreak havoc with the nice, smooth geometry of spacetime. How do the properties of space change when the continuum is all torn up and beaten into a froth on a scale so small it makes the Planck length look like the vast, trackless emptiness of the intergalactic void? Does it still make a suitable background medium for dynamical interactions? Can you even define basic kinematic elements like position and velocity under those conditions?

We just don't know.

All we can say is that things must be different at that scale. New effects must come into play, otherwise the universe never could have escaped the primal singularity (if there was one) and we wouldn't be here.

Or maybe there are no new effects at any scale. Maybe space just gets kinked into little topological defects that propagate around like tiny solitons, and intertwine like tangled balls of yarn, and churn space into a non-quantized frappé which prevents any real singularities form ever forming. In which case, maybe there was no big bang at all. Maybe the universe just oscillates between finite maxima and minima, following the mother of all Poincaré limit cycles.

Again, we just don't know.

wasaadeh:

Yes, that's true. Particles inside the event horizon can tunnel out with some very small but nonzero probability. So the black hole evaporates by tunnelling. This happens extremely slowly, to be sure, but eventually every black hole will evaporate to nothing.

? Wow that was really divergent from the topic of cosmology

Are you absolutely certain of that.....?

Yes I am. The whole rant presented was like wandering off a discussion on bolts and threads to discuss the geopolitical impact of industrialization.

I agree that diverged greatly from the topic. At the same time it brings a well thought through and respectful comment to the discussion. Another example of our need for a linked Off Topic & Good Answer category for votes.

It seems like the speech of a priest not the comment of an engineer/scientist.

"All of mankind's greatest collective efforts will never [repeat: NEVER!] reach harmonious agreement concerning things which, though latent to mortals, remain in complete and consummate control of the Almighty."..... This is a pathetic and pessimistic opinion. So, we should give up any effort to find the ultimate answers (the "why" and "how") of the Universe as it is so vain.

"..... that we are, in fact, spiritual beings: God will (eventually) reveal all these answers to us. That is, assuming that we do as we were so lovingly, passionately instructed....." Okay, so lets just live our small lives in a good way -without caring about the "big questions"- hoping that some day God will give us all the "big answers".

"..... my beliefs (again: my humble opinion, here) would suggest that He will continue to allow us to "make progress", as we live-out the lives with which we have been blessed..... " I prefer to believe that our intelligence is, simply, the result of the evolution.

(The God and the devil -meaning the "good" and the "bad"- is inside everyone. And it is our choice which of these two paths will take in our lives. And if we choose to live good lives without the "reward of heaven" and "the fear of hell" then this is much, much better... this is real free will...)

Yes, this does sound more like a priest than an engineer. But let's not forget the scientist's perspective, too. For I am certain that one day in the future all of today's questions on the making of our universe will be answered. But each answer will generate at least one more unanswered question. Just like the expansion of our universe, our expansion of knowledge will drive the expansion of questions.

Actually this is similar to the kind of red herring commentary you get from politicians or financial project managers responsible for investing in projects with other money, but who are not technically familiar with the basic science and engineering of the topic. It is an attempt to diverge the narrow engineering topic and open it up to a more esoteric discussion where there can be no definitive conclusions that ever develop, just more debate. You could start something similar by stating science is the tool by which our republican democracy has blossomed, or any other subject that is arbitrary, broad, indefinite that you can loosely link to the specific topic of discussion.

Heh heh...the fun of physics! The only field where you can, all at once, deal with stuff so small, so big and bound by unbreakable 'rules' that can be omitted when necessary!

We are guessing what might happen. But if the speed of light is constant then the black hole might not shrink any more than necessary to trap light.

Looking into a black hole we see nothing beyond the event horizon. But then again looking out into the universe we see nothing beyond the cosmic fringe.

But looking outwards to the fringe is the same as looking back in time. If the universe is circa 14 billion years old and if we are able to look back 14 billion light years we must see the universe as it was nearer to the point of Big Bang - when our nearest star was only a couple of inches away.

Whilst the speed of light might be a constant, it is only a ratio of distance and time. Thus either or both time and distance can be adjusted to get an answer that fits.

Thus the mass of a black hole affects size and time to make the speed of light constant.

Nothing comes out; well not in this universe. All matter entering the black hole goes through and pops out the other side into another universe.

If "all matter entering the black hole goes through and pops out the other side into another universe", then would we expect to see an "anti-black hole" spewing matter / energy into our universe from another?

Yes I guess. I think they are call 'white holes' - and maybe if enough galaxies collapsed into one big black hole, that could explain what caused our Big Bang.

Actually something like this may have already been observed. There was a story about a month or so back on the NASA Tech Briefs (I think) site about a column of dark matter with a length of several billion light years streaming through our universe. I thought I had bookmarked the page, but I missed it, and now can't find it on Google either.

There are stars within some globular clusters that appear to be older than our current estimate (~13 billion years) of the universe's age. Assuming that these observations are confirmed, they at least suggest that there could be intrusions into 'our' universe from a 'neighboring' universe.

There was another article on the dark matter halos that seem to envelope and define the size and structure of all galaxies (see link below). If this observation is verified, then it would suggest that there is more requirements to building a galaxy than just a super massive black hole.

http://www.scientificcomputing.com/news-DS-102609.aspx

I think it is a mistake to equate black holes with the 'singularity' that is thought to be the precursor to the big bang. Black holes are made from ordinary baryonic matter (protons, neutrons, electrons, etc.), compressed to unimaginable densities. A black hole has mass. The singularity is assumed to have been composed entirely of energy, which has no mass. According to this theory, it would only be after an initial period of expansion that particles of matter with actual mass would form. What the laws of physics would be like under these conditions is almost pure speculation. As others have pointed out, it was space-time itself that was expanding, and there is no evidence that space-time expansion is subject to the speed of light. Space-time is a field, and presumably has no mass of its own.

Then again, considering the tenuous nature of our current understanding of the subject, there is a tendency for our discussions of such matters to resemble earlier speculations about the number of angels dancing on the head of a pin. It's great fun to think about (at least for some of us), but may have little to do with the actual nature of the universe in which we believe ourselves to exist.

Only if a Black Hole really is a hole...it's a star collapsed under its own mass so it's actually one huge mass emitting no light past its event horizon due to its gravity.

From a more open minded POV...whats to say there isn't something spewing energy back into our universe? Could be a good excuse for scientists to ask for a shed load of research money on?

Back in the palaeolithic era, when I was writing my senior paper on black holes, many people speculated that quasars were White Holes! Not any more...

Any current theory of White Holes would need to explain why they are so scarce, or else so inconspicuous.

Back in the early 70s, as I recall, which dates both of us considerably...

Now, I asked Jorrie about this before, and I don't recall getting a satisfactory answer, but if black holes are characterized by their exceedingly strong gravity, are white holes likewise characterized by their exceedingly strong levity?

(Jorrie: Probably just as bad a pun the second time around, yes? )

Hi europium,

I cannot recall discussing white holes before - know nothing about them...

Did you look at my reply on inflation above?

-J

europium -

That's a terrific groaner! I'll use it in my next Black Hole talk for sure, giving you proper credit. Thanks!

Lots of speculation there Horace. It's nearly certain that the gravity of black holes stays in this universe.

So can the mass of a black hole become so extremely concentrated that it becomes energy? Not real sure of the equation but mass the speed of light squared times is energy? Does that mean if the mass can concentrate itself that many times it becomes energy?

Interesting topic.

I just LOVE stuff like this!

Sad this is how my Brain works, always thinking, always asking questions like this.

Most have answers, this one, just makes my Brain hurt! he he he

Joe

NSS ... if it's any consolation, you're not alone. I always have the sense that a pack of squirrels is fighting in my head.

If properly trained and used, your 'condition' is a gift.

So ... uuuhhh ... swear to use your power only for good, and carry on, hahahaha. But do master the art of discretion ... Socrates was like you and me (and like many other CR4ers), and he was executed for sowing doubt around him (the legal term at the time was 'corrupting youth and disbelieving in the gods', lolll ...).

Cheers!
DZ

"...Does that mean if the mass can concentrate itself that many times it becomes energy?..."

Why not! Look at it another way. Someone approaching our Universe from afar would think the mass was concentrated in a dot of light. Then closer, they would see it was the same mass concentrated in a lot of dots separated by lots of space.

Closer still, the dots would then become galaxies with the same mass, concentrated in even smaller dots but much heavier, separated by lots of space.

The galaxies then become stars, heavier still, with lots of space.

The stars become molecules, holding all the original mass, with still (relatively) lots of space between them. Then atoms - with lots of space between them.

You see what I am getting at; the mass is now in immensely dense microscopic particles spread over a large volume.

Now the Hadron Collider hopes to break these atoms down into something smaller.

So to date we have not yet found anything actually solid to account for the mass - which so far seems to be empty space - except the mass is there somewhere - as anybody hit by a lump of this 'empty space' (a hammer say) will agree.

As Einstein said, mass increases proportional to velocity. So to attain the speed of light, your mass would be infinite. So just under the speed of light, you attain the mass of around 15-20 solar masses and poof, another black hole formed in the accretion disk of an existing black hole. The former gobbles the latter, and you still have not escaped.

"As Einstein said, mass increases proportional to velocity. So to attain the speed of light, your mass would be infinite. So just under the speed of light, you attain the mass of around 15-20 solar masses and poof, another black hole formed in the accretion disk of an existing black hole."

Not quite. Mass and energy are equivalent, but it is rest energy/mass that causes black holes to form through gravitational compression. Your rest energy essentially stays the same, no matter how fast you move.

The only way in which kinetic energy can (maybe) form a black hole, is when two things with enough kinetic energy collide. The immense compression can form other particles and, perhaps, a black hole...

...and that's where the LHC comes in!

Perhaps a quick proof-read would make the discussion a bit more understandable.

NSS,

Interesting ideas. How about considering this idea? In the beginning, after God said, "Let there be Light," the Big Bang occurs and our universe forms as pure energy. There is not yet any matter in existence, since our particle physics boys tell us that even protons and electrons have not yet formed. Matter begins to exist at some point after the universe has expanded and cooled a bit, though it is still extremely hot, and then the "matter" exists in subatomic elementary particles like quarks and various leptons and hadrons. Your black hole comparison to the beginnning universe is based on the thought that all the matter in the universe was present at the beginning, yet, we now know that no matter was present at all. Even more strange, we now know that the universe grows as space itself expands, not by accretion of matter or transmission of light.

Thanks for an interesting idea. I recommend a book, if you can find it, called "The First Three Minutes" by Steven Weinberg, Nobel Prize winning physicist. I think it's no longer in print but probably is available somewhere. Also, "The God Particle" by Leon Lederman, which is the story of the Higgs boson. Very interesting.

As I understand it, nothing can disappear. It merely changes form. From metal to liquid to gas, etc. Atoms realigned from one type of matter to another. Knowing this, the mistery to me is, what happens to it all in a black hole? It cannot just disappear can it?

Actually matter and energy is the way to consider it, because matter can translate into energy, and apparently energy to matter under appropriate conditions.

As I understand it, the atoms are crushed by the gravitation. There is no hydrogen, or sodium, or iron, etc. It collapses into one big nucleus (like a neutron star) and then continues to collapse into quark soup. There is no way to dig through the junk and figure out what kind of atom a particular quark came from. One could speculate that if the black hole is large enough, the quark soup may collapse further, into smaller as yet unknown particles, or maybe into pure energy.

So no, the matter can't just dissapear (probably), but it does get totally wrecked, and may in some cases be converted back into an equivalent amount of energy.

Hindu religion discussed the creation in relatively scientific way. Since time immemorial it said the following:

1. God is in his creation.

2. God is Anant, meaning endless, which is why the scientists are finding ever new galaxies.

3. God is the support of the universe (vishwaadhaaram). That is why the billion galaxies each with billion bodies are floating in the space without accidents.

4. Spiritual man can attain the speed of light, as many yogis have demonstrated to their followers all over this earth. Also read

a. "My Master" by Ramachandra Mission, where a lady visits moon when USA just planned Moon mission.

b. Autobiography of a Yogi by Paramahamsa Yogananda, a widely read book.

No more scientific than the Christian Bible, but somewhat in agreement.

As per Bible earth is about 7000 years old ! Correct me if I am wrong. As per Indians, this age block (they call it as yuga) is of 4,32,000 years of which about 5011 years have passed. Earlier yuga was of 8,64,000 years. Previous yugas were of 12,96,000 years and 17,28,000 years. Four yugas constitute one Big yuga at the end of which there will be total change of solar system. They were fixing eclipse days by astrological calculations long before Galileo and Christ.

Incidentally the book Autobiography of Yogi, I refered has good words about true christianity.

So as per Indians there will not be total destruction in 2012-2013. But massive destructions will take place due to the law of Karma, akin to the law of action and reaction.

How massive is massive destruction, can you give us some previously destructive events on which we can base the range of massive destruction. Are we talking the P-Tr extinction event at one end and the K-T extinction event at the other end of the massive destruction range? Worse? What would the effect be if this does not occur in 2012-2013?

Nice postulation... It inevitably led to an impasse because it was based on a faulty premise.

Since secular scientific explanations fail miserably, consider another approach.

Consider that an all powerful creator God who transcended time and space created it all from His mind with His words. (and God said, "Let there be . . .")

If you approach the subject "Origin of the universe" objectively, without a preconceived bias that it had to happen without divine intervention, things work out more realistically and make sense when you approach them God's way.

There was no One Big Bang. There are billions of Little big bangs.

soaralone1

Ask any physicist or mathematician worth his/her salt and they will tell you singularities are impossible in the physical world. The Big Bang and Black Holes come under this umberella of 'ugly equations'.

Michio Kaku is a prominient futurist and theoretical physicist in this matter.

To refer back to the original question:

When people talk about the escape velocity of a black hole, they generally mean the escape velocity at the event horizon. This velocity is, by definition, the speed of light. A more massive black hole has a bigger event horizon, but the escape velocity from that horizon is the speed of light.

Any point inside the hole -- that is, within the event horizon -- doesn't have a meaningful escape velocity in today's science, because there is no escape! Future generations of scientists will have a lot more to say about this, of course. They might even say that there are no black holes after all, that we simply misinterpreted the data. That's what makes science so much fun.