How do black holes eat? Like Cookie Monster! (Synopsis)

“This is because black holes are incredibly messy eaters, spitting back out well over 90% of all the matter that falls into them, making them more like cosmic Cookie Monsters than any cosmic vacuum cleaner you might envision.”

Disclosure: I haven’t yet read Ethan’s Forbes piece, but I couldn’t wait to express my shock.

See, I am virtually certain that I’ve heard and read numerous times from numerous sources over numerous years that
-black holes WERE like a cosmic vacuum cleaners, but
-were so strong that NOTHING we know of could escape them once inside, not even light.

Has anybody else heard and seen such things about black holes, or am I dreaming?

@Deceiver #1: Why yes, indeed, I have heard such things about black holes, usually from people who don't know or understand sciecne. That's probably why you remember it so well.

I am virtually certain that I’ve heard and read numerous times

This seems to be a very frequent occurence for you, given how often you invoke variations on the theme. The pairing with "I haven’t yet read [whatever I'm 'commenting on']" is, of course, a classic, to the extent such things exist in severely limited repertoires.

To Mickey the SLACer #2:

“Why yes, indeed, I have heard such things about black holes, usually from people who don’t know or understand sciecne.”

Just to make sure I wasn’t dreaming, I did a quick Google and found this, at a site apparently associated with the Cal Tech, the Jet Propulsion Laboratory and NASA:

“A black hole is one of the strangest objects in space. It is an area in space where gravity is so strong that even light cannot escape from it.”

http://coolcosmos.ipac.caltech.edu/ask/229-What-is-a-Black-Hole-

It’s about 12:30 a.m. and I *think* I’m wide awake.

I found a black hole on my very own!
It may be a bridge to another realm.
Sigh.

https://www.youtube.com/watch?v=1g9Hs3rnd6s

Probably one reason for the confusion, is that if you consider an isolated particle interacting with a BH, either it goes into the event horizon, and vanishes without emitting radiation, or it swings around it, and leaves with the same kinetic energy (relative to the BH) that it arrived with. But matter in bulk, is going to suffer from extreme tidal distortion, which allows it to gain energy. But we still have to conserve overall energy (mass-energy), so some matter must be swallowed or at least left in a more tightly bound orbit, in order for other matter to radiate and/or be thrown out at high velocity.

were so strong that NOTHING we know of could escape them once inside, not even light.

You have the tools needed to understand Ethan's 'messy eater' concept in your own phrasing; no other source is needed. What part of your own phrase, "once inside," don't you understand?

One for SN:

Just what do you think you're doing, Dave?

[on Dave's return to the ship, after HAL has killed the rest of the crew]
HAL: Look Dave, I can see you're really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over.

HAL: I know I've made some very poor decisions recently, but I can give you my complete assurance that my work will be back to normal. I've still got the greatest enthusiasm and confidence in the mission. And I want to help you.

[HAL's shutdown]
HAL: I'm afraid. I'm afraid, Dave. Dave, my mind is going. I can feel it. I can feel it. My mind is going. There is no question about it. I can feel it. I can feel it. I can feel it. I'm a... fraid. Good afternoon, gentlemen. I am a HAL 9000 computer. I became operational at the H.A.L. plant in Urbana, Illinois on the 12th of January 1992. My instructor was Mr. Langley, and he taught me to sing a song. If you'd like to hear it I can sing it for you.
Dave Bowman: Yes, I'd like to hear it, HAL. Sing it for me.
HAL: It's called "Daisy."
[sings while slowing down]
HAL: Daisy, Daisy, give me your answer do. I'm half crazy all for the love of you. It won't be a stylish marriage, I can't afford a carriage. But you'll look sweet upon the seat of a bicycle built for two.

To eric #7:

“You have the tools needed to understand Ethan’s ‘messy eater’ concept in your own phrasing; no other source is needed. What part of your own phrase, “once inside,” don’t you understand?”

What part of “spitting back out well over 90% of all the matter that falls into them” don’t YOU understand?

What part of “spitting back out well over 90% of all the matter that falls into them” don’t YOU understand?

Ah, I see. While I don't count you among them, I think a naive layperson could get confused by that. So here's the explanation:

The material falls in to the BH's gravitational well; the area around it where space is significantly curved. However for most BH's the event horizon is deep within that well, and not everything that enters the well will pass the event horizon. Only the material that passes the event horizon cannot get back out. What Ethan is saying is that, in fact, the great majority of material falling in does not pass the event horizon; instead, like a comet around the sun, gravity kicks it back out again.

There, now you can go to bead tonight satisfied with the knowledge that the 'problem' you thought you discovered about BH physics was really just a communication misunderstanding.

@Deceiver #4: There's no contradiction, except in your own mind. A black hole is just a concentrated mass. Over most of space, a test particle will see it and behave just as it would around any other mass -- orbiting, falling, doing gravity assists with some third mass, whatever.

The difference is that a BH is much smaller in circumference than any ordinary object with the same mass. That means you can get much closer to the "center" of a BH (using Newtonian language) than you can to the center of an ordinary planet or star or whatever, with _all_ the BH's mass still between you and that center.

So you can approach regions where gravity becomes really strong, and your rocket can't possibly escape. Do that with the Sun, for example, and you end up far below the visible surface, and gravity there is much _weaker_ than you'd expect (since there's less mass below you).

If you don't understand basic 17th century physics, you probably shouldn't be trying to discuss science.

I found a black hole on my very own!

You bought a mirror?

To eric #10:

Seems to me if an object is not in or past the so-called event horizon, then it is NOT IN the black hole. I think other science websites would agree.

Thus, the black hole is NOT a sloppy eater vomiting out 90% of its "cookies." Something else, not a black hole, is.

But thanks for the effort. I appreciate it.
Maybe you can help with something else.
Somebody said “Mass produces gravity.” And I told somebody that this made me think of something Ethan recently wrote:
“…the mass in stars gives you a number, and the *mass from gravity* gives you a greater number. Not a number greater by a little bit, either: one that was bigger by a factor of fifty.”

I asked somebody if he’d explain the difference between
a) mass in stars/planets/objects and
b) “mass from gravity”?

But somebody wouldn’t answer.

Would you?

Your refusal to accept the explanation doesn't mean the explanation is wrong sn. It simply means you don't know what you're talking about.

Somebody said “Mass produces gravity.” And I told somebody that this made me think of something Ethan recently wrote:
“…the mass in stars gives you a number, and the *mass from gravity* gives you a greater number. Not a number greater by a little bit, either: one that was bigger by a factor of fifty.”

I asked somebody if he’d explain the difference between
a) mass in stars/planets/objects and
b) “mass from gravity”?

Sure: you're randomly picking phrases out of sentences that you're too stupid to actually understand.

Given that S.N. actually stalked Michael to a six-year-old post and is now affecting some sort of snit akin to the Brady Bunch episode in which Mike and Carol stop speaking to each other,* let's play a game called "reading comprehension."

The full paragraph that S.N. weirdly thinks he can make hay from by cherry picking:**

You can do this same measurement today using modern telescopes and our contemporary knowledge of stars and gravity, and you’d get two numbers similar to the ones Zwicky got. What you’d find is that the mass in stars gives you a number, and the mass from gravity gives you a greater number. Not a number greater by a little bit, either: one that was bigger by a factor of fifty.

Now, given that this has proved too complicated for you – and to stay consistent with your own method of "textual analysis," allow me to point you to other words in the paragraph:

You can do this same measurement today

The "direct object" of this sentence suggests that it has an "antecedent." OK, so your homework is to try to read the preceding text and then describe "this same measurement" in your own words.

* At least they were married.
** The mixed metaphor is there for a reason, S.N.

@Narad #15: In fact, Deceiver _was_ answered (in the multi-year-old thread he resurrected), he just can't do fairly simple algebra (no calculus required!).

"Just to make sure I wasn’t dreaming, I did a quick Google and found this, at a site apparently associated with the Cal Tech, the Jet Propulsion Laboratory and NASA:

“A black hole is one of the strangest objects in space. It is an area in space where gravity is so strong that even light cannot escape from it.”"

Just to make sure I wasn't dreaming, I reread your earlier post to which Michaels reply was quoted in that post, and YOU DID NOT MAKE THAT CLAIM THAT NASA DOES in it.

"To eric #10:

Seems to me if an object is not in or past the so-called event horizon, then it is NOT IN the black hole. I think other science websites would agree."

They do agree.

"Thus, the black hole is NOT a sloppy eater vomiting out 90% of its “cookies.” Something else, not a black hole, is.!"

That doesn't apply to the conversation above the line or that others such as Eric, Narad or Mike are having with you. since the quote of your statement I gave at the top there isn't the same thing as the one you're whining about being "nothing can escape a black hole".

A fact you will continue to fail to see because you're incapable of thought,

Thus, the black hole is NOT a sloppy eater vomiting out 90% of its “cookies.” Something else, not a black hole, is.

You can play definition games all day long, and it won't change what Ethan or anyone else is trying to communicate, it will only reveal that you have no substantive complaint about the physics so you're reduced to nitpicking about language. If you want to define "in" a black hole as within the event horizon, then yes, nothing comes out once it's in. For this definition we would simply say the BH is a messy eater because it throws 90% of the mass away from it before that mass goes in. There, does that make your inner pedant happy now?

I asked somebody if he’d explain the difference between
a) mass in stars/planets/objects and
b) “mass from gravity”?

But somebody wouldn’t answer.

I *did* answer, in part. However I also said I'm not an expert and look forward with more information weighing in on this. AIUI (and I could be wrong), we observe many spiral galaxies at different ages. This observation is consistent with the spiral structure being stable over long periods of time. So there must be enough gravity within these galaxies to keep that structure stable; that's the "from gravity" observation.. Its different from the one we get from observing and calculating mass from the stars etc... that make the galaxy up.

To eric #20:

So, I’m not the only one here who would like to see an explanation, from an expert, of the difference between
a) mass in stars/planets/objects and
b) “mass from gravity”.

Wonders never cease.

So, I’m not the only one here who would like to see an explanation, from an expert, of the difference between
a) mass in stars/planets/objects and
b) “mass from gravity”.

You've had this explained to you repeatedly. It's in the foregoing paragraph. Your perseveration with this routine – which you embarrassingly seem to think is clever in some fashion – is purest obnoxiously stupid trolling.

@eric #20: You wrote, "we observe many spiral galaxies at different ages. This observation is consistent with the spiral structure being stable over long periods of time. So there must be enough gravity within these galaxies to keep that structure stable;"

In fact, the spirals are not "structures" in the sense of being fixed collections of specific objects. They are "density waves" in the pseudo-fluid of stars which make up a galactic disk. Individual stars enter and leave the spirals as they orbit around a galaxy, but the spirals themselves stay in place (as seen in many-body gravity simulations).

This is quite analogous to the way that individual air molecules will enter and leave the high (or low) pressure regions of a sound wave, but the region itself is well-defined and long-lived.

@23: Yes I was aware of that; Ethan has written posts before about how our solar system, for example, is not near any of the stars it was born near. I was exercising the KISS principle. But your addition is probably helpful for lurkers because my simplicity probably gave the wrong impression to some, so thanks.

"This is quite analogous to the way that individual air molecules will enter and leave the high (or low) pressure regions of a sound wave,"

Watch also a large flock of starlings at evening. Waves move through the flock, but the features aren't in the structure of the flock, but in the nature of the method of each birds' behaviour AS a flock.

Mickey the SLACer to eric: “In fact, the spirals are not “structures” in the sense of being fixed collections of specific objects. They are “density waves” in the pseudo-fluid of stars which make up a galactic disk.”

Eric: “Yes I was aware of that… your addition is probably helpful for *lurkers* because my simplicity probably gave the wrong impression to some…”

Possible lurker: “How does the spiral structure in galaxies like the Milky Way originate, and what maintains it? To be honest, WE DON’T KNOW completely, BUT there are two IDEAS that at least PARTIALLY EXPLAIN it.”
http://csep10.phys.utk.edu/ojta/c2c/milkyway/structure/orbits_tl.html

And about that analogy, Mickey. I’m thinking of a sound wave moving from A to Z, that goes through a particle at position D. The wave gets to Z, but the particle is still at D.
And I guess I’m not getting the galaxy.

You're not thinking, See Nowt. You're blithering.

Why do you claim a possible lurker doesn't know how but does know how? Are you proposing everyone is as logically insane as yourself???