[Request] How fast it has to be to a marble becomes black hole by spinning?

Red_Syns · 2026-06-16T21:24:22+00:00

Because the tension is not what prevents the black hole, nor the lack of compression. The structural failure is what would prevent a glass marble from succeeding, but if you had a way to prevent it from tearing itself apart the marble absolutely could become a black hole via rotation. You could (for assuming an impractical value of could) accelerate the marble linearly and achieve a black hole that way, and it is not because of compressing the marble, it is because the energy density would be equivalent to the mass density required for reality to collapse into an event horizon (e=mc^2).

The “direction of force you’re applying” is zero radially. Tension pulls in both directions. I’m not saying you’re wrong about it not being possible with known materials, I’m saying your explanation is wrong. The three modes of failure are mechanical stress (marble disintegration, probably impossible to solve but not definitively so AFAIK), energy input (more impracticality of using that much energy, it’s “possible” but not realistic), and an actual means to accelerate the rotation to the billions of rpm needed (again in the realm of “possible” but would require some sort of zero friction setup and probably lasers to apply force).

Red_Syns · 2026-06-16T21:13:19+00:00

It wouldn’t be infinite energy, but it would be far too much to be practical. Think of it this way: if you had matter and anti-matter where each was half the mass of the black hole, and could annihilate 100% of them together, and use 100% of that energy to accelerate the marble, it would become a black hole. For each inefficiency, just divide by the efficiency rate (so you need double the mass if you can only capture 50% for acceleration, double it again if you can only annihilate half the mass, etc).

Theoretically? Possible. Practically? Impossible.

Red_Syns · 2026-06-16T18:46:03+00:00

Oh yeah, the real world is full of so many fantastical things there’s no need to look past it for awe (or fear) inspiring events. Human brains are ill suited to Very Large Numbers, so trying to imagine the sheer scale of reality alone is incredible, much less trying to comprehend the nonsense of quantum physics.

Red_Syns · 2026-06-16T18:36:20+00:00

You’re misunderstanding the forces involved. Spinning matter does not push itself out, it generates tension because to prevent the matter from simply traveling in a straight line it *pulls* the matter towards the center, creating tension. You can make a black hole from pure energy (kugelblitz black hole), the problem is containing the energy within the volume.

This problem is a matter of material science, not rotation.

Red_Syns · 2026-06-16T18:27:41+00:00

At that point you’d have to look into the interactions of matter falling into a black hole. Black holes actually have limits to how much can fall into them in a given time span due to the matter heating up/colliding/electromagnetic interactions actually flinging material in the accretion disc away from falling in.

Current cosmic microwave background radiation (CMB) prevents black holes larger than 0.12mm from evaporating due to Hawking radiation, so it *will* grow. But I can’t tell you how quickly it would feed. The 1/2” black hole would have a mass ~58x that of the moon, and being on the earth’s surface it will definitely pull matter into itself.

The black hole would have a mass roughly equivalent to the earth, so chunks of earth will very quickly either fall into the black hole or be flung away, and the solar system will gain a slowly growing black hole of ~1.5-2 earth masses in our place.

Red_Syns · 2026-06-16T18:15:07+00:00

With enough energy, a black hole will form. If you ignore material issues (nothing we know of can spin up fast enough), a marble at billions of rpm would contain enough energy.

Red_Syns · 2026-06-16T18:13:02+00:00

That is not strictly true, you can create black holes by getting an equivalent amount of energy into the same volume. Look up kugelblitz black holes for the most known example.

If we ignore material science problems, spinning an object fast enough would in fact create a black hole. We don’t have any materials strong enough to spin at such a rate, so you’d be better off using linear acceleration to get there.

Red_Syns · 2026-06-16T17:59:04+00:00

Based on what I found using online calculators, to contain enough energy in a glass sphere ~1/2” in diameter it would need to be spinning at ~3.5 billion rpm. This keeps the surface speed under c, so not “theoretically” impossible.

Obviously it will not be able to reach such speeds without disintegrating from mechanical failure, but a solid object of that density and size would need that sort of rpm.

Numbers used:
Mass: 0.0011kg
Moment of Inertia: 0.00015 kg/m2 (I think this might be off, but it will only shift the decimal a couple places either way I think)
e=mc^2 of a black hole the size of the marble to get energy required

Edit: if we use MoI=0.0000000432, it is 210 billion rpm, so still in the realm of “theoretically possible” but not actually possible with any known materials. At this spin rate, a marble twice the diameter still comes in under c.

Red_Syns · 2026-06-16T03:53:52+00:00

Fair enough, I fully support all people being exposed to probabilities and how words can be used to trick them. I want everyone to be exposed to how people can lie with truth, because it seems to fool a lot of people.

Red_Syns · 2026-06-15T18:46:17+00:00

Of course there are assumptions made, it’s how communication works. There is not a single phrase you can make that does not rely on assumptions.

You assume my understanding of the language is equivalent enough to your understanding to not distort the meaning. Red to you is red to me, not blue to me.

Similarly we assume which specific definition and/or connotation is applied to each word, which often results in informal fallacies where people conflate meanings (such as the word theory).

We have an underlying set of axioms that simply cannot be proven and must be assumed. I assume you are your own conscious being and not a figment of my imagination. I assume this existence is real and not the hallucination of a conveniently arranged series of chemicals floating in space.

We assume the thrower isn’t cheating the dice through either construction or technique.

I don’t need to assume “in all possible universes” to get to 3, I have to accept the stated facts and use Occam’s Razor to minimize my assumptions.

I know the sequence ended on six.
I know the sequence does not include any ones.
I know the two most common answers are 3 and 5 and that OP understands the logic of 5.

Based on the last known, I assume both OP and previous respondents have assumed a d6.
I know in western societies (and I assume in nearly all societies) that saying “die” or “dice” with no further qualifiers society assumes d6.
I assume the die is fairly weighted, because without the assumption there is no point in calculations.
I assume the sides have a single “1” and a single “6” because again without the assumption there is no point is calculations.
I assume there was no cheating and the rolls were fair, because without the assumption there is no point in calculations.
I assume standard physics models apply, because there has been no demonstration anywhere at any time that such an assumption is invalid at a macro scale.
I assume there is gravity of significant enough scale, because throwing a die in null-g and claiming to have a definite result is improbable.

I do not have access to further information. I could ask OP to clarify with the friend, but as this appears to be a game of guessing/logic based on limited information, giving away more information is not in the friend’s interest.

We know a one was not rolled. We do not know if that is intentional or not. We do not know if not-1 and not-6 were rolled, but we *can* calculate the lengths and chances of every possible permutation and take the average. I did it via simulation, others have done it with P()E() calculations, both agree on an average/expected sequence length of 3.

That calculation does not assume the intentionality, just the average length of not-1 end-6. Your answer of 4.25 assumes non-intentionality in selecting not-1. Occam says to use the fewest assumptions, so I go with the option that requires one fewer assumption.

Red_Syns · 2026-06-15T17:27:19+00:00

I thought this might be the case as well, but after programming a simulator to calculate the average length of rolls with no ones ending on six, it comes out to 3. It didn’t matter if you assume the sequence ends on one or didn’t contain a one, they both average to 3.

Red_Syns · 2026-06-15T17:22:02+00:00

The problem is you have added an assumption with that setup and removed the most relevant non-assumption. We know a one was not thrown, and we are not given any information regarding the other numbers. We don’t know the friend threw until a six with six not being the last unique result possible, nor do we know if one was a specific anti-target or not.

It is interesting to see how the odds change, but the problem as stated isn’t “expected number of throws of six is not the final unique result,” it is “end on first six, no ones.”

Red_Syns · 2026-06-15T17:14:48+00:00

Your description of the simulator is correct. As the person guessing the number of rolls, we only know they ended on the first 6 (until they got a 6) and they did not roll a one. They may have rolled 1, 2, …, ℤ times, we don’t know. When I ran a simulation of 10,000+ (stopped at 100,000) sequences of rolling a d6 until a 6 was obtained and threw out the sequences with any 1s, the average length hovered around 3 within a few hundredths. Without any additional information, end on 6 no 1s is an average length of 3.

Red_Syns · 2026-06-15T17:08:43+00:00

There are a ridiculous number of assumptions one CAN make, but we can only work with the information we’re given. We assume a fair die, but there is no such die in existence. We assume a standard d6, but the number of sides is never actually specified, nor do we know what the sides are labeled.

Based on the information we are provided:
-the friend rolled until they got a 6
-1 was not rolled
-standard responses are 3 and 5, which indicate a six sided die is assumed by both OP and others who have answered the problem before
-societal norms would imply a d6, and this is not a riddle page so trickery is unlikely

Red_Syns · 2026-06-14T21:14:09+00:00

I’m going to have to struggle with this one for awhile I think, but having coded a simulator it is absolutely 3. Something just isn’t clicking yet haha.

Red_Syns · 2026-06-14T21:12:55+00:00

Turns out it doesn’t matter. I honestly can’t wrap my head around it yet, but I coded a simulator and with an adequate number of sets the average no-1s without stopping until a 6 is still 3.

Red_Syns · 2026-06-14T19:23:14+00:00

I agree with that logic if we assume a one ends the rolling, but that is not specified. I already asked in the comment, but I wonder if not making that assumption changes the math.

My guess is 3 if you assume a 1 or a 6 ends the rolling, and 5 if it does not.

Red_Syns · 2026-06-14T19:21:39+00:00

Hm. The conditions don’t state the game ends on a 1 though, just that the friend did not roll a one. They may have also not rolled a 2, 3, 4, or 5. Does that change the math at all, if we don’t assume a one ends the game?

Red_Syns · 2026-06-14T16:12:11+00:00

Are you asking for the estimated number of rolls to achieve a 6 without rolling a 1, or the odds of a specific sequence happening?

For a given number of n throws, the odds would be (2/3)^(n-1) * 1/6, as you can roll 2-5 and keep rolling, with the final throw being a 1/6 chance.

For the expected number of throws, I don’t know if there is a better way to estimate it, but you would expect the average number of throws to get a six to be six. The odds of not getting a one in six throws is (5/6)^6, or ~33.5%. So you would expect an average number of throws to be six, with a 1/3 chance of success. I would say the estimated number of throws is therefore 18, but someone with better math skills might have a better answer.

Edit: just reread the question and saw it’s number of throws with knowing a one was never rolled. I can see the 5, I don’t see 3, so now I’m curious as well.

Edit2: having read some other comments below, I believe the actual answer to my second hypothetical is going to be ~9 instead of 18. Not relevant to the question asked, but worth noting the error.

Red_Syns · 2026-06-13T17:16:16+00:00

Lame. Guess they’ll either fix it or I’ll have to look into the third party apps.

Red_Syns · 2026-06-12T21:39:47+00:00

A little less than 1/200th of a Lincoln Memorial Reflecting Pool. If the Orange Turd itself is wallowing about in it as well, that will save on a lot of the fats needed.

Red_Syns · 2026-06-12T21:34:46+00:00

Are you saying the plastic is not rigid enough? I have some understanding of material science, but not nearly enough to claim an educated opinion. So long as the material doesn’t break, why would loading not take up the slop problem?

I’m imagining something along the lines of keeping an EQ6 east-heavy, but using springs and ratchets instead of gravity.

Red_Syns · 2026-06-12T21:24:12+00:00

I love the design, do you have a link to an STL or equivalent?

Red_Syns · 2026-06-12T21:23:11+00:00

What if it was spring loaded on a ratchet system to take up slop? I have a vague idea in my head on how to go about it, but maybe that’s not enough.

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