Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Scientists Discover Teeny Tiny Black Hole

Zonk posted about 6 years ago | from the for-relative-terms-of-teeny-and-tiny dept.

Space 277

AbsoluteXyro writes "According to a Space.com article, NASA scientists have discovered the smallest known black hole to date. The object is known as 'XTE J1650-500'. Weighing in at a scant 3.8 solar masses and measuring only 15 miles across, this finding sheds new light on the lower limit of black hole sizes and the critical threshold at which a star will become a black hole upon its death, rather than a neutron star. XTE J1650-500 beats out the previous record holder, GRO 1655-40, by about 2.5 solar masses."

cancel ×
This is a preview of your comment

No Comment Title Entered

Anonymous Coward 1 minute ago

No Comment Entered


That's nothing... (5, Funny)

Anonymous Coward | about 6 years ago | (#22945880)

They say LHC-001 will be even smaller!

(But who will be there to measure...?)

Re:That's nothing... (0)

Fishead (658061) | about 6 years ago | (#22946330)

OK, I got nothin' on LHC-001. Wiki let me down, and even Google let me down. What's LHC-001 or are you talking out of your ass?

Re:That's nothing... (5, Informative)

Enoxice (993945) | about 6 years ago | (#22946364)

LHC = Large Hadron Collider: http://en.wikipedia.org/wiki/Large_Hadron_Collider [wikipedia.org]

001 = First black hole created by LHC

Some people are afraid the LHC-001 is going to destroy the Earth.

Oh shit... (5, Funny)

neokushan (932374) | about 6 years ago | (#22946782)

If that happens, what are we going to do!? Capitan Picard hasn't been born yet! Hell, even Kirk isn't around yet....

What the article fails to pont out is ... (5, Funny)

celtic_hackr (579828) | about 6 years ago | (#22946906)

This newly discovered Black Hole is the final result of a Large Hadron Collider, that caused a microsopic black hole on the third planet formerly circling the former star now known as 'XTE J1650-500'. So, this is not a naturally occuring black hole, but an alien-created one. Sadly this alien species is now extinct so they can't tell us how to avoid their mistake.

Re:That's nothing... (4, Funny)

B3ryllium (571199) | about 6 years ago | (#22946370)

He's talking out of his hardon-collider.

Re:That's nothing... (4, Funny)

c6gunner (950153) | about 6 years ago | (#22946824)

He's talking out of his hardon-collider.
How exactly did we get from talking about black holes, to talking about gay porn?


Actually, nm, don't say it, it's too obvious....

Re:That's nothing... (5, Funny)

sayfawa (1099071) | about 6 years ago | (#22946392)

There may already be microscopic (more like picoscopic) black holes all around us. The thing with black holes is they are only dangerous if you get close to them. If they are small they can whiz right through us without hitting anything, much like many other particles that pass through us all the time. I'm not saying that creating one would be a good idea, but if, on the off-chance, one were created by the LHC it will probably be innocuous. I wish I could make those sound less like famous last words.

Re:That's nothing... (4, Funny)

ShadowBlasko (597519) | about 6 years ago | (#22946500)

So thats where all my socks keep going!

Re:That's nothing... (-1)

Anonymous Coward | about 6 years ago | (#22946558)

1. Create microscopic (picoscopic) black holes
2. ????
3. Profit!

Name (1, Funny)

Anonymous Coward | about 6 years ago | (#22945890)

But XTE J1650-500 is so bland! I think we should name it Mooseknuckle.

Is it smaller than this one? (3, Funny)

newscloud (1037538) | about 6 years ago | (#22945904)

Re:Is it smaller than this one? (2, Informative)

Compholio (770966) | about 6 years ago | (#22946586)

Is it smaller than this one [newscloud.com]?
Not even close, do you really think that we could make a 3.8 solar mass black hole in the lab (that's several hundred thousand times the mass of our planet)? A more accurate term for the kind of black hole we might make in the lab is the hypothetical "microsingularity".

if i bend over (-1, Troll)

Anonymous Coward | about 6 years ago | (#22945908)

and show you my black hole, will you give me cowboy buttsex?

The Earth in danger from microscopic black holes? (0)

Anonymous Coward | about 6 years ago | (#22945910)

In David Brin's novel Earth [amazon.com] IIRC the Earth's orbit crosses a tiny black hole, which ends up falling into the Earth's core, threatening both the planet and the survival of life on it. What is the real possibility such a thing could occur?

Re:The Earth in danger from microscopic black hole (1)

Vectronic (1221470) | about 6 years ago | (#22946394)

Although I dont have the most indepth knowledge of the matter (punn?)... I would say that the chances are next to impossible...

A wormhole, perhaps, but not a blackhole, unless of course we find out that the two are the same... as far as im aware a blackhole would just suck our planet (our moon, maybe Mars, and the entire soral system with it) outright and instantly, whereas a wormhole (hypothetically of course?) could exist as a smaller "hole", however I dont see why it would linger/stay with our planet and constantly eat away at it... but more along the lines of say every orbit the earth makes around the sun, a tiny piece gets chipped/eaten away at a certain position in that orbit at a rather calculatable frequency (similaily to an eclipse)...

Re:The Earth in danger from microscopic black hole (4, Interesting)

Anonymous Coward | about 6 years ago | (#22946560)

ok, I am ripping most of the info from here: http://www.physicsforums.com/showthread.php?t=122375&page=6 [physicsforums.com]

        "If they were able to make a small blackhole, and it got "loose" and fell to the center of the Earth, the pressures at the Earths core would force material into it so fast that even a very small one would gobble us up very fast. I am not sure what the exact pressure is at the Earths core but it could force material through even a very small "hole" very quickly. I do agree that once it gobbled up the Earth, it would just continue to orbit the Sun, and the Moon would still orbit the blackhole as if it were the Earth..."

No, you should read this thread.

First of all, a black hole that falls to the center of the earth, wouldn't stop there, but would continue falling up on the other side, just to plunge in again, and on and on, because there's no "friction" on the black hole.

Second, there have been posted in this thread a lot of calculations of the speed at which it would gobble up matter.
Don't forget that the black hole we're talking about here IS MUCH MUCH SMALLER THAN A PROTON. As such, pressures on *atomic* level (such as in the center of the earth) matter little: the black hole travels most of the time in the empty space between nucleae.
A way to calculate the probability of hitting a nucleus (and somehow imagining that it would gobble up the entire nucleus, which is MUCH MUCH bigger than the black hole itself - which is a worst-case scenario) is done by calculating the "cross section" of the black hole and its probability to cross a nucleus on its voyages through the earth. We know its speed (just falling), and knowing the cross section and the density of nucleae, we can estimate how many nucleae it could eat per unit of time.

For a classical black hole, the calculation is done in the link provided by Pervect in this post:
http://www.physicsforums.com/showpos...4&postcount=12 [physicsforums.com]

for a MUCH LARGER black hole, about the size of a proton, weighting a billion tons (figure that! A black hole *the size of a proton* weights a billion tonnes ; we're talking here about black holes that weight 10 TeV or 10^(-24) kg - go figure how small it is !)

For more exotic calculations which are more severe, orion made some, and arrived at a time to eat the earth ~ 10^46 years.

All this in the following rather un-natural hypotheses:
- no Hawking radiation (which would make the black hole evaporate almost immediately)
- production of black hole EXACTLY IN THE CENTER OF GRAVITY of the collision (no remnant particles)
- very high production rate, producing billions of black holes per second.

I am not a physicist, but from what little physics I have had, and from reading threw the thread/flamewar, I dont think we have to worry about the LHC

Re:The Earth in danger from microscopic black hole (1)

Akaihiryuu (786040) | about 6 years ago | (#22946668)

Absolutely zero. The smaller a black hole is, the faster it radiates away its mass in the form of energy. A microscopic black hole would cease to exist in a very small amount of time. One created in a particle accelerator would cease to exist almost instantly, leaving only energy behind. It would be possible to detect evidence of its presence by the energy signature it left, but that's about it. If such black holes can even be created in a particle accelerator, then they will have been created by gamma and cosmic radiation for as long as this planet has been here. http://en.wikipedia.org/wiki/Hawking_radiation [wikipedia.org]

LHC countdown (2, Funny)

Anonymous Coward | about 6 years ago | (#22945922)

Is this the point where they say we'll need to re-think our theories on black hole evapouration too? But first, let's switch on the LHC and see what happens...

Black-hole... sheds new light... (5, Funny)

Anonymous Coward | about 6 years ago | (#22945924)


Probably Something Stupid (1)

mactard (1223412) | about 6 years ago | (#22945946)

I thought that Black Holes had no dimensions, but this one is several miles across. Where have I gone wrong?

Re:Probably Something Stupid (3, Informative)

krod77 (953703) | about 6 years ago | (#22946014)

They measure it at where light can no longer escape its gravity, so they measure the "blackness".

Re:Probably Something Stupid (1)

liquidf (1146307) | about 6 years ago | (#22946270)

so they measure the "blackness".
y'know, i was going to make a comment on this and how they cast for blackzilla, but i'll pass in favor of karma...

Re:Probably Something Stupid (0)

Anonymous Coward | about 6 years ago | (#22946620)

It's like, how much more black could this be? And the answer is none. None more black.

Re:Probably Something Stupid (4, Informative)

Ecuador (740021) | about 6 years ago | (#22946032)

While black holes is not my area, I can tell you that when someone talks about the size of the black hole, they refer to the event horizon, since you can't really measure anything going on inside it.
The mass of the black hole is the most defining characteristic.

Re:Probably Something Stupid (5, Informative)

Geoffrey.landis (926948) | about 6 years ago | (#22946064)

I thought that Black Holes had no dimensions, but this one is several miles across. Where have I gone wrong?

A black hole, conventionally, consists of an event horizon surrounding a region of space from which you can't send information to the external world. This region of space is not a point, it has a well-defined circumference. (Because of the non-euclidean nature of general relativity, it doesn't actually have a well-defined radius (since you can't measure across the middle!) but people usually just consider the radius as if it were defined as the circumference divided by 2 pi, and don't worry about the fact that you can't actually measure it.)

At the center of the black hole is, according to general relativity, a point singularity, which indeed has no dimensions.

Re:Probably Something Stupid (1)

dmbasso (1052166) | about 6 years ago | (#22946418)

What would happen if a big star collide with a small black hole? Would it be all swallowed? Is there a theoretical way to revert a singularity?

Re:Probably Something Stupid (0)

Anonymous Coward | about 6 years ago | (#22946622)

Happens all the time that a black hole is one of a binary pair. And yes, the black hole eventually sucks most of its partner in, though not without building up an accretion disk, a gas jet, and getting the other star to pop off a few novas first.

Re:Probably Something Stupid (4, Informative)

The Only Druid (587299) | about 6 years ago | (#22946472)

Actually, that's only true of a non-rotating (or Kerr) singularity. All natural black holes will be rotating (the black hole maintains the rotational momentum of the pre-collapse mass). In a rotating black hole, the singularity is actually a ring (or torus). Inside that ring/torus, there is a tear in space.

It was this tear that lead, if I recall, to the original conjectures of a white hole, and the Einstein-Rosen bridge.

Re:Probably Something Stupid (0)

Anonymous Coward | about 6 years ago | (#22946734)

I think my brain just melted out my ears.

Re:Probably Something Stupid (0)

Anonymous Coward | about 6 years ago | (#22946932)

Strictly speaking, it's the event horizon that either becomes an oblate spheroid or a torus when the black hole is rotating. The singularity is still the "point" in the "center". With a toroidal event horizon, you would get a naked singularity, but to do that you would have to have quite a lot of angular momentum.

Re:Probably Something Stupid (3, Interesting)

dmartin (235398) | about 6 years ago | (#22946714)

Actually, the Schwarzchild solution does have a well-defined radius. In fact, the problem is that it has many well-defined radii, depending on what you mean by the term (as you point out, this comes about because of the non-Euclidean nature of the geometry). The commonly quoted "Schwarzschild radius" r = 2GM/c^2 is obtained by taking the area of the horizon and figuring out which "r" you would have to plug into A = 4 pi r^2 [true for a flat space sphere] to get the right result. Taking the circumference and dividing by 2 pi would achieve the same result. However, it is quite possible to figure out the proper distance between the horizon and the singularity by measuring the distance an infalling observer would travel. This distance is finite.

A problem can occur if you try and use constant time slices, using the "natural" time coordinate as defined by an observer far from the black hole. This gives silly results, but that is only because of badly behaved coordinates.

Re:Probably Something Stupid (1)

myowntrueself (607117) | about 6 years ago | (#22946852)

it doesn't actually have a well-defined radius (since you can't measure across the middle!)

Why do you need to measure *across* the middle to measure the radius?

Is there a (theoretical) problem with using some kind of high tech space calipers to measure the radius without going anywhere near the 'middle'?

Re:Probably Something Stupid (0)

pizzach (1011925) | about 6 years ago | (#22946390)

I thought that Black Holes had no dimensions, but this one is several miles across. Where have I gone wrong?
The scientists most likely rounded off the imaginary numbers to make the dimensions more tangible to the human mind.

We weren't the first (4, Funny)

cryptoluddite (658517) | about 6 years ago | (#22945948)

I see we weren't the first to build a large hadron collider.

Re:We weren't the first (2, Informative)

WarJolt (990309) | about 6 years ago | (#22946076)

Fortunately those crazy atom smashing mad scientists don't have the power to do that. Someone hears the term mini-black hole and everyone freaks out. The artificial kind blinks out almost immediately. We just can't generate a sustainable singularity.

Re:We weren't the first (2, Interesting)

Ironsides (739422) | about 6 years ago | (#22946158)

You're telling me someone has artificially created a black hole? When did this happen?

Re:We weren't the first (3, Funny)

Oktober Sunset (838224) | about 6 years ago | (#22946488)

Wikipedia says Goatse.cx was launched in 1999, but Hello.jpg was on IRC before then, so the black hole much have been created quite a while ago quite a while ago.

Re:We weren't the first (3, Funny)

treeves (963993) | about 6 years ago | (#22946564)

Yuck. I hate those artificial ones. They're full of preservatives. Give me a good old-fashioned, all natural, non-GMO, organic black hole any day.

Great joke, but... (1)

megaditto (982598) | about 6 years ago | (#22946876)

Perhaps this LHC business is exactly why we have never encountered alien civilizations?

By the time any of them evolve enough to develop space travel, some smartass comes up with a bright idea of building a giant particle accelerator...

aha (0)

Anonymous Coward | about 6 years ago | (#22945974)

I guess it sucks less than it's bigger siblings

Awwww, little baby one (5, Funny)

Anonymous Coward | about 6 years ago | (#22945984)

It may look cute now. But they grow up.

15 miles across? (-1, Redundant)

JonTurner (178845) | about 6 years ago | (#22945994)

Ok, it's been a while since physics class, but I thought the whole idea of a black hole was a collapse of space/time to a singularity. Would it be more correct to say this is a measurement of the event horizon?

Re:15 miles across? (2, Informative)

Chris Burke (6130) | about 6 years ago | (#22946042)

Would it be more correct to say this is a measurement of the event horizon?

Yes that's what astronomers mean when they say how "big" a black hole is.

Re:15 miles across? (1)

Dopamine, Redacted (1244524) | about 6 years ago | (#22946074)

The volume enclosed by the Schwarzschild radius (and therefore event horizon) is typically considered the 'size' of a black hole for common purposes.

What else is there to measure? A black hole is an object defined entirely by its gravity (unless it's hairy, but even then).

Re:15 miles across? (1)

Toonol (1057698) | about 6 years ago | (#22946260)

Wouldn't the volume be technically infinite? Or at least undefined? It has a measurable surface area (if you're talking about the event horizon), but the curvature of space would make the radius, hence the volume, infinite.

And just following that through... wouldn't that make the average density of a black hole zero? Mass/volume with infinite volume...

Re:15 miles across? (2, Interesting)

naoursla (99850) | about 6 years ago | (#22946178)

What is the theoretical time before this black hole evaporates through Hawking radiation?

Re:15 miles across? (2, Funny)

Bemopolis (698691) | about 6 years ago | (#22946240)

What is the theoretical time before this black hole evaporates through Hawking radiation?

About 10^68 yr. Bring a book.


Re:15 miles across? (2, Insightful)

imsabbel (611519) | about 6 years ago | (#22946290)


A black hole of any stelar size will only radiate like a body in the femto-kelvin range.

This means that galactic background radiation will "refill" it more than it could ever lose.

Re:15 miles across? (1)

John Marter (3227) | about 6 years ago | (#22946828)

What if we start throwing massive (antimassive?) amounts of antimatter at it. Is there a point at which whatever is left could expand out of the black hole condition or does it just have to evaporate?

I'm working off a vague memory that black holes "evaporate" by virtual particles popping into existence near the event horizon and the antiparticle falling into the hole and the normal matter particle moving away from the hole, and that being the Hawking Radiation. Is that about it or am I completely off my rocker? (It can be both.)

Re:15 miles across? (1)

zoltamatron (841204) | about 6 years ago | (#22946380)

Would it be more correct to say this is a measurement of the event horizon?
Well, we ARE talking about a black hole here and I think that if you dwell upon other instances of holes in the world (that they are empty space) then talking about the size of a black hole does make sense.

Size vs Age (5, Interesting)

SKiRgE (411560) | about 6 years ago | (#22945996)

While it may be possible that this black hole was formed from a relatively small (to form a black hole) star, couldn't it also be the case that it just a really old black hole? Hawkings told of how black holes can 'evaporate' over time with lack of surrounding matter, perhaps that could be the case here.

Re:Size vs Age (2, Informative)

The Living Fractal (162153) | about 6 years ago | (#22946166)

Possible, but I believe they evaporate over the course of trillions of years via Hawking radiation. Based on recent evidence, the universe is only old enough for it to still have been the smallest yet discovered.

At least, if I were a scientist and not someone pulling this directly out of my ass, that might be what is happening here.

Re:Size vs Age (5, Informative)

smolloy (1250188) | about 6 years ago | (#22946170)

It is true that black holes will evaporate over time, but they will also gain mass from infalling matter.


The temperature of a black hole can be defined by the rate at which Hawking photons are streaming away from it. In the case of a black hole of a few solar masses, this temperature will be in the nano-Kelvin (I think -- don't hurt me if I'm wrong by a few orders of magnitude). Now remember everything in the Universe is sitting in a bath of cold photons from the Big Bang (i.e. the microwave background). These photons have a temperature of ~4 Kelvin.

Therefore, black holes whose Hawking temperature is above the microwave background will be net *gaining* mass.

Which is all a long way of saying, no, this isn't a normal size black hole that has decayed over time. It must have been created at this mass (or smaller).

Re:Size vs Age (1)

CodeBuster (516420) | about 6 years ago | (#22946766)

Yes, but the evaporation process is extremely slow. The following is an excerpt from the wiki article on Hawking Radiation [wikipedia.org]:

For a black hole of one solar mass (about 2 × 10^30 kg), we get an evaporation time of 10^67 years--much longer than the current age of the universe.
So even though this hole is evaporating like any other it could not have been much larger at the time of its formation (although it might have been somewhat smaller depending upon how much mass it has sucked in during its existence so far), even if it had existed since the beginning of the Universe which is impossible because stars, and especially lower mass stars like the one that most probably formed this black hole, did not emerge until billions of years after the initial Big Bang. The effect of the hawking radiation does not explain the apparent small size of this black hole or, more precisely, it is not a significant factor.

Re:Size vs Age (1)

General Fault (689426) | about 6 years ago | (#22946794)

Perhaps you can answer a question for me. If I understand the concept correctly (and stop me where I go wrong), the event horizon can be defined as the point where any light that were to be ejected (I know, I know not possible) from the singularity perpendicular to the tangent (straight "up") would stop and return. With some simple evaluation, this means that the frequency of any light at the event horizon would be infinite to the "inside?" observer. A similar effect is observed on the "outside" going in whereas the light at the event horizon falling straight in has an infinite frequency to the outside observer. Given the relativistic time stretching effects that this implies, as I understand it, anybody falling in would experience "the end of the universe" as time around him speeds up infinitely. My question is, assuming that I am not simply mistaken about the relativistic effects of the event horizon, is; what happens to that item falling into the black hole when the black hole evaporates? What doest that item experience? Does the universe speed around it up until the black hole evaporates whereby it is released back into the universe? Does the item evaporate with the black hole? Is the item converted into radiation before it gets to the horizon and thus released over time before the black hole evaporates?

the universe is too young (0)

Anonymous Coward | about 6 years ago | (#22946866)

If my memory is correct, a 1 kg black hole is supposed to take about 10 billion years to evaporate from Hawking radiation. If so, there has not been enough time for Hawking Radiation to do its work.

Re:Size vs Age (1)

shma (863063) | about 6 years ago | (#22946958)

No, the time it takes for a stellar black hole to evaporate is much, much longer [wikipedia.org] than the age of the universe, even assuming that no matter is falling into it. For a mass this large, the time is on the order of 10^69 years. It is only microscopic black holes that decay quickly. For instance, if we take a proton-proton collision at the LHC, where each proton has an energy of 7 TeV, and form a black hole out of it, it would have a mass of 10^-23 kilograms and would evaporate in 10^-84 seconds, which is the main reason we don't need to worry about them.

Well, that's no fun. (-1, Offtopic)

Anonymous Coward | about 6 years ago | (#22946008)

I much prefer supermassive [youtube.com] ones that seem to take the piss.

Just me, though. :)

Goldilocks (5, Funny)

Dopamine, Redacted (1244524) | about 6 years ago | (#22946016)

So, we've now discovered the biggest and smallest black holes known to exist within about a week of each other.

When we find the most average, space bears will come and blast us into porridge.

Astronomy kicks ass.

As someone who skimmed A Brief History of Time (0, Redundant)

agrippa_cash (590103) | about 6 years ago | (#22946018)

I thought that black holes took up no space, and now a small one is 15 miles across.

Re:As someone who skimmed A Brief History of Time (3, Informative)

BoChen456 (1099463) | about 6 years ago | (#22946156)

I believe they are referring to the diameter of the event horizon

untrue statement (5, Interesting)

ILuvRamen (1026668) | about 6 years ago | (#22946056)

They can't figure out the "critical threshold" because there isn't one. It all depends on too many variables to set a universal limit (hehehe get it...universal :-P) It depends on how much nuclear activity there is still going on when it start collapsing and what the amount of heavier atoms is and the amount of other things orbiting the star and any other forces affecting the star at that time and how fast it's moving and spinning. Mass is a smaller part of the calculation than they're making it sound like. If they're going to factor everything in just to find some minimum mass, well duh, two particles and a hell of a lot of force. Haven't they suggested that in that big particle accelerator aka donut of doom. So yeah, a critical mass threshold doesn't exist.

Well, all teenies... (0)

Anonymous Coward | about 6 years ago | (#22946100)

...have tiny black holes.
Those scientists surely do not know a lot (if anything at all) around this subject...
captcha: massacre :-D

Completely Off topic (2, Funny)

ijakings (982830) | about 6 years ago | (#22946104)

But is anyone else seeing these Russian bride adverts all over the site?

True theyve probably got a good market to advertise to, Helena wont need as much inflating as your LatexLove3000 but it just seems odd to see them all over Slashdot.

Re:Completely Off topic (1)

MRe_nl (306212) | about 6 years ago | (#22946198)

I personally haven't seen any Russian bride adverts all over the site, but ...

"[The survey company] randomly selected 1,015 nationally representative adults... Although only 40 percent of the group was familiar with the term 'behavioral targeting,' most users were well aware of the practice. 57 percent reported that they weren't comfortable their activities [were being] tracked for advertising purposes, even if the information couldn't be tied to their names or real-life identities. Simultaneously, 72 percent of those surveyed said that they find online advertising annoying when the ads are not relevant to their needs..."

Obligitory Redundancy (1)

Dopamine, Redacted (1244524) | about 6 years ago | (#22946116)

Enclosed within this post was the 5th response relating to the Large Hadron Collider.

Unfortunately, the planet the post was made on was sucked into a black hole shortly after the post was made and the actual content of the post was forever lost.

Theoretical limit is 1.4 Solar Masses (2, Informative)

syousef (465911) | about 6 years ago | (#22946162)

For those of you who haven't done any Astrophysics...

http://en.wikipedia.org/wiki/Chandrasekhar_limit [wikipedia.org]

Re:Theoretical limit is 1.4 Solar Masses (1)

esampson (223745) | about 6 years ago | (#22946292)

I believe according to the link you sent that the Chandrasekhar limit is the upper limit for how massive a non-rotating star can be before it collapses into a black hole (there are obviously plenty of stars with more mass than this but they have rotation or other things that prevent them from collapsing). What the article is talking about is a theoretical lower limit for how small something can be before naturally forming into a black hole. This is not necessarily the same since you could have a smaller body that is acted upon by some natural force that causes it to form a black hole at a mass lower than the Chandrasekhar limit.

Re:Theoretical limit is 1.4 Solar Masses (1)

syousef (465911) | about 6 years ago | (#22946910)

I've studied Astronomy. The Chandrasekhar limit is a classic piece of Astrophysics that should be part of any popular article discussing the limiting size of an object becoming a black hole. I don't know of a mechanism that might cause a smaller body to form a black hole. That force would need to be applied in such a way as to overcome electron degeneracy pressure.

1.4 solar masses is much smaller than the masses we're observing for black holes. My point was we haven't approached this yet. There are other forces acting but 1.4 is the absolute limit for a black hole at time of formation.

Now there is one way a black hole can be smaller and that is if it loses mass. Stephen Hawking and Jacob Bekenstein found a way that this could happen that involves quantum mechanics.

http://en.wikipedia.org/wiki/Hawking_radiation [wikipedia.org]

Re:Theoretical limit is 1.4 Solar Masses (1)

jlkelley (35651) | about 6 years ago | (#22946340)

No, the Chandrasekhar limit is based on electron degeneracy pressure versus self-gravitation and is the maximum mass for a white dwarf. From the wikipedia article you reference:

As white dwarf stars are supported by electron degeneracy pressure, this is an upper limit for the mass of a white dwarf. Main-sequence stars with a mass exceeding approximately 8 solar masses therefore cannot lose enough mass to form a stable white dwarf at the end of their lives, and instead form either a neutron star or black hole.
[emphasis mine]

Re:Theoretical limit is 1.4 Solar Masses (1)

syousef (465911) | about 6 years ago | (#22946950)

Yes, thanks for quoting the article I linked to back at me. Now what was your point?

Mine was that the Chandrasekhar limit is important to any discussion on black holes.
>1.4 solar masses - possible black hole
1.4 solar masses - not enough mass to collapse the thing.

Now there is a way a black hole can form then lose mass - Hawking radiation.

A glitch (0, Offtopic)

Apoorv Khatreja (1263418) | about 6 years ago | (#22946258)

Albert Einstein's image in the post is running over and overlapping the 'Related Stories' bar which is not looking decent. I do not understang the need for three images when you could do with one.

moron discovering new directions home (-1, Offtopic)

Anonymous Coward | about 6 years ago | (#22946718)

it's becoming clear that we can get there from here. see you there? let yOUR conscience be yOUR guide. you can be more helpful than you might have imagined. there are still some choices. if they do not suit you, consider the likely results of continuing to follow the corepirate nazi hypenosys story LIEn, whereas anything of relevance is replaced almost instantly with pr ?firm? scriptdead mindphuking propaganda or 'celebrity' trivia 'foam'. meanwhile; don't forget to get a little more oxygen on yOUR brain, & look up in the sky from time to time, starting early in the day. there's lots going on up there.

http://news.yahoo.com/s/ap/20071229/ap_on_sc/ye_climate_records;_ylt=A0WTcVgednZHP2gB9wms0NUE [yahoo.com]
http://news.yahoo.com/s/afp/20080108/ts_alt_afp/ushealthfrancemortality;_ylt=A9G_RngbRIVHsYAAfCas0NUE [yahoo.com]
http://www.nytimes.com/2007/12/31/opinion/31mon1.html?em&ex=1199336400&en=c4b5414371631707&ei=5087%0A [nytimes.com]

is it time to get real yet? A LOT of energy is being squandered in attempts to keep US in the dark. in the end (give or take a few 1000 years), the creators will prevail (world without end, etc...), as it has always been. the process of gaining yOUR release from the current hostage situation may not be what you might think it is. butt of course, most of US don't know, or care what a precarious/fatal situation we're in. for example; the insidious attempts by the felonious corepirate nazi execrable to block the suns' light, interfering with a requirement (sunlight) for us to stay healthy/alive. it's likely not good for yOUR health/memories 'else they'd be bragging about it? we're intending for the whoreabully deceptive (they'll do ANYTHING for a bit more monIE/power) felons to give up/fail even further, in attempting to control the 'weather', as well as a # of other things/events.

http://video.google.com/videosearch?hl=en&q=video+cloud+spraying [google.com]

dictator style micro management has never worked (for very long). it's an illness. tie that with life0cidal aggression & softwar gangster style bullying, & what do we have? a greed/fear/ego based recipe for disaster. meanwhile, you can help to stop the bleeding (loss of life & limb);

http://www.cnn.com/2007/POLITICS/12/28/vermont.banning.bush.ap/index.html [cnn.com]

the bleeding must be stopped before any healing can begin. jailing a couple of corepirate nazi hired goons would send a clear message to the rest of the world from US. any truthful look at the 'scorecard' would reveal that we are a society in decline/deep doo-doo, despite all of the scriptdead pr ?firm? generated drum beating & flag waving propaganda that we are constantly bombarded with. is it time to get real yet? please consider carefully ALL of yOUR other 'options'. the creators will prevail. as it has always been.

corepirate nazi execrable costs outweigh benefits
(Score:-)mynuts won, the king is a fink)
by ourselves on everyday 24/7

as there are no benefits, just more&more death/debt & disruption. fortunately there's an 'army' of light bringers, coming yOUR way. the little ones/innocents must/will be protected. after the big flash, ALL of yOUR imaginary 'borders' may blur a bit? for each of the creators' innocents harmed in any way, there is a debt that must/will be repaid by you/us, as the perpetrators/minions of unprecedented evile, will not be available. 'vote' with (what's left in) yOUR wallet, & by your behaviors. help bring an end to unprecedented evile's manifestation through yOUR owned felonious corepirate nazi glowbull warmongering execrable. some of US should consider ourselves somewhat fortunate to be among those scheduled to survive after the big flash/implementation of the creators' wwwildly popular planet/population rescue initiative/mandate. it's right in the manual, 'world without end', etc.... as we all ?know?, change is inevitable, & denying/ignoring gravity, logic, morality, etc..., is only possible, on a temporary basis. concern about the course of events that will occur should the life0cidal execrable fail to be intervened upon is in order. 'do not be dismayed' (also from the manual). however, it's ok/recommended, to not attempt to live under/accept, fauxking nazi felon greed/fear/ego based pr ?firm? scriptdead mindphuking hypenosys.

consult with/trust in yOUR creators. providing more than enough of everything for everyone (without any distracting/spiritdead personal gain motives), whilst badtolling unprecedented evile, using an unlimited supply of newclear power, since/until forever. see you there?

"If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land."

meanwhile, the life0cidal philistines continue on their path of death, debt, & disruption for most of US. gov. bush denies health care for the little ones;

http://www.cnn.com/2007/POLITICS/10/03/bush.veto/index.html [cnn.com]

whilst demanding/extorting billions to paint more targets on the bigger kids;

http://www.cnn.com/2007/POLITICS/12/12/bush.war.funding/index.html [cnn.com]

& pretending that it isn't happening here;

http://www.timesonline.co.uk/tol/news/world/us_and_americas/article3086937.ece [timesonline.co.uk]
all is not lost/forgotten/forgiven

(yOUR elected) president al gore (deciding not to wait for the much anticipated 'lonesome al answers yOUR questions' interview here on /.) continues to attempt to shed some light on yOUR foibles. talk about reverse polarity;

http://www.timesonline.co.uk/tol/news/environment/article3046116.ece [timesonline.co.uk]

Wouldn't the smallest black hole (0)

Anonymous Coward | about 6 years ago | (#22946802)

be Goatse? (no links; if you have not seen one yet, then you do not belong on /. or in the white house).
Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account