Star Falls Into Black Hole

thodelu writes with news that astronomers recently got a look at what they believe is a star falling into a black hole. Phil Plait explains: "As the star approached this bottomless pit, the side of the star facing the black hole was pulled far harder than the other side of the star, which may have been a million or more kilometers farther away from the black hole. This change in pull stretched the star — this stretching is called a 'tide,' and is essentially the same thing that causes tides on the Earth from the Moon’s gravity and when the star wandered too close to the black hole, the strength of that pull became irresistible, overcoming the star’s own internal gravity. In a flash, the star was torn apart, and octillions of tons of ionized gas burst outward! This material whipped around the black hole, forming a disk of plasma called an accretion disk. Magnetic fields, friction, and turbulence superheated the plasma, and also focused twin beams of matter and energy which blasted out from the poles of the disk, away from the black hole itself. The energy stored in these beams is incredible, crushing our imagination into dust: for a time, they shone with the light of a trillion Suns!"

Comments

Is there no escape?

[Anonymous Coward]

Why is Slashdot covering Charlie Sheen now?

Re:Is there no escape?

[Tablizer]

Dammification! You beat me by one minute. Now my Sheen joke will join the black hole of /. moderation

How long does this process take?

[nebaz]

I would be quite surprised if one was able to witness the entire event through a telescope from start to finish. I'm curious how long it takes a star to "fall into a black hole" from start to finish.

Re:How long does this process take?

[barrtender]

Unfortunately I think the only signs we got were x-rays, not anything visible.

As for the duration - there's a couple answers. From our perspective the best I can tell is 41 hours from the note on this picture saying it was a 41 hour exposure.

From the sun's perspective it should take forever if I remember relativity right. Someone with more knowledge can correct me here, as I'm not positive and would like to know more.

Re:How long does this process take?

[barrtender]

I wish I could edit my post. The follow up article has much more information.

There was some (not much though) light that could have been visible:

from our distance of nearly four billion light years, the flash of light was only bright enough to see with big telescopes.

As for the duration:

And this event is not over. As the material whirls around the black hole, turbulence and other forces inside the disk can cause the brightness to change. There have been several flares, and while it had been fading for a few days, suddenly on April 3rd the overall brightness increased by a factor of five!

crushing our imagination into dust

[Ezekiel68]

Inexplicably, no witty comment comes to mind.

Gravity...

[ackthpt]

Is a distortion of both Time and Space.

While a star being stretched and pulled into a Black Hole, and perhaps giving out a death cry (rather poetically written as: "The energy stored in these beams is incredible, crushing our imagination into dust: for a time, they shone with the light of a trillion Suns!") is certainly fascinating stuff. It seems to me that within its own reality the Sun remains unstreched, unbent and happy as can be until it merges with that which is the black hole (which itself is converting matter to energy, emitted from its poles.)

Re:Gravity...

[mmcuh]

No, the tidal effects exist for any observer.

Re:Gravity...

[Charliemopps]

No, tidal forces literally do rip the star apart as it approaches the black hole. It would be torn to its constituent atoms long before it ever got near the event horizon.

Re:Gravity...

[ackthpt]

No, tidal forces literally do rip the star apart as it approaches the black hole. It would be torn to its constituent atoms long before it ever got near the event horizon.

Usually, and what I'm seeing described in the article, is that the gas from the star is pulled from it, which isn't too unusual where one large star with low density orbits a higher density star with greater mass. Energy emitted from the poles is only from the Black Hole itself, not the star being drawn in - likely the matter from the star will eventually contribute to that stream, though - as pole and disc are quite different locations.

Re:Protection

[vuke69]

Do not look into incredible beam shining with the light of a trillion suns with remaining eye.

The force of a trillion suns?

[GameboyRMH]

That's OVER 9000 times the force of 1000 suns!

Light of a trillion Suns!

[Culture20]

You lose, Sentry! Trillion suns beats a million!

Silly question:

[UncleTogie]

As I was thinking about black holes the other day, a few questions came to mind. I'm no astrophysicist, so pardon if they're silly.

The setup: If you pass the event horizon, you're going in, obviously. While you won't take forever to hit the singularity once you're past the event horizon, it APPEARS as such.

1. If I took a cube 100 meters on a side, carved information on it that could be read from a distance, and slung it past the EH, how long would it remain visible? Forever? For the life of the singularity?

2. If for a long period of time, could this be used as a method of "permanent" information storage? I've read too much sci-fi, as I keep picturing an intergalactic bulletin board... just waiting to be read...

4. If the block DOES remain visible, and the singularity eventually has enough dropped blocks into it, would it render the black hole "visible"?

Re:Silly question:

[Anonymous Coward]

carved information on it that could be read from a distance, and slung it past the EH, how long would it remain visible?

It wouldn't be visible once it passed the event horizon. That's the defining characteristic of a black hole's event horizon: nothing escapes, including light.

Re:Silly question:

[mmell]

There's an interesting theory which relates (tangentially) to your question. You see, from your perspective the cube would never quite reach the EH and would appear frozen in time. However, yon cube will sail uneventfully through the event horizon and in short order strike the singularity. This is a paradox, and we all know that any theory which results in a paradox is by definition false. Reducto ad absurdum is a recognized tool for disproving a hypothesis or theory. The Holographic Principal reconciles the paradox.

(the following quoted from Wikipedia)

The holographic principle was inspired by black hole thermodynamics, which implies that the maximal entropy in any region scales with the radius squared, and not cubed as might be expected. In the case of a black hole, the insight was that the description of all the objects which have fallen into the hole, can be entirely contained in surface fluctuations of the event horizon. The holographic principle resolves the black hole information paradox within the framework of string theory.

So, to answer your first question - your cube full of information would remain visible and appear to be outside/on the surface of the event horizon forever.

Yes, you could use this as some form of optical storage - except that other objects will almost certainly be drawn in, obscuring your view of your stored information, and there's absolutely no way to clear your visual field.

To answer your fourth question (I'm going to skip the third, as you did) you'll have the opposite effect - you'll never render the singularity "visible". There is no such thing as a naked singularity. Current theory forbids it. Period. You can completely obscure the event horizon, but the net effect would be to render the singularity more obscured, not the opposite.

Clear as mud?

Re:Silly question:

[MoralHazard]

You have this all backwards WRT how time dilation affects the two frames of reference:

  1) The observer falling into the black hole experiences the trip to the event horizon *normally*. In a finite amount of time, this moving observer will cross the event horizon and reach the singularity--or, at least, his constituent subatomic particles will (tidal force). Crossing the EH is a non-event, for this guy--if the black hole is massive enough, he won't even notice the tidal forces until well after he passes the EH.)

  2) The stationary, outside observer never actually sees the moving observer cross the event horizon. Instead, the outsider sees the moving guy get slower and slower, the closer he gets to that point. (I.e., the moving guy will appear to approach the EH asymptotically.)

For example, consider a hypothetical non-rotating black hole with an EH radius of ~1,000 km. Our two observers are sitting at a distance of ~1,000 km outside of the EH (that's 2,000 km away from the singularity). Suddenly, the more suicidal of the two observers backs off, takes a running start, and hurls himself directly toward the center (singularity) of the black hole with a velocity of 1,000 km/hour.

The suicidal (now moving) observer checks his watch about an hour later and measures his distance to his ship: ~1,000 km from his ship (also 1,000 km from the singularity, in the other direction). Around this time, he's crossing the EH, and probably not noticing anything funny. In his frame of reference, plunging into the black hole, time just moves along normally. Sometime during the next hour, the tidal forces will rip him to shreds. Presuming his consciousness continues the trip along with his shreds (staying in that same moving frame of reference), he'll reach the singularity at the end of the second hour. God only knows what happens, there.

The stationary observer, on the other hand, watches his moving buddy seem to slow down as falls. At the end of the first hour, the stationary observer checks his watch and measures the distance to his buddy: somewhat LESS than 1,000 km from the ship (and MORE than 1,000 km from the singularity. At the end of the second hour, his buddy will still not have reached the 1,000 km mark--the buddy's velocity drops in direct proportion to his distance from the event horizon. With a telescope, the stationary observer would actually see the second hand on his buddy's wristwatch sweep slower and slower as gets closer and closer to the black hole.

Capiche?

Re:Silly question:

[MoralHazard]

NO, absolutely not. An outside observer sees time "slow down" for objects that are approaching a black hole, so that each falling object approaches the event horizon asymptotically BUT NEVER ACTUALLY REACHES IT.

If you watched somebody falling into a black hole, and you kept a telescope trained on his wristwatch, you would see the second hand sweep slower and slower as he got closer to the EH distance. No matter how long your wait, you'll never actually see anything cross the EH from the outside.

(I am not kidding, this is what actually would happen. If this seems unpossible, don't worry too much--unless you've already studied special relativity and grasped at least that much, this is pretty counter-intuitive.)

Re:Silly question:

[MoralHazard]

Time dilation and length contraction are NOT optical illusions. They are very, very real *physical* effects, and there are a number of unarguable, concrete experimental results showing them at work.

You're probably getting confused by the concept of gravity lensing, which is black hole-related phenomenon described by General Relativity.

Re:Silly question:

[Jeremi]

If I took a cube 100 meters on a side, carved information on it that could be read from a distance, and slung it past the EH

You euthanized your faithful Companion Cube more quickly than any test subject on record. Congratulations.

Re:Silly question:

[Anonymous Coward]

No matter how long your wait, you'll never actually see anything cross the EH from the outside.

Not to burst your bubble or anything, but if nothing ever appears to cross the Event Horizon from an outside perspective then everything that has ever fell in would still look as though it hadn't. All the fallen objects would appear to be continuing to circle the black hole just like everything else in the universe appears to be doing. This could quite possibly, if not probably, mean we have all already passed the Event Horizon of a black hole and are on the inside looking out, rather than the outside looking in.

Personally, methinks the math needs a little more work if you calculate an object traveling a minute distance pulled by incredible force would take an infinite amount of time.

Re:Silly question:

[Altrag]

No he wouldn't. He looks back and sees the stationary guy 1000km away, but the light took a certain amount of time to get to him, negating any possibility of seeing the "future". The further out into the universe he looks, the further back in time he looks -- the same as happens to us when we stare really far into the sky from Earth -- if we're looking at something 1000 light years away, we know that it happened 1000 years ago (or more, if something managed to slow down the light for part of the journey). We can NEVER see the future (or for that matter, the present). Even reading this on your screen is old news by a tiny fraction of a second as the light moves from your screen to your eye.

Basically from the moving observer's perspective, nothing unusual is happening at all until the tidal forces kick in.

As he gets closer and closer to the singularity the tidal forces would rip him into atoms, then the atoms get ripped apart layer by layer until you end up with individual quarks (and who knows what it means to rip a quark or an electron apart.. ie: what happens when space is so warped that a signal can't make it from one side of a quark to the other without exceeding c.)

All that said, the stationary observer would NOT see the moving guy forever. As others have noted, along with seeing him slow down indefinitely, we'd also see him redshift indefinitely. Eventually he'd be so redshifted that he'd no longer be detectable by the instruments of the stationary observer. He'd still "be there" but could no longer be seen. A more sensitive instrument could see him for a longer period of time, but he'd still fade out eventually as all instruments no matter how good will have a finite cutoff for what they can detect.

Re:why is is part of the bad astronomy blog?

[Anonymous Coward]

Wild stab in the dark here on that one, 'cause the guy who writes the blog is a professional gamma-ray astronomer, maybe?

Re:Octillions?

[ackthpt]

Is this a rhetorical phrase like ginormous, or is this number actually defined somewhere?

An Octillion is 1,000 Septillions.

A Septillion is 1,000 Augustillions.

An Augustillion is 1,000 Julytillions.

A Julytillion is 1,000 Junetillions.

A Junetillion is 1,000 Maytillions.

A Maytillion is 1,000 Apriltillions.

An Apriltillion is 1,000 Marchtillions.

And a Marchtillion is 1,074 Februarytillions (except every 4 years when it's exactly 1,000 Februarytillions.)

Next time look it up in Googol.

Re:Quick! Let's hurry!

[ackthpt]

Unleash the kerosene powered tubes and *colonize* that sumbitch! Wrap a few trillion kilometers of copper wire around that thing and beam the power back to Earth, we need the energy!

It was probably a publicity stunt for another civilisation's equivalent of Coca-Cola and involved the band Disaster Area.

How The Simpsons influences technology

[cvtan]

Any site that "embiggens" images when you click on them is OK with me.

"Crushing Our Imagination Into Dust"

[guttentag]

I was intrigued by the summary until I read this:

"The energy stored in these beams is incredible, crushing our imagination into dust..."

Black hole = awesome. Black hole swallowing a sun = probably beyond the scope of our comprehension, but not quite so amazing that it can turn an intangible thing like imagination into a tangible thing like dust. The author of the summary may have had his brain turned to dust, but to make a claim like this indicates that the imagination is functioning quite well. Perhaps too well.

Re:"Crushing Our Imagination Into Dust"

[Kufat]

Are you demanding the revocation of the author's poetic license?

Obligatory Niven

[Nom du Keyboard]

If you want to understand the tidal gradient around a very dense object, go read Larry Niven's Neutron Star.

And you shouldn't have had to scan down 123 postings to find this. /. is slipping.

Detection

[VernonNemitz]

It occurs to me that the gravitational-wave astronomers will be looking for a signal from this event. If any gravitational waves produced by it happen to be heading in our direction, that is. From what I understand regarding how such waves would be produced, and how the href="http://www.ligo.caltech.edu/">LIGO system works, detection of a signal may be reasonably expect-able.