Astronomers may have found youngest black hole

By Phil Plait | November 15, 2010 11:26 am

Astronomers using the Chandra X-Ray Observatory may have found evidence for a young black hole: it was born in a titanic explosion just 31 years ago.

Black holes form when massive stars explode. The core of the star collapses, and if it’s massive enough (more than about 3 times the mass of the Sun), the gravity of the core can crush it down into a black hole.

Enter Supernova 1979c, a star that exploded in the nearby galaxy M100. About 50 million light years away, M100 is a lovely face-on spiral galaxy in the constellation Coma Berenices. SN1979c was discovered in — duh — 1979, and has been heavily studied for years since it was so bright, making it easy to see.


SN1979c was an interesting event, even for something as mind-numbingly violent as a supernova. The star that exploded was right on the edge of being massive enough to create a black hole; the total mass of the star was about 20 times the mass of the Sun, with a core of just about 3 solar masses. The question is, was the star big enough to create a black hole, or would the core collapse to form an incredibly dense neutron star?

Chandra observations may have answered this question. The way a neutron star emits X-rays is different than that of a black hole. As a neutron star cools, the X-ray emission will fade. However, a black hole blasts out X-rays as material falls in; that stuff forms a flat disk, called an accretion disk, around the black hole. As this matter falls onto the newly created black hole, it gets heated to unimaginable temperatures — millions of degrees — and blasts out X-rays. In that case, the X-rays emitted would be steady over time.

What astronomers have found is that the X-rays from SN1979c have been steady in brightness over observations from 1995 – 2007. This is very strong evidence that the star’s core did indeed collapse into a black hole.

Illustration of a pulsarThere is another possibility, though: the X-rays could be generated by a pulsar wind. The neutron star is extremely hot after it’s born, and has an incredibly strong magnetic field. It’s also spinning rapidly. These characteristics make it like a cosmic light house, sending out two beams of energy and matter sweeping around. In this case we call this neutron star a pulsar, because from Earth we see it pulsing as the beams sweep over us. This young pulsar dumps a vast amount of energy into the surrounding material, blowing it outward as a wind (we see this in some pulsars, like the one at the heart of the Crab Nebula). If SN1979c did indeed form a neutron star, it’s possible that could also explain the steady X-rays we see. Only further observations will tell for sure (and I’ll note that the press releases by NASA make it seem a lot more certain this is a black hole, but I think that’s premature; beware of news article making the same claim).

Either way, this is an important result for many reasons. One is that we’ve had the math to calculate the borderline mass between a neuron star and black hole for decades, but it’s nice to see the Universe agrees with our calculations. Whether it turns out to be a neutron star or a black hole, the numbers for the mass that astrophysicists have crunched are pretty close; the very fact that this is a borderline object means our math is solid!

Second, we know almost the precise moment this object was born. That helps nail down a lot of the physics. Black holes and neutron stars are objects of immense power, and when they are this young they can change rapidly on a cosmic scale; observations over just a few decades can show large differences in the brightness or energy of the emitted radiation. Knowing the date of birth to within a few days anchors the calculations and models used by scientists to explain the phenomena.

While this result is in some ways maddening — we don’t really know if it’s a young black hole or a young neutron star — it’s the kind of thing astronomers live for. Excellent observations of a landmark object with cutting edge technology are helping to slice ever-finer the dividing line between two of the weirdest objects the Universe makes. And it’s usually in those thin slivers where the fun lies!

Image credit: X-ray: NASA/CXC/SAO/D.Patnaude et al, Optical: ESO/VLT, Infrared: NASA/JPL/Caltech; Pulsar illustration: NASA

Related posts:

- The Crab is still crabby
- Crabby Hubble
- 1300 black holes
- Just how low can a black hole go?

CATEGORIZED UNDER: Astronomy, Cool stuff, Top Post

Comments (63)

  1. And so the much-awaited news conference with its mysterious topic turned out to be about a paper almost a year out in the open – and apparently ignored by everyone in the science writing/blogging business. Hmm …?

  2. Ed H.

    Wouldn’t it technically be “about 50 million plus 31 years” old? I mean, if the galaxy it’s in is about 50 million light years away, the supernova happened about 50 million years ago, not 31 years ago.

    Maybe “Astronomers may have observed the formation of a black hole”…

  3. Mike

    To Ed H. :

    A light year is a measure unit of distance, and not time. A light year means the distance that you would cover if you could travel with the speed of light for 1 year continously.

    Thus, the young black hole is 50 million light years away from us, but it is just 31 years old.

    Hoped it helped

  4. Tom Ames

    To Mike:

    The light from SN1979c left M100 how many years ago?

    “A lot more than 31 years” was Ed’s point, I believe.

  5. Chris

    I think Ed is right.

    If the super nova became a black hole 31 yrs ago we would have notice that only 50 million years from now – the time needed by the X-rays that proves it is a black hole to reach us.

  6. Mike… Um, no. The supernova took place about 50 million years ago, and the light from it just reached us 31 years ago.

    So, although we are seeing a 31-year-old black hole (if the data is correct), it was formed “50 million and 31″ years ago.

  7. The So called Controversial NASA Discovery is a young Black hole.. This excites me about as much as putting ointment on my Roids. Please someone tell me why I actually should be excited about this? Not feeling it. But if you are please enlighten me?

    How about coming clean and quit lying about other life in our Universe and on our planet. That might actually make me percolate a little bit more.

  8. But as Ed says, if the event happened 50 million light years away, by the time we see it, it happened 50 million years ago.

    I think the point is, what you are looking at is, in fact, a 31 year old black hole–we’re seeing it as it appeared 31 years after its formation. Yes, it took the light 50 million years to get here, but in the end that’s pretty irrelevant.

  9. Ed H.

    Um, no. Because it is 50 million light years away, it means the light from it took 50 million years to reach us. (Or, more precisely, the electromagnetic radiation, which encompasses not just “light”, but also the X-Rays.)

    If the supernova happened 31 years ago, we wouldn’t get *ANY* evidence of it happening for another 50 million years.

    Similarly, if our own sun had spontaneously exploded three minutes ago, it would very definitely be exploded, but we wouldn’t find out for another five and a half minutes – because the Earth is approximately eight and a half light-minutes away from the Sun. The planet Mercury would already be destroyed, but we wouldn’t know about it because the electromagnetic radiation (including light,) hasn’t reached us yet.

    Likewise, if we witness Jupiter spontaneously turn into a star (a la “2010: Odyssey Two”,) one minute later it would not be proper to say “this happened 60 second ago”, it would be proper to say that it happened between 33 and 53 minutes ago. (Depending on the precise position in orbit of each the Earth and Jupiter. If at conjunction, ~53 minutes, if at opposition, ~33 minutes.)

  10. mike burkhart

    Of course this happened 50 millon years ago and we are just seeing it today . This is one of the strangest things about the universe the time diferences: if a new star formed today at 10 light years away then it won’t show up in our sky untill 2020 . You know if we had a spacecraft that could travel 13 to 15 billon light years form Earth we could watch the big bang live. That would be quite a show.

  11. Elix

    In my experience, events observed from Earth are typically referred to as time elapsed in Earth’s frame of reference, just to make things simple. So, yes, SN1979c went nova around 51mil+31 years ago, but our observations were made 31 years ago. So, if the Hubble Space Telescope were to have observed SN1979c in 2008, it’s a lot easier to mention that Hubble observed it 2 years ago, not 51mil+2 years ago, since HST actually pointed at it in 2008.

    It’s a convention to avoid putting large numbers in events that occurred within our lifetime. It’s understood that the light from SN1979c actually left its immediate vicinity far longer than 31 years ago.

  12. Prophet Zarquon

    Really cool research! I love the intelligent discussion of the various possible interpretations and their pros and cons – this is what science reporting should be all about, not just copying press releases.

    (On a probably off-topic note: what the hell? Velikovsky-meets-Descartes pseudoscience? has some rather bizarre ideas, amongst others a dislike for the Big Bang, and they see vortices everywhere.)

  13. SouthernFried

    A quote from the Hayden Planetarium’s website I thought was appropriately neat, “The nearest star to the Sun is more than 4 light-years away. Look to that star in the sky tonight and you’re seeing it as it was 4 years ago. The center of our Galaxy is 26,000 light-years away. The light we see from there left when our ancestors were painting primitive scenes in caves. The farthest object we can see with our eyes, in a dark sky without the aid of a telescope, is the Andromeda Galaxy, more than 2 million light-years away. What was happening on Earth 2 million years ago?” So 50 million years ago we weren’t even a twinkle in evolutions eye.

  14. Chris Winter

    Both Ed H. and Elix are correct. The fact that astronomical distances are temporal as well as spatial is often omitted in order to avoid bogging down the reader in details.

    To be completely accurate, I would not only mention the fact that the supernova in question occurred some 500,000 centuries ago, but also point out the uncertainty in the measurement of M100′s distance from us and the fact that SN1979C lies far out in one of the galaxy’s spiral arms, hence is not quite the same distance as the core…

    …thus giving you all a pedantry overload.

  15. Oli

    “One is that we’ve had the math to calculate the borderline mass between a neuron star and black hole for decades,”

    A neuron star? Is that a star made out of brains? ;-)

    And how his this supposed to have happened 50 million years ago? God created the world 6000 years ago! [/sarcasm]

  16. OmegaBaby

    How the heck do they calculate the mass on a speck in the sky 50 million light years away? I’m curious to know what methodology they use and how accurate they are.

  17. Almost as interesting as the science result is the story behind its publication – the paper spent a full year in review hell, was rejected by both the ApJ and MNRAS and got a “possible” added to the “evidence” for the black hole before it was accepted by a third journal.

  18. felix

    since it’s in a different galaxy I’m assuming there is no immediate threat.

  19. Steve K

    Phil said that the explosion happened “just 31 years ago” because the explosion happened when the light got here. This has come up before:

  20. AJKamper

    Why does a black hole form an accretion disk but not a neutron star? I noticed that wikipedia suggested that neutron stars could have accretion disks hot enough to emit X-rays; obviously I don’t take their word as gospel, but it occurred to me that both have monstrously strong gravitational pulls; either the additional energy would have to be the result of the smaller size of the black hole (with the correspondingly more powerful gravitational pull) or the larger mass of the black hole generally. Is that the case?

  21. QuietDesperation

    What was happening on Earth 2 million years ago?

    An empire of strange water beings was using the Earth as an ammo dump and strike base for attacks along the Sagittarius Arm against their mortal enemies. Their idle tinkering with the primitive life here on Earth led to Homo habilis.

    What? He asked!

  22. timur

    I feel a bit cheated since you said first “Chandra observations may have answered this question”, suggesting that it is a black hole, but then you said it maybe also a neutron star (pulsar), so in the end Chandra observations did not answer the original question. It answered a different question though, I am just thinking that it maybe better if you said it at the outset.

  23. Steve Bryan

    No, pedantry is not finished yet. Simultaneity as a concept only makes sense locally. The elapsed time between two events is path dependent. In the reference frame of a photon traveling 50 million light years the time that has elapsed is zero, nada, zilch! The time that would elapse for something of non-zero mass to travel to that potential black is not 50 million years plus some delta, but rather 0 years plus some delta. The size of delta depends on the acceleration and decceleration and is surprisingly small using only 1 g for both. Special and general relativity scramble our common sense ideas of space and time but they are not controversial, they are verified on a daily basis in the vast number of particle accelerators.

    On the other hand if a photon were reflected back it would have experienced zero time interval along its round trip but the black hole would have experienced a time interval of 100 million years. Just a variant of the old twin astronaut paradox. So even if you gave me my super starship I would not be able to get up close to the black hole before it had aged 100 million years. But more important for me is that I could get there in my lifetime. For the gory details see Gravitation by Misner, Thorne and Wheeler (the big blue book).

  24. andy

    Arguments as to whether it happened 30 years or 50 million years ago are pretty meaningless really. Special relativity tells us that time is a local observer-dependent quantity. It is only because we live in a very small region of space, at very slow speeds that we can get away with thinking of space and time as distinct from each other: on these kind of scales you have to deal with space-time. Perhaps the value c should be called the “speed of causality”, as it has much wider implications than the behaviour of photons.

  25. MaDeR

    “The So called Controversial NASA Discovery is a young Black hole.”
    Who calls it controversial except you?

    “This excites me about as much as putting ointment on my Roids.”
    Well, if space and astronomy does not interes you, what you doing here? Apparently trolling.

    ” Please someone tell me why I actually should be excited about this?”
    You do not have to do. I like this kind of things because Universe fascinates and scares me (in good way).

    “How about coming clean and quit lying about other life in our Universe and on our planet.”
    Er, what? Last I heard, NASA does not claim alien life was discovered*. Or you mean THAT kind of lie (alien coverup)?

    *But apparently for some folks saying this is possible is enough to make tempest in their tea cups… er, brains.

  26. Chief

    re #15 oli

    Brains… Time to haul out the Scooty puff Jr. and put forth the question as to what the star is now, Neutron or Black Hole.

  27. *facepalm* There is no direct observation of the black hole. It’s a calculation based on the effect of what happened 50 million plus years ago. Whatever insane physics equations they worked out; they have determined that if their interpretation of the 50 million year old data is correct, a black hole would have formed 31 years ago.

  28. Chris

    Because of time-dilation, aren’t all black holes the same age? Time should be frozen in the black hole.

  29. Vasha

    Weighing in on the perennial time debate…

    If you could see the entire universe simultaneously, you’d see our Earth as we see it and SN1979c some 50-odd million years on from its explosion. But there’s no way to do this: information travels no faster than light. So, when the light from SN1979c gets to us, it’s “now”, it’s really simultaneous, and the supernova happened 31 years ago. Either that, or you could imagine being near the 31-year-0ld supernova remnant, looking at our star, and seeing it as we see it in 2010; when SN1979c is 50 million years old, they will see us 50 million years on.

    Simultaneity only has any meaning if you take information travel time into account; there is no looking at the universe “from the outside”.

  30. but the BIG question is… could it support life? intelligent life? and would that life want our women?

  31. Tom Ames


    So all of those galaxies with huge red-shifts are NOT representative of what the universe looked like at an early age? And all of the cosmologists who say they’re looking at the development of galaxies in the early universe by studying Hubble deep fields are lying to us?

  32. Aerimus

    hahaha! Semantics strike again!

  33. spcMIKE

    Look, in regards to the 50 million or 31 years question, you’re all wrong. The light stopped at the Quik-E-Mart, got an all syrup super squishy and was able to get to Earth in only 15 years.

  34. Yojimbo

    Interesting! All these comments about time and black holes really shows how inadequate our (locally and experientially derived) language is for describing the real world.

  35. Ed H.

    The only downside with referring to some astronomical phenomena that occurred long ago as happening “right now” is that we also refer to “looking back in time”, for example, at the big bang via the background microwave radiation.

    Either we are looking back in time, or we are seeing “the relativistic present” across distance – pick one. You can’t have it both ways.

    While the article Steve K. links to does have Phil’s disclaimer “as far as we are concerned, that star really did blow up 330 years ago, not 10,330,” the key words are “as far as we are concerned”. Very true. Obviously, even though the star in question (for THIS article,) blew its lid 50 million years ago, there was no way for us to know until 31 years ago. Therefore, “as far as we are concerned”, the star blew 31 years ago. But to state as fact “it blew up 31 years ago” is as patently false as me telling the bill collector “it’s in the mail”, when I know full well I won’t be sending it until tomorrow. :-P To the bill collector, it doesn’t matter – it gets there when it gets there, regardless of when I send it. It’s not “real” to the bill collector until it arrives. But I know the truth. The truth is that transit time matters.

  36. Opinion – Time is a perception based on our four abilities to:

    1. Observe events
    2. Record our observations
    3. Recall our observations
    4. Sequentially analyze our observations

    Remove any of these abilities and the perception of time ends. An example of this is demonstrated by an individual ID’d as HM in literature. In 1953 at age 27 HM had brain surgery to alleviate severe epileptic seizures by destroying brain tissue in the amygdale. Althought the surgery was successful in its intent, there was a horrific unintended consequence of apparently destroying the part of the brain where observations are transferred to memory. After the surgery HM could recall prior events, but had a recall of no more than 5 or 6 seconds. He lived more than 50 years waking up each day expecting to see his 27 year old face in the mirror in the morning. Time had ended for him, much as it has for my 90 year old father with senile dementia. If I visit we can carry on a lucid conversation, but seconds after I walk out the door he doesn’t recall that I was there.

    Consider what is measured to establish what we call time. We take the motion of the earth’s rotation, divide it into 24 segments, those into 60 segments and those into 60 more and so on. We add up rotations to establish weeks, months and so on. For example we establish that when there has been one second of earthly rotation, light has moved about 300,000 kilometers. But all we’ve done is comparatively measure two motions.

    Consider what we call a time and date. It’s like the real estate agents say about the value of real estate; Location, Location, Location. Say you wanted to travel back to a specific date and change something. Nine o’clock AM September 10, 2001 comes to mind. In order for that to happen the earth must occupy the same position relative to the sun, the sun to the galaxy etc. Every photon that was hitting your eyeballs and every neutrino that was passing through your body at that instant must be in precisely the same location and by extension every thing in the universe must be in the same location at 9:00 AM September 10, 2001. That is not going to happen and there is no way to make it happen. As they say the arrow of time goes one way and that is the way the universe is going. All the convoluted mathematical formulas anyone can devise won’t change this. Non-existent wormholes and the effects of black holes won’t change things either.

    So is what we call time a dimension? Perhaps not. I can travel back and forth on a line, add side motion on a plane and up down in cubic space, but can only go with the flow on what is called time. Maybe time doesn’t actually exist. Perhaps the motion of the universe, its contents that we can perceive and hold briefly in our minds while we exist is all there is to “time”.

  37. Dave

    I thought Kanye West was the youngest…

  38. Gary Ansorge

    7. Jim Morrison

    Dude, if you’re color blind, no amount of explanation on my part can inspire a sense of a rainbows beauty in you.

    The same is true here. You either get it,,,or you don’t. So sorry for you,,,

    20. AJKamper

    “either the additional energy would have to be the result of the smaller size of the black hole (with the correspondingly more powerful gravitational pull) or the larger mass of the black hole generally. Is that the case?”

    It’s just the gravitational GRADIENT that pulls people, space craft or planets apart. The gradient is the difference in acceleration between, say, your head and your feet.At four thousand miles from the earths center, that gradient is miniscule. If earth was a black hole(about the size of a marble) the gradient would be extreme when close to its(event horizon), but of course, at 4000 miles away the gradient would be the same as it is now. All that flows from the inverse square law,ie, double your distance from the point source and intensity decreases by the square(ie, 1/4th as intense). I’m only 6’1″ so to experience a significant gradient way out here I’d have to be about 4000 miles tall(twice the distance from earths center as I was to begin with). Then my feet would still experience 1 G but my head would experience 1/4th G.

    Gary 7

  39. Brian Too

    The easiest way to understand the universe (IMO) is as a gigantic time machine. Every time we look out, we see images of objects as they were in the past. The farther away those objects are, the farther in the past we are looking.

    It is entirely correct, as an entry level of understanding, to say that this supernova took place ~31 years ago. The fastest known achievable speed is the speed of light in a vacuum. This is a pretty good match for what really happens in space all the time. The reason is that we can say this supernova is only 31 years old, is that it was only in this timeframe that it was detectable to us. It is not possible even in principle, to have detected it any sooner. That is a true statement of our understanding of General Relativity.

    The master class can allow that this supernova actually took place 50 MYA + 31 years. However even then, there is no technology*, no physics*, that would have allowed us to see it prior to 31 years ago. This is interesting but not actionable information.

    It works in the reverse too. An observer of us in the vicinity of the supernova, would only be able to see us with a time lag of 50 million years. We are eternally separated not only by space, but by time as well.

    * = This discounts speculative warp drives, hypothetical tachyons, and unobtainium.

  40. fuzzyeric

    @20: A recently formed neutron star emits large quantities of radiation in its vicinity, “clearing out the neighborhood”. A black hole cannot emit this radiation. (The material falling into the back hole can, but then simple processes limit most of that radiation along the polar directions, so it doesn’t successfully clear its neighborhood.)

  41. Mark Hansen

    Jim Morrison, this is real. Your fairy-story type aliens are not. Welcome to life in the real world. Please try to enjoy your stay.

  42. Bob H

    Why do black holes emit x-rays when nothing is supposed to escape from them?

  43. Messier Tidy Upper

    Congratulations and thanks to the astronomers of the Chandraspace observatory inviolved. :-)

    Neutron star wind or Black hole, either way these findings enhance and add to our astronomical store of knowledge and this is a fascinating bit of news. Well done. :-)

    Youngest though? What of SN1987 A and its central object :

    Do we still have no idea if a neutron star or Black Hole formed there? Any developments there likely to come to light soon~ish?


    PS. Haven’t yet read the comments here – sorry if this has been said already.

  44. chris j.

    Gary @39: thanks for bringing the discussion away from the distance/time “debate.” i had the same question as AJKamper. i think that you’re right that it’s the gradient that results in such a violent accretion disk, but wouldn’t the gradient for a low-mass black hole be similar to that of a high-mass neutron star? i would certainly expect the disk around a stellar-mass black hole to be more than a few miles out, which would be safely above the surface of a neutron star.

  45. Richard Woods

    Bob H @43

    “Why do black holes emit x-rays when nothing is supposed to escape from them?”

    The X-rays are emitted from material traveling just outside the event horizon. Saying that the BH emits them (or emits any other radiation) is just a verbal shortcut for that situation.

  46. Messier Tidy Upper

    7. Jim Morrison Says:

    This excites me about as much as putting ointment on my Roids.

    Too much information there, mate. :roll: :-(

    I don’t want to know about your haemorrhoids and I strongly suspect nobody else here does either. Please spare us.

    Also if you find this that uninteresting why bother commenting to say so?

    How about coming clean and quit lying about other life in our Universe and on our planet.

    Why assume people are lying? What evidence do you have to support your extraordinary and rather offensive claim there?

    Other life on our planet? Yeah, there’s stacks of it – from chimpanzees and elephants to goldfish and insects – all of it natural and evolving here over aeons. But I take it that’s NOT what you’re referring to though? :roll:

    Alien life elsewhere? Well a lot of smart people are looking for it. If you want to help then why not sign up to SETI at home or something like that, do some research and don’t just troll or believe nonsense, please. That would be much more fun and much more useful than falling for and trolling about dumb and tedious “flying saucer” conspiracy theories.

  47. LittleJim

    @Jim Morrison;

    If you were not able to gather from this article why this is exciting for astronomers, there’s really no help for you here.

    Try something more like this, maybe ->

  48. Smitty

    @ everyone

    Has anyone clicked on #7′s name?

    Wow. Just, wow.

    @ OmegaBaby

    By monitoring the explosion. Astronomers can mathematically predict that a star of a certain level of mass will go supernova in a certain way and with a certain level of intensity.

    It is also possible that they might have been “monitoring” that star because it was showing signs of its imminent death. IE: shedding massive amounts of mass which then results in another type of supernova, also with predictable mass levels and outcomes. At 50M Ly though, I’m not sure if direct monitoring is possible though.

  49. Gary Ansorge

    45. chris j.

    “but wouldn’t the gradient for a low-mass black hole be similar to that of a high-mass neutron star? i would certainly expect the disk around a stellar-mass black hole to be more than a few miles out, which would be safely above the surface of a neutron star.”

    From what I can recall of black hole dynamics, if earth was of neutron star density it would be about the size of a basketball. To collapse it to a black hole, it would be about the size of a marble(2 or 3 cm diameter). The gradient would then be much sharper, since we’re talking a G field sufficient to stop light at a distance of a cm from the BH “center”, another one cm. further out would reduce that G field to 1/4 as intense. For the neutron body, we’re talking 20 cm or so for each such reduction and with equal masses, that G field would already be 1/100 th (just above the surface of the neutron body), as intense as for the BH at its event horizon.

    We don’t really know what goes on inside the BH, we just have a lot of speculation but one idea is that the particles that transfer force between particles(even inside neutrons) can’t go “uphill” against the intense G field, so the particles just collapse into the false vacuum, thus, in this POV, there is no “singularity”(ie, infinitely dense matter) at the center of the black hole. All the mass just becomes the energy of the false vacuum.

    Gary 7

  50. Messier Tidy Upper

    @ 10. mike burkhart Says:

    You know if we had a spacecraft that could travel 13 to 15 billon light years form Earth we could watch the big bang live.

    Unfortunately, that hypothetical spacecraft would still have missed the Big Bang’s Opening Act by over 13~15 million years. The show would be long over – and the space over *there* would be as old as the space *here* – although it’d still be an awesome feat to accomplish! ;-)

    I imagine that if we could such a craft, it would show us something very different about the region it arrived in and how it had evolved from how *we* see it now – & looking back towards us it might see the light leaving the Milky Way when our own home Galaxy was just forming – or even beforehand.

    That’s as I (rather fuzzily) understand things anyhow. If someone with a better understanding of this question than me wants to chime in and correct me that’d be excellent. :-)

    @48. Smitty Says:

    @ everyone – Has anyone clicked on #7’s name?

    Yes, just now out of sheer morbid curiousity & .. Oh. Dear. What. The! :-o

  51. Yeebok Shu'in

    From what I can gather, this hasn’t been covered but not only has it taken that light 50m years (or whatever) to get here, *but* the space in between it has expanded – as such, it may have been far less distance when it set out (hit wikipedia for ‘ant on a rubber band’). The fact remains it’s simplest to talk about when things were seen (aka ‘happened’) here. It’s confusing to consider that we’re seeing something “as it was” but these things need to be kept in mind. When you look at the sun you’re seeing approximately “eight minutes ago”. The centre of the moon is (on average) 238857 miles from the centre of the Earth (miles used for you US lot), and with light going ~186,000miles/sec you’re looking almost 2 seconds into the past when you look at the moon. If the moon blew up at 18:00:00 you would not realise until 18:00:02 – so what time did it happen ? When you saw it.

  52. Anchor

    “this result is in some ways maddening — we don’t really know if it’s a young black hole or a young neutron star”

    Nevertheless, the observed sustained strong x-ray emission from the spot indicates one or the other must be there. There isn’t any other known way to account for it.

    This suggests that the expanding gaseous remnant SN 1987A might begin to clear enough to reveal a signal from the collapsed remnant (expected to be a pulsar) within the next 5 to 10 years. Stay tuned to THAT guy’s coming-out party.

  53. Anchor

    #51 Yeebok Shu’in: What time did it happen? That’s exactly right: “When you see it”. That MUST be ‘now’.

    Most astronomers constantly toil away at the half-assed conventional ‘explanation’ designed to soothe what they consider to be the typical public’s capacity to understand how it works (that is, dumb it down to nearly opaque levels) in which all they ever offer is based on the idea that light takes some finite time to travel from one point to another through an intervening space.

    Then they declare that we are looking at distant stuff “in the past” and leave it at that.

    That is grossly incomplete.

    There is no need for this ridiculous confusion. Yes, from our standpoint 50 million light-years away, the light left the source 50 million years ago. BUT, we receive the information the light carries in proper sequence 50 million years later over here. We apparently see things as they transpired in M100 50 million years ago, to the tiniest fraction of a second, believe it or not.

    HOWEVER, there are certain caveats:

    1. The M100 galaxy contains stars and other stuff that emits detectable light that is not all situated at exactly the same distance. Some parts of that galaxy are tens of thousands of light-years farther away than other parts. It doesn’t matter: what we actually see is a galaxy in which the nearer parts ARE tens of thousands of years displaced from other parts further removed. This is true of ANY galaxy we look at. In other words, we can NEVER observe any galaxy to see it as it is at any given time, nor can the galaxy view ITSELF as occupying any particular moment in time that is contemporary with any point oberver within it.

    2. While we perceive light to travel over some finite distance over some finite span of time, the theory of Special Relativity emphatically informs us that, from the point of view of photons of light, no time whatsoever elapses between emission and absorption. THAT means, quite obviously, that from the viewpoint of photons, absolutely no spatial distance has been bridged, and the ‘crossing’ was instantaneous. The implication is that – from the viewpoint of the photon – no time has elapsed and no space has been crossed: the instant a photon is ‘emitted’, is actually the same instant that it is absorbed by some suitable detector, like our eyes or our instruments. Special Relativity loudly proclaims this, yet few have been paying it any attention.

    The ultimate implication is that we do NOT see the Sun as it “was” 8.3 minutes ago, but as it is in our mutual ‘now’. We look at a quasar 8 billion light-years away, we are looking at it is in our mutual NOW, NOT as it was 8 billion years ago. We capture microwave photons from the Cosmic Microwave Background and declare it some 13.7 billion years old and as distant at the time of emission, but that’s just not true: we are viewing that CMB as it is in our mutual NOW, NOT as it was 13.7 billion years ago.

    There can be no swifter conveyance of information than light, and whatever causal influence that is transmitted at a distance must necessarily arrive as soon as it is transmitted. Special Relativity demands it. Quantum mechanics demands it. The popular notion of “now” (which most astronomers and physicists themselves stubbornly harbor) MUST adjust and assimilate the more complete definition that makes proper sense according to what our theories actually say. Special Relativity and Quantum Mechanics have been howling loudly for the better part of a century, but we haven’t been very good at listening. In fact, we’ve been as good as deaf.

    To continue to wow ourselves over the mezmerizing illusion of ‘lookback time’ interpretations is to erase the essential gifts of Special Relativity. How this stubborn delusion might have messed up our theoretical thinking in the meantime (over the course of a full century!) remains to be seen, but it seems quite clear that the pop explanations have done nothing but confuse an issue which shouldn’t have been confusing at all – and encouraged physicists themselves to think in equivalently dumbed-down terms.

    How long shall it take to shift this entrenched paradigm? And, in the current atmosphere of physics theory which properly casts a wary eye on every detail and crackpot submission, how can the likes of an independent genius such as an Einstein flower? Many noteworthy theoretical physicists have gone on record to say that the insight of an individual genius such as that exhibited by the equivalent of a Newton or an Einstein is probably required to break through the apparent current impasse towards a new understanding, String Theory or Loop Quantum Gravity notwithstanding. That may be true even though there are very interesting flights on the wing produced by a fantastic legion of gifted people. I just doubt that the physics community has exhausted all the fundamental implications they have already had to work with over the last 100 years.

  54. JMW

    Applying our concepts of simultaneity…

    Since SN 1979c happened 50 million light years away, and is therefore approximately 50 million + 31 years old, while SN 1987A was seen by us 8 years later, but is located in the Large Magellanic cloud, about 168,000 ly away, so it actually blew about 168,000 + 23 years ago, and is far more recent.

    Not only that, but SN 1054 was seen 956 years ago, but is only about 6,500 ly away, so it happened approximately 6,456 years ago, and is by far the youngest supernova we know about…

    …assuming a hypothetical objectivity that is, in practice, impossible.

    But then both SN 1987a and SN 1054 formed pulsars, not black holes; unless someone has information I’m not aware of?

  55. Messier Tidy Upper

    @57. JMW :

    But then both SN 1987a and SN 1054 formed pulsars, not black holes; unless someone has information I’m not aware of?

    SN 1054 formed Messier 1 the Crab Nebula.

    Alas, in the case of SN 1987a I’m not sure *what* it formed and I don’t know that anyone, really is. I believe folks have been looking for an expected neutron star remnant and haven’t as yet found one.

    Unless I’m mistaken which is, natch, always a possibility.

    This could mean that it formed a black hole instead or it could, alternatively, mean that a neutron star was formed but that we can’t see it for some reason or perhaps the whole star just blew apart without leaving a stellar corpse of any kind at all.

    After all, SN1987a was unusual in a number of respects – not least being that its precursor star, Sanduleak -69° 202a, was a blue supergiant rather than the expected red variety.


    BTW. Wikipedia gives a distance of 168,000 light-years for SN 1987a meaning the supernova happened approximately 168,000 years prior to its observation in 1987.

    By comparison SN 1054 detonated at a distance (& thus light travel time of) 6,300 hence was still younger in real terms.

  56. Messier Tidy Upper

    Sources for the above info :

    Crab supernova



    Just so I can cut & paste to ensure the correct spelling! ;-)

    Minor note from that last one there :

    Four other LBVs (Eta Carinae included) might join it in a few million years.

    If I recall right, then Eta Carinae could go off anytime or in a few hundred thousand years. I’d be surprised if it lasted another million years or so – although I probably won’t be around still then to be surprised but y’know what I mean! ;-)


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