7 ms·
30-year-old black hole discovered by
- ojbyrne 16y agoSo if this is 50 million light years away, shouldn't it be a 50,000,030 year old black hole?
- allenp 16y agoYou beat me to it but yes, I believe so. I think the important part really is just that we are able to see it at such a young stage though.
- cschmidt 16y agoThe article does call it an "observed age" of 30 years later on, but it should have been clearer at the beginning.
- archgoon 16y agoIt's perfectly clear, even if they hadn't said 'observed age'. The entire point of the article is that we're witnessing the development of black hole, thirty years in. How far away it is and 'how long ago' doesn't affect this.
- Cushman 16y agoDepends on your frame of reference. No, really: http://en.wikipedia.org/wiki/Relativity_of_simultaneity http://en.wikipedia.org/wiki/Relativity_of_simultaneity There's not really such a thing as "right now, over there". To use the obvious example, from the perspective of the light, no time has passed since it was emitted at the object and our observing it.
- pyre 16y agoI think the point is that if we were able to instantaneously transport ourselves there we would be observing a 50 million + 30 year old black hole. Nobody talks about things from the the perspective of a photon (in casual conversation, at least).
- eru 16y agoIf you could transfer yourself in an instant, you can even go back in time---with some relativistic trickery.
- baddox 16y agoThat's false, or rather, undefined. To "instantaneously transport ourselves" implies that there is an absolute time frame shared by us and the black hole, i.e. if it's 3:00 PM our time when we transport ourselves, we'll appear at 3:00 PM "black hole time." There simply is no such concept in relativity. For two events A and B separated in space, some observers will see them happening simultaneously, some will see A occur before B, and still other will see B occur before A.
- JoeAltmaier 16y agoYeah, we hear that a lot. But we also know to the millisecond "how long" it took the light to get here etc. Yes, they are different frames of reference. But if we crawled over there we know exactly how much time had passed there, and how old the black hole would be when we got there.
- jerf 16y agoYou said "instantaneously". That usually would imply traveling outside of your lightcone. That really is undefined; an "instantaneous" transport from here can end up anywhere outside of your lightcone, which are all equally well(/poorly) defined in relativity. You can't distinguish those points in either time or space without creating a preferred reference frame. This is the same reason FTL drives are also, fundamentally, time machines. It's really a very profound thing; there's no "yeah, but really we know there's an absolute time frame underneath it all"... there really, really isn't an absolute time frame, and you really, really can't say how old the black hole would be if you "instantaneously" transported there; it is just as valid to instantaneously appear when it is 31 years old as it would be to appear when it is 100,000,029 years old (taking of course the estimated age as its true age). Or, IMHO, just as invalid because FTL and instantaneous truly don't exist. Yes, if you change your claim to be sublight and non-instantaneous we can compute how old it would be, but that's a profound goal post shift. The Minkowski metric is a mindbender, the moreso once you realize that it is not some weird mathematical abstraction with no connection to reality, it is reality, or at least a much better approximation than the one we instinctively use. The "weird mathematical abstraction with no connection to reality" is the implicitly Euclidean/Galilean metric that exists in our heads. (Which can actually be demonstrated to contain fundamental contradictions if you poke them hard enough.)
- steve19 16y agoDid the object exist 31 years ago? Sure it did.
- zohebv 16y agoNot in all frames of reference. There is a frame of reference in which the object appeared just 30.5 years ago. This would be a frame of reference which would be moving from the star towards the earth at 0.9999999999999999*c
- steve19 16y agoDon't we generally report the age of objects relative to themselves (generally not in astronomy or physics)? You are not -1 or +5 in age (relative to myself).
- zohebv 16y agoGenerally yes (but not at astronomical scales), when everyone shares the same frame of reference. Moreover the star and earth in all likelihood don't share the same frame of reference. The distance between the two of us is very tiny. The error in simultaneity between the two of us would be the time it takes a light ray to travel between the two of us. 84 milliseconds in the worst case. So I cannot have a -1 or +5 in age difference with you. The wiggle room is around 84 ms. If you are 1 light year away, the wiggle room now expands to 1 year! Depending on the observer I am 0 or +1 years older than you. On astronomical scales the wiggle room is quite huge. For example there is a frame of reference in which the blackhole celebrates its 30th birthday AFTER the year 2009. When such a frame exists it does not make sense to say that the star is now 50M years old. There is no notion of simultaneity. The word "now" is profoundly misleading. There is no absolute time. Lets say you are a soldier that drops a bomb that kills 30 people. However from your POV you see only 3 dead people. You cannot claim that in your frame of reference only 3 people died. You can only say "I saw 3 dead people". In reality 30 people died. Similarly, there are innumerable frames of reference in which the 30th birthday of the blackhole occured after the year 2009 on earth. So it is misleading to say that the star is now 50M years old.
- zohebv 16y agoThis is correct. Relativity destroys all notions of simultaneity between 2 distant objects. We only have causally and non-causally related events. In this case, the black hole at age 35 can only causally affect us in the year 2015. To put it simply, there exists a frame of reference in which the year 2010 on earth occurs before the 35th birthday of the black hole. So to say that the black hole is 50,000,030 years old in the year 2010 on earth is misleading. It is only true for one very particular frame of reference i.e. the earth.
- alphaBetaGamma 16y agoThat's what Newton said. If you want to nitpick, the only thing we can say is that the black hole's birth is in our past light cone.
- eru 16y agoAnd it wasn't in our past light cone 30 years earlier (earth-time).
- bamazizi 16y ago50 mil light years is a reference of distance (distance light travels in a year) where as 30 years old is a reference of time and age. two very different things.
- NHQ 16y agoIt means that If we looked at this 31 years ago, it wouldn't be a block hole yet. If you were to transport yourself there at 50,000,000 times the speed of light (eg. in a relative instant), you would find it much older than we perceive it now.
- Florin_Andrei 16y agoWell, it's 30 years old as seen in this place, from a light-cone perspective.
- EGreg 16y agoIt should technically be 50,000,030 years old, from our frame of reference. If you were riding the photon, then basically time would stand completely still for you. But that is theoretically impossible...
- siegler 16y agoThey wait until the end to say that it could be just a neutron star. Although the evidence points to a newly formed black hole in SN 1979C, another intriguing possibility is that a young, rapidly spinning neutron star with a powerful wind of high energy particles could be responsible for the X-ray emission
- rbanffy 16y ago50 million light-years away? They called that our "neighborhood" a couple days ago... I think a lesson on expectations management is due.
- toppy 16y agoIs it possible to even notice 30 years in 50M-year frame?
- ceejayoz 16y agoIt is when time zero begins with an explosion that outshines the whole galaxy.
- Confusion 16y agoThirty years ago, an observation was made of an event that happened 50M years ago, 50M lightyears away. Today, we are still making observations of events happening in that same location, 50M years ago. All the observations in between span 30 years here. Given that time is considered to be 'the same' everywhere in the universe, at least in reference frames with a relative velocity of 0, supposing we were there in a reference frame identical to ours, except for the location (so with the same relative velocity to the source of the observations,(obviously neglecting some minor gravitational effects caused by the different surroundings)), the observations would have spanned 30 years there as well.
- psadauskas 16y agoNice human-readable summary here, too: http://blogs.discovermagazine.com/badastronomy/2010/11/15/astronomers-may-have-found-youngest-black-hole http://blogs.discovermagazine.com/badastronomy/2010/11/15/as...
- hartror 16y agoI think every space article I have read on HN has had a better write up by Phil linked in the comments.
- joeycfan 16y agoAnd now the Onion version... '30-year old black hole discovered to still be living with it's mother...'
- deleted 16y ago[deleted]