A Mysterious Burst of Energy In Space Has Smashed Records (vice.com) 82
For the first time, astrophysicists have observed a cosmic explosion emit particles that are a trillion times more energetic than visible light, a record-setting measurement from a phenomenon that scientists are still seeking to fully understand. Motherboard reports: The observation of this powerful gamma-ray burst (GRB), as these explosions are known, adds another layer to what scientists think happens when a star implodes. The findings were published on November 20 in two papers in the journal Nature. [...] After the GRB was detected, telescopes on the island of La Palma in the Canary Islands quickly adjusted to observe it. The telescopes are overseen by the MAGIC collaboration, weigh 64 tons each, and were designed to measure extremely high-energy emissions from gamma-ray bursts. They automatically process alerts from satellites and adjust to face the bursts in less than a minute. A fast response time is crucial: Gamma-ray bursts can last from a fraction of a second to mere minutes. Elena Moretti was one of the scientists working the night of the GRB's detection, and a co-author of the two studies.
The burst came from a progenitor star that was 4.5 billion light-years away, according to the studies -- relatively close, astronomically speaking. The farther away high-energy particles are from Earth, the more likely they are to be absorbed by extragalactic background light and not reach our telescopes. After verifying that the GRB observed emitted photons in the TeV range, scientists realized the process used to explain and model these bursts could not account for such a high energy. Instead, Moretti said they are nearly certain that the emitted photons were raised to a TeV-level energy after colliding with nearby electrons.
The burst came from a progenitor star that was 4.5 billion light-years away, according to the studies -- relatively close, astronomically speaking. The farther away high-energy particles are from Earth, the more likely they are to be absorbed by extragalactic background light and not reach our telescopes. After verifying that the GRB observed emitted photons in the TeV range, scientists realized the process used to explain and model these bursts could not account for such a high energy. Instead, Moretti said they are nearly certain that the emitted photons were raised to a TeV-level energy after colliding with nearby electrons.
What a waste (Score:1)
I just got dental X-rays done, if I had timed it right I could have avoided a double dose.
Well, they are x-rays too, at the very least. (Score:1)
[Off-topic, but ...]
To if you had done it just right, you would by definition have gotten the same dosage.
Although there may be a differece, when energies are so high that it would have given an electron in your teeth the energy of a whole apple.
"Absorbed by light" (Score:1)
Did somebody fail basic physics?
I didn't know I could turn a light dark, by turning on another light! ;)
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A photon can be blocked by another photon: they interact, and are destroyed, to produce an electron-positron pair. But it only works for high-energy photons: you can't do this with visible light.
alerts from satellites (Score:1)
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What the terrestric telescopes are actually measuring is Cherenkov light produced by the atmosphere hit by the gamma rays.
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Such high-energy gamma rays will rarely, if ever, make it to the surface of the Earth. The cross-section for scattering in the atmosphere is high. Unlike charged particles, gamma rays become less penetrating as their energy increases above about 1 MeV. It's because of pair production.
Re:alerts from satellites (Score:5, Informative)
There are telescopes on satellites that detect low-energy (~GeV) gamma rays, and see most of the sky at once. There are telescopes on the ground that detect high-energy (~TeV) gamma rays, and see only a small patch of sky at a time. If a gamma-ray burst happens, at first it'll probably be seen only by the satellite-based telescopes. These can then signal the ground-based telescopes to point at the right part of the sky to see the rest of it. That way, you get to see both the low-energy and the high-energy gamma rays.
As to why there are different types of telescopes: low-energy gamma rays are blocked by the atmosphere, so you need to put your telescope on a satellite to see them. High-energy gamma rays are so rare that they're all going to miss your satellite - you can't put a big enough telescope in space to see them - and they're still blocked by the atmosphere, so you can't detect them directly on the ground. But they're high-energy enough that you can detect them from the ground by the flash they produce when they hit the atmosphere. (More specifically, that flash is the Cherenkov radiation from the particle cascade they create.)
Not close (Score:2, Insightful)
4.5 billion light-years in not "relatively close", astronomically or otherwise, considering the universe is less than 14 billion years old.
Re:Not close (Score:5, Informative)
What does the age of the universe have to do with it? The universe expanded at a speed greater than the speed of light, so the observable universe is 93 billion light years in diameter (see first paragraph of wikipedia universe article [wikipedia.org]) and the actual universe is potentially much larger. So yes, 4.5 billion light years is "relatively close".
I can't imagine why your comment is currently 4, Insightful. I can only assume a lot of people think the universe is 14 billion light years in diameter.
Re:Not close (Score:5, Insightful)
Re: Not close (Score:2)
Relative to the other 95%? Why wouldn't it be?
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Are you arguing that 5% of the observable universe diameter is relatively close?
The poster was mistaken to try to compare an estimated "true" size of the Universe with an astronomical observation, which are never quoted using observational distances translated into some cosmological model.
If he wants to do that he needs to inflate the observation using the same cosmological model. If the scaling were linear (I'm sure it it isn't) that would be 30 billion light years or so.
Following this fundamentally wrong procedure the OP would have absurdly concluded that stuff at the edge of observ
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Astronomical observations measure distance using redshift, due to the lack of objects with unknown absolute luminosity broadcasting their distance to us.
This object has a redshift of 0.4245. That's close as hell. The further objects have a redshift of 11, meaning this object is about 4% the redshift of the most distant objects, meaning this thing is "relatively" close.
You're making the mistake of using light-travel distance as a unit of measurement, which no Astronomer does- except
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Now wait a second...
4.5 billion light years away is "relatively close" compared to what, exactly? The entire observable universe could be "relatively close" to the entire universe (including what we can't observe) and so on.
So unless we specify a frame of reference, "relatively close" means nothing.
OTOH considering the type of astronomical events that could affect the Earth and the distance at which they produced, 4.5 billion light years away (or "ago", if you think about it) is relatively far, far away.
Re:Not close (Score:4, Interesting)
I can't find any info on how the distance of the progenitor star was intended to be understood: whether it's proper or light-travel distance. However, the difference between those two are not that big at that distance. At 90 billion ly proper distance, however, the light-travel distance is "only" about 14 billion ly. In any case, 4.5 billion ly is about a third of the distance from us to the cosmological horizon, that could be considered pretty far.
I would like to propose the following definition for whether an object is "relatively close" at cosmic scales: everything that could not be reached from Earth, even if you fired a ray of light at it right now, because due to the expansion of the universe that ray will never reach the target - let's define that as "far away". On the other hand, stuff that is reachable at light speed could be considered "relatively close". And stuff that is reachable at insane but theoretically achievable travel speeds could said to be "close".
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the light-travel distance is "only" about 14 billion ly. In any case, 4.5 billion ly is about a third of the distance from us to the cosmological horizon, that could be considered pretty far.
Yes, but being observations are of the distant past, I'm not sure the cosmological horizon holds any relevance for distance relation.
The observable Universe is, as you noted, ~90Gly in diameter. It's hard to argue that 4.5 is not "relatively" close by any definition of relatively.
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You're wrong. The farthest objects oberved are about 13 billion light-years away. Next neighbor is Alpha Centauri at about 4ly. If we were talking about 1500ly, I might agree about that being still quite close, e.g. some nebulae in our milky way, let's say the great Orion nebula. Andromeda is about 2.5 million ly away, so we might agree on a few million ly being close if we're talking galaxies. Over 4 billion ly? Not close. Really not.
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Furthermore- there is more Universe beyond that even.
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Ok, lmgtfy [lmgtfy.com]
Or the first link there:
Wikipedia list of the most distant astronomical objects [wikipedia.org].
I'll accept your apologies.
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I'm sure since you were going for a snarky retort, you didn't bother to click it and learn what that meant.
Here, I'll go ahead and click the next couple links for you. [wikipedia.org]
Now this is a legitimately confusing topic, and you shouldn't feel ashamed for not understanding how it works.
You should however feel pretty stupid for having been smacked down on a snarky retort that was wrong.
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To be honest, I doubt most of us actually knew what you just posted. I certainly didn't realize the universe was 93 billion light years in diameter. No clue. The ~14 billion light years was what I was thinking as well.
If the universe is ~14 billion years old I assumed (incorrectly) that we were roughly 14 billion years from the center and then 4.5 billion years to this reach this event is relatively close compared to the total age of the universe.
But yeah, your post definitely educated me. It's why I like t
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If the universe is ~14 billion years old I assumed (incorrectly) that we were roughly 14 billion years from the center
Another confusing concept is the Universe doesn't appear to have a "center." No matter where you are in the Universe, everything appears to be moving away from you as if you are the center. This is because spacetime itself is expanding.
To get a sense of why this is, consider a balloon. Before inflating the balloon, mark a few spots on it with a Sharpie. Now inflate the balloon. All the spots will move further from each other, yet none of them are the "center" of the balloon. Each spot might consider i
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To be honest, I doubt most of us actually knew what you just posted. I certainly didn't realize the universe was 93 billion light years in diameter. No clue. The ~14 billion light years was what I was thinking as well.
If the universe is ~14 billion years old I assumed (incorrectly) that we were roughly 14 billion years from the center and then 4.5 billion years to this reach this event is relatively close compared to the total age of the universe.
But yeah, your post definitely educated me. It's why I like to read /. Never know when something like that will come out.
Conceptually the "big bang" is a royal PITA. Because 13.5 to 14 billion years in linear time after a singularity explosion is turning out to be far too short a time frame given the size of the universe. You do notice that the age of the universe in popular mythology of cosmologists swings back and forth from 13.5+ billion years to 14 billion. A mathematical discrepancy that seems to be only explainable as one of convenience.
Then comes the kicker how did that mess of differing intensity that is the cosmic ba
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Then comes the kicker how did that mess of differing intensity that is the cosmic background radiation become lumpy and does it change in shapes over time? If the shape changes then something other than a big bang is going on. My take is that there was no singularity of origin but there have always been little pops that increase the volume of the universe and give the cosmic background radiation its lumpy gravy consistency that allows matter to come into existence. In 4.5 billion years when we collide with the Andromeda galaxy just maybe another little pop will occur as the two black wholes combine and swallow all the matter in both galaxies creating enough dark mass to trigger a little pop.
And you have the balls to call developed cosmological models mythology... LOL.
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What does the age of the universe have to do with it? The universe expanded at a speed greater than the speed of light, so the observable universe is 93 billion light years in diameter (see first paragraph of wikipedia universe article [wikipedia.org]) and the actual universe is potentially much larger. So yes, 4.5 billion light years is "relatively close".
I can't imagine why your comment is currently 4, Insightful. I can only assume a lot of people think the universe is 14 billion light years in diameter.
You are confusing observational astronomers with cosmologists. Astronomers make all of their measurements with respect to apparent directly measurable distance. Estimates of a "true size" of the Universe require employing a cosmological model, of which there are variations. When astronomers report observations they are talking about what they direct;y observe, and yes the the apparent directly observable size of the observable Universe is 13.8 blllion light years and that is what the GRB measurement should
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Redshift is the only unambiguous measurement. Light travel distance is nonsense in any metric except time.
That light traveled for x billion years. When that light was emitted, it was not x billion miles away, and today, it is not x million miles away.
The universe expanded the whole time as that light was traveling- so light-travel distance is not a meaningful unit for measurement of distance. Only the age of the observation.
The redshift of this object is 0.4245 (from the paper)
Redshift (Score:2)
When you look at cosmological scales a more appropriate measure of "how far it is" in space (or time) is the redshift.
A distance of 4.5 billion light years is about 0.3 redshift, so that is relatively close compared with redshifts over 1.0 where some gamma-ray bursts are detected.
This kind of measure captures the fact that the universe had evolved in the time between the emission of the gamma photons and their detection on Earth.
Dodged a bullet (Score:4, Interesting)
A (local) Gamma Ray Burst is one of the Six cosmic catastrophes that could wipe out life on Earth [theconversation.com]
1. High energy solar flare
2. Asteroid impact
3. Expanding sun
4. Local gamma ray burst
5. Nearby supernovas
6. Moving stars
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" 6. Moving stars"
Yeah stars do move. I think perhaps more information is needed on this before we call it am extinction level threat.
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Probably moving close enough to us to perturb our orbit and knock us too close/far from our own star or better still, out of the solar system entirely.
Ya that's it. There was also a PBS series exploring the different types of cosmic events that could end life on Earth or the Earth itself. It included the ones on this list and others like a rouge/wandering Black Hole -- that seemed *really* unpleasant. The only upside to a local gamma ray burst is that it would initially only affect the side of the planet facing the burst. Everyone on the other side would survive the initial event, but probably slowly die off as the damage to the ozone layer spread wo
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... and Gliese 710 [wikipedia.org] might even get closer. There is a 1/10,000 chance, that within 1.3 million years, it will get into the Kuiper belt.
And don't forget that Gliese_710 will be bringing along its own Kuiper belt and Ort Cloud.
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A star passing close to the solar system with a hige delta-v would be *very* catastrophic, as it shared some of its momentum with our currently solar orbiting bodies.
Re: Dodged a bullet (Score:1)
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GRBs and similar events don't have to be so local for be disastrous to life because often their radation is in highly collimated beams. I recall reading an analysis suggesting that assuming life is found throughout the galaxy (forget the universe), it has only a 100M year window of opportunity to develop and advance before it gets illuminated by a sterilizing-strength beam. For me, this is by far the best argument as to why we have not seen evidence of other life forms despite our best efforts to find the
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I recall reading an analysis suggesting that assuming life is found throughout the galaxy (forget the universe), it has only a 100M year window of opportunity to develop and advance before it gets illuminated by a sterilizing-strength beam
Life on Earth began about 3.5 to 4 billion years ago, so if you number is accurate it has survived over 35 of them.
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That is about right. They don't exterminate all life of Earth, just some of it. The more complex and surface dwelling life is most vulnerable.
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A (local) Gamma Ray Burst is one of the Six cosmic catastrophes that could wipe out life on Earth [theconversation.com] 1. High energy solar flare 2. Asteroid impact 3. Expanding sun 4. Local gamma ray burst 5. Nearby supernovas 6. Moving stars
I can see why scientists want to extrapolate data from such an event, and not just for these reasons alone.
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A (local) Gamma Ray Burst is one of the Six cosmic catastrophes that could wipe out life on Earth [theconversation.com]
1. High energy solar flare 2. Asteroid impact 3. Expanding sun 4. Local gamma ray burst 5. Nearby supernovas 6. Moving stars
Wipe out life on Earth is correct for these, but only some life, not all life. We know Earth was hit by 3, 4 and 5 repeatedly in the past, which caused great extinction events when they were large enough, but life always recovered.
Of this list the only one we live in danger of right now (as in could strike tomorrow or next year) is the gamma ray burst, which could hit us with destructive power from even 50,000 light years away. We cannot see the galaxy well enough to know if we are under threat from a poten
Relatively close (Score:1)
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We can 'see' up to about 45 billion light years away (for various reasons)
https://en.wikipedia.org/wiki/... [wikipedia.org]
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Wow another mysterious event that buffles scientists,
I"m sure there is a rational explanation for this and it will fit in the known laws of physics.
With that being said I still can't help but wonder how many of these baffling events are really alien experiments gone wrong. Some green egghead didn't carry the 1.
"We will now throw this switch and have unlimited energy." ...... NO CARRIER
Probably none but one could still wonder.
1TeV = 1kg at 1 furlong per fortnight (Score:2)
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To put that in Slashdot terms, one Tera-electronvolt is about the kinetic energy of a 1kg hand weight crawling along at 1 furlong per fortnight.
If you want it in slashdot terms you need to convert your furlong to football fields and probably rewrap the whole thing in a bad car analogy.
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No Libraries of Congress involved? I'm outta here.
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Its been a while, but we're no longer using 'beowulf clusters' or 'Natalie Portman hot grits' as units?
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Its been a while, but we're no longer using 'beowulf clusters' or 'Natalie Portman hot grits' as units?
How about "Courics" ? Please tel me we are still measuring the volume of bowel movements in "Courics"
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To put that in Slashdot terms, one Tera-electronvolt is about the kinetic energy of a 1kg hand weight crawling along at 1 furlong per fortnight.
If you want it in slashdot terms you need to convert your furlong to football fields and probably rewrap the whole thing in a bad car analogy.
I do seem to see bad car analogies around here far too often.
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Most of you 7-digit ID folks have never had to repair or tune up your own car, and they all look almost identical to each other, so the car analogies aren't as popular as they used to be.
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Most of you 7-digit ID folks have never had to repair or tune up your own car, and they all look almost identical to each other, so the car analogies aren't as popular as they used to be.
My original account was created circa '97-99. Credentials were lost to time.
Re: 1TeV = 1kg at 1 furlong per fortnight (Score:1)
Or 1kg at one acre per chain and per fortnight in more convenient units.
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According to the wikipedia, one TeV is about the kinetic energy of a flying mosquito (in a chart that's part of the wikipedia article on electron volt.)
On the other hand, there's also the "Oh My God" particle, which has its own entry in the wikipedia:
Its energy was estimated as (3.2±0.9)Ã--1020 eV, or 51 J. This is 20 million times more energetic than the highest energy measured in electromagnetic radiation emitted by an extragalactic object[4] and 1020 (100 quintillion) times the photon energy of visible light, equivalent to a 142-gram (5 oz) baseball travelling at about 26 m/s (94 km/h; 58 mph).
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It says nothing about whether they naturally occur, or how often.
You must have known this...
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Re: It's a record (Score:1)
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You will have to clarify. Do you mean there's nothing to detect it, or if we didn't detect it?
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After it strips the atmosphere off the planet and melts the surface, sure.
I'm turning green and ANGRY! Smash! (Score:1)
Notification / Data Feed (Score:2)
I wonder if there is a public service that provides close-to realtime alerts of such events. Not for any practical reason, it's just so I would get a kick out of it...
Electrical/Plasma related Event. (Score:1)
Gamma Ray Telescope are in Space ... (Score:3)
The summary, and the article, make it sound like the telescopes in the Canaries observe the gamma rays emitted by the event.
That is not the case, since gamma rays (and X-Rays) cannot be observed by telescopes on earth's surface. The reason is that our atmosphere makes it opaque for gamma and X-rays. See this atmospheric transmission across the spectrum [humboldt.edu].
What happens is that one or more space telescopes specializing in the gamma ray wavelength detects the event, then astronomers point ground based telescopes to the coordinates trying to detect anything that is going on in the visible spectrum.
I am no specialist, but I am an amateur astronomers and read a lot about astronomy.
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Replying to my own post.
As I said above, the MAGIC telescope [wikipedia.org] does not detect Gamma Rays directly, since the atmosphere is opaque to gamma rays.
But it detects them indirectly, using the Cherenkov radiation [wikipedia.org] emitted when a high energy TeV photon hits the upper atmosphere.
It is the same technique used to detect neutrons in deep mines in Japan and Canada.
The telescopes ... weigh 64 tons each (Score:1)
What does the weight of the telescope matter at all??
At least they don't say, "which is about the weight of 150 mid sized cars" or something even more stupid.
Good thing I keep my music on DVDs, not LPs (Score:2)
Missed it by that much!