APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

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APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby APOD Robot » Wed Jul 22, 2015 4:07 am

Image Gamma-ray Rain from 3C 279

Explanation: If gamma-rays were raindrops a flare from a supermassive black hole might look like this. Not so gently falling on the Fermi Gamma-ray Space Telescope from June 14 to June 16 the gamma-ray photons, with energies up to 50 billion electron volts, originated in active galaxy 3C 279 some 5 billion light-years away. Each gamma-ray "drop" is an expanding circle in the timelapse visualization, the color and maximum size determined by the gamma-ray's measured energy. Starting with a background drizzle, the sudden downpour that then trails off is the intense, high energy flare. The creative and calming presentation of the historically bright flare covers a 5 degree wide region of the gamma-ray sky centered on 3C 279.

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby ems57fcva » Wed Jul 22, 2015 4:14 am

There is a problem here: The video is for New Horizons and not Fermi's gamma ray "rain".

I did find the Fermi video under the first link in the text. It is very interesting and worthy of being on APOD. I have the you get this APOD corrected quickly.

Perk Cartel

Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Perk Cartel » Wed Jul 22, 2015 4:27 am

This fascinating animation conjures bubble formation and foamed structures, much like the distribution of massive scale structure in the greater universe. Might sitting in a spa bath watching the rapid formation movement and dissipation of mounds of roiling foam be a high speed version of a model of the cosmos and its chaotic complexity?

Perk Cartel

Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Perk Cartel » Wed Jul 22, 2015 4:35 am

Why is "Sol" ruled invalid by the securtiy question please?

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby geckzilla » Wed Jul 22, 2015 4:36 am

ems57fcva wrote:There is a problem here: The video is for New Horizons and not Fermi's gamma ray "rain".

I did find the Fermi video under the first link in the text. It is very interesting and worthy of being on APOD. I have the you get this APOD corrected quickly.

It's actually correct. This is an unusual problem that I think has to do with ISP caching of websites. It's not your fault though, so don't fret. The problem usually resolves itself eventually.
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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby geckzilla » Wed Jul 22, 2015 4:37 am

Perk Cartel wrote:Why is "Sol" ruled invalid by the securtiy question please?

Because I didn't think to accept that answer when I came up with the CAPTCHA months ago. It will now accept it.
Just call me "geck" because "zilla" is like a last name.

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Ann » Wed Jul 22, 2015 5:37 am

Today's APOD video is fascinating, but personally I prefer a presentation like this. It shows the blazar flaring and puts it in perspective. I particularly like the comparison with the Vela pulsar. The creative and calming link of today's APOD brings us to a page which said this:

The brightest persistent source in the gamma-ray sky is the Vela pulsar, which is about 1,000 light-years away. 3C 279 is millions of times farther off, but during this flare it became four times brighter than Vela.
:shock:

I suppose 3C 279 must have sucked a particularly nourishing morsel of matter down its awful black hole and had a most tremendous case of bad table manners as a result of what it couldn't swallow.

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Boomer12k » Wed Jul 22, 2015 7:53 am

An interesting way of presenting it...

:---[===] *

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby hoohaw » Wed Jul 22, 2015 9:17 am

I'm glad Ann provided that additional view, but I am delighted with today's APOD. One gamma ray photon at a time! Absolutely terrific!

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Don D » Wed Jul 22, 2015 11:27 am

Wow did our tax money actually pay for this?

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby emc » Wed Jul 22, 2015 12:42 pm

Maybe this helps with my argument that “Milky Way” is just too wimpy of a name. If I lived in 3C 279, I would scoff at such a puny preponderance. I would not be so quick to arms however if “Milky Way” were named... say, “Dragon’s Lair”... or “Death Trap To All Hostile Intergalactic Alien Invaders, Especially Those That Eat Meat”.

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby videobear » Wed Jul 22, 2015 1:45 pm

Why do the gammas appear to arrive in clumps? There seems to be about a half to 3/4 second pulsing in the arrival of the little buggers.

MountainJim

Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby MountainJim » Wed Jul 22, 2015 2:19 pm

Why is it NASA almost never gives music credits for these videos?

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Jim Leff » Wed Jul 22, 2015 2:31 pm

We are frequently reminded that gamma ray bursts are among the most dangerous phenomena that can impact our planet. Yet in all the reports I've seen about 3C 279, including this one, no one's discussed any health impact. I understand this galaxy is way too far away for this to pose danger of any cataclysm, but, given that the purpose of this visualization is to impress us re: the strength of the burst, I can't help but wonder if some small background health effect (ie a handful of quiet, mostly dead-end mutations) may be involved.

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Chris Peterson » Wed Jul 22, 2015 2:40 pm

Jim Leff wrote:We are frequently reminded that gamma ray bursts are among the most dangerous phenomena that can impact our planet. Yet in all the reports I've seen about 3C 279, including this one, no one's discussed any health impact. I understand this galaxy is way too far away for this to pose danger of any cataclysm, but, given that the purpose of this visualization is to impress us re: the strength of the burst, I can't help but wonder if some small background health effect (ie a handful of quiet, mostly dead-end mutations) may be involved.

There is no doubt that cosmic rays represent a source of mutations, impacting both evolution and individual diseases such as cancer. But the health impact of any one event like this is surely lost in the noise, indistinguishable from a million other tiny causative agents (like that coal burning plant in the next town, or the radon in your basement).
Chris

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Chris Peterson » Wed Jul 22, 2015 2:52 pm

videobear wrote:Why do the gammas appear to arrive in clumps? There seems to be about a half to 3/4 second pulsing in the arrival of the little buggers.

Most likely the timing is described by a modulated Poisson distribution, which generally shows such clumping. It is statistically insignificant, but our brains are very adept at detecting such coincident events. Although the events are purely random, there is a finite probability of any two (or three, or four...) happening in any given interval. Our brain, being tuned for correlated events, overemphasizes the occasional clumps in comparison with the steady random background.

This effect is everywhere. We tend to imagine all sorts of random events as clustered- deaths of famous people are reported to come in threes, bright meteors are reported in temporal clusters, plane crashes and natural disasters seem to cluster.
Chris

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby neufer » Wed Jul 22, 2015 3:11 pm

Chris Peterson wrote:
Jim Leff wrote:
We are frequently reminded that gamma ray bursts are among the most dangerous phenomena that can impact our planet. Yet in all the reports I've seen about 3C 279, including this one, no one's discussed any health impact. I understand this galaxy is way too far away for this to pose danger of any cataclysm, but, given that the purpose of this visualization is to impress us re: the strength of the burst, I can't help but wonder if some small background health effect (ie a handful of quiet, mostly dead-end mutations) may be involved.

There is no doubt that cosmic rays represent a source of mutations, impacting both evolution and individual diseases such as cancer. But the health impact of any one event like this is surely lost in the noise, indistinguishable from a million other tiny causative agents (like that coal burning plant in the next town, or the radon in your basement).
https://en.wikipedia.org/wiki/Blazar wrote:
<<A blazar is a very compact quasar (quasi-stellar radio source) associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy. Blazars emit a relativistic jet that is pointing in the general direction of the Earth. The jet's path corresponds with our line of sight, which accounts for the rapid variability and compact features of blazars.>>
https://en.wikipedia.org/wiki/Gamma-ray_burst wrote:
<<Gamma-ray bursts (GRBs) are believed to consist of a narrow beam of intense radiation released during a supernova or hypernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. All GRBs observed to date have occurred well outside the Milky Way galaxy and have been harmless to Earth. However, if a GRB were to occur within the Milky Way, and its emission were beamed straight towards Earth, the effects could be devastating for the planet. GRBs close enough to affect life in some way might occur once every five million years or so – around a thousand times since life on Earth began.

Depending on its distance from Earth, a GRB and its ultraviolet radiation could damage even the most radiation resistant organism known, the bacterium Deinococcus radiodurans. Life surviving an initial onslaught, including those located on the side of the earth facing away from the burst, would have to contend with the potentially lethal after-effect of the depletion of the atmosphere's protective ozone layer by the burst.

The greatest danger is believed to come from Wolf–Rayet stars, regarded by astronomers as likely GRB candidates. When such stars transition to supernovae, they may emit intense beams of gamma rays, and if Earth were to lie in the beam zone, devastating effects may occur. Gamma rays would not penetrate Earth's atmosphere to impact the surface directly, but they would chemically damage the stratosphere.

For example, if WR 104, at a distance of 8,000 light-years, were to hit Earth with a burst of 10 seconds duration, its gamma rays could deplete about 25 percent of the world's ozone layer. This would result in mass extinction, food chain depletion, and starvation. The side of Earth facing the GRB would receive potentially lethal radiation exposure, which can cause radiation sickness in the short term, and, in the long term, results in serious impacts to life due to ozone layer depletion.

Longer-term, gamma ray energy may cause chemical reactions involving oxygen and nitrogen molecules which may create nitrogen oxide then nitrogen dioxide gas, causing photochemical smog. The GRB may produce enough of the gas to cover the sky and darken it. Gas would prevent sunlight from reaching Earth's surface, producing a "cosmic winter" effect – a similar situation to an impact winter, but not caused by an impact. GRB-produced gas could also even further deplete the ozone layer.>>
Art Neuendorffer

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Ron-Astro Pharmacist » Wed Jul 22, 2015 4:56 pm

Chris Peterson wrote:
Jim Leff wrote:We are frequently reminded that gamma ray bursts are among the most dangerous phenomena that can impact our planet. Yet in all the reports I've seen about 3C 279, including this one, no one's discussed any health impact. I understand this galaxy is way too far away for this to pose danger of any cataclysm, but, given that the purpose of this visualization is to impress us re: the strength of the burst, I can't help but wonder if some small background health effect (ie a handful of quiet, mostly dead-end mutations) may be involved.

There is no doubt that cosmic rays represent a source of mutations, impacting both evolution and individual diseases such as cancer. But the health impact of any one event like this is surely lost in the noise, indistinguishable from a million other tiny causative agents (like that coal burning plant in the next town, or the radon in your basement).


We've come a long way in discovering the causes of most cancers in humans. Working in this field it surprises me that, considering the fear the disease evokes, we have the ability to limit, statistically, the most common causes but often don't avoid those exposures. Though it's usually impossible to prove what causes a specific cancer avoidance of known carcinogens seems a no brainer. Gamma-ray rain probably wouldn't be avoidable even with the most spectacular of umbrellas. Making smarter choices, enjoying healthy habits and living life one day at a time appreciating every moment seems to be what I hear from those who both live and die from this cause.
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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby LLAP » Wed Jul 22, 2015 6:22 pm

Awesome. Gamma rain drops are fallin' on my head.

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Chris Peterson » Wed Jul 22, 2015 6:35 pm

Ron-Astro Pharmacist wrote:We've come a long way in discovering the causes of most cancers in humans. Working in this field it surprises me that, considering the fear the disease evokes, we have the ability to limit, statistically, the most common causes but often don't avoid those exposures.

Most people limit their exposure to some known causes, and many limit their exposure to most. In some cases addictions are involved, but even without that, there's always a reward/risk ratio to account for. I'm willing to increase my risks in certain ways in exchange for the increased value I receive in terms of lifestyle. That's true for everyone (even if they don't explicitly calculate those risks).
Chris

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby HomeAl0ne » Wed Jul 22, 2015 10:06 pm

Chris Peterson wrote:
videobear wrote:Why do the gammas appear to arrive in clumps? There seems to be about a half to 3/4 second pulsing in the arrival of the little buggers.

Most likely the timing is described by a modulated Poisson distribution, which generally shows such clumping. It is statistically insignificant, but our brains are very adept at detecting such coincident events. Although the events are purely random, there is a finite probability of any two (or three, or four...) happening in any given interval. Our brain, being tuned for correlated events, overemphasizes the occasional clumps in comparison with the steady random background.


It also seems to me that the events are spatially correlated. When you get a clump, there tends to be several in a straight line, and often the spacing seems regular. Is that an artifact of the detector? I seem to remember something about gamma-ray detectors using concentric metal tubes as lenses...

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Chris Peterson » Wed Jul 22, 2015 11:43 pm

HomeAl0ne wrote:
Chris Peterson wrote:Most likely the timing is described by a modulated Poisson distribution, which generally shows such clumping. It is statistically insignificant, but our brains are very adept at detecting such coincident events. Although the events are purely random, there is a finite probability of any two (or three, or four...) happening in any given interval. Our brain, being tuned for correlated events, overemphasizes the occasional clumps in comparison with the steady random background.

It also seems to me that the events are spatially correlated. When you get a clump, there tends to be several in a straight line, and often the spacing seems regular. Is that an artifact of the detector? I seem to remember something about gamma-ray detectors using concentric metal tubes as lenses...

That's how x-ray imaging systems sometimes work (that is, for photons some thousand times less energetic than the sort this gamma ray sensor is designed for). The gamma ray detector detects photons as they plow through thin conductive foil layers. But the same thing that makes a single Poisson source appear to have temporally clumped events works to make a sky full of them appear to produce spatially correlated events. The clumping is real, but it has no physical significance beyond the mathematics of distributions.
Chris

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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Pianosorplanets » Thu Jul 23, 2015 12:18 am

emc wrote:Maybe this helps with my argument that “Milky Way” is just too wimpy of a name. If I lived in 3C 279, I would scoff at such a puny preponderance. I would not be so quick to arms however if “Milky Way” were named... say, “Dragon’s Lair”... or “Death Trap To All Hostile Intergalactic Alien Invaders, Especially Those That Eat Meat”.

I'm afraid that 3C 279 would look upon our Galaxy as precisely that, though; a nice bit of milk to wash down whatever made it "yack" in the first place. We must look like a snow angel on a Christmas tree to that monster.
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Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby dbooksta » Thu Jul 23, 2015 1:19 am

If I'm reading the description correctly and looking at the aggregated signals: This galaxy 5 billion light years away has a burst that spans about half a degree? The same as the sun and moon? How can that possibly be right?

Norm

Re: APOD: Gamma-ray Rain from 3C 279 (2015 Jul 22)

Postby Norm » Thu Jul 23, 2015 1:22 am

Very nice video of the "rain" of Gamma rays.
My question regards the time lapse that this video represents. Did it happen in days, hours, minutes ?


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