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>> A powerful outburst in a distant galaxy produced photons with high enough energies to be detected by ground-based telescopes for the first time First sentence makes no sense. several galaxies produce photons with high enough energies to be detected by ground-based mark-1 eyeballs every night. Staggering numbers of galaxies produce photons with high enough energies to be detected by ground-based telescopes every ni…
Earlier quoted context omitted.
If you can look up and see gamma rays with your eyeballs, marvel has a movie deal for you.
The wording of the article made it sound like it went thru the atmosphere only because it’s got high energy. Which is wrong, it should be despite of.
Earlier quoted context omitted.
The wording of the article made it sound like it went thru the atmosphere only because it’s got high energy. Which is wrong, it should be despite of.
Its not really wrong. The atmosphere absorbed most of it but some made it through because there was so much of it. The atmosphere happens to absorb most of the high energy wavelengths involved, it also absorbs many low energy wavelengths. There are 'windows' of wavelengths which get to pass through to different degrees. The details are intricately grasped by quantum electrodynamics, but don't really lend themselves t…
A gamma ray is just light, we would expect the signal to get attenuated early on in the atmosphere. This particular one had enough oomph to punch down to ground level instruments and actually generate a response. Either it lucked out statistically and had a momentary straight shot to the ground (I mean, it could happen), or the thing had so much energy it ploughed straight through anything that got in its way before dumping the rest of its energy in the detector/ground beneath it.
Regardless, that is one hell of a signal. The worst case of starburn imaginable. Short of death by neutrino flux in proximity to a supernova any way.
Are GRBs a danger to astronauts and people in the International Space Station?
Are people on Earth safe from GRBs?
A magnetar quake 500 light years away would sterilize the planet (but not harm the magnetar at all). Fortunately, the nearest magnetar we know about is 9000 light years away, so its blast would be ~300 times weaker, just enough for a garden-variety mass extinction, and end of civilization. But there might be one closer.
All the ones we detect happen millions of times farther away. So they are only terrifying if you think about how we can even tell something happened that far away.
>> A powerful outburst in a distant galaxy produced photons with high enough energies to be detected by ground-based telescopes for the first time First sentence makes no sense. several galaxies produce photons with high enough energies to be detected by ground-based mark-1 eyeballs every night. Staggering numbers of galaxies produce photons with high enough energies to be detected by ground-based telescopes every ni…
The subject of the sentence is "a powerful outburst" not "a distant galaxy". The powerful outburst produced photons with high enough energies to be detected by ground-based telescopes for the first time.
>> A powerful outburst in a distant galaxy produced photons with high enough energies to be detected by ground-based telescopes for the first time First sentence makes no sense. several galaxies produce photons with high enough energies to be detected by ground-based mark-1 eyeballs every night. Staggering numbers of galaxies produce photons with high enough energies to be detected by ground-based telescopes every ni…
Maybe they mean it was the first time for that particular galaxy?
This is so insane to me. I knew the wavelengths were small but not this small. Nature is so cool!
AMA ;)
>> A powerful outburst in a distant galaxy produced photons with high enough energies to be detected by ground-based telescopes for the first time First sentence makes no sense. several galaxies produce photons with high enough energies to be detected by ground-based mark-1 eyeballs every night. Staggering numbers of galaxies produce photons with high enough energies to be detected by ground-based telescopes every ni…
Well, the sentence has to be understood in the context of the headline, which specifically talks about gamma radiation, which so far was not possible to observe from earth as the atmosphere absorbs it. So this must have been a really scary event, sending photons over 4 billion light years, energetic enough to pass through the absorbing atmosphere. We can only hope to never be hit by a GRB from our cosmic neighbourhoo…
We only detect the particles indirectly.
When a high energy particle enters the atmosphere, it creates a cascade of particles called an air shower. In that cascade, charged particles, mainly electrons and positrons, travel faster than the speed of light in air and thus produce Cherenkov radiation.
This is light in the UV to blue visible range, you may know it from pictures of nuclear power plants.
The telescope measure the Cherenkov light and from that reconstruct the properties of the particle that created the air shower.
This event was not the first time we measured high energy photons on the ground, we do each night. But it was the first time we measured them from a GRB.