Ultrahigh-energy photons up to 1.4 PeV from 12 γ-ray Galactic sources (2021)

https://www.nature.com/articles/s41586-021-03498-z

by gone35 • 4 years ago

67 38 4 years ago

For laymen, can someone who is knowledge put this into persepective ?

planck01• 4 years ago

Its 100 times as much energy per photon than we as humans are able to accelerate particles in the cern large hadron collider with everything we have. It is a stupendous amount of energy per photon.

eesmith• 4 years ago

https://en.wikipedia.org/wiki/Oh-My-God_particle might help.

_Microft• 4 years ago

There is another, imo even better, page on this particle:

https://www.fourmilab.ch/documents/OhMyGodParticle/

adhesive_wombat4• 4 years ago

At 320 EeV, the OMG particle is over 5 orders of magnitude more than 1.4 PeV. It's a completely nuts amount if energy to have in a single particle: about the same as a decently moving baseball. From the particle's frame, it takes only a day to go a billion light years.

johndough• 4 years ago

1.4 PeV are about 0.224 millijoules or roughly an 8 billionth of a phone charge, so not much really. However, the photons we usually deal with are weaker by an unimaginable amount, but also much more plentiful. For example, a 100 W light bulb emits something in the order of 10^21 photons per second. If you had a light bulb that emitted the same amount of photons with 1.4 PeV each, you'd have a device equivalent to one Tsar bomb (the most powerful bomb ever detonated in the history of mankind) every second.

contravariant• 4 years ago

It's roughly the amount of kinetic energy in a single grain of rice if you gently throw a handful of them. It's not much, but it's not an inconceivably small amount of energy either.

Comparing it to a phone charge is less useful because batteries store a lot of energy (especially when converted to kinetic energy).

adhesive_wombat4• 4 years ago

That's a big old phone battery: 8 billion times 0.2mJ is a 120000mAh 3.7V battery.

But yes, it's in that ballpark and it's a loooot of energy to pack into a proton.

elorant• 4 years ago

It’s x100 times more powerful than the collider at CERN. 14TeV vs 1.4 PeV. To put it into context, 1 TeV is the energy a mosquito uses to fly. It doesn't sound like much, but for a particle as small as a photon it's a huge amount of energy.

immmmmm• 4 years ago

It's maybe worth mentioning that the beams at CERN are made of quite a few particles and there was as much energy in the beam as in a high speed train (and same in the magnets), before the high luminosity upgrade. The beam dumps are massive pieces of graphite and concrete with water cooling.

Also at these energies the wavelength is very small so the energy can be quite concentrated in a small region of space-time.

reactspa2• 4 years ago

Question: how come a photon can carry a variable amount of energy? (Layman here, I would have guessed that photons travel at the speed of sound, and are of fixed size and energy, like electrons.)

teraflop2• 4 years ago

Here's another way to put this into perspective:

Photons carry momentum, although it's too small to be perceptible under ordinary circumstances. If a typical photon of sunlight hits an oxygen molecule in the Earth's atmosphere, and deposits all its momentum, it's enough to give that molecule a "kick" of a few centimeters per second.

In contrast, a single one of these cosmic ray photons carries enough momentum (if it could somehow be delivered in the right way) to accelerate an entire E. coli bacterium, weighing as much as billions of oxygen molecules, to supersonic speeds.

pmayrgundter2• 4 years ago

Imagining a cartoon image of it flying through the air yelling "Wheeeeee!" :)

belter• 4 years ago

One of the coolest and easiest Physics home experiments, is to build your own cloud chamber, and use it as a particle detector.

https://www.snolab.ca/outreach/resources-for-students-educat...

"Build a particle detector":

https://www.snolab.ca/wp-content/uploads/2021/11/Build-a-par...

https://youtu.be/xky3f1aSkB8

"Cosmic Rays and the Cloud Chamber":

https://crater.unh.edu/pdfs/CosmicRayBook.pdf

hyperbovine• 4 years ago

This was always my favorite exhibit at the Exploratorium.

xattt• 4 years ago

About 20 years ago, I was on trans-oceanic flight. Coffee was served at some point in the flight, and I am convinced the steam coming off the beverage, along with the higher altitude created a cloud chamber in front of me.

While the coffee cooled, there were very distinct cosmic ray patterns within the steam that I cannot come up with any other explanation for.

pmayrgundter2• 4 years ago

Thanks for saying this. I've seen the same and wouldn't have thought of this explanation

saiya-jin• 4 years ago

https://youtu.be/xky3f1aSkB8

On a highly unrelated note, looking at the video, the lady looks and sounds kind of familiar. US LHC, nah, too far, not probable. But then - "Filmed in CERN's S'Cool Lab". Bingo (I live in Geneva, Switzerland where we have CERN) - I did some hikes and climbing with her maybe some 7 years ago.

The world is sometimes surprisingly small. And yeah, its amazing how little equipment can get you so far.

jeffbee• 4 years ago

And people say they don’t need ECC.

a9h74j• 4 years ago

In this context, Energetic Collision Correction

Ultrahigh-energy photons up to 1.4 PeV from 12 γ-ray Galactic sources (2021)

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