“Energy is liberated matter, matter is energy waiting to happen.” -Bill Bryson
When it comes to the Universe, you might think that energy really is only limited by rarity: get enough particles accelerated by enough supermassive, super-energetic sources, and it's only a matter of time (and flux) before you get one that reaches any arbitrary energy threshold. After all, we've got no shortage of, say, supermassive black holes at the hearts of active galaxies.
Image credit: NASA, ESA, Hubble Heritage (STScI/AURA).
And yes, we do find cosmic rays hundreds, thousands or even millions of times the energy that the LHC can achieve. But when we think about the Universe in detail, these cosmic rays aren't unlimited in their energy, but are rather stopped in their tracks by the most unlikely of sources: the ultra-low-energy cosmic microwave background, left over some 13.8 billion years after the Big Bang.
Image credit: Hillas 2006, preprint arXiv:astro-ph/0607109 v2, via University of Hamburg.
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Once again Ethan you explain your field of expertise with such laymen clarity. You Are The Best.
Thanks
Question to anyone, Ethan says this:
"We even know — thanks to NASA’s Interstellar Boundary Explorer (IBEX) — that there are about 10 times as many cosmic rays out there in deep space as we detect here on-and-around Earth, as the Sun’s heliosheath protects us from the vast majority of them!"
Is this "heliosheath" around the sun like the Earth magnetic field?
@Ragtag Media #1: Sort of. It's the region just outboard of the "termination shock", which is the surface at which the solar wind streaming outward contacts the surrounding interstellar medium and comes to a stop. See https://en.wikipedia.org/wiki/Heliosphere#Heliosheath
Presumably the heliosphere magnetically deflects the low energy (actually energy/mass) part of the spectrum. I presume the really energetic ones barely feel it. The distance to the heiliopause, and presumably the average strength of the fields contained within is stronger near the maximum of the solar cycle. So the lower energy portion of the spectrum varies inversely with the solar cycle.
Thank You Miguel for the link. Michael, Why is NASA concerned with the effects of Galactic Cosmic Ray effects on humans during long travels to other planets in our solar system like Mars if if the Sun acts as a barrier ans also the cmb like Ethan says here:"
But when we think about the Universe in detail, these cosmic rays aren’t unlimited in their energy, but are rather stopped in their tracks by the most unlikely of sources: the ultra-low-energy cosmic microwave background, left over some 13.8 billion years after the Big Bang."
So now we have the magnetic field of the sun and the CMB or the ultra-low-energy cosmic microwave background, that absorbs these high energy particles of radiation that can damage living tissue on long space journeys supposedly.
But in fact may really be no issue with travel from within our own solar system provided the sun stays the same correct?
@Ragtag Media #4
Space is an awful place. Don't think that just because Interstellar Space outside the sun's heliosheath is worse that conditions inside the heliosphere are even remotely friendly.
Electronics are far more resistant to the effects of the types of radiation experienced in space and even to get electronics to survive in that environment even inside the heliosphere is a challenge.
To help drive this point home, I want to tell you about one of the best people I've ever known. His name was Doug Millward. He was a Physicist and his job was designing systems to withstand the harsh conditions in space.
Through the course of his education and job, he had subjected all sorts of systems and various other things to environments of the type that would be experienced in space. He of course never went into space, and was an expert in the field so knew how to take the proper precautions, but he was around the tests and tested items.
My friend Doug Millward was diagnosed with Acute Lymphoblastic Leukemia and quickly succumbed to it back in 2003. He had no family history of cancer.
I don't care what shielding they claim to have invented. Space, especially outside the Earth magnetosphere, is no place for people. Send a robot.
Because the levels unshielded by the earth's field plus the Sun's field is less than the levels with only the sun's shielding effect.
Sit down somewhere quiet and before posting, think of what you're saying and concoct 10 ways your query COULD be answered. Then investigate.
Either you'll discover your question is already answered or you'll work out where your query is unclear.
There's a thing which was not mentioned in this very interesting article and I've been wondering about: redshift. If the ultra-high energy particles have been created millions to billions of lightyears away, due to expansion of space, they should exhibit a much lower energy now than when they've been created. I suppose this means that they must originate from somewhere relatively close to us or else the GZK cutoff would have bitten them relatively early, right? (on the other hand, a hotter CMB might modify the GZK cutoff, I don't know...)
Most high energy cosmic rays are within our galaxy. Not really for reasons of redshift, but that the very high energy ones are created by the galactic magnetic currents (the addition of all those magnetic fields from the objects in the galaxy, acting as a sort of huge cyclotron. With a huge radius and lots of time, this allows a huge acceleration of particles to very high energies.
@ Denier #5
Thank you very much Denier for sharing that tragic and yet personal story.
Had I of taken the ill advised path of old school thinker here stuck in the past and not ask questions, I would have never known of your personal story.
This at least helps me put a human interaction with what space radiation can do to a person into perspective.
Thanks again
The problem with traveling through Interstellar Space isn't just the CMB radiation. There is also a lot of of Hydrogen just floating around out there, and if you hit it at high speed it turns into radiation that fries everything.
I had brought up the idea of building a linear accelerator around the moon that could accelerate probes using giant moon-based power plants and fling them off in any direction you wanted at incredible speed.
As usual, smart people rained on my parade. I was advised that even if we could do every other part of my plan, we can't send a probe through Interstellar space faster than 0.5c and expect it to remain functional for any reasonable amount of time.
Stupid Universe.
@Denier #10: Relativity (in this case, the Galilean sort) strikes again! Your spaceship hitting the ISM at 0.7 c is exactly the same as sweeping a wide 375 MeV proton beam over the whole ship and its contents (the math is just E = gamma m, gamma = 1/sqrt(1-v^2), and E(kinetic) = E - m, all in units of c=1).
For comparison, the beams used for proton therapy is typically below 100 MeV, but up to 200 MeV for really deep tissue tumors.
@ Michael Kelsey
Mike, just saw this :
http://www.scanpyramids.org/
They are using a way to scan developed by the Japs using cosmic rays via muon radiography imaging.
How much potential is there with this technology? Could the internals of a planet conceivably be scanned this way?
@Ragtag Media #12: 1) Don't appreciate your gratuitous racism. 2) Muon tomography was developed in the 1950s. It was used on one of the pyramids at Giza by Luis Alvarez of Berkeley in the 1960s. 3) No, planets cannot be scanned with muons.
@ Michael Kelsey b#13
1) Don't appreciate your faux sympathy of others causes by showing a lack of gratitude to the 100,000+ lost American lives, quarter million wounded, 20,000+ POW's. All to make you feel like your some how a better person for feigning your down with a cheap cause..... LOL
2) Thanks, for that info, that's eems the case New tech is really old tech refined.
3) OK, but perhaps not with today's technology, but perhaps with future advancements.
Thanks Mike... Urr I mean Miguel :)
@Cracker Media #14: I didn't spend twelve years defending my country to let a bigoted twat use a false equivalence to promote his ignorant and narrow-minded worldview.
Why don't you talk about the 2 MILLION lost Japanese lives, the roughly 1 MILLION civilian deaths, the roughly 600,000 Japanese POWs? Are their lives worth only 1/20 of American lives?
Why don't you talk about the 20+ MILLION lost Soviet lives, additional 20+ million wounded, two million POWs? Are their lives worth only 1/100 of American lives?
Should I call you a cracker? Or a spic? Or a mick? Or a hymie? Tell me, please, which offensive label do you prefer to have applied to yourself, your family, and your friends?
"All to make you feel like your some how a better person "
As you've amply demonstrated ragtag, the only person posting on science blogs who is not a better person than you is see noevo - and it's a draw between you two.
"Tell me, please, which offensive label do you prefer to have applied to yourself, your family, and your friends?"
You see Oh Pompous one, I was raised to understand and appreciate the idiom "Sticks and stones may break my bones (but words will never hurt me)."
and you obviously were not. and as far as " Are their lives worth only 1/20 of American lives?"
Nope, to me they are not. I am about my countryman first and foremost.
Are you?
"As you’ve amply demonstrated ragtag, the only person posting on science blogs who is not a better person than you is see noevo – and it’s a draw between you two."
Dean do you actually comprehend the English language OR even your own thought process?
How the hell can SN not be a better person and yet we be equal?
Dean, with all due respect brother; perhaps "you" should spend "less" time on a science blog and "MORE" time on a proper English one.
Ciao :)