Ask a physicist anything.

[gipsy]

General relativity describes gravity as warping of the spacetime continuum. Quantum mechanically, it seems to be gravitons. And quantum mechanics is usually held to overrule general relativity...


It's a British term, don't go by the literal translation!

If quantum physics wouldn't be so extremely fascinating, I would hate it

 

[Cabal]

Thanks for your explanations. I'm reading (trying to read) the books of Anton Zeilinger (he's austrian too, so this is the nearest thing for me )

Yeah, I did a summer school at IQOQI in Innsbruck earlier this summer -quantum information is my area - treasure the guys there, they are seriously skilled and have many interesting projects on the go!

and I believe that I have a very basic "understanding" about quantum physics, or at least what it's all about and I've heard the term "virtual photon" from time to time, but there stops every understanding I have

Yeah, QED is tough stuff, as I'm finding out!

I know that gravity is the weakest of the fundamental forces, but still it has (on the macroscopic level) the biggest effects. So if I think of a "force" transportet by any kind of particle, these "particles" should absolutely fill all of space because from the smallest atom to a mega black hole all matter should send out "gravitons", that's why I'm wondering why it's so impossible to find this beast, especially as it's effects are so clearly visible ...

Indeed, but again, it does depend on the degree of interaction these particles will have. A few bajillion (it's a unit, sh'up...) neutrinos pass through you every second, space is full of them, and yet you have to really try hard to detect them. While the graviton is a massless boson, if it's virtual I don't think they have any meaningful capability to interact with instrumentation and be detectable as such.

I think I have to learn more about what a particle is or could be

Yeah, quantum field theories are an interesting avenue of research there - both in particle physics and solid state physics.

This sounds for me much more understandable

Glad it did, but I would definitely ask someone who knows more about GR, I've had surprisingly little education in it so far, which needs fixing (bit more of a quantum person myself....).

 

[gipsy]

Yeah, I did a summer school at IQOQI in Innsbruck earlier this summer -quantum information is my area - treasure the guys there, they are seriously skilled and have many interesting projects on the go!

Sweet, Innsbruck is my birth town, and I started studying physics on the Uni Innsbruck in the 90's with the goal to become a great experimental physicist .
But as it turned out the first few semesters were simply to dry for me, and being a more practical guy I ended up as a Software Engineer.
I also went to school with the brother of Gregor Weihs whom you might possibly have met there?!

Yeah, QED is tough stuff, as I'm finding out!

Yup, especially if you only try to learn it as a hobby with limited time capacities

Indeed, but again, it does depend on the degree of interaction these particles will have. A few bajillion (it's a unit, sh'up...) neutrinos pass through you every second, space is full of them, and yet you have to really try hard to detect them. While the graviton is a massless boson, if it's virtual I don't think they have any meaningful capability to interact with instrumentation and be detectable as such.

OK, massless and virtual ... all nice and not really graspable, but if a graviton exists it should imho have a high degree of interaction as it's effecting every other "mass having"!? particle. Or am I here totally on the wrong track somehow?

Yeah, quantum field theories are an interesting avenue of research there - both in particle physics and solid state physics.

Glad it did, but I would definitely ask someone who knows more about GR, I've had surprisingly little education in it so far, which needs fixing (bit more of a quantum person myself....).

QED & GR are my two pet projects, because they're both fascinating and not really graspable with everyday logic, but as I said only as a hobby, so I don't await to be in any way really knowledgable about them

 

[Wiccan_Child]

Do we really "see" the graviton? ... I think we only see it's effect.

We don't 'see' anything, only their effects on EM waves.

Of course I understand that we'll possibly never be able to see the graviton, but quarks, which we also can't see, have been observerd and evidenced in accelerators.

True, and gravitons have only been inferred to exist because the theory that predicts them is oh-so right about everything else. It would be nice to have something more... concrete.

 

[canehdianhotstuff]

Anyone read about the CRU getting hacked 5 days ago and the release of 72 emails (another source said 61) in an attempt to discredit the man-made part of global warming?

CRU hacked emails taint global warming researchers

 

[Cabal]

Anyone read about the CRU getting hacked 5 days ago and the release of 72 emails (another source said 61) in an attempt to discredit the man-made part of global warming?

CRU hacked emails taint global warming researchers

Only today. Seems like a quote miners' paradise, but that said, this is one research institute, and aren't they the ones coming up with the seriously overdramatic quotes (think the UK government was touting one recently saying that disaster was due in two months or something like that).

The massive irony for me is the number of people who think AGW is all political and yet seem utterly blind to the fact that anti-AGW is as political if not more so.

As I've been pointing out, unless the four facts I've been listing suddenly change, then AGW is a problem - maybe not a critical one right now, but most certainly in the future.

 

[catzrfluffy]

How come cuts only hurt when you see them?

 

[Belk]

How come cuts only hurt when you see them?

Never heard that one before. I guarantee you I have had cuts that hurt prior to seeing it.

 

[pgp_protector]

Never heard that one before. I guarantee you I have had cuts that hurt prior to seeing it.

And I've had cuts that Didn't hurt when I did see them
(Didn't know I was cut tell I saw it either, darn X-acto razor blades )

 

[Wiccan_Child]

How come cuts only hurt when you see them?

Because your brain might not recognise that you've been injured, given the quantity of information you receive. When you look at it, your brain suddenly thinks "Gosh, we're bleeding from Sector 18-β! Focus our attention at that area!", and BOOM, you're feeling the pain.

The brain is fantastic like that. And also a bloody pain.

 

[Doveaman]

The general idea is that it zips to higher dimensions where it can't be found. Or it's too small.

Yes: spacetime. It's a physical thing, though not in the sense of an actual member that holds our guts together.

Nah, just your bog-standard degree

Exactly, we can see the particle: gravity. When we feel the effects of gravity, we're effectively 'seeing' gravitons.

Then again, we know quarks exist, and we've never seen one alone. Some things just don't like to be seen!

"higher dimensions", "can't be found", "too small", "never seen one", "don't like to be seen", "bog-standard degree".
Wow, I'm learning so much here.

 

[Wiccan_Child]

Wow, I'm learning so much here.

I wouldn't be doing very will if you weren't .

 

[catzrfluffy]

What instrument does Patrick Moore play?

 

[Cabal]

What instrument does Patrick Moore play?

PATRICK MOORE
PLAYS THE XYLOPHONE

patrick moore - Weebl's Stuff

ETA: <3<3<3

 

[catzrfluffy]

Is Brian May really an astrophysicist?

 

[Cabal]

Is Brian May really an astrophysicist?

Apparently so!

I've heard a rumour my PhD supervisor was in Dire Straits before they got famous....

 

[Sanguis]

PATRICK MOORE
PLAYS THE XYLOPHONE

patrick moore - Weebl's Stuff

ETA: <3<3<3

CLASSIC!

 

[catzrfluffy]

Just for you:

 

[Thistlethorn]

Nor do I care if you believe me. Your problem, not mine.

So, you come to a science board, spew a bunch of easily refuted crap and then try to twist the burden of evidence? Nice.

I didn't intimate a thing. The news did the intimation. You took it the way it was written. I put nothing into the facts of the stories, which were citing scientific research. That's the way YOU read them.

YOU made the argument. It's YOUR words. Especially since you have still failed to evidence your claim.

Again, I have no need for you to believe that the stories I read are, in fact, stories that I actually read. You wanna be lazy.? Not my business. I already did the work. Passed it on, and you had a conundrum. Then decided that I was the bringer of the information rather that the passer on.

Jebus, it's like talking to a wall. YOU made the assertion, then it's YOUR job to back it up. If YOU fail to back it up nobody is going to take YOU seriously. Go get an education, pal, then come back here.

I made no assertions. I merely posed three questions, which you rode like that guy rode the bomb down in Dr. Strangelove.

You made assertions. Stop lying.

That's the best you got?

I didn't know this was a competition.

 

[TerranceL]

The only time I've injured myself and not felt the pain was when I drove a ice pick into my hand while trying to put holes in a bottle lid that I was going to put bees into.

I'm pretty sure I was in shock.

I have a question: Why when you magnify the light of the sun it causes things to burn, but when you magnify the light of a lamp or something like that it doesn't?