Ask a physicist anything.

[Wiccan_Child]

So what exactly is the deal with the Higgs-boson they are trying to find with the LHC?

The Higgs boson is a particle that gives objects mass. Particles exist in space, and space is filled with Higgs bosons. When they move through this field of Higgs bosons, they are attracted to certain particles and slow them down. We see this as mass.

Basically, the standard model for particle physics has been proven right at every turn, but it predicts that a Higgs boson should exist. If it does, then yay! the standard model is proven once more. If it doesn't, then yay! we know there is something fundamentally wrong with our picture of particles.

The LHC can accelerate particles to such a speed that, when they collide, the Higgs boson should become visable (in some esoteric form). There's a lot of other stuff the LHC will do, but the Higgs boson is essentially it's primary role.

Would a dinosaur with a navel be considered evolution's Achilles Heel?

Yes, though I'm not thrilled about the colloquial terminology going on; I feel you're going to lead me into a semantic trap .

This always confuses me. Newton's third law states that every action has an opposite and equal reaction, that when objects collide, they exert the same force on each other. Why then, does a one ton truck accelerating at lets say 15 m/s2 seem to not react to the 13,000 odd newtons of force exerted on it when it hits a fly?

The only way I've made it through physics so far is by ignoring logic and just doing the equations, but I don't like it!

Because a fly doesn't exert 13,000 Newtons on a truck . Flies, while fast, are extremely light, so the force exerted on a truck is tiny. Flies weigh about 12mg, so the force exerted when a fly hits a truck is about a millinewton. One Newton is about the force an apple exerts on your hand when you hold it, so a fly hitting a truck is hardly anything. Coupled with the facts that a) such a tiny force on such a heavy truck would yield an even tinier deceleration, and b) a truck has a big machine to accelerate it, you won't see any change when a fly hits it.

Basically, the fly's too small to do anything noticeable.

Is that why some wheels on modern cars have alloys that actually go backwards? So you can film them going forwards?

I've never heard of that, and I'd be surprised it's true. It seems a waste of components, space, and thrust, for such a superficial effect.

 

[Thistlethorn]

If 15 people make 15 posts in 15 minutes, how long does it take 1 person to make 1 post?

15 minutes.

 

[Belk]

* bump *
​

Depends on how fast he types and how much he has to say.

 

[AV1611VET]

Yes, though I'm not thrilled about the colloquial terminology going on; I feel you're going to lead me into a semantic trap .

No, sir; but I am going to assume that Behemoth is proof that evolution is wrong:

15 Behold now behemoth, which I made with thee; he eateth grass as an ox.
16 Lo now, his strength is in his loins, and his force is in the navel of his belly.

Note to readers: And I will not discuss this in this thread.

 

[AV1611VET]

15 minutes.

 

[thaumaturgy]

Is that why some wheels on modern cars have alloys that actually go backwards? So you can film them going forwards?

I've never heard of that, and I'd be surprised it's true. It seems a waste of components, space, and thrust, for such a superficial effect.

I think Jazmyn was referring more to spinners (just a guess). And indeed the dudes rolling down the freeways of SoCal on their 20" rims with spinners are probably doing it in the offchance that someone is filming them and they don't want the potential viewers later on to be confused by the apparent backward spin of their tires.

It of course requires a significant amount of technology since it requires the rims to be able to ascertain that indeed the photons bouncing off of them are being captured by a film camera and then to attempt to adjust to the frame rate of the recording device.

But the entire "SoCal Low Rider" subculture is one of the most technologically savvy groups here in Cali. They have spent a significant amount of time improving their gas mileage by the simple act of occasionally defying gravity:

YouTube - Impala 64 Lowrider Hopping

This is what we scientists refer to as a "low low" or more appropriately a "Low[sup]2[/sup]"

 

[pgp_protector]

No, sir; but I am going to assume that Behemoth is proof that evolution is wrong:Note to readers: And I will not discuss this in this thread.

Then why bring it up?

 

[super animator]

I got some questions:

I got the CRC Hand book of chemistry and physics that is publish between 1979-1980 and I wondering to know that most of it is reliable.

Do you have any good reliable websites that is like the book that I was talking about?

What do you enjoy about physics?

 

[IzzyPop]

Has Schrodinger's cat been declawed? And if not, ya'll let the grad students open the box, right?

 

[Jazmyn]

If it does, then yay! the standard model is proven once more. If it doesn't, then yay! we know there is something fundamentally wrong with our picture of particles.

Physics is craaaaaazy.

One Newton is about the force an apple exerts

Is that why it's called a Newton?

And indeed the dudes rolling down the freeways of SoCal on their 20" rims with spinners are probably doing it in the offchance that someone is filming them and they don't want the potential viewers later on to be confused by the apparent backward spin of their tires.

LOLLOLLOL

when a really big star explodes and its centre implodes, is it because the force of the explosion on the outside pushes back the inside, making it implode, or is it something else?

ok, our galaxy is swirling around something in the middle - what is it? 0_0

(now into the chunkier stuff):

1. ...if it's a black hole, why can't we see the bright radiation?

2. Apparently the sun is hottest on the outside, hotter than the middle, why?

3. Asteroids also sometimes orbit other asteroids, even two of equal size orbit each other around a central point, what causes them to do this?

4. Why is the expansion of the universe accelerating?

5. Is there truly such a thing as nothing?

 

[SimplyNothing]

What is the significance of vacuum energy in regards to the structure of the Universe? What is the significance of space being a vacuum itself?

I assume it follows than that the vacuum itself is everywhere correct?

Could the dynamics of the vacuum potentially have something to do with the formation of some of the large scale structures we see in the Universe?

 

[Wiccan_Child]

No, sir; but I am going to assume that Behemoth is proof that evolution is wrong:

15 Behold now behemoth, which I made with thee; he eateth grass as an ox.
16 Lo now, his strength is in his loins, and his force is in the navel of his belly.

Hah, I know you too well. 'Course, this could be used as proof that Job 40:15-16 is allegorical, or that the Behemoth was in fact a placental mammal, or that "navel of his belly" refers to the middle where the navel would be had he had one.

I think Jazmyn was referring more to spinners (just a guess). And indeed the dudes rolling down the freeways of SoCal on their 20" rims with spinners are probably doing it in the offchance that someone is filming them and they don't want the potential viewers later on to be confused by the apparent backward spin of their tires.

It of course requires a significant amount of technology since it requires the rims to be able to ascertain that indeed the photons bouncing off of them are being captured by a film camera and then to attempt to adjust to the frame rate of the recording device.

But the entire "SoCal Low Rider" subculture is one of the most technologically savvy groups here in Cali. They have spent a significant amount of time improving their gas mileage by the simple act of occasionally defying gravity:

YouTube - Impala 64 Lowrider Hopping

This is what we scientists refer to as a "low low" or more appropriately a "Low[sup]2[/sup]"

That's... wow. I had no idea those things existed. Clever invention, if utterly pointless .

I got some questions:

I got the CRC Hand book of chemistry and physics that is publish between 1979-1980 and I wondering to know that most of it is reliable.

Pretty much all of it's reliable, though we've discovered a few more elements on the periodic table.

Do you have any good reliable websites that is like the book that I was talking about?

I know the flak I'll get for citing it, but I'm a massive fan of Wikipedia. Also, if you want the cutting edge, PubMed is really good.

However, without a doubt, the Britney Spears website is the best source of physics info.

What do you enjoy about physics?

Learning how things work, why they do what they do, and not what they don't. It was a real thrill when I finally sussed out how diodes work. Better than crack .

Is that why it's called a Newton?

It's called a Newton because Isaac Newton was the guy to put together the idea of a 'force'. I think it's just a coincidence that an apple is about 1N

when a really big star explodes and its centre implodes, is it because the force of the explosion on the outside pushes back the inside, making it implode, or is it something else?

When a star reaches the end of its life, it can't fuse elements as well as it used to, so gravity begins to overcome the internal pressure. This causes it to collapse.
However, as it collapses, the internal temperature and pressure rockets, which makes the star suddenly able to fuse even the heavy elements (normally, if can only fuse the lightest elements, H, He, Li, etc), which massively increases its energy output. It's this energy that causes the outer layers to suddenly blow away, and it's also the energy that we see here on Earth.
But once that's happened, the inner core is no longer under enough pressure to undergo fusion, so it starts to collapse again under gravity. This is when the remaining, exposed, inner core can turn into a black hole (or something else).

ok, our galaxy is swirling around something in the middle - what is it? 0_0

A supermassive black hole. Basically, a black hole that's... big.

1. ...if it's a black hole, why can't we see the bright radiation?

Black holes aren't that bright - that's why they're black holes . What radiation they do emit is paltry at best. That said, entire stars are sucked into the middle of the galaxy because of the black hole, which is why the middle of a galaxy looks so bright:

2. Apparently the sun is hottest on the outside, hotter than the middle, why?

It's actually hotter in the middle. The surface is about 10,000 K, but the middle is millions of Kelvin. Maybe you're thinking of the Earth, with it's gooey centre?

3. Asteroids also sometimes orbit other asteroids, even two of equal size orbit each other around a central point, what causes them to do this?

It'd be a quirk of gravity. Two large masses moving through space, minding their own business, and they happen to come near each other. Gravity makes them double back, and they've been orbiting each other ever since.

4. Why is the expansion of the universe accelerating?

We honestly don't know. There are all sorts of exotic theories, but I'm hedging my bets till we're more certain.

5. Is there truly such a thing as nothing?

No, because we exist, and we count as somethingness.

 

[Wiccan_Child]

What is the significance of vacuum energy in regards to the structure of the Universe? What is the significance of space being a vacuum itself?

Space isn't a true vacuum, mainly because of vacuum energy itself. A sea of virtual particles continually pop into and out of existence, so even the 'vacuum' of space isn't really much of a vacuum at all.

I assume it follows than that the vacuum itself is everywhere correct?

The vacuum, such that it is, exists anywhere that something else does not. That said, even in the deepest reaches of space, there's a very low-density plasma permeating through.

Could the dynamics of the vacuum potentially have something to do with the formation of some of the large scale structures we see in the Universe?

Almost certainly. The results of COBE show thermal fluctuations in space, which I believe are a result of quantum fluctuations when the universe was a wee nipper:

 

[TheReasoner]

The universe is somewhat larger than my bathroom. It has no walls as far as I know for radiation to bounce off of, so light or radiation shone in one direction will continue unabated in that direction unless reflected by planets, stars, dust etc. or deviated by gravity. So, how come the background radiation from the big bang is still so potent we can detect it fairly easily (in space)? It should be roughly 13.7 billion years old, but there's still plenty around. Why? Is what we see the stuff that's bouncing around or do we see it for some other reason?

 

[thaumaturgy]

That's... wow. I had no idea those things existed. Clever invention, if utterly pointless .

Pointless? Well, if you want people to respect you as you roll straight pimpin' I can think of no better expediency.

I believe it was either DeBroglie, Heisenberg or perhaps Dre (PhD) and Dogg who said "I'm representing for the gangsters all across the world. Still hitting them corners in them low lows, girl."

Of course all scientists know the true value of impressing the ladies as well. Even Lise Meitner knew that!

However, without a doubt, the Britney Spears website is the best source of physics info.

Indeed this is where I learned all the Semiconductor Physics that I need to know!

 

[Wiccan_Child]

The universe is somewhat larger than my bathroom. It has no walls as far as I know for radiation to bounce off of, so light or radiation shone in one direction will continue unabated in that direction unless reflected by planets, stars, dust etc. or deviated by gravity. So, how come the background radiation from the big bang is still so potent we can detect it fairly easily (in space)? It should be roughly 13.7 billion years old, but there's still plenty around. Why? Is what we see the stuff that's bouncing around or do we see it for some other reason?

The truth is there's not that much of it around. It's so old and so redshifted, that it's a paltry 2.3 Kelvin. The light we look at when do things like COBE, is light that originated when the universe was very young. It's just taken it 13.5 billion years to reach us. There's light that originated at the same time, but it has still to reach us; that's why we can look up at any time we like and still see this primordial EM field.

There is, of course, some deflection, since space isn't a perfect vacuum. A cool image I came across once showed you the actual path a beam of light takes:

Another cool image is a (rather stylised) map of how dark matter is distributed:

Science is so sexy.

 

[Chesterton]

Pointless? Well, if you want people to respect you as you roll straight pimpin' I can think of no better expediency.

I believe it was either DeBroglie, Heisenberg or perhaps Dre (PhD) and Dogg who said "I'm representing for the gangsters all across the world. Still hitting them corners in them low lows, girl."

Of course all scientists know the true value of impressing the ladies as well. Even Lise Meitner knew that!

Ah, you beat me to it. Somewhere in that man's enviornment is a female who will find that bouncing car good enough reason to mate with him. They will produce little baby Californians who will in turn grow up to do silly, pointless things. And on it goes.

 

[thaumaturgy]

Ah, you beat me to it. Somewhere in that man's enviornment is a female who will find that bouncing car good enough reason to mate with him. They will produce little baby Californians who will in turn grow up to do silly, pointless things. And on it goes.

It is the "Circle of Life" here in California.

(I should also clarify my point about Lise Meitner. I was not making any claims about her orientation (her Quantum Sexual Orientation Number, m[sub]h[/sub], if you will) I was merely suggesting that all scientists, male and female, know that it is important to choose a mate based on only the most valid selection criteria. Hydraulics being near the top.)

 

[TheReasoner]

The truth is there's not that much of it around. It's so old and so redshifted, that it's a paltry 2.3 Kelvin. The light we look at when do things like COBE, is light that originated when the universe was very young. It's just taken it 13.5 billion years to reach us. There's light that originated at the same time, but it has still to reach us; that's why we can look up at any time we like and still see this primordial EM field.

Thank you! That actually cleared a bit up for me!

Some light has not reached us yet, that means the expansion at the time of it leaving it's source was so much faster than light that we're still ahead of some of it. Since matter cannot travel faster than light this would mean that space itself must have expanded causing the speed of expansion to be much greater than C. I find this fascinating! As I understand, the Alcubierre drive is a theoretical engine which works on the same principle. Do you know if this drive is lunatic fringe stuff, fringe stuff or just 'too complex to do now' stuff?

There is, of course, some deflection, since space isn't a perfect vacuum. A cool image I came across once showed you the actual path a beam of light takes:

Neat!

Another cool image is a (rather stylised) map of how dark matter is distributed:

Sweet!

Science is so sexy.

For real! If it could cook I'd marry it! (Provided I wasn't married already.... Maybe bigamy is OK in this case )

 

[Chesterton]

Hydraulics being near the top.)

Hydraulics, eh? I'll assume you realize the parallel you drew. Freud would have a field day with that car.