Any physicists in the house?

[AkumaNoZeta]

A while ago the History Channel had that special on Einstein and I was in and out of it because every time I tried to watch it I was always busy with something else. Well a part that really got me thinking was when one of the guys on there stated that gravity isn't a pulling force from the Earth but in fact a pushing force caused by the deformation of the fabric of space and time. Which is all well and good but then I started to think that if it's pushing down to Earth like that then air pressure should be all the same just like with liquids and hydraulics so that bothered me until I remembered the Bernoulli Principle while reading Race Car aerodynamics and then it all fell into place with me. The air further away has a bigger circumfrence to go around and therefore moves faster causing it's pressure to be lower and the air closer to the ground is slowed down by trees, building, mountains, etc. causing it to be a high pressure. I don't know if it's right or not but it sure helped me understand it.

[ZZZeee]

I'm sure as heck no Einstein nor do I know anything about quantum physics or relativity. But... no, I don't think that's the answer.

 

I'm more inclined to believe gasses and everything else is/are denser at or below sea level because my boss is at sea level. He is an inestimably dense individual. I strongly suspect that, if he were to ever climb to the top of mount everest, the entire climate would invert... would probably even rain upwards.

[X64v]

...then air pressure should be all the same just like with liquids and hydraulics...

 

False. The water pressure in something like the ocean or a bath tub or a cup of water is proportional to depth, just like air pressure.

 

...the air closer to the ground is slowed down by trees, building, mountains, etc. causing it to be a high pressure...

 

Also false. Yes, the air closer to the ground is under more pressure, but it has absolutely nothing to do with fact that mountains and trees are slowing the wind down. In this situation, the amount of pressure a fluid is under (air is a fluid) is dependent only on the weight of the column of fluid above it.

 

Edit: Don't take any of that personally, I'm not trying to rain on your parade, just to help you understand.

[JIM73240Z]

+1 for x64z. As a side note, dams are only designed to hold back the first foot or two of water that is behind them. pressure is pressure, no matter what the medium is.

 

jimbo

[AkumaNoZeta]

I wasn't gonna take it personally. I strive to learn and understand, that's why I'm here. I already knew the first part you said was false was wrong, I stated that as why I couldn't get any grasp on it at all until I found a way to prove it wrong. I also knew air is a fluid, which is why I made the liquid and hydraulic comparison. I am glad you corrected me on the restricted flow idea of ground anomalies (I spelt that wrong for sure, lol) and I remember wieght of the column thing from my high school physics class now, it was years ago and I've forgotten a lot from it. Thank you for the corrections, any more comments?

[NCchris]

Thank you for the corrections, any more comments?

 

Good read: A Brief History of Time by Stephen Hawking.................

[cygnusx1]

I think they used the flexing of the fabric of space as an analogy to help visualize the how pull of gravity relates to everything in space.

 

Imagine a bunch of weights sitting on a rubber sheet. They sink into the sheet deeper, the larger they are. A black hole, such as cygnusx1, would flex the sheet down to infiniti forming a funnel to infiniti.

 

Every mass has a gravitational pull proportional to it's density. Apparently ZZZeee's boss is so dense he might be a black hole.

 

 

http://library.thinkquest.org/04apr/01330/currentphysics/conflicts.htm

In this photo you can see how the moon spins around the "funnel" formed by earths mass.

 

This shows a black hole:

[ZZZeee]

It's always bothered me how they use 2-dimensional imagery to represent 3 or 4 dimensional space.

[dr_hunt]

What you heard is complete bunk. Everything that has mass has gravity associated with it, that includes yourself and everthing on the planet. It is a calculatable gravitational force.

 

Space is zero vaccuum, there is not much there as far as gasses go. There are other planets, solar systems and much much more. Our planet revolves around the sun whose gravity keeps us right here where we are.

 

The z's around here have gravity and they affect my wallet, money seems to fly out of it and go right into the car, never to return.

[(goldfish)]

I would guess that they are describing gravity like a you would a vacuum. Air does not get "Sucked" in to a lower pressure area. It gets Pushed from a Higher pressure area.

[blue72]

To paraphrase “Understanding the Universe”:

“Gravity isn't magnetism, it's a property of matter and space. Matter bends space. The more mass, the more space around the mass is warped.” The moon is orbiting in Earth's 'dimple' if you will.

 

The tricky bit comes when you try to apply gravity to very tiny things like particles.

 

To paraphrase "The Elegant Universe":

Gravity is terribly feeble. Electromagnetism is quite a bit stronger. The outer shell of every atom contains a negative electrical charge. When you stand on the floor, your atom's electrical charges are repelled by the electrical charges of the floor's atoms. The electromagnetic force is billions of times stronger than gravity. At the level of individual atoms, gravity is an incredibly weak force in comparison. That's why you don't fall through the floor and get sucked to the center of the Earth.

 

The theories of both Einstein (new gravity/relativity) and Maxwell (electromagnetism) can't account for particles in the atomic and quantum level though. Neither gravity nor electromagnetism are strong enough to create the links that neutrons, protons and other sub-atomic particles share. That's where quantum mechanics comes in. That's where things are ruled by chance and probability.

At this level, particles obey the strong nuclear force and weak nuclear force. These two forces together with electromagnetism completely overshadow gravity for all things subatomic.

[240hoke]

You guys should take some Philosophy classes, they will tell you science is all bogus anyway, and yall are all just believing an intricate mess of laws and theories that are all fallible.

 

Stop wasting your time!

 

 

Yea Im reading for my BS class in the morning to fullfill my humanities requirement for engineering and make me a more rounded person!

[AkumaNoZeta]

Whats wrong with science? I love science, I may not be any good at it but I love it. The Z is nothing but science, everything in it has been a science experiment at one point or another. I'm in a tech school right now because of my love of cars, but I want to join the military afterwards so I can take the more general classes at college levels such as math and science.

[Globerunner513]

pretty sure he was being sarcastic

 

If i recall, Austin is an engineering major.

[AkumaNoZeta]

Wow, really? I wish I was that smart. I can't even work a CADD program ...Then again I tried that without any tutorial or anything, just playing around. But I reformatted my computer shortly after that and lost it

[woldson]

Space is zero vaccuum, there is nothing there as far as gasses go. There are other planets, solar systems and much much more. Our planet revolves around the sun whose gravity keeps us right here where we are.

 

Mabey no gases but, dark matter may be someday classified as a fuild.

In witch case space would be more like an ocean.

 

Also there is no best in HybridZ, and there is no perfect in science.

The perfect is the assumtion in order to have something unprovable.

Ever see something in motion for eternity?

The laws of physics are only "un-unprovable" at this time.

[dr_hunt]

Ever see something in motion for eternity?

 

Nope, haven't lived that long and was planning on not living that long.

 

Besides, the z proves that theory wrong, it's always not in motion except for brief periods of time! :lmao:

 

 

Space is not empty. Most people find this statement surprising since we generally think of space as a vacuum. To a certain degree this is true, but space is not an absolute vacuum. It is filled with very thin electrically charged gas consisting mostly of protons and electrons. The gas is so thin that a thimbleful of air holds as many atoms as does a cube 2 miles on each side in space. Pretty thin, but it is still there.

[blue72]

Thinking that space is empty is what got us to find out about dark matter in the first place.

 

In the 1970's astronomers noticed that stars in the middle of a galactic arm orbited around a galaxy's center at the same speed as the stars at the fringe of the galactic arm. That wouldn't be possible if there weren't a very large gravitational pull at the center of the galaxy. Much more gravity than what telescopes told us there should be. That's where dark matter, WIMPs, MACHOs, neutrinos, axions and other theoretical and real pieces of matter come into play.

[nando280zxt]

Ohhh the God particle =)

 

Come on Large Hadron Collider!!!

[strotter]

OK. Here's a metaphor. Think of a solid glass cube, say, one foot on a side. This cube represents a volume of spacetime. You know that the molecules that make up the glass are evenly and smoothly distributed throughout the structure. If you had a magic microscope, you could see the molecules lined up nice and straight. A light shined through it, a laser beam for instance, will move in a straight line. Nothing surprising here, it's as we know from the "common" world.

 

Now, lets move some molecules around. Let's move a bunch of them toward some particular area. We move molecules away from all over the cube toward that one area, squeezing the molecules together tighter. The rest of the cube is less dense, but that one point is more dense. It's still a cube, and to the casual eye it looks the same, but if we shine the laser beam through the cube *now*, we'd see that the beam would curve as it passes through. In fact, it would start by curving *toward* the denser area until it reached the tangent, and then it would curve *away* from the denser area as it moved passes - though not as much. The bottom line is that the beam will have been bent in much the same way as it would have been in a lens. In fact, we would have created a (rather crappy) lens, the same way that you can see the surface of a road shimmer on a hot day - the change in density of the air causes the light to be bent.

 

Spacetime is much the same. The presence of mass causes spacetime to become more "dense" (though that's not the right word, you'll get my drift), or to squish down tighter. As a result, spacetime is irregular - not smooth any more. The metaphor is exactly the same as the cube, 'cause if you shoot a light beam near that area you cause it to bend in a lens-like way. As a matter of fact, the effect is called a "gravity lens" because it lets you see things *behind* very dense objects. Einstein proved his General Theory using just this technique back during WW1.

 

OK, now here's the hard-to-get part. Spacetime is the actual fabric of the things we know. If some giant were to come down from space and stretch the spacetime around your house, stretch your house a thousand miles long with you in it, you wouldn't know. Why? Because everything in your house, including you, is "embedded" in the spacetime of your house. As the spacetime stretches so would the molecules of your house, your own molecules, yourself. But so would the "units of measure" - so, if in your spaghetti condition you were to pull out a tape measure (which would look perfectly normal to you), and measure the length of your coffee table it would be the same as before, say 40 inches. Your neighbor, though, looking into your house from outside of the spaghetti would be able to clearly measure your coffee table as being 100 miles long. Both of you would be right, because the length of the coffee table depends on your point of view - it's "relative" to your point of view (thus the term). Also, your neighbor would be treated to an excellent light show, as the gravitational lensing effect (though now it would be a Giant Induced Spaghetti Effect) would cause lensing to occur all around the outside of the stretchy area, probably visible as glowing rainbow light.

 

Gravity is doing the same thing to all of us all the time, but the effect is so small as to be difficult to measure. As you could guess from the metaphor, it's best (but not mandatory) if you measure from the outside to get some idea. Those experiments were some of the first ones done from high orbit. Interestingly, a number of observations of the very edge of spacetime (and thus farther back in time) were recently made by observing the gravitational lenses on the edges of a cluster of galaxies.