Ask any question you want about Physics

originally posted by: ImaFungi
a reply to: Arbitrageur

With further thought on my part, I realize I do not comprehend why/how an object is forced to earths surface.

Einstein provided further insights but Newton said he didn't know and we still don't.

If there is 'pulling or pushing' there must be 'touching';

I'm agnostic on this point. I see magnets doing that without touching and whether virtual particles represent something physical or are just a mathematical tool for the model again I'm agnostic, either could be the case. I'm also agnostic about gravitons.

When I see solid evidence to believe something I tend to believe it. When I see a hypothesis where the evidence isn't great I keep an open mind that it might be correct, or maybe not.

The atmosphere is constantly being forced toward the earths surface as well, but it is not done so so compressed and densified that objects cannot move the relative particles of atmosphere, atmosphere in that sense is not turned into a solid by the constant force of gravity forcing atmosphere towards the surface, and whatever the nature of the 4d gravity phenomenon material is, it has easier access to forcing an object such as a brick toward the surface, than random particles of atmosphere at that bricks same height of which it is dropped. What a curious mystery. I will comprehend this, and it will be nowhere near the last thing I do.

The true nature of gravity remains a mystery. The atmosphere, not so much, but it can create some apparent paradoxes. Here's one I used to think about. Ever been in the mountains?

If you're on the side of a mountain, you can drive down into the valley and see lower temperatures if your car has one of those digital thermometer displays for the outside air temp. This seems to fit with the "hot air rises, cold air sinks" idea many of us were taught in grade school experiments. But if you drive to the top of the mountain instead, the temperature also drops, or at least the reading on the car's thermometer does, and of course we've all seen at least pictures of snow-capped mountains where it certainly looks like it's colder on top.

So figuring out how the top of a mountain can be colder if "hot air rises" requires a deeper understanding of the complexity of the atmosphere. As for your statement that "it is not done so so compressed and densified that objects cannot move the relative particles of atmosphere", while it's true we can move the particles, there is some resistance which you can actually feel if you ride a bicycle, and yes gas is less dense than water so you feel even more resistance to motion in water, but these things I don't find mysterious. So I don't understand your thinking on the atmosphere but I realized our brains don't work the same way so maybe you're seeing something I'm not which isn't clear from your description.

The true nature of gravity remains a mystery. The atmosphere, not so much, but it can create some apparent paradoxes. Here's one I used to think about. Ever been in the mountains?

If you're on the side of a mountain, you can drive down into the valley and see lower temperatures if your car has one of those digital thermometer displays for the outside air temp. This seems to fit with the "hot air rises, cold air sinks" idea many of us were taught in grade school experiments. But if you drive to the top of the mountain instead, the temperature also drops, or at least the reading on the car's thermometer does, and of course we've all seen at least pictures of snow-capped mountains where it certainly looks like it's colder on top.

So figuring out how the top of a mountain can be colder if "hot air rises" requires a deeper understanding of the complexity of the atmosphere. As for your statement that "it is not done so so compressed and densified that objects cannot move the relative particles of atmosphere", while it's true we can move the particles, there is some resistance which you can actually feel if you ride a bicycle, and yes gas is less dense than water so you feel even more resistance to motion in water, but these things I don't find mysterious. So I don't understand your thinking on the atmosphere but I realized our brains don't work the same way so maybe you're seeing something I'm not which isn't clear from your description.

Why is it thought hot air rises, which just means, the vibrations of air are passed on upwards? Is it because really the vibrations of air are distributed evenly all around the source, but the sources we are referring to are usually very near the ground, so the vibrations ground direction quickly hit the ground and thats that, but the vibrations skyward continue to vibrate skyward, so have more area to cover?

Well I suppose consistent with my thinking would be that the top of the mountain is colder, simply because it is less dense? And/or by that point the vibrations have larger area to dissipate?

a reply to: ImaFungi
Hot air rises because it's less dense and yes the air on the mountaintop is less dense too but the snow covering doesn't make it look hot.

If you fell into the sun you'd burn up in the 5800 degree K heat.

But what if you went to an interstallar gas cloud with the same temperature of 5800K? Would you burn to death there too? Or freeze to death?

originally posted by: moebius
a reply to: ImaFungi

Define 'touching' and 'physical material'.

Physical material: That which is not absolutely nothing.

There is only conceptually (rough, raw, categorically) and really; 1. Absolutely nothing. 2. That which is not absolutely nothing. 3. And the movement and potential movement of that which is not absolutely nothing. (3. appears to be what is referred to as energy and potential energy, respectively)

Touching: In order for that which is not absolutely nothing, to be moved by that which is absolutely not it (canceling out internal mechanisms of motion), that which is not absolutely nothing (or that which is physical material, or that which is something, or that which exists) must absolutely be touched, by that which is not absolutely nothing, to be moved.

That which is not absolutely nothing, which has no internal mechanism by which it may, randomly or not, 'internally move' to relatively objectively move (for instance of that, how a mind makes internal movements to make objective movements, or how the internal movements of an atom can result in certain decays which objectively alter the make up and location or prior momentum of that atom) must have its body actually definitely touched by something (something else which is absolutely not nothing) in order for it to move.

If an object is raised from the ground, and let go, and that object does not have an internal mechanism which decides, and has the thrustful abilities to turn that decision into action, to force itself toward the ground; but that object is forced to the ground, without forceful help from the hand that lets it go; I have never come across any concept which would suggest it to be scientific, reasonable, factual to propose that the brick, while raised from the ground in hand, is relatively not moving, and then let go, is forced to be relatively moving towards the ground, and does so, because absolutely nothing forces it to do so.

originally posted by: Arbitrageur

If you fell into the sun you'd burn up in the 5800 degree K heat.

But what if you went to an interstallar gas cloud with the same temperature of 5800K? Would you burn to death there too? Or freeze to death?

If you entered the gas cloud and you entered in an area where it was relatively enough volume of vacuum for your entire body to be in vacuum surrounded by the gas cloud, then you would freeze; though there might be a lot of radiation going on anywhere in the vicinity, enough to cook you, but ignoring radiation, if you are just talking about heat being the interactive vibrations of molecules (so molecules rubbing against you near you) then if you were placed in an area surrounded by the gas densely enough you may burn from the heat; but a potential trick aspect of the question may be that the gas cloud is so non dense, that even if you entered any area, the molecules would be so easily bounced off your body, that prior to being bounced off their body if anything they might thermodynamically absorb the heat from your body, and/or bounce off your body leaving you in an area of vacuum to freeze.

a reply to: ImaFungi

YOU CAN'T IGNORE RADIATION since most if it will be thermal radiation you would cook like a turkey on a spit. Very similar to an easy bake oven thr thermal radiation from thr bulb cooks food.

originally posted by: ImaFungi
but a potential trick aspect of the question may be that the gas cloud is so non dense

Yes, the temperature of the gas cloud might be hotter than the sun but there are too few molecules in the gas cloud to keep you from freezing to death so you'd freeze to death. For heat to be transferred to you, temperature is only one factor, and as you pointed out, the density of the atoms or molecules matters too (as in how many atoms or molecules per unit volume).

a reply to: Pirvonen

Sorry, but I dont think you get what im talking about.

thanks wikipedia!

Structure[edit]
They generally are composed of several subunits arranged in such a way that there is a central pore through which ions can travel down their electrochemical gradients. The channels tend to be ion-specific, although similarly sized and charged ions may sometimes travel through them.

a reply to: Arbitrageur

A valid reference frame can be established which is at rest with the Cosmic Microwave Background radiation. That's basically a reference frame of the big bang/universe. If a mass is at rest in that frame I would find it hard to argue that it's moving, and it's certainly not with respect to the CMB.

what kind of nonsense is that ??
due to the theory you believe, radiation is particles ( photons ) moving at speed C
due to the theory you believe, those particle always move with C regardless your own speed ( Einstein )

do you even think before you talk BS like that ??

...regardless those big bang nonsense

a reply to: Phage

Acceleration compared to yourself. Acceleration is a change in the velocity of an object. It is relative to the object itself.

WHAT ???
please...
you need a reference point and it can not be the same point to have any velocity at all.

"It is relative to the object itself."
LOL !!!

a reply to: KrzYma

you need a reference point and it can not be the same point to have any velocity at all.

If a velocity is being assigned it must be relative to something, yes. If something is accelerating, the rate of change in velocity is relative to the velocity of the object which is accelerating. By definition. If you would like to change the definition of acceleration, be my guest. But it won't make you correct.

originally posted by: dragonridr
a reply to: ImaFungi

YOU CAN'T IGNORE RADIATION since most if it will be thermal radiation you would cook like a turkey on a spit. Very similar to an easy bake oven thr thermal radiation from thr bulb cooks food.

Correct, you cant ignore radiation and that's why you'd get cooked in the 5800K temperature of the sun's surface, from all the radiation.

But in the interstellar medium at 5800K, the same temperature as the sun, where you only have maybe one atom for every two cubic centimeters, you'd emit more radiation than you'd absorb, which is why you'd freeze instead of cook there.

originally posted by: KrzYma
do you even think before you talk BS like that ??

No reason to throw insults at me when you're the one who doesn't understand the subject matter.

due to the theory you believe, radiation is particles ( photons ) moving at speed C
due to the theory you believe, those particle always move with C regardless your own speed ( Einstein )

Yes the CMB photons all move at C, but the way to determine if you're at rest with respect to the CMB isn't by comparing your speed to theirs, it's by looking in various directions for red or blue shift.

Big Bang

The CBR is slightly warmer (0.0033 K) in the direction of Leo and slightly cooler toward Aquarius. This effect is directly related to the movement of the Milky Way toward Leo, which causes the radiation from Leo to be Doppler blue-shifted and radiation from Aquarius to be red-shifted.

So the way you'd get at rest relative to the CMB (called CBR at that source) is by heading back in the direction you see redshift, until the CMB looks isotropic (the same in all directions).

back to Einstein...

"For an observer falling freely from the roof of a house, the gravitational field does not exist". Conversely, an observer in a closed box—such as an elevator or spaceship—cannot tell whether his weight is due to gravity or acceleration.

SCENARIO 1>
a guy in a box (elevator)

first of all, this box with this guy has to be somewhere, in a universe or any other reference frame.
If not, there is no way to even talk about anything rather than the inside of the box, so there is no gravity, acceleration or anything, just the box with the guy inside.

so... for the guy in the box, nothing is happening and he has no weight if >
A. the box doesn't move at all,
B. it moves with a constant speed
C. it "falls" is an gravitational field, means both are accelerating at the same rate

in case of C, this box and the guy inside will accelerate forever and due to the theory the time inside will get slower and slower as the box moves faster and faster but never approaches C.

SCENARIO 2
a guy in a box (elevator) but this time the elevator is accelerating

a. the guy in the box see the bottom coming towards him, or he sees himself falling onto the floor.


all cool and simple, BUT... where is the explanation for the gravity in this ???

>sarcasm on<
should I assume Earth surface is accelerating ? is Earth growing all the time ??
>sarcasm off<

all Einstein is saying, is that if you go left you go left and if you go right , you go right

originally posted by: ImaFungi

originally posted by: moebius
a reply to: ImaFungi

Define 'touching' and 'physical material'.

Physical material: That which is not absolutely nothing.

There is only conceptually (rough, raw, categorically) and really; 1. Absolutely nothing. 2. That which is not absolutely nothing. 3. And the movement and potential movement of that which is not absolutely nothing. (3. appears to be what is referred to as energy and potential energy, respectively)

Touching: In order for that which is not absolutely nothing, to be moved by that which is absolutely not it (canceling out internal mechanisms of motion), that which is not absolutely nothing (or that which is physical material, or that which is something, or that which exists) must absolutely be touched, by that which is not absolutely nothing, to be moved.

That which is not absolutely nothing, which has no internal mechanism by which it may, randomly or not, 'internally move' to relatively objectively move (for instance of that, how a mind makes internal movements to make objective movements, or how the internal movements of an atom can result in certain decays which objectively alter the make up and location or prior momentum of that atom) must have its body actually definitely touched by something (something else which is absolutely not nothing) in order for it to move.

If an object is raised from the ground, and let go, and that object does not have an internal mechanism which decides, and has the thrustful abilities to turn that decision into action, to force itself toward the ground; but that object is forced to the ground, without forceful help from the hand that lets it go; I have never come across any concept which would suggest it to be scientific, reasonable, factual to propose that the brick, while raised from the ground in hand, is relatively not moving, and then let go, is forced to be relatively moving towards the ground, and does so, because absolutely nothing forces it to do so.

Okay, so a 'physical material' is not absolutely nothing. Not an exactly useful definition, but I can live with it.

But you need to work on your "touching" definition. Touching is when something has to actually definitely touch something is somewhat circular. Isn't it?

Btw are you aware of the Geiger–Marsden experiments (aka gold foil experiments) that demonstrated about 100 years ago that matter is mostly empty space (or as you would probably call it, absolutely nothing)?

a reply to: KrzYma
The illustration was provided for a purpose. The right view shows the man in the box standing on a weigh scale with some weight registering, so your A, B and C proposals are all inconsistent with that diagram, showing you missed the point and or didn't pay attention to the illustration.

If the scale is registering weight it's either due to gravity or acceleration and he can't tell which inside a closed box. If he happens to be standing in a box on Earth he's probably guess his weight is due to gravity, but he could experience a similar effect on the weigh scale as an astronaut away from earth in an accelerating spaceship.

a reply to: Arbitrageur

I knew you will explain one nonsense with another nonsense...

anyway... here some on the "cosmic background radiation"

originally posted by: Arbitrageur

originally posted by: ImaFungi
but a potential trick aspect of the question may be that the gas cloud is so non dense

Yes, the temperature of the gas cloud might be hotter than the sun but there are too few molecules in the gas cloud to keep you from freezing to death so you'd freeze to death. For heat to be transferred to you, temperature is only one factor, and as you pointed out, the density of the atoms or molecules matters too (as in how many atoms or molecules per unit volume).

Humans would never freeze to death in thr vacuum of space we did animal studies on this not to mention thr many accidents that occurred. What kills you is your heart stops at amour thr 90 second mark. Basically what happens is you lose consciousness at 15 tO 2O seconds. Provided you didn't try to hold air in your lungs causing them to rupture then a layer of ice will form in mouth nose and eyes. This is actually a good thing it buys you time. This ice layer prevents the further loss of fluids to thr vacuum. Then next your body will expand to about twice its size skin is very elastic so it will hold all the stuff in. In fact experiments show that even an elastic jump suit can prevent this to some extent. If pressure is restored before 90 seconds you can survive.some chimpanzees have gone always right around 90 seconds. However some dogs have lasted as long as 3 minutes with full recovery.The longest a human has survived a vaccum was about was just under a minute.Cosmonauts were exposed almost 3 Minutes though they suffered only minor tissue damage they didn't survive so we know this is to long for us.

As for freezing our bodies would retain heat for years before cooling off for thr same reason arb mentions hard to lose heat in space its a great insulator

a reply to: Arbitrageur

Actually you could never tell of your moving even against CMB your wrong. You cant tell of your moving or it is moving as relativity tells us. All you can determine is you an an object are moving towards or away from each other which one is moving would be entirely relative. So even determining you were standing still relative to CMB is impossible.Same reason we could never use it for guidance between stars. Locally it is no help whatsoever.

a reply to: dragonridr
So what would the Cosmic Microwave Background me moving with respect to? It's the signature of the big bang, which is the universe's signature.

A physicist who runs a faq board called "Ask The Van" agrees with me that it means we're moving, and I don't know what it would even mean to say the CMB is moving (he's posted in this thread at least once about something else):

van.physics.illinois.edu...

We find a slight asymmetry in the CMB intensity we see, indicating that, compared to the average of everything within sight, we're moving a bit. That Doppler shifts the CMB in one direction up a bit, and down a bit in the opposite direction. For further discussion, see ned.ipac.caltech.edu...

Another physicist at the source he cites spelled it out even more clearly:

The dipole is a frame dependent quantity, and one can thus determine the `absolute rest frame' of the Universe as that in which the CMB dipole would be zero. Our velocity relative to the Local Group, as well as the velocity of the Earth around the Sun, and any velocity of the receiver relative to the Earth, is normally removed for the purposes of CMB anisotropy study.

That "Absolute Rest Frame" of the universe is what I'm talking about. It's certainly possible that a lot of us are wrong and you're right but in this case I doubt it.

Anyway even if you argued the CMB is moving (again with respect to what?), you'd still be stationary with respect to the CMB if you didn't see any red or blue shifting of the CMB in any direction, right?