your bladder, however, can contain more urine when you're deep underwater. #1 reason you have to pee when you get back to the surfaceWizard .3 wrote:Divers need to come to the surface slowly so they don't get the bends. This is from gases in the body forming bubbles in the blood and has nothing to do with compression of liquid.Sanction wrote:Why must divers come back up to the surface slowly and why do submarines have crush depth ratings if liquids can't be compressed?ToxicBug wrote:You can't compress a liquid unless you heat it and turn it into a gas.
:icon27:
Actually, both result from pressure and have nothing to do with incompressibility :icon32:
compressing liquids.(science question)
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universe.zipmjrpes wrote:I remember reading somewhere an interesting fact about the universe. The amount of space between matter is so great, that if all the matter in the (visible) universe were squeezed together as tightly as possible (to the planck level), it would take up less space than the nucleus of an atom.
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Massive Quasars
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deleted a post about deletion, fancy that
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You couldn't, it would become a singularity long before it got down to that size. Even hypothetically I doubt it could occupy a volume as small as a nucleus as a nucleus is already pretty much solid matter (from a nucleon point of view, you could try going down to quarks but I'm not aware that anyone's managed to measure the physical volume of a quark). Maybe you could compress it into the volume of an atom (though I'm still VERY sceptical, but not a nucleus.)mjrpes wrote:I remember reading somewhere an interesting fact about the universe. The amount of space between matter is so great, that if all the matter in the (visible) universe were squeezed together as tightly as possible (to the planck level), it would take up less space than the nucleus of an atom.
Actually, bag of fag-packet calculation:-
Diameter of proton = 10^-15m
Number of atoms in observable universe= 10^80
Assume all atoms in universe are hydrogen (fair assumption, volume of other atomic elements varies very little anyway) so we have 10^80 protons to cram together.
Volume of a single proton (4/3*pi*r^3) = 5 * 10^-46 m3
Therefore Volume of all the protons in the universe = 5 * 10^34 m3
That would be solid sphere of protons (assuming perfect packing) 232079441680m in radius, or roughly 230 million kilometres.
That's a LOT bigger than a nucleus!
(Sorry, there's few things worse than a bored scientist...) :icon25:
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GONNAFISTYA
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I think people get confused because we talk of the big bang originating from a single 'point' of sorts, a very small volume, much smaller than the 230 million km...but what was 'blown out of' the big bang was not all of the elementary particles in the form they are today...the compression of matter and energy at the big bang was much greater than the 230 million km radius calculated for the volume of all the protons in the universe today.SIK wrote:You couldn't, it would become a singularity long before it got down to that size. Even hypothetically I doubt it could occupy a volume as small as a nucleus as a nucleus is already pretty much solid matter (from a nucleon point of view, you could try going down to quarks but I'm not aware that anyone's managed to measure the physical volume of a quark). Maybe you could compress it into the volume of an atom (though I'm still VERY sceptical, but not a nucleus.)mjrpes wrote:I remember reading somewhere an interesting fact about the universe. The amount of space between matter is so great, that if all the matter in the (visible) universe were squeezed together as tightly as possible (to the planck level), it would take up less space than the nucleus of an atom.
Actually, bag of fag-packet calculation:-
Diameter of proton = 10^-15m
Number of atoms in observable universe= 10^80
Assume all atoms in universe are hydrogen (fair assumption, volume of other atomic elements varies very little anyway) so we have 10^80 protons to cram together.
Volume of a single proton (4/3*pi*r^3) = 5 * 10^-46 m3
Therefore Volume of all the protons in the universe = 5 * 10^34 m3
That would be solid sphere of protons (assuming perfect packing) 232079441680m in radius, or roughly 230 million kilometres.
That's a LOT bigger than a nucleus!
(Sorry, there's few things worse than a bored scientist...) :icon25:
OK, I found a site that mentions this.SIK wrote:
Even hypothetically I doubt it could occupy a volume as small as a nucleus as a nucleus is already pretty much solid matter (from a nucleon point of view, you could try going down to quarks but I'm not aware that anyone's managed to measure the physical volume of a quark).
http://www.ncsu.edu/felder-public/kenny ... ation.html
Skip down to where it says
Part of the problems is I wasn't clear... I wasn't talking as much about matter (protons, neutrons) as I was the parts that make up matter.... and at the most basic level that seems to be quantum fluctuations, working at the plank level.The Planck density is enormous. It corresponds to the mass of 100 billion galaxies being squeezed into a space the size of an atomic nucleus. If we could extrapolate general relativity all the way back to the big bang the universe would have gone from infinite density to the Planck density in roughly 10-43 seconds. So saying something happened, say, three minutes after the big bang is equivalent to saying it happened three minutes after the time the universe was at Planck density.