The story so far:
Soopytwist started it by posting this -
soopytwist wrote:If you want to visualize how big a Minecraft world is...
This is taken from the extraordinary Scale of the Universe 2 by Cary and Michael Huang, here: http://htwins.net/scale2/
Helios wrote:That image makes no sense.
Neptune is bigger than Sirius B?
Wow it really is.
I find that 10^7.6 more interesting than the Minecraft bit.
soopytwist wrote:What I can't quite get my head around is the absolutely enormous size of VY Canis Majoris compared to our own sun! Kind of puts you in your place doesn't it?
Polito45 wrote:That is a very cool site.
Yeah, I remember seeing an image a few years ago that showed the sun and then sequentially bigger and bigger named stars.
It changes your perspective on the universe that such truly massive stars exist.
I was reading last night that to make our star - the sun into a black hole you would to shrink its radius from the 450,000 miles that it is
down to less than 2 miles, keeping its mass the same of course.
Apparently the dark star (black hole) at the centre of our galaxy is 2.5 million times the mass of our sun.
soopytwist wrote:Mass is weird. The star Sirius B is roughly the same size in volume as Earth but it's mass is near equal to our Sun! So it's both smaller than our sun and as big at the same time!
This happens at the other extreme end of the scale too. Quarks, the building blocks of Protons and Neutrons are smaller than the particles they make up but their mass is greater! Strange Quarks are smaller than Up Quarks but are 50 times as massive.
Stars, planets, atoms, protons and quarks - all very similar wouldn't you say? Boy it's tough being an atheist.
There came the sound of heavy boots stomping down the hallway, the door flew open and -
Tinlad wrote:soopytwist wrote:Quarks, the building blocks of Protons and Neutrons are smaller than the particles they make up but their mass is greater!
I should probably elaborate slightly. The mass of a neutron is about 940 MeV, and it's made up of one up and two down quarks, the masses of which are 2.3 and 4.8 MeV respectively. However, the gluon field associated associated with each quark is considerably more massive (but still not greater than that of a neutron or proton). It's this gluon field that binds the quarks together into a particle (strong nuclear force). For further reading see: mass-energy equivalence and binding energy.
Also, this...soopytwist wrote:Mass is weird. The star Sirius B is roughly the same size in volume as Earth but it's mass is near equal to our Sun! So it's both smaller than our sun and as big at the same time!
... is not really that weird. A grapefruit and a shot put are about the same size, but have very different masses. It's called 'density'. Sirius B is smaller than the Sun, but as massive. It's the same size as Earth, but more massive. "It's both smaller than our sun and as big at the same time" is just... wrong.
You've awakened the physicist.
Polito45 wrote:Tinlad wrote:...the gluon field associated associated with each quark is considerably more massive...
I thought the force carrying particles didn't have any mass?
Photon, Gluon, (shit, can't remember what the weak force particle's called - is it weak gauge boson?) & Graviton.
What I found myself doing the other night (I have insomnia) was trying to imagine a dark star in all 4 dimensions.
You know the way you always see one graphically represented in 2D as a funnel with an event horizon around the upper part of the funnel
and a singularity where the funnel reaches a point at its base?
In truth of course it exists in all 4 dimensions just like any other star, but it gives off no light.
And, it's mass is so great that if you were to station yourself close to it's event horizon and look back at another ship at some distance away
you would see them moving unnaturally quickly, just as they would see you moving unnaturally slowly.
But to each of you time would appear to be moving normally. That to me is one of the hardest things to get your head around -
How can mass grip and warp time?
soopytwist wrote:Too much science...I'm out.
Not yet.Polito45 wrote:How can mass grip and warp time?
That'll be Quantum Foam, the fabric of space time. The more mass an object has the more it distorts space time - hence the warping of time and the gravitational pull of an event horizon....I think. Sheldon Cooper, help me out here!
Now I'm out.
Tinlad wrote:Polito45 wrote:I thought the force carrying particles didn't have any mass?
The photon doesn't. The gluon (probably) doesn't. The W and Z bosons do.
But despite (probably) not having mass, the energy of the force the gluon mediates (the strong nuclear force) results in the mass of the hadrons they create being higher than just the sum of the quarks. This is mass-energy equivalence: E = mc^2 in action!Polito45 wrote:How can mass grip and warp time?soopytwist wrote:That'll be Quantum Foam, the fabric of space time.
Quantum foam is a theory concerning the nature of spacetime at the planck scale, primarily regarding the creation of virtual particles out of vacuum energy. It has little to do with general relativity.
There are hand-wavy explanations of why gravity distorts time (typically involving bowling balls on rubber sheets), but they typically aren't very satisfactory... and are often misleading. A proper explanation is a little bit more involved, but if you really want to know, I can do my best...
... but it probably belongs in a different thread.
Isn't Quantum foam from String theory? It sets a limit on how small things can be - around the Planck length - both matter & time.
Which smooths out the quantum foam and allows for a joining of quantum theory and general relativity?
Anyway, yes. Please have a go at explaining how mass warps time.