Expanding Universe

[kendor]

they'd fall off the table as it's upside down

 

[mildmanneredjanitor]

OK, so if everything emerged from a singularity with all material moving away from this point, then as it moves further away, then there will be less of a gravitational pull from this point. Less 'drag' if you like, so would this explain the accelaration?

The other thing is that as matter emerged from the singularity I would have envisaged that every single particle would be moving away relative to each other aswell. So why do bits clump together to form planets etc.? Unless of course big bits of matter emerged together? Or particles from different big bangs colliding?....

Presumably each atom has it's own gravitational pull? (though obviously very tiny) Is gravity directly proportional to mass?

That's enough for now...

 

[kendor]

One thing amuses me when they mention that the laws of physics don't apply to singularities (can you get more than one??!? or do you call them pluralities?) then why would it behave in any rational way and explode in the first place?

 

[pipme]

Get stuck into this Ken, Looks promising ......

http://www.btinternet.com/~mtgradwell/

Methinks you are trying to smoke out old FWL ......
P

 

[AdamW]

So why do bits clump together to form planets etc

Simply put, accretion. Small particles clump together via gravity and electromagnetic forces to form big particles. Big particles clump together to form dust, dust clumps together to form rocks and before you know it, you have a big rocky planet.

If you read this, it is a timeline of the Big Bang. You don't need to read the whole thing, but bear it in mind.

Now, no-one knows what was there at t=0 of the big bang. No-one knows what was there before, but we think we have a pretty good idea about what happened very quickly after it. What you start off with is a primordial soup of energy, manifested as a unified force (i.e. no discrete gravity, electromagnetic, weak, strong forces). Then as everything expands due to the fact it is so freakin' hot and there is that much energy, things cool down a bit (pretty basic thermodynamics, something hot expanding gets cooler, if its total energy remains the same).

So then you start to get forces separating out. No-one has fully figured this one out, or we would also have a proper working Grand Unified Theory by now too. There is still a Nobel Prize waiting for the clever s*d who works that one out!

Anyway, if you go to the "Epoch of Nucelosynthesis", near the bottom of that page, you will see that hydrogen forms, along with helium and a trace amount of light elements.

So, we have a universe full of vacuus hydrogen. Things are never perfect (even the Big Bang!) so instead of absolutely everything heading out at the same speed in a totally different direction, you will end up with lumpy bits, and also bits going off at different speeds etc. So you will end up with clouds of hydrogen amalgamating (if that is the right word). When these are massive enough, and have collapsed far enough under their own gravity you get a star.

The first stars "burned" hydrogen, there were no planets, no heavy elements, nothing "solid". When a star burns it of course produces heavier elements by fusing together lighter elements (fusion). When the star dies it explodes, heavy elements are strewn out all over the place. When you get enough of this you have big amounts of dust, this will accrete into solid bodies such as rocky planets and asteroids.

 

[AdamW]

Oooh, 3 billion years from now the Andromeda Spiral and the Milky Way will collide, due to gravitational attraction. That's going to be rather funky, two large galaxies colliding into each other. S'gonna be big!

 

[pipme]

More to the point, will a futuristic CNN be there to capture it ? Even more thrilling will we have advanced to the point where we might postpone the whole thing 'til we are ready to properly promote it ?

 

[AdamW]

More to the point, will a futuristic CNN be there to capture it ? Even more thrilling will we have advanced to the point where we might postpone the whole thing 'til we are ready to properly promote it ?

Sounds a bit like "Restaurant at the End of the Universe"

 

[TexMex]

Oooh, 3 billion years from now the Andromeda Spiral and the Milky Way will collide, due to gravitational attraction. That's going to be rather funky, two large galaxies colliding into each other. S'gonna be big!

Probably not as big as you may imagine. Since the galaxies themselves consist mainly of space, a large number of the individual stars will pass straight through the other galaxy without actually touching. Very few will actually collide, but a large number of them will have their course altered, and therefore the shapes of the two galaxies will be distorted, to some degree, by the whole event. (which will take millions of years to complete). It will be like watching two pairs of underpants tumbling in the washing machine spinning at one revolution per million years.

 

[AdamW]

Well, they reckon it will become an elipsoid galaxy.

I for one am going to start panic buying for this cataclysmic event.

 

[pipme]

Shouldn't bother mate, you have said elsewhere .. in debt .. stressed .. probably be dead by 40 ... You'll miss the old coming together I suppose.
Better make the most of it .... the ASers will be queueing up for your abode ..
Blo ody he ll !! what if they find life on another world ? They'll all be hot foot (feet) to get on the gravy train down this here way !!!
P

 

[CORNIO]

did you know that a snooker player from the UK would play badly in Australia because the balls would go the wrong way?

Disagree I lived in oz and I still kicked arse on the pool tables over there.

 

[AdamW]

Blo ody he ll !! what if they find life on another world ? They'll all be hot foot (feet) to get on the gravy train down this here way !!!
P

S*d that, I'll be straight on a tomato lorry bound for Alpha Centauri!

 

[TexMex]

I get regular Email updates from the American Institute of Physics. Found this in my mailbox last week. It may be relevant.

IS SPECIAL RELATIVITY WRONG? The centennial of Albert Einstein's
miracle year of 1905 has arrived and so it is pertinent to ask how
one of his most famous theories is doing. Physicists don't
necessarily believe that Einstein's rules about the nature of
spacetime are mistaken, but as part of the continual scientific
effort to extend what is known about the universe physicists search
for subtle hints of a departure from expected behavior. Special
relativity predicts that clocks traveling in various directions and
with various fixed speeds relative to each other will tell time
differently, but in such a way that spacetime has no preferred or
distinguishable direction, a proposition known as Lorentz
invariance. Physicists, always on the lookout for departures from
received opinion, and also motivated by theoretical suggestions that
such effects might be expected, take this as an invitation precisely
to search for such a special direction or to find that the variation
of clock rates does not adhere to Einstein's equations. Such
effects are described by the "Standard-Model Extension" (SME) and
they can come in several forms. One disproof of special relativity
would be the finding that matter and antimatter behaved
differently. Another would be a birefringence violation: observing
that light with different polarizations travels at different
velocities through vacuum. Still another disruption of the
Einsteinian view would occur if the universe were pervaded by an
underlying oriented energy field, one that interacted weakly with
known particles so as to favor one direction over another.
A new experiment puts this latter violation to its most stringent
test yet. As so often happens when searching for extremely subtle
effects, no departure from known physics was found but a new upper
bound could be established. Ronald Walsworth and his
Harvard-Smithsonian colleagues, in conjunction with theorist Alan
Kostelecky at Indiana University, look at how atoms prepared in
special magnetic states (the precision of their light emissions
allow them to serve as "clocks") vary in their timekeeping when
moving at certain velocities (or "boosts") relative to the
hypothetical Lorentz-symmetry-violating fields that may permeate the
universe. In this case the two clocks consist of a sample of
helium-3 atoms and a sample of xenon-129 atoms held in a container
within a fixed magnetic field. The clock rate in each case is the
rate at which the atomic nuclei precess in the magnetic field. The
emissions from one atomic species were fed into a feedback mechanism
for controlling the magnetic field, so in effect the one set of
atoms (or, to be more precise, their nuclear spins) acted as a
reference clock while the other species served as the test clock.
The whole apparatus, and the absolute orientation of the applied
magnetic field in spacetime (and along with it the orientation of
the atoms and their emissions) change as the Earth rotates daily and
as the Earth takes its annual course around the sun. Furthermore,
to achieve the necessary level of precision (based on the light let
loose by the atoms), the Harvard researchers achieved the difficult
experimental feat of having the two atom samples operate in a maser
mode (that is, they performed like a laser) within the same
container. The existence of a Lorentz-violating field, one that
like a magnetic field favors a particular orientation in an
otherwise isotropic spacetime, could cause the two clocks to become
more out of synch as they move relative to the Lorentz-violating
field. The main result of the experiment was to put a stringent new
limit on a coupling of material particles (primarily the neutron) to
such fields. The upshot: no Lorentz "boost" violations are seen at a
level of one part in 10^-27. (Cane et al., Physical Review Letters,
3 December 2004

The way I see it, It still doesn't disprove that Einstein was wrong. I think it more likely that there is no "pervasive underlying oriented energy field, that interacts weakly with known particles". Just an opinion.

 

[mildmanneredjanitor]

Blah blah blah...

The way I see it, It still doesn't disprove that Einstein was wrong. I think it more likely that there is no "pervasive underlying oriented energy field, that interacts weakly with known particles". Just an opinion.

Yeh, all very clever but Einstein only had a pencil

And back on topic, how do they get that 'smashing orangey bit in the middle'?