Natural Science Forum / Physics / Relativity / January 2006

You went wrong by listening to morons.
http://www.androcles01.pwp.blueyonder.co.uk/
Hexenmeister

No...*Any* observer is not meant to apply where the dielectric
properties of long paths have to be considered.

*Any* observer with effective coupling to the path
can *alter* ...

http://www.conformity.com/0102reflectionsfig3.gif
http://www.conformity.com/0102reflections.html

...the E and H plane power distribution in
his near-field and break what is only an apparent
conundrum with Maxwell's field equations and the
principle of relativity.

There are many techniques for considering the dielectric properties
of long, changing, paths. I think you'll find most discussed here:
http://www.astro.ucla.edu/~wright/cosmolog.htm

Sue...

        Relativistic cosmology is interesting, a few years
ago I wrote a usenet article asserting that the angles
subtended in all directions do not add up to 360 degrees,
because at a certain percentage of the speed of light
there is a problem.  (I tried to find it, but was unable to).

        I was told that is the case, and that distant large
galaxies do not appear smaller and smaller with distance.

        This might be a fun thing to try to find.

Joe Fischer   gravity981   gravity1   ken fischer   joegravity ???

Good point Erik!

One problem however is that the distance between us and a distant
galaxy may be increasing at much faster than the speed of light, at
least according to the usual expanding universe theories.

Still, as you say, if these galaxies were 12b light years away 12b
years ago, when they had high metalicities and show similar features to
local galaxies, there is no way these objects are only 13b years old
now.    

cheers -  shevek

No. The simple reason is that when they say it's 12 billion light years
away, they mean that it's that far away now (extrapolated), not when the
light was emitted. "Now" in this context refers to cosmological time. The
complicated reason is that you can't use your spatial intuition in this
realm, because the visible universe as a whole is very far from the flat
space-time of Newtonian physics or special relativity.

Ned Wright's cosmology tutorial is a great place to learn more about this:

    http://www.astro.ucla.edu/~wright/cosmolog.htm

-- Ben

Thanks for the replies =)
I'll check out the links you posted.

 wrote:

Forget the age of the universe think of the age of the object. Because
it is travelling away from us at a speed which is an appreciable
proportion of c, time dilation says that it isn't ageing very quickly at
all. I think latest estimates make the age of the universe about 14.5
billion years old. If you don't take time dilation into account then
even if we were separating from a distant object at c it would take 7.25
billion years to get 7.25 billion light years away from us and if the
light set out then it would only reach us now so we could never see
anything older than half the age of the universe.

It is claimed that we can see objects only a few million years after the
big bang. If objects were travelling away from us at c then according to
relativity the object's time would stop so in theory we could see the
big bang itself (ignoring inflation and such) except that we couldn't
actually see it because at c all light would be Doppler shifted to zero
frequency. For an object travelling at nearly c we can see nearly back
to the BB because it is ageing only very slowly. That is assuming you
believe in BB theory which seems to be in a bit of trouble at the
moment, and if you believe in relativity.

The alternative to relativity theory, ballistic theory, actually
predicts the exactly the same thing observationally. It says that the
speed of light is c relative to the source so if something is travelling
at a velocity v which is an appreciable proportion of c then the speed
of light relative to us is c-v so it may have left the object only x
million years after the Big Bang it has taken 14.5 billion years to
catch us up because of the relatively low value of c-v. Again if it were
travelling at c then c-v = 0 we would travelling at the same speed as
the image and permanently see it as it was at the Big Bang but again we
wouldn't see anything because it would again be Doppler shifted to zero.

Of course Ballistic theory does not say that an object couldn't travel
away from us at greater than c but we would never see the light from it
because it would never catch us but it might account for some of the
missing mass in the universe :o).

Hope I have helped.