Light matter

[shannon.spink@gmail.com]

Just a thought everyone - for there to be dark matter and dark energy,
must there not then be light energy and light matter?

So, if the scientists who think they have the universe figured out -
that the universe is atoms, dark matter and dark energy. I think that
the dark energy and dark matter are just half of the missing 96% and
that the other half is light energy and light matter. If you go and
look for this I think you will then have the entire universe figured -
well as far as what is there.

[Igor]

On Aug 2, 8:45=A0am, shannon.sp...@gmail.com wrote:
> Just a thought everyone - for there to be dark matter and dark energy,
> must there not then be light energy and light matter?
>
> So, if the scientists who think they have the universe figured out -
> that the universe is atoms, dark matter and dark energy. =A0I think that
> the dark energy and dark matter are just half of the missing 96% and
> that the other half is light energy and light matter. =A0If you go and
> look for this I think you will then have the entire universe figured -
> well as far as what is there.

The basic definition of dark matter is matter that does not interact
electromagnetically and thus cannot emit or absorb light. The
opposite, your so-called light matter would be matter that is able to
interact electromagnetically, thus it would be matter that's already
accounted for. So we wouldn't need to look for it. We're made of
it.

[Phillip Helbig---remove CLOTHES to reply]

In article
<aa3c5bbc-ec37-436b-a2c6-7ad431070cf5@j7g2000prm.googlegroups.com>,
shannon.spink@gmail.com writes:

> Just a thought everyone - for there to be dark matter and dark energy,
> must there not then be light energy and light matter?

"Light matter" is matter associated with stars. The contrast is the
origin of the term "dark matter".

Dark energy used to be called the cosmological constant. Dark energy is
one of the worst names in the history of science. I think it was
dreamed up to sound good in low-quality popular-science articles. As
Sean Carrol pointed out, lots of things are dark, and everything has
energy. If one wants a sexier name, why not something based on
important properties of the cosmological constant: it is distributed
completely smoothly in space, and has negative pressure. Nothing else
fits this bill, so "smooth tension" is a much better name.

> So, if the scientists who think they have the universe figured out -
> that the universe is atoms, dark matter and dark energy. I think that
> the dark energy and dark matter are just half of the missing 96% and
> that the other half is light energy and light matter.

For a scientific hypothesis, you need to point out WHY it should be half
and half.

> If you go and
> look for this I think you will then have the entire universe figured -
> well as far as what is there.

People have looked, and they get a few percent "light matter", about 30%
dark matter and about 70% smooth tension. "Light energy", the energy
associated with radiation in the universe, is negligible today.
However, in the early universe, it was the dominant component.

[Phillip Helbig---remove CLOTHES to reply]

In article
<88699d89-b6e1-4983-aa2b-26e522580737@p25g2000hsf.googlegroups.com>,
Igor <thoovler@excite.com> writes:

> The basic definition of dark matter is matter that does not interact
> electromagnetically

Not really. The basic definition is that it is dark. That could be
because it cannot interact electromagnetically, but could also be
because it doesn't emit light. Some dark-matter candidates (perhaps by
now ruled out on other grounds) which don't emit light but can or even
do interact electromagnetically: cold gas, planet-type objects, "failed"
stars (just slightly not massive enough to initiate fusion).

> and thus cannot emit or absorb light.

A black hole can absorb light, but in so doing it is not interacting
electromagnetically.

> The
> opposite, your so-called light matter would be matter that is able to
> interact electromagnetically, thus it would be matter that's already
> accounted for. So we wouldn't need to look for it. We're made of
> it.

We are not luminous beings, but we are made of matter which CAN glow, so
in this sense, his "light matter" is ordinary matter.

[Gerry Quinn]

In article <g71lf9$cqn$2@online.de>, helbig@astro.multiCLOTHESvax.de
says...

> Dark energy used to be called the cosmological constant. Dark energy is
> one of the worst names in the history of science. I think it was
> dreamed up to sound good in low-quality popular-science articles. As
> Sean Carrol pointed out, lots of things are dark, and everything has
> energy. If one wants a sexier name, why not something based on
> important properties of the cosmological constant: it is distributed
> completely smoothly in space, and has negative pressure. Nothing else
> fits this bill, so "smooth tension" is a much better name.

I'm not a big fan of the geometric interpretation of general relativity.

So what does this 'dark energy' look like, non-geometrically? Some kind
of force emanating from the vacuum that repels mass/energy? Or causes
red-shifting of light passing through it? (The latter idea sounds a bit
like the old 'tired light' concept.)

Suppose we put some dark energy in the Milne universe. How would we see
its effects in the non-expanding interpretation of this universe?

- Gerry Quinn

[JoMo]

[QUOTE=Gerry Quinn;1825635]In article <g71lf9$cqn$2@online.de>, helbig@astro.multiCLOTHESvax.de

Or causes red-shifting of light passing through it? (The latter idea sounds a bit
like the old 'tired light' concept.)


JoMo > what is the "tired light" concept?

[Oh No]

Thus spake Phillip Helbig---remove CLOTHES to reply <helbig@astro.multiC
LOTHESvax.de>
>In article
><88699d89-b6e1-4983-aa2b-26e522580737@p25g2000hsf.googlegroups.com>,
>Igor <thoovler@excite.com> writes:
>
>> The basic definition of dark matter is matter that does not interact
>> electromagnetically
>
>Not really. The basic definition is that it is dark. That could be
>because it cannot interact electromagnetically, but could also be
>because it doesn't emit light. Some dark-matter candidates (perhaps by
>now ruled out on other grounds) which don't emit light but can or even
>do interact electromagnetically: cold gas, planet-type objects, "failed"
>stars (just slightly not massive enough to initiate fusion).

I do not know why you say ruled out. These conventional matter objects
are dark matter (not just candidates), and they exist in large numbers,
though not sufficient numbers to explain galaxy rotation curves or
cosmological parameters. Hence the quest for exotic, or cold dark
matter.


Regards

--
Charles Francis
moderator sci.physics.foundations.
charles (dot) e (dot) h (dot) francis (at) googlemail.com (remove spaces and
braces)

http://www.teleconnection.info/rqg/MainIndex

[Oh No]

Thus spake Gerry Quinn <gerryq@indigo.ie>
>In article <g71lf9$cqn$2@online.de>, helbig@astro.multiCLOTHESvax.de
>says...
>
>> Dark energy used to be called the cosmological constant. Dark energy is
>> one of the worst names in the history of science. I think it was
>> dreamed up to sound good in low-quality popular-science articles. As
>> Sean Carrol pointed out, lots of things are dark, and everything has
>> energy. If one wants a sexier name, why not something based on
>> important properties of the cosmological constant: it is distributed
>> completely smoothly in space, and has negative pressure. Nothing else
>> fits this bill, so "smooth tension" is a much better name.
>
>I'm not a big fan of the geometric interpretation of general relativity.
>
>So what does this 'dark energy' look like, non-geometrically? Some kind
>of force emanating from the vacuum that repels mass/energy? Or causes
>red-shifting of light passing through it? (The latter idea sounds a bit
>like the old 'tired light' concept.)

It is a repelling force.

>Suppose we put some dark energy in the Milne universe. How would we see
>its effects in the non-expanding interpretation of this universe?
>
The Milne universe violates Einstein's field equation, so it does not
make sense to add a term to the field equation and ask what happens.

Regards

--
Charles Francis
moderator sci.physics.foundations.
charles (dot) e (dot) h (dot) francis (at) googlemail.com (remove spaces and
braces)

http://www.teleconnection.info/rqg/MainIndex

[Gerry Quinn]

In article <v9PxWWAoYUmIFws9@charlesfrancis.wanadoo.co.uk>,
NotI@charlesfrancis.wanadoo.co.uk says...
> Thus spake Gerry Quinn <gerryq@indigo.ie>
> >In article <g71lf9$cqn$2@online.de>, helbig@astro.multiCLOTHESvax.de
> >says...
> >
> >> Dark energy used to be called the cosmological constant. Dark energy is
> >> one of the worst names in the history of science. I think it was
> >> dreamed up to sound good in low-quality popular-science articles. As
> >> Sean Carrol pointed out, lots of things are dark, and everything has
> >> energy. If one wants a sexier name, why not something based on
> >> important properties of the cosmological constant: it is distributed
> >> completely smoothly in space, and has negative pressure. Nothing else
> >> fits this bill, so "smooth tension" is a much better name.
> >
> >I'm not a big fan of the geometric interpretation of general relativity.
> >
> >So what does this 'dark energy' look like, non-geometrically? Some kind
> >of force emanating from the vacuum that repels mass/energy? Or causes
> >red-shifting of light passing through it? (The latter idea sounds a bit
> >like the old 'tired light' concept.)
>
> It is a repelling force.
>
> >Suppose we put some dark energy in the Milne universe. How would we see
> >its effects in the non-expanding interpretation of this universe?
> >
> The Milne universe violates Einstein's field equation, so it does not
> make sense to add a term to the field equation and ask what happens.

I thought it was supposed to be something physical, not just 'a term
added to an equation'.

The Milne universe does not require general relativity to describe. It
can exist as a portion of a flat universe; nothing in it is subject to
gravity, after all!

Are you saying that the concept of dark energy can make no sense in a
universe without gravity?

- Gerry Quinn