Stargazers spot dark energy

"The distribution of galaxies and the time it takes for
galactic clusters to form are behind a University of
Queensland claim confirming the existence of dark
energy.

Dark energy has been predicted as a defender of
Einsteinian models of the universe, ever since the
1990s when astrophysicists identified the accelerating
expansion of the universe."

See:

http://www.theregister.co.uk/2011/05...t_dark_energy/

On 21/05/2011 12:12 PM, wrote:
"The distribution of galaxies and the time it takes for
galactic clusters to form are behind a University of
Queensland claim confirming the existence of dark
energy.

Dark energy has been predicted as a defender of
Einsteinian models of the universe, ever since the
1990s when astrophysicists identified the accelerating
expansion of the universe."

See:

http://www.theregister.co.uk/2011/05...t_dark_energy/

Have they considered the possibility that, as the galaxies get further
apart, their mutual gravitational attractionalso diminishes? That would
also result in an increased rate of separation without resorting to any
'celestial magic'.

wrote:
"The distribution of galaxies and the time it takes for
galactic clusters to form are behind a University of
Queensland claim confirming the existence of dark
energy.

Dark energy has been predicted as a defender of
Einsteinian models of the universe, ever since the
1990s when astrophysicists identified the accelerating
expansion of the universe."

Only problem is explaining from whence dark energy comes.

?

I could make a comment about star gazing while wearing sunglasses.
But I'll abstain... :-)

What they have "confirmed" is that the universe is expanding and will
to the best of our knowledge not close. GR works fine with that,
in fact in its original unadulterated (non-cosmological constant)
form it 'predicted' it.

What is conjectured is an 'energy' to drive that expansion.
What we have in-hand is an incomplete theory, both of gravitation and QM.

Why is gravity exempt from QM treatment? If QM statistics don't apply to
gravity then from whence does gravitation 'magically' spring into existence
moving from the Planck scale up? Why should gravitation by exempt of QM
statistics at all? Hm?

'Dark Energy' as a defense for GR is about as effective as an 'Insanity
Defense' is for most accused murders.

I don't have an issue with conjectures to explain the observed.
What I do object to is having it taught as truth, esp. to those in
the middle school levels. Remember 'trickle-down' isn't just confined
to economics.

Dave

wrote:
"The distribution of galaxies and the time it takes for
galactic clusters to form are behind a University of
Queensland claim confirming the existence of dark
energy.

Dark energy has been predicted as a defender of
Einsteinian models of the universe, ever since the
1990s when astrophysicists identified the accelerating
expansion of the universe."

Only problem is explaining from whence dark energy comes.

?

I could make a comment about star gazing while wearing sunglasses.
But I'll abstain... :-)

What they have "confirmed" is that the universe is expanding and will
to the best of our knowledge not close. GR works fine with that,
in fact in its original unadulterated (non-cosmological constant)
form it 'predicted' it.

What is conjectured is an 'energy' to drive that expansion.
What we have in-hand is an incomplete theory, both of gravitation and QM.

Why is gravity exempt from QM treatment? If QM statistics don't apply to
gravity then from whence does gravitation 'magically' spring into existence
moving from the Planck scale up? Why should gravitation by exempt of QM
statistics at all? Hm?

'Dark Energy' as a defense for GR is about as effective as an 'Insanity
Defense' is for most accused murders.

I don't have an issue with conjectures to explain the observed.
What I do object to is having it taught as truth, esp. to those in
the middle school levels. Remember 'trickle-down' isn't just confined
to economics.

Dave

David Spain wrote:

Only problem is explaining from whence dark energy comes.

Right. Expanding universe means space itself is expanding. There's
more space now when you read this than there was when I wrote this. How
clear is it that more is needed than that?

Once the volume reached some level the amount of expansion grew to the
point that gravitational bonding among galaxies was smaller than
gravitational weakening to expansion and red shift. The result was a
switch from decelleration to acceleration. If the math works out right
for that.

What is conjectured is an 'energy' to drive that expansion.

Which is definitely into epicycles.

More space means more mean distance. If gravitation works at C then
gravity is attenuated with distance on galatic scales because there's
more space for it to cross for it to have an effect. Why isn't the
strength of gravity assumed to be reduced by the same amount as the red
shift of observed light?

What we have in-hand is an incomplete theory, both of gravitation and QM.

Why is gravity exempt from QM treatment? If QM statistics don't apply to
gravity then from whence does gravitation 'magically' spring into existence
moving from the Planck scale up? Why should gravitation by exempt of QM
statistics at all? Hm?

We know from the wave particle duality of nature that both QM and GR are
close approximations to truth. We know from the fact that QM has no
gravity that QM is incomplete, but that's how science works in general.
All knowledge is provisional in science. Some knowledge gets overturned
completely (philogiston) some is close enough to the underlying truth
that it probably never will be (atomic theory of chemistry and scanning
electron photographs of individual atoms). We know from dark energy
that GR is incomplete.

QM depicts space as a foam. Sort of like having cells but cells are too
simple a model to really work. Expanding universe doesn't say that
galaxies are receding within space; it says that more quantum cells are
forming within space to draw galaxies apart and galaxies happen to
reside in specific ranges of cells. The way galaxies go faster at more
distance isn't that they accelerated it's that more cells formed between
here and there.

Should QM explain local gravity and "more foam" it would explain the
expanding universe.

On 22/05/2011 4:12 AM, Fred J. McCall wrote:
Alan wrote:


Have they considered the possibility that, as the galaxies get further
apart, their mutual gravitational attractionalso diminishes? That would
also result in an increased rate of separation without resorting to any
'celestial magic'.


Uh, no. To result in an 'increased rate of separation' they either
need to REPEL each other or be under some other form of acceleration.


Really? Couldn't the mutual gravity be holding them together? By
increasing the distance between galaxies, you also reduce the mutual
gravitational bond, so that would enable an increase in speed.

The further apart they become, the faster they would travel away from
each other.

::: To result in an 'increased rate of separation' they either need to
::: REPEL each other or be under some other form of acceleration.

:: Really?

Yes.

:: Couldn't the mutual gravity be holding them together?

Yes.

:: By increasing the distance between galaxies, you also reduce the
:: mutual gravitational bond,

Yes.

:: so that would enable an increase in speed.

No. At most it would enable the decrease in speed to occur at a lower rate.

Wayne Throop wrote:

::: To result in an 'increased rate of separation' they either need to
::: REPEL each other or be under some other form of acceleration.

:: Really?

Yes.

No. That's the deal with the expanding universe. The amount of space
between here and there grows without any acceleration of either object.
The question is whether the accelerating expansion is because the amount
of space is growing faster or if there's now so much space between here
and there that there's more of it to expand.

Doug Freyburger wrote:
Wayne Throop wrote:

::: To result in an 'increased rate of separation' they either need to
::: REPEL each other or be under some other form of acceleration.

:: Really?

Yes.

No. That's the deal with the expanding universe. The amount of space
between here and there grows without any acceleration of either object.
The question is whether the accelerating expansion is because the amount
of space is growing faster or if there's now so much space between here
and there that there's more of it to expand.

And I can't help but believe this is also intertwined with the 2nd Law Of
Thermodynamics. We are not only expanding, we are cooling too.

Dave (now colder than when I started typing this) Spain

David Spain wrote:
Doug Freyburger wrote:

No. That's the deal with the expanding universe. The amount of space
between here and there grows without any acceleration of either object.
The question is whether the accelerating expansion is because the amount
of space is growing faster or if there's now so much space between here
and there that there's more of it to expand.

And I can't help but believe this is also intertwined with the 2nd Law Of
Thermodynamics. We are not only expanding, we are cooling too.

That is the idea behind the frequency spectrum of the background
microwave radiation. It's a black body emission spectrum that gives a
specific temperature. It's part of how the age of the universe is
estimated.

In a sense the photons expand as the box they are in expands. It's
adiabatic expansion so it's cooling expansion.

Recent discussion about when life could have emerged in the universe are
partially based on the temperature of the background radiation. Go far
enough back and it heats biochemicals to the point of denaturing them.