Re: Is the universe coming or going?

oriel36 wrote:


There are no theories here,just the confidence of an astronomer doing
what all astronomers should do,intepret the images correctly and put
them in proper context.Your crowd try to talk about stuff in between
objects,dark this and dark that,and come up with ridiculous
notions.

"Dark Matter" and "Dark Energy" currently have those names
because neither is fully understood as of today.

Background on Dark Matter
http://en.wikipedia.org/wiki/Dark_matter

Background on Dark Energy
http://en.wikipedia.org/wiki/Dark_energy



More on Dark Matter
http://www.astro.ucla.edu/~wright/cosmolog.htm#News

21 Aug 2006 - NASA announced updated information about the "bullet
cluster" 1E0657-56 today. Two clusters of galaxies have recently
collided in this X-ray source. This cluster is filled with hot gas
so X-ray observations by the Chandra X-ray Observatory show where
the ordinary matter is located. 90% of the ordinary matter (the
"baryonic" matter) is hot gas.

The new results [Clowe et al., Bradac et al.] use gravitational
lensing of background galaxies to show where the sources of gravity
are located. The sources of gravity in the cluster are not located
where the ordinary matter is located, so this cluster is a
counter-example to MOND. All of this was known in 2003 but with
less precision. Sean Carroll has a nice post about this at Cosmic
Variance.

The Matter of the Bullet Cluster
http://antwrp.gsfc.nasa.gov/apod/ap060824.html

Explanation: The matter in galaxy cluster 1E 0657-56, fondly known
as the "bullet cluster", is shown in this composite image. A mere
3.4 billion light-years away, the bullet cluster's individual
galaxies are seen in the optical image data, but their total mass
adds up to far less than the mass of the cluster's two clouds of
hot x-ray emitting gas shown in red. Representing even more mass
than the optical galaxies and x-ray gas combined, the blue hues
show the distribution of dark matter in the cluster. Otherwise
invisible to telescopic views, the dark matter was mapped by
observations of gravitational lensing of background galaxies.

In a text book example of a shock front, the bullet-shaped cloud of
gas at the right was distorted during the titanic collision between
two galaxy clusters that created the larger bullet cluster itself.
But the dark matter present has not interacted with the cluster gas
except by gravity. The clear separation of dark matter and gas
clouds is considered direct evidence that dark matter exists.


.

Relevant Pages

  • Daily Report #4962
    ... Direct Observations of Dark Matter from a Second Bullet: ... Vigorous cluster mergers provide a unique opportunity to directly ... the formation of stars and planetary systems. ... become PNe when the gas is ionized. ...
    (sci.astro.hubble)
  • Re: Dark matter swirling into a black hole?
    ... be borne out by the recent evidence from the Bullet Cluster: ... The gas in the two parts of the cluster interacted to create ... the "bullet" shaped shock front but the blue clouds of dark ... "dark matter clouds" are dark matter that came from opposite sides of ...
    (sci.astro)
  • Re: Dark matter is dead stars.
    ... Dark Matter candidates of dead starts and black holes doesn't fit the ... Two clusters of galaxies have recently ... This cluster is filled with hot gas ...
    (sci.physics)
  • Cosmic collision explained without dark matter
    ... Cosmic collision explained without dark matter ... Lying over three billion light years away, the Bullet Cluster ... emitted from very distant galaxies travelling through the Bullet ...
    (sci.physics)
  • Re: Superstring Theory, Dark Energy, and MOND
    ... The matter in galaxy cluster 1E 0657-56, ... hot x-ray emitting gas shown in red. ... show the distribution of dark matter in the cluster. ... two galaxy clusters that created the larger bullet cluster itself. ...
    (sci.physics)