🚀 go-pugleaf

On 19 Dec 2003 03:10:09 -0800, jupiter@k.st (Jupiter) wrote:

>Science breakthrough of the year: proof of our exploding universe 
>http://www.guardian.co.uk/spacedocumentary/story/0,2763,1110244,00.html
>
>Tim Radford, science editor
>Friday December 19, 2003
>The Guardian 
>
>Welcome to the dark side. Around 73% of the universe is made
>not of matter or radiation but of a mysterious force called dark
>energy, a kind of gravity in reverse. Dark energy is listed as the
>breakthrough of the year in the US journal Science today. 

73% of the mass of universe may be made up of dark energy, but it's
not proven yet.

>The discovery - in fact a systematic confirmation of a puzzling
>observation first made five years ago - paints an even more
>puzzling picture of an already mysterious universe. Around
>200bn galaxies, each containing 200bn stars, are detectable by
>telescopes. But these add up to only 4% of the whole cosmos. 

It's long been known that dark matter made up a significant amount of
the mass of galaxies and the universe.

>Now, on the evidence of a recent space-based probe and a
>meticulous survey of a million galaxies, astronomers have filled
>in at least some of the picture. 
>
>Around 23% of the universe is made up of another substance,
>called "dark matter". Nobody knows what this undetected stuff
>could be, but it massively outweighs all the atoms in all the
>stars in all the galaxies across the whole detectable range of
>space. The remaining 73% is the new discovery: dark energy.
>This bizarre force seems to be pushing the universe apart at an
>accelerating rate, when gravitational pull should be making it
>slow down or contract. 
>
>"The implications for these discoveries about the universe are
>truly stunning," said Don Kennedy, the editor of Science.
>"Cosmologists have been trying for years to confirm the
>hypothesis of a dark universe." 
>
>Sir Martin Rees, Britain's astronomer royal, called it a "discovery
>of the first magnitude". 
>
>The findings were made by an orbiting observatory called the
>Wilkinson Microwave Anisotropy Probe (WMAP). This measured
>tiny fluctuations in the cosmic microwave background, in effect
>the dying echoes of the Big Bang that launched time, space and
>matter in a tiny universal fireball. 
>
>These painstaking measurements were then backed up by the
>telescopes of the Sloan Digital Sky Survey, which mapped a
>million galaxies to see how they clumped together or spread
>out. Both confirmed that dark energy must exist. 

There was a recent X-ray study which cast doubt on the existance of
dark energy.

>The findings settle a number of arguments about the universe,
>its age, its expansion rate, and its composition, all at once.
>Thanks to the two studies, astronomers now believe the age of
>the universe is 13.7bn years, plus or minus a few hundred
>thousand. And its rate of expansion is a bewildering 71km per
>second per megaparsec. One megaparsec is an astronomical
>measure, totting up to 3.26m light years. Something latent in
>space itself is acting as a form of antigravity, exerting a push on
>the universe, rather than a pull. 
>
>Dark matter was proposed more than 20 years ago when it
>became clear that all the galaxies behaved as if they were far
>more massive than they seemed to be. All sorts of explanations
>- black holes, brown dwarfs and undetectable particles that are
>very different from atoms - have been suggested. None has been
>confirmed. 

According to calculations only a small amount of dark matter is
"baryonic" - matter we are familiar with, including black holes. Most
of dark matter is something that scientists can't explain.

>But dark matter exists, all the same. The dark energy story
>began in 1998 when astronomers reported that the most distant
>galaxies seemed to be receding far faster than calculations
>predicted. A study of a certain kind of supernova confirmed that
>they had not been misled: the universe was indeed expanding
>ever faster, rather than decelerating. 
>
>The discovery that some unexpected and undetectable force
>was pushing the fabric of space apart seemed to confirm a
>famous observation decades ago by the British scientist JBS
>Haldane: "The universe is not only queerer than we suppose. It
>is queerer than we can suppose." It once again raised profound
>questions about the nature of the universe: about space, and
>time, and energy, and matter. And it set the theorists on the
>hunt first for an explanation, and then for an experiment that
>would confirm their hypothesis. 
>
>So they turned once again to the original evidence for the Big
>Bang, the cosmic microwave background radiation. This is the
>original blaze of creation, cooled to minus 270 C - just about 3 C
>above absolute zero. Several lines of research, including
>experiments in the Antarctic and from high-flying balloons,
>began to provide a clearer picture: the universe simply had to
>consist of something more than just atoms and so-called dark
>matter. 
>
>"But WMAP, with superbly precise data beamed back from a
>little spacecraft a million miles away, has made the evidence
>more precise," said Sir Martin, of the Institute of Astronomy at
>Cambridge. 
>
>"The dark energy is spread uniformly through the universe, latent
>in empty space. Its nature is a mystery. Whereas there's a real
>chance of learning what the dark matter is within the next five to
>10 years, I'd hold out less hope of understanding the dark
>energy unless or until there's a unified theory that takes us
>closer to the 'bedrock' of space and time." 
>
>http://www.guardian.co.uk/spacedocumentary/story/0,2763,1110244,00.html

--
with no helmet
she's safe
right past the airport
and past the lotus
with the cure
-"Ariel vs Lotus"