Willkommen auf Tagtt!
Thursday, 28. March 2024
Tagebücher » tao » News, Bilder, Videos - Online
Tagebuch tao
2005-04-29 17:38
Normal vs dark Simple but true
The fingerprint takes the form of pressure waves or sound waves - "acoustic peaks" or "baryon wiggles" as the scientists call them - which have nudged matter on its very discrete course.
Its most obvious manifestation is the startling discovery that there is a slight excess of galaxies with separations of 500 million light-years.
We've been told for years that galaxies originated in the quantum fluctuations coming out of the first few seconds of the Universe - these galaxies have grown through gravitational collapse and that's all that was needed.
Today, we have striking evidence that that is exactly what happened. It seems to be that simple.
It is amazing that they have taken a simple theory and they have produced these incredibly detailed and beautiful observations and it all matches.
Both the Sloan and 2dFGRS teams say the work has given them a new "yardstick" with which to determine distances in the Universe and the rate at which the cosmos is expanding.
Central to this will be the investigation of dark matter and dark energy.
The former is made from material unknown to science and invisible to current telescope technology. Its existence was only discovered because of the effect its gravity has on galaxies.
The even more mysterious dark energy is believed to emerge from the vacuum of empty space. It acts as an anti-gravity force that is driving galaxies apart from one another at an accelerating rate.
The amazing thing about all these results is that they are in perfect accord with the predictions of the standard cosmological model, including dark matter and dark energy.
So while it all fits together it sill leaves us 'in the dark' about the nature of these two mysterious components which dominate the energy of the Universe.
The 2dFGRS team says its analysis has enabled the Universe to be weighed with unprecedented accuracy: it turns out that normal, or "baryonic", matter, including all the galaxies, stars and planets, makes up only 18% of all the mass in the cosmos, with the remaining 82% accounted for by dark matter.
The Sloan group says its work has given the clearest demonstration yet that the geometry of the Universe is "flat".
This means the usual rules of Euclidean geometry taught in schools apply all over the cosmos: straight lines can be extended to infinity and the angles of a triangle add up to 180 degrees, etc.

Kommentare

Noch keine Kommentare!
Kommentieren


Nur für registrierte User.

tao Offline

Mitglied seit: 30.06.2004
71 Jahre, DE mehr...
Wirklich beenden?
Ja | Nein

2005-04-29 17:38