Thursday, March 27, 2008
Universe is 13.73 Billion Years Old
The latest on the "age of the unoverse" thread of this blog is news from NASA that it's been estimated to be 13.73 billion years old, see WMAP Reveals Neutrinos, End of Dark Ages, First Second of Universe
"NASA released this week five years of data collected by the Wilkinson Microwave Anisotropy Probe (WMAP) that refines our understanding of the universe and its development. ... WMAP measures a remnant of the early universe - its oldest light. The conditions of the early times are imprinted on this light. It is the result of what happened earlier, and a backlight for the later development of the universe. This light lost energy as the universe expanded over 13.7 billion years, so WMAP now sees the light as microwaves. By making accurate measurements of microwave patterns, WMAP has answered many longstanding questions about the universe's age, composition and development.
Microwave light seen by WMAP from when the universe was only 380,000 years old, shows that, at the time, neutrinos made up 10% of the universe, atoms 12%, dark matter 63%, photons 15%, and dark energy was negligible. In contrast, estimates from WMAP data show the current universe consists of 4.6% percent atoms, 23% dark matter, 72% dark energy and less than 1 percent neutrinos.WMAP cosmic microwave fluctuations over the full sky with 5-years of data. Colors [in the image] represent the tiny temperature fluctuations of the remnant glow from the infant universe: red regions are warmer and blue are cooler."
Labels: Age, Cosmology, Universe
Monday, March 10, 2008
Scientific American tells all?
I've been reading articles from Scientific American for fifty years or more, and still enjoy it tremendously. While there are many other extremely worthwhile scientific journals, I'm a creature of habit and this one is good enough for me!
Relative to the "Basic Questions" theme of this blog, I would heartily recommend that you read various online Scientific American articles. The following two articles in particular are very cogent summaries of several aspects of cosmology that I've mentioned in earlier posts, and they're well worth a read:
Relative to the "Basic Questions" theme of this blog, I would heartily recommend that you read various online Scientific American articles. The following two articles in particular are very cogent summaries of several aspects of cosmology that I've mentioned in earlier posts, and they're well worth a read:
- Misconceptions about the Big Bang - Baffled by the expansion of the universe? You're not alone. Even astronomers frequently get it wrong. ... Expansion is a beguilingly simple idea, but what exactly does it mean to say the universe is expanding? What does it expand into? Is Earth expanding, too? To add to the befuddlement, the expansion of the universe now seems to be accelerating, a process with truly mind-stretching consequences. ... The universe does not seem to have an edge or a center or an outside, so how can it expand?
- The Universe's Invisible Hand - Dark energy does more than hurry along the expansion of the universe. It also has a stranglehold on the shape and spacing of galaxies. ... Scientists are just starting the long process of figuring out what dark energy is and what its implications are. One realization has already sunk in: although dark energy betrayed its existence through its effect on the universe as a whole, it may also shape the evolution of the universe's inhabitants--stars, galaxies, galaxy clusters. Astronomers may have been staring at its handiwork for decades without realizing it.
Labels: Cosmology, Science, Scientific American
