A Picture Worth a Thousand Answers

Scientists Capture Best Image Ever of Universe's Beginning
by Rob Stein

The new picture of the universe comes from the first data collected by the Wilkinson Microwave Anisotrophy Probe (WMAP), a small $145 million satellite launched on a Delta 2 rocket June 30, 2001. The craft is equipped with a suite of instruments designed to gather the most precise measurements of cosmic microwave background radiation, the technical term for the light left over from the big bang.

The image, created from a year's worth of data collected by the WMAP, 1 million miles from Earth, has solved long-standing puzzles, such as what the universe looked like right after it was forged in the violent inferno of the big bang, when the first stars blinked on in the coalescing heavens and what kind of matter makes up the expanding universe that exists today.

Astronomers calculated that the universe is 13.7 billion years old, that the first stars lighted up just 200 million years after the cosmos was born, and that it will expand forever, thinning and cooling until it eventually reaches nothingness. The new estimate of 13.7 billion years has a margin of error of only 1 percent, compared with about 30 percent for the best previous estimates.

The data also have enabled scientists to produce the most exact calculation ever of what the cosmos is made of today. It turns out that only 4 percent of the universe is made up of atoms with known forces such as electromagnetism and gravity, the ordinary stuff that makes people, potatoes, porcelain and everything else that humans know. Twenty-three percent of the universe is made from mysterious unseen material dubbed "dark matter" because scientists know so little about it. The remainder -- 73 percent -- is made up of yet another poorly understood force called "dark energy."

One possible explanation for dark energy is the "cosmological constant," an energy in empty space that would oppose gravity and was originally predicted by Albert Einstein, who later discarded it as his biggest blunder. This dark energy, astronomers said, is the reason why the universe seems to be expanding at an accelerating rate. There is not enough normal matter to counteract the effects of dark energy, which is also known as anti-gravity. As a result, the astronomers said, they can now predict confidently that the universe will continue to expand forever instead of eventually collapsing back in on itself in a "big crunch," as some had predicted.

Extract from an article by Rob Stein, Washington Post Staff Writer, February 12, 2003

The full article may be found at the following URL:
http://www.washingtonpost.com/ac2/wp-dyn?pagename=article&node=&contentId=A59406-2003Feb11&notFound=true

Submitted by:- Lerika Cross