Wednesday, 12 Mar, 2008 Science

The Evolution of the First Stars that Lighted Up the Universe Revealed


The space investigations performed by scientists from NASA are currently focused on the oldest lights in the universe. Scientists discovered that cosmic neutrinos composed 10 percent of matter right after the Big Bang.

For about five years researchers studied the Universe and came up with the idea that it took 500 million years for the first stars to bring light to the Universe. In 2001 NASA launched WMAP, the mission of which was to estimate the particles of light that was left shortly after the Big Bang.

According to scientists, Wilkinson Microwave Anisotropy probe (WMAP) gathers information about the shape, the age and the way Universe was formed. It is drawing a map of the Cosmic Microwave Background (CMB) radiation, which scientists found in the sky. Apparently this radiation represents the oldest light in the Universe.

According to researchers from NASA, the Universe is full of this afterglow light, which can provide answers regarding the shape, history, essence and the fate of the Universe. Dr. Joanna Dunkley from the University of Oxford, UK, and Princeton University, US, who is currently one of the WMAP team members said: "We see patterns in light, light that has been traveling for billions of years, affected in the early infancy of the Universe by whatever the Universe was composed of at that point. We expected to see neutrinos. It's a nice piece of evidence that they are in the Universe at large and affecting the light signals we see."

Neutrinos occupied a much bigger fraction of the early Universe than today. According to the cosmologists, shortly after the Big Bang there was such an amount of neutrinos that they were able to influence the early development of the Universe.

The light that Wilkinson Microwave Anisotropy probe currently sees provides an impression of things that occurred billions of years ago. In such a way, according to the scientists, the information collected by the WMAP proves the theories linked with the level of helium observed today. The early Universe resembled a hot, nuclear reactor that produced helium. Particle physics state that because of such resemblance, there must have been a sea of neutrinos.

The data from Wilkinson Microwave Anisotropy probe also gives evidence that it took a very long period of time for the stars to start glowing, creating a cosmic "fog," which was caused by electrons dispersing microwaves. WMAP data provides the image of when the first stars started glowing in the Universe.

"We basically have the first evidence that how the first stars switched on was a long, drawn-out process that took half a billion years. We weren't able to see that before," said Dr. Joanna Dunkley.

Wilkinson Microwave Anisotropy probe is building a map of microwave light from its orbit, which is about four times more distant from the Earth than the Moon, tracing our planet around the Sun.

More details regarding the research are available in the Astrophysical Journal.

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