Milky Way is twice as thick than previously believed

February 20th, 2008 - 4:51 pm ICT by admin  

Washington, Feb 20 (ANI): Astrophysicists have discovered that the Milky Way is twice as thick than previously believed.

According to a report in ABC, the discovery was made by Professor Bryan Gaensler from the University of Sydney and his team.

The research team found out that the enormous spiral-shaped collection gas and stars is 12,000 light-years thick when seen edge-on, not 6000 as scientists previously thought.

“This was quite a stunning result,” said Gaensler. “It was a bit of a shock to us. It’s like walking out into your backyard and finding your tree is twice the size you remembered,” he added.

The researchers made their discovery without high-tech equipment or powerful telescopes. Instead, they downloaded publicly available data from the Internet and carefully analyzed it.

“It took us just a few hours to calculate this for ourselves,” said Gaensler. “We thought we had to be wrong, so we checked and rechecked and couldn’t find any mistakes,” he added.

To measure the size of the Milky Way, researchers study light coming from a pulsar, a type of star that sends beams of light through space like a searchlight.

“As light from these pulsars travels to us, it interacts with electrons scattered between the stars, which slows the light down,” said Gaensler.

Scientists refer to those electrons as the Warm Ionised Medium, or WIM.

The WIM has a bigger effect on longer wavelengths of light, which are redder, than on the shorter, bluer, light.

“So by seeing how far the red lags behind the blue, we can calculate how much of the WIM the pulse has travelled through,” said Gaensler.

By comparing this effect on the light from stars different distances away from us, researchers can find where the WIM stops; in other words, the galaxy’s edge.

According to Gaensler, the trick for getting a more accurate figure lay in choosing the right pulsars to include in that analysis.

“What we did in terms of picking better data was picking pulsars that are either high above the galaxy or underneath it, and not the ones sitting inside the galaxy, which is what nobody had bothered to do before,” he said.

By making the galaxy twice as thick, dozens of other seemingly unrelated calculations seem plausible now.

For example, it helps make sense of how magnetic the galaxy is, said Gaensler.

The new figure could also lead to a rethink about the wider universe.

“Many of detailed calculations people do on galaxies across the universe - how gas is converted to stars, and stars are converted into gas, and how gravity and pressure balance to stop the galaxy flying apart - use that number,” he said. (ANI)

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