Scientists discover minimum weight of galaxies
Thursday, 28 Aug 2008 09:04
Scientists believe they have discovered the minimum weight for galaxies
Scientists believe they have discovered the minimum weight for galaxies in the Milky Way.
A new report from the University of California out today claims that the galaxy's minimum mass is equal to ten million times the weight of the sun.
It is claimed that this mass could be the smallest known building block of the substance known as dark matter.
Stars form within these building blocks before clumping together and develop into galaxies.
The properties that make up dark matter are still unknown to scientists, despite the fact they make up about five-sixths of all matter in the universe.
"By knowing this minimum galaxy mass, we can better understand how dark matter behaves, which is essential to one day learning how our universe and life as we know it came to be," said Louis Strigari, lead author of this study.
The researchers studied 18 dwarf galaxies orbiting the Milky Way, using the Keck telescope in Hawaii and the Magellan telescope in Chile, with the aim of calculating their mass.
By looking at the star's light in each galaxy, they were able to determine how fast the stars were moving and therefore the mass of each galaxy.
It was expected that the galaxies would vary in mass, with the brightest weighing the most. However, all the dwarf galaxies weighed the same amount – ten million times the mass of the sun.
Authors of the report said the discovery was an exciting development in understanding how galaxies form in the universe.
"We are excited because these galaxies are virtually invisible, yet contain a tremendous amount of dark matter," said James Bullock, director of University of California's Center for Cosmology.
"This helps us better understand the particle that makes up dark matter, and it teaches us something about how galaxies form in the universe."