Milky Way galaxy lighter than previously presumed
Milky Way`s dark matter mass suggests that the galaxy weighs just 25 - 33 percent of the amount that was previously estimated, according to a study.
London: Milky Way`s dark matter mass suggests that the galaxy weighs just 25 - 33 percent of the amount that was previously estimated, according to a study.
The new radical theory can help explain the lack of smaller galaxies in our galaxy.
It`s believed that the first galaxies took births as normal matter united around globs of dark matter, the invisible thing thought to consist of 80 percent Universe`s matter.
Many stars located on the edges of large spirals such as the Milky Way are orbiting at such high speeds that they should fly off, but something has been holding on to them, which is believed to be a halo of dark matter that encircles the visible disc.
Many stars are located in the Milky Way`s dark matter halo, and studies conducted earlier have used motion to determine the halo`s mass.
But as we are embedded in a spiral arm, meaning that dust and gas blocks most of our viewing range of our galaxy, the models had to make assumptions about parts that cannot be viewed by us.
For this, Alis Deason of the University of California, Santa Cruz and her co-workers compared two supercomputer simulations that mixed various amounts of normal and dark matter to construct the Milky Way galaxy.
One simulation built a Milky Way with a halo as massive as that of 800 billion suns while the other`s weighed an incredible 2 trillion suns.
The research team found that the smaller one was the better fit to actual observations, New Scientist reported.
The galaxies grow by capturing and merging with smaller galaxies and if the Milky Way is as heavy, as believed, then thousands of satellites should be surrounding it but only 26 were observed.
A lighter Milky Way commands fewer followers, much like as it right now.
The findings have been published in Astrophysical Journal Letters.