[ad_1]
LONDON, March 9 (Xinhua) – The Milky Way weighs 1.5 trillion suns and measures 256,000 light-years, according to the latest findings.
The measurement is by far the most accurate of the galaxy, thanks to data provided by NASA / ESA's Hubble Space Telescope and ESA's Gaia mission.
Previous estimates of the mass of the Milky Way ranged from 500 billion to 3,000 billion times the mass of the Sun. This enormous uncertainty comes mainly from the different methods used to measure the distribution of dark matter, which represents about 90% of the mass of the galaxy.
"We can not directly detect dark matter," said Laura Watkins, who led the analysis team, in an ESA statement. "That's what leads to the current uncertainty in the mass of the Milky Way – you can not accurately measure what you can not see!"
As dark matter is difficult to calculate, scientists must weigh the Milky Way by measuring the velocities of globular clusters – dense clusters of stars that revolve around the spiral disk of the galaxy.
"The more massive a galaxy, the faster its clusters move under the effect of its gravity," says astrophysicist Wyn Evans of the University of Cambridge in Britain in the press release. 39; ESA.
"Most of the previous measurements have revealed the speed with which a group approaches the Earth or retreats, that is to say the speed along our line of sight. could measure the lateral movement of the groups, to and therefore, the galactic mass can be calculated, "said Evans.
All these measures would not have been done without the Gaia and Hubble data. Scientists believe that the precise determination of the mass of the Milky Way would allow us to better understand where our galaxy is located in a cosmological context.
[ad_2]
Source link