Scientists determine more accurate weight of Milky Way

Milky Way's mass mostly made up of dark matter, new research into the galaxy reveals - 10-Mar-2019 - NZ International news

Milky Way's mass mostly made up of dark matter, new research into the galaxy reveals - 10-Mar-2019 - NZ International news

"For some context, the lowest mass galaxies are around a billion solar masses and the most massive are around 30 trillion solar masses, so the Milky Way is on the higher end of this range-but we already knew that", said Watkins. They combined data from Gaia and Hubble space telescopes, and they managed to estimate the mass of the galaxy, and it amounts to 1.5 trillion solar masses. One solar mass is the mass of our Sun. NASA notes that the estimate of 1.5 trillion solar masses is typical of galaxies of the Milky Way's brightness.

Data from the Gaia mission is key with measurements of these globular clusters extending up to 65,000 light-years away from Earth, while the observations from Hubble added data from globular clusters as far as 130,000 light-years from the planet.

The findings are an important breakthrough for astronomers, who had been relying on earlier research dating back several decades that estimated the galaxy's mass as somewhere between 500 billion to 3 trillion solar masses.

Dark matter makes up 90 percent of the galaxy's mass, but European Southern Observatory's Laura Watkins reveals that it is not possible to see and observe dark matter directly, which made it hard to get an accurate figure for the scientists.

"We just can't detect dark matter directly", Laura Watkins, of the European Southern Observatory in Garching, Germany, said in a statement.

"The more massive a galaxy, the faster its clusters move under the pull of its gravity", explains astrophysicist Wyn Evans of the University of Cambridge in Britain in the ESA statement. "Most previous measurements have found the speed at which a cluster is approaching or receding from Earth, that is the velocity along our line of sight". Gaia was designed to create a precise three-dimensional map of astronomical objects throughout the Milky Way and to track their motions.

In order to narrow it down, astronomers set out to measure the velocities of globular star clusters.

Astronomers have come up with one of the most accurate measurements of the galaxy's mass yet - and as it turns out, it's "on the beefier side".

In the ESA press release, study co-author Roeland van der Marel, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland, said his team was able to "pin down the Milky Way's mass in a way that would be impossible without these two space telescopes", so this is a good example of scientists pooling their resources to produce research that wouldn't otherwise be achievable. By combining data from two space telescopes-NASA's Hubble and the European Space Agency's Gaia-the researchers have measured the galaxy's mass to new precision. Dark matter is an invisible and mysterious substance that is described as a sort of scaffolding distributed throughout the universe that keeps the stars in their galaxies.