Milky Way’s mass mostly made up of dark matter, new research into the galaxy reveals


March 10, 2019 17: 15: 04

Astronomers have actually come up with one of the most precise measurements of the galaxy’s mass yet — and as it ends up, it’s “on the beefier side”.

Bottom line:

  • The mass is available in on the much heavier end of previous price quotes, which put it someplace in between 500 billion and 3 trillion times the weight of Earth’s Sun
  • Astronomers discovered just a small portion of the galaxy’s mass might be credited to the 200 billion stars in the Milky Method — the rest remains in dark matter
  • The research is because of be released in The Astrophysical Journal

Utilizing NASA’s Hubble Space Telescope and the European Space Company’s Gaia satellite, a group of global researchers identified the Milky Method (the galaxy which contains our planetary system) weighs in at about 1.5 trillion solar masses.

For those playing along in the house, that has to do with 1.5 trillion times the weight of the Earth’s Sun.

The findings are a crucial development for astronomers, who had actually been depending on earlier research going back a number of years that approximated the galaxy’s mass as someplace in between 500 billion to 3 trillion solar masses.

“We want to know the mass of the Milky Way more accurately so that we can put it into a cosmological context and compare it to simulations of galaxies in the evolving universe,” Roeland van der Marel of the Space Telescope Science Institute (STScI) composed in a blog post for NASA.

“Not knowing the precise mass of the Milky Way presents a problem for a lot of cosmological questions.”

Remarkably, astronomers identified that just a small portion of the galaxy’s mass might be credited to the around 200 billion stars in the Milky Method.

Rather, most of its mass is locked up in dark matter, an undetectable compound that, according to the space administration, “acts like scaffolding throughout the universe and keeps the stars in their galaxies”.

“We just can’t detect dark matter directly,” stated Laura Watkins from the European Southern Observatory, who led the group carrying out the analysis.

“That’s what leads to the present uncertainty in the Milky Way’s mass — you can’t measure accurately what you can’t see!”

The research, collected by astronomers from the European Southern Observatory, the Space Telescope Science Institute and University of Cambridge, is because of be released in The Astrophysical Journal.

Globular star clusters crucial to determining mass

NASA stated the new mass price quote puts the galaxy “on the beefier side compared to other galaxies in the universe”, which vary from 1 billion solar masses to 30 trillion solar masses.

Nevertheless, determining the Milky Way’s mass is not as basic as stepping on a scale.

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

It’s a bit of a mouthful, however not as overwhelming as it sounds.

Globular star clusters are basically separated islands, each including hundreds of thousands of stars — consisting of the oldest-known stars, going back to a couple of hundred million years after the huge bang — that orbit the centre of the galaxy.

Scientists utilized information from the Hubble telescope and Gaia satellite, which is tape-recording the positions of stars to produce a three-dimensional map of the Milky Method, to determine the motion of these clusters.

“Globular clusters extend out to a great distance, so they are considered the best tracers astronomers use to measure the mass of our galaxy,” stated Tony Sohn from the STScI, who led the Hubble measurements.

When those measurements were integrated as anchor points, astronomers had the ability to approximate the circulation of the Milky Way’s mass out to almost 1 million light-years from Earth.

“We were lucky to have such a great combination of data,” Mr van der Marel composed.

“By combining Gaia’s measurements of 34 globular clusters with measurements of 12 more distant clusters from Hubble, we could pin down the Milky Way’s mass in a way that would be impossible without these two space telescopes.”








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