The stars in our galaxy are moving slower than previously thought.

Stars further out than the Milky Way’s galactic disk are moving more slowly than expected compared to stars closer to the center of our galaxy.

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This was established by a new study by physicists at the Massachusetts Institute of Technology (USA), who recorded the speed of the stars in the Galaxy, the university’s press service reports.

These findings open up a surprising possibility: the Milky Way’s gravitational core may be lighter mass and contain less dark matter than previously thought, the paper notes.

As part of the study, analyzing data collected by the orbiting Gaia telescope and the ground-based APOGEE survey of more than 33 thousand stars, including some of the most distant in the galaxy, scientists:

• determined the “circular velocity” of each star (how quickly the star rotates across the galactic disk);
• plotted each star’s speed against its distance to produce a “spin curve,” a standard graph in astronomy that shows how fast matter spins at a certain distance from the center of a galaxy. The shape of this curve can give scientists an idea of ​​how much visible and dark matter is distributed in the galaxy.

What really surprised us was that this curve remained flat, flat until a certain distance, and then began to bend, the researchers note. “This means that the outer stars are rotating a little slower than expected, which is a very surprising result.”

The scientists subsequently translated the rotation curve into a dark matter distribution that could explain the slowing rotation of the outer stars, and found that the resulting map produced a lighter galactic core than expected. That is, the center of the Milky Way may be less dense, with less dark matter, than scientists thought.

This puts this result at odds with other measurements, the researchers note. “Something suspicious is happening somewhere, and it’s very interesting to find out where exactly in order to get a complete picture of the Milky Way.”

Source: Racurs

David

I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.