Research

Scientists from ESA more accurately calculated the mass of the Milky Way

Astronomers from the European Space Agency(ESA) were able to more accurately calculate the approximate mass of our Milky Way galaxy. It turned out that it is two times more than the results of previous studies predicted. How much? Almost doubled. The findings of the 2016 study suggested that the mass of the Milky Way could be about 750 billion solar masses. ESA experts indicate another figure - almost 1.5 trillion. Why such difference?

More accurately calculate the mass of our galaxytwo spacecraft, the NASA Hubble telescope and the ESA Gaia space observatory, helped. By combining their observations of the speed of dense star groups, which revolve around the spiral disk of the Galaxy at a great distance from it, scientists were able to derive more accurate figures.

"The greater the mass of the galaxy, the faster the globular clusters in it move under the influence of gravity," comments astrophysicist at Cambridge University Win Evans.

"In the course of most previous researchscientists carried out the calculation only taking into account the speed of approximation or distance of the globular clusters relative to the Earth, that is, the clusters calculated the speed only along the observation line. In the new study, we were also able to measure the lateral velocity of the displacement of clusters and from this we were able to more accurately calculate both the mass and the total velocity of the galaxy. ”

According to current estimates, inside the Milky Waycontains about 200 billion stars. At the center of our galaxy is a supermassive black hole Sagittarius A *, which adds another 4 million solar masses to the total mass. Another part of the mass falls on galactic dust and gas, as well as planets. But all this, as scientists say, is only a small fraction of the total mass of our galaxy - no more than 10 percent. Where does the rest of the mass come from? From dark matter. And as noted in the ESA statement, such a strong difference in mass estimates "is mainly due to the difference in the methods of calculating its distribution within the Milky Way." Since dark matter does not emit electromagnetic radiation and does not directly interact with it, this makes it difficult or even impossible to directly observe it.

Despite the fact that the new mass estimates make ourThe Milky Way is one of the largest galaxies in its class, our galaxy is no match for real “hippo”, whose mass can exceed 30 trillion solar. Nevertheless, in the Local Group of Milky Way galaxies took the place of the king (or queen, if you will). Scientists have long believed that the largest galaxy of local clusters is the Andromeda galaxy with its eight hundred billions of solar masses, and the Milky Way is second. Apparently, now the leadership has changed.

You can discuss the news in our Telegram-chat.