New data on the age of the Milky Way’s talk about its history – BBC Russian

Image copyright MPIA

Image caption The Milky Way extends from the center to the perimeter for the past 13.6 billion years

Astronomers have measured the age of 70 thousand stars in our galaxy – the Milky Way – and applied results on the galactic map.

They confirm what cosmologists have guessed long ago – our galaxy is expanding, and the most ancient stars are in the center.

The new galactic map, the largest in the history of astronomy, was presented at the 227th meeting of the American Astronomical society.

“We are for the first time with unprecedented precision tracked, how to form our galaxy,” – told BBC BBC head of the research team, Melissa Ness.

According to her, she received age cut Milky Way from the galactic center to the extreme limit of the galactic disk.

“Now we have data on the age of the stars not only in the plane of the disk, but also in the space above the plane of the galaxy,” – said Dr. Ness, who works at the Astronomical Institute of the Max Planck in Germany.

In order to calculate the age of each star, the astronomers compared the data from the two telescopes.

First, the data received in the framework of the project “Apogee” which based on the use of ground-based telescopes, automatically measure radiation up to 300 stars simultaneously in a wide range of the electromagnetic spectrum.

However, only the spectra of stars of their age can not be determined. So astronomers used the data coming from the Space Telescope “Kepler”. This telescope for a long time directed at star clusters and can be installed mass of the star.

“If we know the mass of the star, we can determine its age,” – explains Dr. Ness. Scientists were able to create a model of the relation mass of the star and its age to its range.

Then, this model was used to determine the age of the other stars, now only using their spectrum.

“This is a revolutionary achievement, because earlier the age of the star only on the basis of its spectrum to determine it was very difficult, “- says Dr. Ness.

Other methods of determining the age of a star – for example, the measurement of the speed of rotation – take a very long time.

Image copyright SPL

Image caption Age Star correlated with its weight and range of

All Stars applied to a new card, are classified as red giants. Explains Dr. Ness, these stars have a very high brightness and can be easily seen in the galactic distances.

This age cut our galaxy provides an unambiguous picture: “Our galaxy began its history in the form of a small disc, which is constantly expanding in from the center “.

” We have long suspected something like this, but now for the first time got the instrumental support of this growth model based on analysis of the age of the stars across virtually the entire radius of the galactic disk, not just the star closest to our Sun. “.