How to measure the distance through the center of the Milky Way?

Previously astronomers could only measure quite accurately the objects on this side of the Milky Way, compared to the Earth, but now, with new techniques, we have measured an object in the other side of the heart of the Milky Way.

Thanks to new studies based on old astronomical algorithms, scientists have a more precise idea to measure the distance to celestial bodies on the other side of the Milky Way than Earth, supplementing Add our understanding of the universe on that side.

When observing the sky in the starry nights, we can easily see the center of the Milky Way in the sky as a region full of bright stars. The amount of stars here is too dense, making it difficult to look at the space behind it.

The Milky Way when viewed from Earth is a flat disk, so we have to build its 3D model with simulations from the outside, to be able to measure distances to celestial bodies far away from the center. Galaxy.

But how to do that? Astronomers in the past still took the brightness of stars to determine their size and measure relative distance to them. However, this gives an incorrect number.

Measure the distance to the stars on the other side of the Milky Way.(Graphics: Saxton Bill, NRAO / AUI / NSF; Robert Hurt, NASA).

So, in order to carry out this measurement, astronomers from the Max-Planck Radio Astronomy Research Institute in Germany and the Harvard-Smithsonian Center for Astrophysics in the United States, used a celestial technique. written from 180 years ago to build his method.

The old technique, called parallax , was first used in 1838 by the German astronomer Friedrich Bessel, to measure the distance to a star in the constellation Cygnus (Swan). He produced 10.3 light years - not too bad when measured with a simple telescope.

Explain this measurement, place your finger in front of your eyes, close your left eye, open your right eye, then close your eyes and open your left eye, repeat the opening of this eye and you will notice a change in your finger position. hand. Because the position of the eyes is quite close, we don't see this position change too big.

Fortunately, the Earth moves around the Sun, and the Earth's position on orbit every 6 months is far away from each other, so we will measure the distance of distant stars by this method. .

The Hubble Space Telescope's wide-angle field view camera can determine the position displacement of stars within 10,000 light years, the Milky Way's diameter is 10 times this distance. But further does not mean more accurate when looking through the heart of the Milky Way.

In this new study, astronomers have measured a group of stars located 66,000 light-years away and on the other side of the Milky Way than Earth. This number far exceeds the previous record, with 36,000 light years measured in 2013.

These gaps are measured by a technology called VLBA. Simply put, the VLBA is 10 large antennas located separately and thousands of kilometers apart, located in North America, Hawaii, and the Caribbean, together forming a large telescope network.

This network allows astronomers to detect the displacement of a star's position. Its sensitivity can be likened to seeing a baseball moving a small amount of space on the Moon.

This study was conducted observations from 2014 and 2015, showing light emanating from an area in space - where new stars are born.

The surrounding clouds of steam and methanol molecules have increased their luminous intensity and that light can be transmitted as far as it can be - to the astronomers' observations on Earth - and Walk through the cloud of thick dust covered the way.

'With the VLBA technology, we can measure new stars at great distances and lie in the spiral arms on the other side of the Milky Way. Not only that, we will quickly build a complete map of the entire Milky Way and learn a lot about its shape , 'said researcher Alberto Sanna from the Max-Planck Research Institute.

However, this is just the first step. To complete the map of the whole Milky Way, we need at least another decade. And soon, we can admire a giant selfie picture of the Milky Way.