Yesterday, April 25, 2018, the European Space Agency released to the public the second release of the data set collected by the Gaia space telescope. This is a special device that is designed for surveillance of all 360 o celestial sphere in the optical range.

Assembling the Gaia Telescope

It uses a wide-angle lens (which is, of course, a simplified description, in reality there are several lenses at different angles and focuses), and unlike, say, the Hubble telescope, which aims at a very narrow section of the sky in order to clearly observe a particular star or galaxy, this one takes pictures of several million stars at once. And he has been doing this continuously for five years now. And, most importantly, it does not orbit around the Earth, like the Hubble telescope, but is located at the Lagrange point L2. A very populated place today, it is there that the most powerful James Webb space telescope will go, replacing the Hubble in 2019. Rotating with the Earth around the Sun, Gaia takes pictures of the same part of the sky from different points of the orbit about 70 times and eventually gets picture of the parallax of each particular star.

As a result, something like such a scheme comes out, although the video, of course, is modeling, and even exaggerated in effects for clarity. In reality, the displacement of stars is completely miserable, very good optics and computer processing are needed. Therefore, only space telescopes can build these maps, the inhomogeneities of the atmosphere completely negate all the efforts of any terrestrial telescopes, and the parallax method from the Earth can only measure the distance to the nearest 10,000 stars or so.

But when observing from space, where nothing interferes, you can very accurately calculate the position of a star not only in the sky, in a plane, but also in 3D, that is, build a good three-dimensional map of our part of the galaxy. In 2016, Gaia made the first test release, which contained the coordinates of two million nearby stars, and now it has posted an archive that already contains data on 1.7 billion stars in our galaxy.

New refined image of our Milky Way galaxy

It's good that the data is publicly available. Available for all mankind, for any specific person. I won't be surprised that beautiful 3D videos or even interactive 3D maps will appear in the near future, the past such simulation was based on the position of just something.

In general, this is a very correct and necessary undertaking - to spread scientific data in the public domain. Not those beautiful pictures that are published for the general public, and which are only suitable for pulling on the desktop, but a real array of scientific data. So that anyone with access to the Internet can at least check what these soaked scientists intended there, and even put forward some kind of theory, or even commit scientific discovery based on data processing by their numerical methods. Which, by the way, happens from time to time.

It's great that we are slowly refining the map of the Milky Way galaxy, I remind you that 1.7 billion stars is a tiny part of it, less than 2%. In total, in our galaxy, according to various estimates, from 100 to 400 billion stars. And in the observable Universe there are at least the same or approximately similar galaxies.

By the way, cartography is now an expensive pleasure. The Gaia mission cost approximately $1 billion and is planned to last until at least 2020. In addition to the positions of the stars in our galaxy, Gaia will also provide a more accurate map of nearby galaxies, and has already compiled an updated catalog (about 14,000) of asteroids in our solar system. The Gaia space telescope was launched from the Kourou cosmodrome using a Soyuz launch vehicle and a Fregat upper stage in 2013.

P.S. By the way, experts should note that the above picture of the galaxy is located "upside down". Which one I found with a quick googling, I inserted this one into the post. The two white spots above and to the left are the satellite galaxies of the Large and Small Magellanic Clouds, they are usually located below, under the disk of the galaxy, but go figure out where in space is “above” and where is “below”. Now scientists have accepted what points where North Pole Earth, there is the north pole (that is, the top) of the plane of the ecliptic of the solar system. There is also the "top" of the Milky Way galaxy, but it's all at tricky angles, and conventions in general, so...

If you look at the sky on a clear starry night, the first thing that will attract your attention will most likely be a wide whitish stripe, like a road stretching across the entire sky. This is the Milky Way, mysterious, intriguing, exciting the imagination. After all, it consists of many billions of stars scattered in outer space for many thousands of light years. And among all this multitude there is one star, the most dear to us - our Sun.

What is the Milky Way?

Milky Way- This galaxy which includes the solar system. It can be seen from anywhere on the Earth's surface. It forms a ring encircling the Earth. In the Northern Hemisphere, it passes through the constellation Cassiopeia, a little east of Orion's Belt, approaching the horizon not far from the brightest star, Sirius. The brightest parts of the Milky Way are the inhabitants northern hemisphere they cannot admire. They are available to those who live closer to the equator. The bright uniform glow of many stars, indistinguishable to the eye, is interspersed with dark "clouds" of cosmic dust.

origin of name

The ancient Chinese called the Milky Way the "Celestial River", while the Romans and Greeks called it the "Heavenly Road". Modern name comes from the Latin "via lacteal", which translates as "milk road". This name goes back to ancient Greek mythology. According to one of the myths, the son of Zeus Hercules was born from a mortal woman. Zeus offered the baby to his wife Hera when she was sleeping, so that he would drink her divine milk and gain immortality. Waking up and seeing that she was feeding someone else's child, the goddess pushed him away from her. A stream of milk spouted from her chest and froze in the sky, turning into the Milky Way. The word "Galaxy", by the way, has the same meaning: it is formed from the Greek word γαλακτικός, which translates as "milk".

The history of the discovery and study of the Milky Way

The fact that the Milky Way is a huge cluster of stars that are invisible to the naked eye was proved by Galileo Galilei. In 1610 he invented and made a telescope. When he pointed it at the Milky Way, he was amazed: instead of a whitish haze, countless sparkling stars appeared before his eyes. Now they can be considered separately.

In the 18th century, the English scientist William Herschel, counting the number of stars in different parts of the sky, discovered a large circle, later called the galactic equator. It was in this circle that the Milky Way was located. Thus, Herschel came to the conclusion that the stars are united in a colossal system, flattened towards the galactic equator.

The Milky Way is not the only galaxy, it is one of the many galaxies that make up our Universe. This was proven by Edwin Hubble in the 1920s.

By being able to measure the distance to some of the nebulae, Hubble proved that they cannot enter our Galaxy, based on their remoteness.

Structure of the Milky Way

Milky Way belongs to the species spiral galaxies with jumper. Its diameter is 100-120 thousand light years (in kilometers it is one quintillion). It is a relatively flat disk (its thickness is about a thousand light years). The galaxy contains at least 200 billion stars. According to modern estimates, their number is approaching 400 billion. The densest cluster of stars is observed closer to the center of the Milky Way, and towards its edges the density drops sharply.

Centre milky way

At the center of the disk of the Milky Way is the galactic core, which consists of many billions of old stars. And the center of the nucleus, in turn, is only a few light-years across, an extraordinarily massive region (its mass is several million Suns). Modern research show that there is a black hole here, and maybe several.

Around the galactic disk there is a kind of corona - a spherical halo. It is made up of globular star clusters, dwarf galaxies (Small and Large Magellanic Clouds and others), individual stars, and hot gas.
Spiral arms (Orion, Perseus, Sagittarius, Cygnus, Centaurus) stretched in the plane of the disk of the galaxy from its center to the edges.

On the outskirts of the Milky Way, in addition to stars, there are areas of gas of high density and several thousand light-years in size.

Our Sun is located at a distance of 28 thousand light years from the center (two-thirds of the radius), on the periphery of the Milky Way. Plane solar system does not coincide with the plane of the Galaxy, they lie at an angle to each other.

Interactive maps of the Milky Way online.

Several services today provide the opportunity to get acquainted in detail with many pictures of the Milky Way. The best ones are listed below:

Milky way map 3D. This card high resolution with several functions, which consists of 5,000 megapixel photos. It allows you to change the scale of the image and its angle. In addition, it includes an additional layer with which you can familiarize yourself with a map of the starry sky (see the constellations and their names). The map can be rotated with the mouse in any direction directly on the screen. To go to the map, you need to click on the image:

Map 1

The second map is an infrared image of the Milky Way. Over 800,000 frames from the Spitzer Telescope were stitched together to create such a precise and beautiful image. To go to the map, you need to click on the image:

Map 2

The following map is unique in that it provides an opportunity to see a wide variety of pictures of the Milky Way. You can choose the type of image in the lower left window from the many options presented. To go to the map, you need to click on the image:

Map 3

What is the future of our galaxy? Are collisions possible with other galaxies? While scientists can not give accurate predictions. The study and solution of these issues is still ahead.

And in conclusion, a very beautiful shot of the Milky Way from the very high point in Spain:

Artistic a photo milky way

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