Post by Andrei Tchentchik on Jun 22, 2019 14:49:00 GMT 2
(.#209).- Discover a billion stars in 3D, thanks to the European satellite Gaia.
Discover more than a billion stars in 3D and in motion with the European Gaia satellite.
By Tristan Vey - Published 25/04/2018 at 17:37
The European Gaia satellite has measured the position of stars in the sky since 2012. It has already placed 1.7 billion on the celestial arch. As the Earth revolves around the Sun, the stars describe tiny ellipses in the sky. Reality, they are so small that they are invisible to the naked eye. Here, they have been magnified 100,000 times! the ellipse is large, the closer the star is: this is how astronomers can know their distance. In this way, astronomers can see clusters of stars, the closest to us, in 3D. But Gaia also manages to detect how the stars move in relation to each other. Can this movement, invisible on the scale of a human life, over tens of thousands of years. The satellite does not only see stars. He can also distinguish objects from our solar system: asteroids. Astronomers have been able to reconstruct with incredible precision the orbits of 14,000 of these objects that measure only a few hundred meters to a few kilometers in diameter.
The '' European Gaia satellite '' this starfighter has identified the brilliance and very precise position of 1.7 billion stars and has determined their distance and speed of movement on the celestial vault for 1.35 billion of them. Allowing to realize breathtaking modeling.
The European satellite Gaia is a fantastic starfighter. Since 2012, this insatiable celestial surveyor, who accompanies us in our race around the Sun to 1.5 million km from the Earth, measures every second the positions of 5000 stars, scanning the entire sky. Wednesday, the European Space Agency (ESA) has unveiled an unparalleled census of 1.7 billion light points on the sky. A perfectly astronomical figure, it is the case to say, when one knows that with the naked eye, a human can not distinguish more than 3000 "points" in the purest and most spared starry sky. light pollution. Gaia has detected 500,000 times more, characterizing their brightness and their position on the sky with diabolical precision.
Its exceptional instruments, a million times more sensitive than our retina, also allow it to distinguish at 1000 km distance, two points separated from the thickness of a hair. It did not take less to succeed in detecting the tiny ellipses that describe the stars in the sky as the Earth revolves around the Sun. These microscopic movements are all the more important as the stars are close to us, which allows us to deduce their distance, by a simple geometric rule. Gaia was able to measure the distance that separates us from 1.35 billion stars.
This is not a vulgar world map, but a three-dimensional map that has just been drawn And an animated map that is more. The stars also move in relation to each other on the celestial vault (see video above).
If these displacements are tiny on the scale of a life, they deform on the other hand the constellations over tens of thousands of years. We now know these travel speeds for each of these 1.35 billion stars. And for a "small" part of them, more than 7 million all the same, astronomers have managed to measure their "radial" velocity, that is to say the rate at which they are getting closer or farther from we (the researchers rely for this on the "color" of the star that shifts towards blue or red by Doppler effect, in the same way that the sound of an approaching ambulance is more acute than that of an ambulance moving away).
Finally, we can also discover the position and orbits of 14,000 satellites in this catalog of unprecedented wealth that promises a cascade of discoveries in the coming years.
F I N .
Discover more than a billion stars in 3D and in motion with the European Gaia satellite.
By Tristan Vey - Published 25/04/2018 at 17:37
The European Gaia satellite has measured the position of stars in the sky since 2012. It has already placed 1.7 billion on the celestial arch. As the Earth revolves around the Sun, the stars describe tiny ellipses in the sky. Reality, they are so small that they are invisible to the naked eye. Here, they have been magnified 100,000 times! the ellipse is large, the closer the star is: this is how astronomers can know their distance. In this way, astronomers can see clusters of stars, the closest to us, in 3D. But Gaia also manages to detect how the stars move in relation to each other. Can this movement, invisible on the scale of a human life, over tens of thousands of years. The satellite does not only see stars. He can also distinguish objects from our solar system: asteroids. Astronomers have been able to reconstruct with incredible precision the orbits of 14,000 of these objects that measure only a few hundred meters to a few kilometers in diameter.
The '' European Gaia satellite '' this starfighter has identified the brilliance and very precise position of 1.7 billion stars and has determined their distance and speed of movement on the celestial vault for 1.35 billion of them. Allowing to realize breathtaking modeling.
The European satellite Gaia is a fantastic starfighter. Since 2012, this insatiable celestial surveyor, who accompanies us in our race around the Sun to 1.5 million km from the Earth, measures every second the positions of 5000 stars, scanning the entire sky. Wednesday, the European Space Agency (ESA) has unveiled an unparalleled census of 1.7 billion light points on the sky. A perfectly astronomical figure, it is the case to say, when one knows that with the naked eye, a human can not distinguish more than 3000 "points" in the purest and most spared starry sky. light pollution. Gaia has detected 500,000 times more, characterizing their brightness and their position on the sky with diabolical precision.
Its exceptional instruments, a million times more sensitive than our retina, also allow it to distinguish at 1000 km distance, two points separated from the thickness of a hair. It did not take less to succeed in detecting the tiny ellipses that describe the stars in the sky as the Earth revolves around the Sun. These microscopic movements are all the more important as the stars are close to us, which allows us to deduce their distance, by a simple geometric rule. Gaia was able to measure the distance that separates us from 1.35 billion stars.
This is not a vulgar world map, but a three-dimensional map that has just been drawn And an animated map that is more. The stars also move in relation to each other on the celestial vault (see video above).
If these displacements are tiny on the scale of a life, they deform on the other hand the constellations over tens of thousands of years. We now know these travel speeds for each of these 1.35 billion stars. And for a "small" part of them, more than 7 million all the same, astronomers have managed to measure their "radial" velocity, that is to say the rate at which they are getting closer or farther from we (the researchers rely for this on the "color" of the star that shifts towards blue or red by Doppler effect, in the same way that the sound of an approaching ambulance is more acute than that of an ambulance moving away).
Finally, we can also discover the position and orbits of 14,000 satellites in this catalog of unprecedented wealth that promises a cascade of discoveries in the coming years.
F I N .
