Space
400 million new stars are discovered
For over two years, the space probe Gaia, and it is missing the milky way as accurately as ever. Now the ESA has presented the first results: A catalogue with more than 400 million stars.
The announcement of the European space Agency, ESA, for lay people are not particularly understandable, but she has it all: On 14. September was published the first data packet, the space probe Gaia. It is only a small part of the huge amount of data to deliver Gaia until the end of the Mission in 2022. But it is already clear that there are a lot more stars than the ESA astronomers had expected. ESA experts presented the catalog on Wednesday in Villanueva de la Canada near Madrid, the Spanish capital.
So far, about two million stars were known. The last data had been collected by a previous probe, named Hipparcos between 1989 and 1993. Now, the number has literally exploded: In the short period of its Mission, Gaia was able to make so far, about 400 million new stars. Alone in the milky way, the experts estimate the number at about 100 billion.
Fred Jansen, the ESA for the Gaia Mission.
“It is the largest star catalog of the milky way, ever,” said Fred Jansen, Manager of the Gaia Mission, in an Interview with Deutsche Welle. By 2017, Gaia should have more than a billion stars measured.
A thousand times more than we are a tiny part of the universe know – but
Thus, the Knowledge about our universe would be about a thousand times more precise than it was yesterday – although it is still only about one percent of all stars in our universe. The stars, which you can find Gaia, are located up to 500 light-years. The whole universe is, however, much larger: It has a diameter of about 100,000 light-years. The Gaia data will form a three-dimensional mapping of our Milk.
19. December 2013 started the probe from the earth, and has on 8. January reaches its location at the long-range point L2. This is a point deep in space – about four times as far from earth as the moon. It is named after the Italian astronomer Joseph-Louis Lagrange, in the 18th century. Century theoretically calculated.
At the Lagrange point L2, the gravitational forces of the earth and the sun behave in a way that a satellite circles in orbit around the sun, is always in a fixed Position to the earth. Viewed from this place the earth, it acts so as if the complete shear weightlessness Lord.
This giant radio antenna in Australia, the ESA maintains contact with Gaia.
Telescopes and detectors
Is equipped the probe with a classic optical mirror telescope, which is connected to a plurality of pixel detectors – similar to a giant digital camera with a billion pixels. The lens is so good that it could perceive from 1000 kilometers of distance of a human hair.
But the detectors of the camera can be much more than the Chips in a digital camera. There are three detector types, and each type has different tasks: 62 Astrometric detectors measure the celestial objects and determine their exact Position and speed. 14 photometric detectors detect the brightness and the wave length of the light reflected from the stars. You can break down the color spectrum of the individual stars.
And the so-called radial velocity spectrometer misses with twelve pixel detectors, the line spectra of the objects. That is, each spectral range of light that a star emits can be displayed individually. This helps in the identification of the occurring elements.
All detectors are provide in the course of the Mission, over a Million gigabytes of data – the equivalent of one thousand commercially available hard drives.
The milky way is about 500 light-years large – 0.5 per cent, of the whole universe
What is the origin of the universe?
The aim of the Mission is to understand the origin of the milky way and our galaxy better. GAIA should not be able to determine only the location and movement of the stars and heavenly bodies, but to produce about the chemical composition of the individual objects of a kind of tree. Then the researchers could calculate back the history of the universe almost to the big Bang.
Even brown dwarfs have it done to them. This is a very light, weak, so-called failed stars, drifting almost invisibly through space. Also, the Explosion of stars at the end of their life cycle fascinates scientists. About ten thousand of these as a Supernova, to be referred to heavenly bodies in distant galaxies could track down GAIA. An idea: The data from GAIA will give astronomers an indication of when and where such explosions are seen from the earth.
But not only astronomers and geophysicists, also very down-to-earth earthlings could practically benefit from the observations of the probe. So GAIA holds also for asteroids and comets on the look-out. Some could certainly be the earth dangerous.