5/26/2023 0 Comments Half gaia project![]() ![]() For comparison, our sun is 4.6 billion-year-old and will die in 5 billion years.)Īgain, Gaia doesn't only see the spiral arms as they are today it allows astronomers to model the arms' evolution into the past and the future. So, with the new data, we can look, for instance, at stars that are no older than 100 million years." (In stellar terms, 100 million years is infancy. "We know that the spiral arms are mostly made of young stars. "With the astrophysical parameters that we now have, we can directly create samples of stars for specific science cases," De Bruijne said. The new data might help reveal the spiral structure with better clarity. But there are quite a few points of contention around these spiral arms: Astronomers still debate the size and prominence of the individual arms, as well as their exact position in the Milky Way's disk. Astronomers mostly agree that the Milky Way has four spiral arms, the dense twisting streams of stars and gas that appear to emanate from the galaxy's center. One of the lingering uncertainties related to the distribution of stars in the Milky Way is the galaxy's trademark spiral structure. And that is really important for figuring out how the galaxy hangs together." "So by measuring motions of stars, you also probe the matter distribution in the Milky Way. "All the stuff in the galaxy is exerting gravity at every star, and this gravity determines how fast the star moves," De Bruijne said. That means we're getting closer to solving some of the great puzzles, including the distribution of dark matter in the galaxy. Because we are inside the galaxy, we cannot "see the forest for the trees." It is impossible even for Gaia to peer through the thick dust and gas clouds obscuring the Milky Way's center (where the recently photographed supermassive black hole Sagittarius A* lurks) to the other side of the galactic disk.īut through the gradual improvements in Gaia data - and with the help of other observation techniques, such as radio astronomy - the big picture is coming together, piece by piece. Studying our galactic home is not an easy task. How does the galaxy "hang" together?Īlthough Gaia has been scanning the Milky Way since 2014, there is still a lot astronomers don't understand about the galaxy. "That's something that is otherwise really difficult and expensive to do with ground-based telescopes, as it takes a lot of time." 2. "It's really unique that we now can do this with such a high number of stars," De Bruijne said. ![]() By combining the information about chemical composition with the modeling of the stellar trajectories, astronomers will be able to track groups of stars to their birthplaces inside (but also outside) the Milky Way. ![]() It's like having an anonymous group of 500 million people and now you get to know every single one of them - their names, how old they are, where they came from."įor 2 million of these stars, Gaia measured the chemical composition of stellar atmospheres, which is identical to the chemical composition of the molecular clouds that these stars were born in billions of years ago, De Bruijne said. ![]() "You will really get to know the stars," De Bruijne said. The Milky Way has four spiral arms, but astronomers still debate about their sizes and positions. And that is a big deal, Gaia project scientist Jos de Bruijne told. These parameters, derived from the light spectra of the stars measured by Gaia (which are essentially the fingerprints of how these stars absorb light), reveal information about the chemical composition, mass, age, temperature and brightness of each of the measured stars. With the new data set, astronomers will be able to look for more.įor the first time, the Gaia mission team will release what they call "astrophysical parameters" for half a billion stars. But that was already possible with the previously released data. Because objects in the universe follow the rules of physics, astronomers can model the past trajectories of those stars and essentially play the movie of the Milky Way backward and forward millions, or even billions, of years. By measuring the precise positions, distances and velocities of vast quantities of stars, Gaia does much more than map the Milky Way as it is today. ![]()
0 Comments
Leave a Reply. |