On Thursday, one of the most important events in space travel in recent years took place: The European Space Agency successfully launched its €2 billion ($2.73 billion) Gaia satellite, which will beam back from space reams of data that scientists believe will give them insight into the more than one billion stars in the Milky Way, and beyond.
According to Professor Shay Zucker, an Israeli scientist who will be working with ESA scientists to analyze the data Gaia sends back to Earth, the satellite could find hundreds of thousands of planets in deep space, constituting the greatest advancement ever of human knowledge about the galaxy.
Over the next five years, Gaia will, using the latest technology, send photos, data, measurements, charts, and much more back to Earth, where scientists will analyze, decipher, and attempt to understand the history of the galaxy, discover other solar systems, map asteroids and comets as yet unknown, and learn more about Earth’s “celestial neighborhood.” Zucker will work with ESA scientists in analyzing the data and drawing conclusions that will be released to scientists around the world for further study.
Gaia, the ESA said, will “log the position, brightness and colour of every visible celestial object that falls within its field of view. By repeating these observations throughout its mission, astronomers will be able to calculate the distance, speed and direction of motion of each of the celestial objects, chart variations in their brightness, and determine whether they have nearby companions.”
That data will be gathered by state-of-the-art instruments, including two high-resolution and high-power telescopes, astrometric instruments, photometric instruments, spectrometers, and more. The sensors in the cameras that will record the photos seen by the telescope, said Zucker, contain over a billion pixels, and are by far the most powerful ever launched into space; the findings will be used to build a 3D-map of the Milky Way.
Zucker, a professor at the Department of Geophysics, Atmospheric, and Planetary Sciences of Tel Aviv University, is in charge of finding transiting extrasolar planets, which are planets that revolve around stars other than our sun. “The telescopes are so sensitive that they will be able to detect a planet based on the fact that the star it revolves around will be a little less bright as the planet passes the star,” Zucker told the Times of Israel.
Of course, there is a limit to the telescopes’ sensitivity, so they will only “see” so far — “up to several thousand light years,” said Zucker. “We already know about 1,000 planets circling other stars, but Gaia’s telescopes will see farther and more intensively than any that have been in space to date. It’s impossible to know how many planets will be discovered, of course, but I am optimistic. My educated guess is hundreds of thousands.”
As to whether there is life on those planets, that will remain a mystery, at least for now. “Gaia is equipped to detect motion, not light and shadow, which scientists can analyze to guess if a planet may have life as we know it. However, I would say that the planets it does discover are likely not to host life.” This is because, Zucker said, the planets Gaia will be able to detect are likely to be the largest ones in a solar system, “similar to Jupiter and Saturn in our own Solar System. But according to most scientists today, large planets, like ours, are largely gaseous, so they are not good hosts for life.” Gaia may pick up on smaller planets in orbit around close-by stars, but not in the Milky Way’s outer regions.
Scientists, Zucker said, will digest, analyze, and catalog the information Gaia sends home, eventually releasing it to the scientific community. “We will be searching for a lot more than planets, of course,” he said. “One of the most exciting projects Gaia will carry out will be to determine the true nature of dark matter, which many scientists believe holds secrets about the origins of the universe. It is because of dark matter, many scientists believe, that the universe is constantly expanding.
Hundreds of scientists are working on different aspects of Gaia. The scientists are divided into ten teams scattered around Europe. Zucker’s is headquartered in Geneva, but he will be able to do most of his analytical work in Tel Aviv. “We do get together every six months, though, and I am set to host the next meeting, in Tel Aviv, next May,” Zucker said.
By which time Gaia should have sent back enough data to make for a very interesting gathering.