- The European Space Agency is working on a new mission set to launch in 2026 in search of a “second Earth in the universe.”
- The Plato telescope will look at the stars in hopes of observing “transits” of habitable exoplanets, meaning the light variations that occur when an object crosses the field of view during an “eclipse.”
- “It is believed that there is an average of one planet per star. It is estimated that there may be at least 100 billion stars and 2,000 billion galaxies per galaxy. This really leaves a lot of possibilities,” explains Jean-Luc Petit, former head of the PLATO program at satellite maker Thales Alenia Space.
In the immensity of the universe, is there a twin Earth ? Another place where life might have developed in one form or another. Over thirty years, observations of aliens (5,346 identified to date) and promises to find an almost incalculable number of them, leading scientists to imagine that no, we are not really alone. the universe.
In Cannes, to the satellite manufacturer Thales Alenia Space (TAS), European Space Agency (Isa) A new mission is underway to search for a “second Earth in the universe”. Or at least other “habitable” environments outside our solar system. 20 minutes The Plato telescope and its 26 eyes were able to move into clean rooms ready to scan the horizons of our galaxy.
What is a “habitable” planet?
As of March 31, we have already observed and cataloged 5,346 exoplanets. A drop of water in the ocean. “It is believed that there is an average of one planet per star. It is estimated that there may be at least 100 billion stars and 2,000 billion galaxies per galaxy. This really leaves a lot of possibilities,” explains Jean-Luc Petit, former head of the PLATO project at Thales Alenia Space, where the satellite’s solar generators Vibration tests are now arranged.
Of this number of 23 zeros of potential candidates, “one in five is estimated to be located in the habitable zone”, the expert further notes. Along with Plato, Isa will target regions around the so-called “Golden Loops” stars. Not too close or too close, but “temperatures well suited for the presence of liquid water on the surface of a planet”. It should be obvious, i.e. made of rock.
How does the Plato telescope work?
To raise the counter of exoplanets, Plato would look to the stars in hopes of observing the “traffic” of objects orbiting them. The telescope and its 26 cameras will make it possible to create a mosaic of nearly 2 billion pixel images, focusing on photometry, that is, telling the light variations of observed stars. With a simple rule: if their brightness decreases at regular intervals, something is blocking the view. “During an eclipse, Jean-Luc Petit describes. The amplitude of this drop makes it possible to specify the size of the object in question. »
The first two missions launched to find exoplanets, CoRot between 2006 and 2014 and Kepler from 2009 to 2018, used the same process. But Plato will offer unparalleled precision with a “unique ability to make persistent and very long-term observations,” boasts Thales Alenia Space. “Pointing accuracy can be very high. One condition is that it’s very accurate,” says Catherine Vogel, the new head of the PLATO project at TAS. No In order to obtain reliable data, the satellite will coordinate thanks to asteroseismology. This “study of the sound waves that pass through stars and vibrate them” helps determine their mass, their age, and their radius. Information needed to characterize the planets orbiting them.
The same areas were scanned over two years
The €700 million mission is due to take off from Gouro in French Guiana by the end of 2026. And to go aboard the Ariane 62 rocket. In a Sun-centered orbit, i.e. placed around the Sun at the Lagrange L2 point. , 1.5 million kilometers from Earth, the telescope will focus on space (much wider than during previous missions) for two and a half years before replacing it. “If we want to find planets with characteristics close to Earth, we have to rely on orbits with similar periods. Therefore, it will take at least two years to confirm their presence around satellite-viewing stars, and two more transits of observations,” says Jean-Luc Petit.
Esa hopes the mission, which is planned for at least six years, will be able to analyze at least two different zones. “Aiming at sectors where stars are aligned with the Sun gives us the highest chance of finding habitable planets. But that’s not all fixed yet,” says Katharine Vogel. “Experts are still thinking about the best places. We’re like Christopher Columbus’s time. We’re really in the process of exploring.”