By: Yvonne Ye
After China sent robots to the moon, landed others on Mars, and built its own space station, it is now setting its sights on distant solar systems; This month, scientists will publish detailed plans for China’s first mission to discover planets outside our solar system.
The mission will search for these planets in other regions of the Milky Way, with the aim of finding the first Earth-like planet orbiting in the habitable zone around a star similar to the Sun; Astronomers believe that such a planet, which they call “Earth 2.0”, will have the right conditions for the existence of liquid water, and possibly life forms.
Already 5,000 planets have been discovered outside our solar system in the Milky Way, most of them by NASA’s Kepler telescope, which operated for nine years before it ran out of fuel in 2018. Some of the discovered planets were rocky Earth-like bodies orbiting About small red dwarf stars, but not all of them meet the definition of “Earth 2.0”.
With current technologies and telescopes, it’s very difficult to spot indications of the presence of Earth-like small planets, when their host stars are a million times heavier and more than a million times heavier, says Jesse Christiansen, an astrophysicist at NASA’s Institute of Exoplanet Science, located in the California Institute of Technology in Pasadena. A billion times brighter.
However, the Chinese mission, called “Earth 2.0”, hopes to change that. This mission will be funded by the Chinese Academy of Sciences, and is currently at the end of the initial design phase, and the designs are scheduled to be reviewed by a panel of experts in June, and if approved, a team will receive The mission has secured funding to begin building the satellite, and the team plans to launch the spacecraft aboard a Long March rocket before the end of 2026.
seven eyes
The satellite of the “Earth 2.0” mission is designed to carry seven telescopes, and these telescopes will monitor the sky for four years, six of which will survey the constellations of the Cygnus and Lyre, the same area that the Kepler telescope surveyed, and about that, Jian Jie, the astronomer who leads the mission says At the Shanghai Astronomical Observatory of the Chinese Academy of Sciences: “The range of the Kepler telescope is easy to survey because we have very good data for this region.”
Telescopes will look for planets outside our solar system by observing small changes in the brightness of stars, those changes that indicate that a planet has passed in front of them, and using several small telescopes together allows scientists a wider field of view, compared to using a single large telescope such as “Kepler”. The six mission is about 1.2 million stars, in a patch of sky measuring 500 square degrees, which is five times larger than the Kepler range. ) of NASA, which monitors bright stars near Earth.
“Our satellite can be ten or fifteen times more powerful than NASA’s Kepler telescope, in terms of its ability to scan the sky,” Ji says of the Chinese mission.
The satellite’s seventh instrument will be a telescope that monitors the effect of microgravity lenses, its purpose is to survey rogue planets – rogue celestial bodies that do not orbit any star – and exoplanets far from their star, such as Neptune in our solar system, the device will monitor changes in starlight when they cause The gravity of a planet or star passing in front of it in the deflection of the light emitted by it, and the telescope will target the center of the Milky Way, where huge numbers of stars are located.
“Our satellite can basically perform a census that monitors exoplanets of different sizes, masses and ages, and the mission will provide a good set of exoplanet samples for future research,” Ji explained.
data doubling
NASA launched the Kepler telescope in 2009, with the aim of discovering how common Earth-like planets are in the galaxy. Such planets should have the same orbital period as Earth, and pass between telescopes and its sun about once a year, says Chelsea Huang, an astrophysicist at the University of Southern Queensland in Toowoomba, Australia, that the planets must pass between telescopes and their suns three times. At least so that scientists can accurately determine their orbital periods, which is an estimated three years of data, and sometimes more if there are gaps in the data.
But four years after the Kepler mission began, parts of it broke down, causing the telescope to be unable to monitor any patch of sky for a long time. He was about to discover some very Earth-like planets.
Through the “Earth 2.0” mission, astronomers can have another four years of data, and when combined with what Kepler observed, that data can confirm which exoplanets are really similar to Earth, and about that, says Christiansen, who hopes Examination of mission data when available: “I am very excited about the prospect of returning to the Kepler range.”
Ji hopes to find dozens of Earth-like planets, and says he plans to release the data within a year or two of collecting it. “It’s going to be a huge amount of data, so we’ll need all the help available,” the mission team already includes about 300 scientists and engineers, mostly from China. But Ji hopes more astronomers from around the world will join in. “The Earth 2.0 mission is an opportunity to strengthen international cooperation,” he says.
It is worth noting that the European Space Agency is also planning a mission to explore the outer planets, called Planet Transit and Star Oscillation (PLATO), and it is planned to launch in 2026. The design of that mission contains 26 telescopes, which means that its field of observation will be much larger than the “Earth 2.0” mission. But the mission’s satellite will change its angle of observation every two years, to detect different celestial areas.