China wants to find an Earth like exoplanet: Earth 2.0

beijingwalker · Apr 13, 2022

China wants to find an Earth like exoplanet: Earth 2.0

The mission plans to find planets that can support life and eventually be habitable by humans.

TN Science Desk

Updated Apr 14, 2022 | 01:26 AM IST

Chinese space scientists will be releasing detailed plans for the country’s first mission to discover Earth like habitable exoplanets. China’s space program is experienced with sending robots to the Moon and Mars in addition to building its own space station.

The mission aims to find planets out the Solar System in other parts of the Milky Way galaxy, but not just any planet. The mission has a goal of finding Earth like planets, that are orbiting a Sun like star. The distance of the orbit of these planets are critical to make it habitable, closer to a Sun like star would mean the planet would be too hot to survive, while too far from the star would mean it will be too cold. Astronomers call such a planet Earth 2.0, having the right conditions for liquid water and possibility for life to exist.

NASA’s Kepler telescope has found over 5000 exoplanets before running out fuel in 2018. None of the planets found seemed to fit the requirements of Earth 2.0. The Chinese space agency plans to change this with their mission aptly named “Earth 2.0”. The mission, funded by Chinese Academy of Sciences, plans to build a satellite to carry seven telescopes that will operate for 4 years. While these telescopes are smaller in size than NASA’s Kepler telescope, but the using multiple smaller telescopes will provide a wider field of view. Earth 2.0’s 6 telescopes will together stare at about 1.2 million stars across a 500-square-degree patch of sky, about 5 times the FoV from Kepler.

"Our satellite can be 10–15 times more powerful than NASA's Kepler telescope in its sky-surveying capacity," says Jian Ge, the astronomer leading the Earth 2.0 mission at the Shanghai Astronomical Observatory of the Chinese Academy of Sciences.

While 6 telescopes will be looking for exoplanets together, the seventh telescope will be looking for rogue planets. Rogue planets are free-roaming celestial objects that do not orbit any star. “If successfully launched, this would be the first gravitational microlensing telescope that operates from space,” says Ge The telescope will target the centre of the Milky Way where massive numbers of stars are located.

How will the telescopes locate exoplanets?

Since stars are brighter than planets, as planets only reflect the light they receive from the star they orbit around. The Chinese mission, will use the telescopes to detect small changes in a star’s brightness that indicate the planet has passed in front of it.

For rogue planets that do not orbit a star, the telescopes will look for changes in starlight when the gravity of the planet or star warps the light of a background star that it is passing in front of.

Combining the data already available from Kepler telescope, and 4 years of data from the Chinese mission astronomers are optimistic about finding an Earth like planet. The team plans to launch the spacecraft before the end of 2026.

Another space mission to find exoplanets is scheduled to launch in 2026, and that is by the European Space Agency. The mission is called Planetary Transits and Oscillations of Stars (PLATO). PLATO will have 26 telescopes and a much a larger field of view than Earth 2.0 but the satellite will observing different regions of space ever two years.