Although there have been high-profile historic missions to search for an Earth-like planet around a Sun-like star, astronomers have yet to achieve success. Now, the Chinese are launching their own space telescopes in search of Earth 2.0.
Looking for another Earth
The Kepler space telescope has made extremely interesting discoveries in astronomy. Launched in 2009, the telescope observed 13 million stars until it stopped working in 2018.
During that time, Kepler discovered more than 2,600 planets orbiting other stars. One of them is completely unlike anything in our Solar System, forcing astronomers to add two new classes to the planetary classification system.
Kepler has detected one or two cases where the planet is in the habitable zone of the parent star, although the region is around different red dwarfs than our Sun.
This is extremely interesting because this region with a mild climate, where water can exist in liquid form, has conditions that are thought to be important for the existence of life.
But with all of that, Kepler still failed in the end. Its mission is to find another Earth, or in other words an Earth-like planet, and orbit a Sun-like star. But in nearly a decade of observations, Kepler did not find a single Earth 2.0.
That’s partly because Sun-like stars turn out to be more volatile than expected and therefore require longer observation periods. But also because in 2013, two of the telescope’s four jet flywheels failed, making long-term observations impossible. As a result, astronomers have yet to find another Earth out there.
Sweeping across the sky
That could now be changed, thanks to a Chinese mission called Earth 2.0 that will launch in 2026. The mission will scan the sky for Earth-like planets around. Sun-like stars, with instruments designed to deal with stellar fluctuations that Kepler had inadvertently discovered.
The research team includes about 300 scientists and engineers from more than 40 institutions, most of which are in China. And this week, the team published detailed descriptions of the mission on arXiv.
One problem with any space telescope is to cover the widest possible field of view while minimizing the cost and mass of the spacecraft. The Chinese team has solved this problem by not using a single telescope that is both expensive and heavy.
Instead, the spacecraft will carry six telescopes smaller than 30cm, observing the same sky as Kepler (Kepler’s mirror is 1.4m in diameter). These telescopes will observe the distinctive changes in stellar brightness when a planet passes in front of them.
The spacecraft will also carry a seventh telescope designed to look for microlensing events, where the star’s gravitational field focuses light from a star far behind it, making it light up temporarily.
By monitoring variations in luminosity, astronomers can tell if a star has a planet orbiting it. This seventh instrument may also detect free-floating planets, shedding more light on strange, solitary objects.
Huge amount of data
The Chinese team plans to launch Earth 2.0 to the Lagrange L2 point, one of the regions of space that balances the gravitational fields of the Earth and the Moon, and away from where the Earth is likely to affect. .
L2 is a popular choice for telescopes and is home to a number of past and present telescopes, such as the Herschel Space Telescope and the James Webb Space Telescope. The Earth 2.0 spacecraft will be at the L2 point for four years, sending back about 169 GB of data per day.
This increases the likelihood of interesting discoveries. “The simulation shows that this survey trip will be able to detect about 20,000 new planets, including about 4,900 Earth-sized planets,” the team said. That means this mission will find between 10 – 20 Earth 2.0s by 2030.
The discovery of the first Earth 2.0 will likely be a pivotal moment in the history of astronomy. It generated a great deal of interest in the nature of these planets, the composition of their atmospheres, and the habitability of water.
Then there’s the search for biomarkers that suggest the existence of life, molecules like methane and oxygen, and the light-absorbing properties of photosynthesis. Going further would be to look for technological structures that might indicate the existence of a civilization, signs for example industrial pollutants containing chlorofluorocarbons (CFCs) and even transmission. narrowband radio.
Of course, Earth 2.0 isn’t the only mission capable of spotting another Earth out there. Others are also likely, such as the ESA’s Plato mission, which will also launch in 2026. But they will have to be luckier than Earth 2.0 to succeed.
This will create a race among nations to find another Earth and start a new era in the study of habitable planets.
