Michel Mayor and Didier Queloz have been observing an “impossible planet” for months. It is called 55 Cancri e and it is somewhat larger than Earth. It’s so strange that it shouldn’t exist, but there it is: 40 light years from Earth; orbiting a twin star of the Sun. In this world, a hemisphere always faces its star. The surface is over 2,000 degrees. The dark side is 1,300 degrees. The entire planet is probably covered in molten rock. It is what astronomers call a world of lava.
“This is the only planet of this type that we can observe”, explains to EL PAÍS the Swiss Queloz, who recently visited Madrid with his mentor, his veteran compatriot Michel Mayor, to give a conference at the center of the European Space Agency THAT C. Both won the 2019 Nobel Prize in Physics for discovering the first planet beyond the Sun, or exoplanet, in 1995. It was a gas giant orbiting the star 51 Pegasi, 50 light years from Earth. Today – just 26 years later – there are more than 4,500 identified exoplanets. One of the first objectives of this Swiss astronomer in front of the space telescope Cheops has been looking at 55 Cancri e, renamed Janssen.
“We have observations in the infrared on the thermal emission of this planet,” says Queloz. “Also, there is some observation in the visible light spectrum. These data do not give us a clear idea of what this planet is like. We do not know if it has an atmosphere or if there is any part of its surface that is solid. We also do not know if there is a seasonal evolution. Why is it important then? Because it is not very different from how the newborn Earth was, in its first 50 million years of life. It is a little bigger, but very similar. So we need to understand it. The best part is that this planet is just in the right place. With Cheops we will be able to study its evolution, its reflectivity. We’ll even find out if it has a permanent or temporary atmosphere. That’s why I’m so excited, ”he confesses.
I am convinced that in 10 years we will have found an Earth twin
Didier Queloz, astronomer
It is tempting to imagine if 4.5 billion years from now, the age of the Earth, there will still be humans following the evolution of this world of lava.
Mayor, 78, explains the other great goal of exoplanetary exploration for the next few decades: to find Earth’s twin planets in other stars. “In our searches we have found many stars that could host equivalents of our solar system,” he highlights. “For a moment we can imagine that we are aliens in another area of the universe looking at our own solar system with telescopes like the current ones. If this were so, by now we would only have discovered Jupiter and we would have suspicions that Saturn exists. We would have no idea where the Earth is, ”he highlights. Many of the exoplanets discovered so far are gas giants like Jupiter. It is very possible that some of them are the prelude to solar systems, they are rocky planets in the inner zones, just like ours, “but our technology is still too young to discover them”, acknowledges Mayor.
Queloz leads an international project to hunt new lands. The project is based on HARPS-3, a new instrument specially conceived to carry out the greatest search for planets like Earth in stars similar to the Sun. The HARPS-3 will be installed at the Newton Telescope on the island of La Palma, in the Canary Islands. This instrument will push the current technology for detecting planets in other stars to the limit to achieve something that has not been done before. Stars like the Sun have atmospheres and these emit light signals – noise – that can mask the presence of a terrestrial planet. “We have to kill this noise and we do not know when we will be able to do it,” sums up Mayor.
The HARPS3 will start working in 2023 and will analyze 60 stars similar to the Sun. “My goal is that within 10 years, when I am retiring, this experiment will be over,” says Queloz, 55 years old. “I am convinced that by then we will have found an Earth twin. It is possible that they are even 10. But there can also be bad luck and that the 10 are like Venus. I believe that the Earth cannot be so rare, so unique ”, he predicts.
Hunting that planet will be just the first step. Then it will be necessary to know if there is life in it. And this is where things get the most complicated. The current telescopes and those that will shape the future of astronomical exploration in the coming decades, such as the space telescope James webbThey can only find hints of life. It is for example oxygen, water and other atmospheric compounds that could indicate that there is something alive in these worlds. “Even with the right equipment, we will never be sure we have detected life,” acknowledges Queloz. “A biologist is not going to believe you until there is a lot of evidence, he will probably not accept it until you bring him the extraterrestrial living being,” he adds.
But reaching these worlds is impossible, remembers Mayor. “They are too far away. Remember the trip to the Moon. It took us three days to arrive. The light makes that journey in a second. Imagine that we find a twin from Earth just 30 light years away. At that distance he would be a very, very close neighbor. It would take light for the light to travel 1 billion seconds. It is a billion times farther than Apollo 11 and that trip was the farthest humans have traveled with manned missions. If you want to reach an exoplanet you need to be able to make a rocket that skims the speed of light and, more importantly, slows down when it gets close to its destination. The energy required is simply enormous, impossible to achieve ”, he details.
One day after winning the Nobel, this veteran physicist offered an interview to EL PAÍS in which he said: “Religion says that God decided that there would only be life here, on Earth, and created it. Scientific facts show that life is a natural process. I believe that the only answer is to investigate and find the answer, but for me there is no place for God in the universe ”. However, Mayor recognizes that the technical limitations of the human being will make it impossible to answer without a doubt if there is life on an exoplanet for many centuries. There is a much shorter path, the physicist recalls: looking for life elsewhere in our own solar system, especially the icy moons of Jupiter and Saturn. “It is much more possible that we can analyze and find extraterrestrial life in these places”, adventure.
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Two Nobel Laureates Observe an “Impossible Planet” That Looks Like the Newborn Earth