“There are more planets like ours.”

But the facilities, hard work and acquired skills were not lost. Some displays are dedicated to tracking scientific nanosatellites. The most important thing is what is not seen. The knowledge that Gómez de Castro and his team have gained over all these years will be put at the service of an even more ambitious mission, the Habitable Worlds Observatory (HWO) of… a pot. This space telescope will be the first specifically designed to search for signs of life on planets orbiting other stars, a titanic effort whose results could change human history. The researcher was selected by European Space Agency (ESA) As one of the three representatives of the continent in the team that will determine the mission, which consists of a thousand scientists from all over the world. “We already have many exoplanets. Now it's time to search for clones on Earth.” And regain your enthusiasm.

Since the discovery of the first exoplanet in 1995, the list has continued to grow thanks to new missions and detection techniques, with more than 5,000 planets already confirmed. But we have no idea whether any of them are capable of harboring life because there is currently no instrument, neither on Earth nor in space, that can detect them. Hopefully this will change with HWO, which is capable of observing in the range from the ultraviolet to the near infrared.

25 candidates

The length of the new telescope, in the development of which billions of euros will be invested, will be about six or eight meters, compared to the James Webb Telescope, the current jewel in the crown of observing the universe. Its location will be at the Lagrange point 2 (L2), located one and a half million kilometers behind the Earth in the opposite direction to the Sun “and its main goal will be to identify and obtain at least 25 systems.” The astrophysicist explains a planet “with its mass and environment (the characteristics of its star and the distance between them) ) can sustain life. This represents an unprecedented effort. “We want to observe a planet very close to a star billions of times brighter. The first thought that comes to my mind is to block the light from that star, right? But it turns out that during this process, echoes are generated, rings of light that are more intense than the signal coming from the planet. “We have to develop very complex optical engineering so that this effect does not compromise image quality.”

The 25 candidates have not yet been selected, and they could be worlds that have not yet been discovered. It must orbit relatively close stars, at a distance of between three and 50 light-years, so that in the image it is far enough from its star that it can be recognized. Once the target is reached, HWO will search for chemical “biosignatures” in the planet’s atmosphere, “gases such as oxygen or methane, which could indicate the presence of life, evidence of clouds, chlorophyll, and global weather patterns…” The observatory. “It will be able to detect signs of life, but it will hardly organize life itself.” He emphasizes that the biggest challenge is detecting plant masses. “Imagine we found a planet with plants that resembles Earth. The global community will focus on following it to find out if it harbors life. And if it has technological life.” “We can send a message that will arrive decades later,” he says. “Philosophically, this will have a huge impact.”

Gomez de Castro is convinced that at least one habitable world will be found. “I firmly believe there should be more planets. It's not a gratuitous statement, he says.

Space bombing

“A year ago, a mission from the Japan Aerospace Exploration Agency (JAXA) announced the first detection of uracil (nucleotides that are part of RNA) on an asteroid called Ryugu. We know that life on Earth arose about 3.7 billion years ago, which coincided with a powerful comet bombardment. It is possible that the bases of life arrived on our planet from space. This means that these bases are produced naturally by chemical reactions in space. The only thing you need is a star like the sun, ice, ammonia and carbon dioxide, which are very abundant ingredients. He points out that life could arise at any point in the universe, and that it would be very similar to what we know.

This similarity is an advantage not only when searching for a habitable planet, but also in the event that we have to leave Earth one day. “You have to go there. We must preserve our planet, but our survival as a species may depend on it.” A defender of the Spanish scientific tradition – “very strong” – Gómez de Castro knows that when she flies the HWO she will be “more than just retired”, but she doesn’t care. These great spatial projects “are modern cathedrals. They start with one generation and end with another. “That's the idea.”