Chris Evans, Astronomer: “Looking at other planetary systems teaches us that Earth is in a very special place” | Science

On December 25, 2021, the space telescope launched into space James Webb. From a privileged vantage point 1.5 million kilometers from Earth, shielded from solar and terrestrial radiation, it promises images that can change our image of the universe and question our place in it. During a visit to the European Space Agency's European Space Astronomy Centre, near M…

On December 25, 2021, the space telescope launched into space James Webb. From a privileged vantage point 1.5 million kilometers from Earth, shielded from solar and terrestrial radiation, it promises images that can change our image of the universe and question our place in it. On a visit to the European Space Agency's European Space Astronomy Centre, near Madrid, Chris Evans (Hertford, United Kingdom, 47 years old), is responsible for ESA's representation in the organization that manages the agency. webSome of the findings of this 10 billion euro artifact are reviewed two years after its introduction.

What is the universe made of?

He web Captures five times more light than a space telescope Hubble. It allows us to detect weak signals from distant planets or galaxies after the Big Bang, but thanks to its spectroscopic capabilities, it breaks up the light and measures the wavelengths emitted by each object, allowing us to know its composition. “Although you see all these beautiful images being released, three-quarters of the observing programs are for spectroscopy,” explains Evans. With these images, it was possible for the first time to detect carbon dioxide in the atmosphere of an exoplanet, WASP 39b, and to analyze the effects of flares launched by red dwarfs. The universe, in the atmospheres of the planets around them. This is an important step in finding out whether life could have developed on these massive worlds, but under a hostile star.

This will allow you to ask questions that were previously impossible

“If we look at galaxies that are relatively 20 million light-years away Hubble You can observe these beautiful and iconic spiral galaxies. You can see light from stars and spiral arms, and you can also see dust lanes, where there is a lot of interstellar gas and dust that obscures the light. Hubble Observes in the ultraviolet, visible light and infrared. But now, [con el Webb]We have observations with longer wavelengths, and we can see inside that dust, and reach further regions than ever before. Hubble, could not be accessed. The backbone of galaxies, inside them we see a lot of star formation and all the interstellar material. If you are interested in understanding how stars form and the history of these galaxies, The Hubble This gives you a good starting point, but there are many areas you miss because of these dark areas.

Everything happened very quickly after the Big Bang

One of the skills webWith its NIRCam (near-infrared camera) camera, it creates images of the deep universe and beyond Hubble. With its sensitivity and long wavelength, it can reach galaxies that formed when the universe was less than 1 billion years old, about 7% of its current age. There they discovered strange objects like tiny red dots, which were apparently very large, perhaps too large for that stage of the universe. “In some of these galaxies, hundreds of millions of years after the Big Bang, we see evidence that they have supermassive black holes at their cores, and there's a lot of excitement in the scientific community to understand how such massive objects can accumulate so quickly,” says Evans.

“We know it's something that happens in galaxies, but seeing it at such an early stage makes us wonder how such rapid chemical enrichment occurred. You need very massive stars of many generations, burning through their fuel very quickly and exploding into supernovae, releasing all the enriched material. [con nuevos elementos] “These processes are repeated over and over again until they produce the chemistry we see in these distant galaxies,” the astronomer adds. All of this changes the way we understand the evolution of galaxies.

In search of habitable planets

Evans admits that “it will be necessary to wait for the next generation of facilities” to find signs of life on an Earth-like planet next to a Sun-like star. However, in early work web Exoplanets like the one orbiting the red dwarf Trappist-1 have already been detected in a system of seven Earth-sized planets next to a very different star, one with no atmosphere and the other very thin. Most distant planets continue. We are beginning to understand the diversity of worlds in the universe and what conditions might exist for life in very different places on our planet. “Looking at other planetary systems teaches us that Earth is in a very special place,” says the astronomer.

“We recently published a study of the disk around a star forming in a large star-forming region with a large number of massive stars. We thought that if you had all these massive stars, you would have strong fields of ultraviolet radiation that would disperse the gas and break the chemical bonds necessary for planet formation. But, Max Planck's team in Heidelberg (Germany) observed that in one of these disks, along with that environment, there is a rich spectrum of molecules, carbon dioxide, cyanide or water. “This is very exciting because we think that most stars form in these regions, which means what we expect.” “There may be more rocky planetary systems than that,” says Evans.

The interior of the solar system and the origin of water on Earth

There is a complementarity between the work of space telescopes such as Hubble oh James Webb and missions to visit other planets in the solar system. Surveys take more detailed measurements, but telescopes can do more continuous monitoring. According to Evans, our planetary system has been able to study the presence of water in the comet belt beyond Pluto and in the asteroid belt between Mars and Jupiter. “We saw water escaping from an asteroid as it approached the Sun. It seems like a small detail, but it's an important part of understanding how water got into the inner part of the Solar System and how it can explain the water in our oceans, or the chemistry of the planet,” Evans points out.

A lens to see the first stars

One of the features highlighted by Evans is images of the deep universe web. “We deliberately target galaxies that, because of their gravity, act like a giant lens that magnifies the objects behind them,” explains Evans. “This is how you see all these warped galaxies, allowing you to see them magnified and reach objects that are too faint or too far away to see otherwise,” he adds. This technique allows us to capture the light of the first stars born after the Big Bang and all kinds of exotic objects.

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