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

On December 25, 2021, the space telescope left for space James Webb. From a privileged observation point, in an orbit 1.5 million kilometers away from Earth, protected from solar and terrestrial radiation, he promises images capable of changing our image of the universe and questioning our place in it. On a visit to the European Space Agency's European Space Astronomy Center near…

On December 25, 2021, the space telescope left for space James Webb. From a privileged observation point, in an orbit 1.5 million kilometers away from Earth, protected from solar and terrestrial radiation, he promises images capable of changing our image of the universe and questioning our place in it. On a visit to ESA's European Space Astronomy Centre, near Madrid, was Chris Evans (Hertford, UK, 47 years old), who is responsible for representing ESA at the institute that runs the European Space Observatory. Webreviews some of the discoveries of this artifact, which is worth 10 billion euros, two years after its launch.

What is the universe made of?

he Web It captures five times more light than a space telescope Hubble. This allows it to detect weak signals from distant planets or galaxies shortly after the Big Bang, but thanks to its spectroscopic capabilities, which analyze light and measure the wavelengths emitted by each object, it can learn its composition. “Even though all these beautiful images are published, three-quarters of the observing programs are dedicated to spectroscopy,” Evans explains. Using these images, it has become possible to detect carbon dioxide for the first time in the atmosphere of an exoplanet, in WASP 39b, and it will be possible to analyze the effects of flares released by red dwarfs, the most common in the universe, on the atmospheres of the planets surrounding them. This is an important step in determining whether life has evolved on these abundant worlds, but controlled by a hostile star.

It will allow you to ask previously impossible questions

“If we look at relatively close galaxies, like 20 million light-years away, with Hubble You can observe these beautiful and iconic spiral galaxies. You can see the light coming from the stars and the spiral arms, and you can also see the dust lanes, where there is a lot of interstellar gas and dust that blocks the light coming through. Hubble It is observed in the range of ultraviolet, visible and infrared light. but now, [con el Webb]We have observations with longer wavelengths, and we can see into this dust, and we can reach more areas than before, with Hubble, it was not possible to access it. We see the backbone of galaxies, a lot of star formation inside them and all the galactic material. If you are interested in understanding how stars form and the history of these galaxies,… Hubble It gives you a good starting point, but there are a lot of parts you miss because they fall into these dark areas.

Everything happened very quickly after the Big Bang

One of the abilities Webusing NIRCam (Near Infrared Camera), is taking pictures of the deep universe, beyond Hubble. Thanks to its sensitivity and longer wavelength, it can reach galaxies that were forming when the universe was less than a billion years old, 7% of its current age. There they found strange objects, like tiny red dots that looked very massive, perhaps even too massive for that stage of the universe. “In some of these galaxies we see evidence of supermassive black holes at their centers, hundreds of millions of years after the Big Bang, and there is a lot of excitement in the scientific community to try to understand how these massive objects could accrete so quickly.” “Evans says.

“We know this is something that happens in galaxies, but seeing it at such an early stage makes us wonder how such rapid chemical enrichment happened. You need many generations of very massive stars, burning up their fuel very quickly, exploding as supernovas, and releasing all Those enriched materials. [con nuevos elementos] “To be processed over and over again until the chemistry that we see in these distant galaxies is built.” All of this changes our way of understanding the evolution of galaxies.

In search of habitable planets

Evans admits that to find signs of life on an Earth-like planet next to a sun-like star, “it will be necessary to wait for a next-generation facility.” However, in the early works of L Web With exoplanets like the one orbiting the red dwarf Trappist-1, a system of seven Earth-sized planets next to a completely different star, we've already seen that one has no atmosphere and the other has a very thin atmosphere. Distant planets persist. 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,” the astronomer says.

“We recently published a study of a disk around a forming star located in a larger star-forming region with a large number of massive stars. We thought that if you had all these massive stars, there would be strong fields of ultraviolet radiation, which would scatter the gas and break Chemical bonds needed to form planets. But this team from Max Planck in Heidelberg (Germany) saw that in one of these disks, in that environment, there was a rich spectrum of molecules, carbon dioxide, cyanide or even water. “This is something that “Very exciting, because we think most stars form in these regions, and this means there may be more rocky planetary systems than we expect.”

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

There is an integration between the work of space telescopes, such as: Hubble also James Webb And missions that visit other planets in the solar system. Probes take very detailed measurements, but telescopes can perform more continuous observations. According to Evans, it was also possible within our own planetary system to study the presence of water in the comet belt beyond Pluto and the asteroid belt between Mars and Jupiter. “We saw water coming out of an asteroid as it approached the Sun. It seems like a small detail, but it is an important part of understanding how water gets to the interior of the solar system and could explain the presence of water in our oceans. Or the chemistry of the planet.” Evans points out.

A lens to see the first stars

One aspect highlighted by Evans is the images of the deep universe that… Web. “We deliberately targeted clusters of galaxies that, due to their gravity, act like a large lens that magnifies the objects behind them,” Evans explains. He adds: “This is how you see all these distorted galaxies that allow you to see them in a magnified way and reach very faint or very distant objects that cannot be seen otherwise.” This technology allows us to capture the light of the first stars born after the Big Bang and all kinds of strange objects.

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