James Webb sets out on his search for the first stars and habitable planets

While the first stunning images taken by the James Webb Space Telescope were revealed in recent days, its mission to discover the history of the universe is still in its infancy... Scientists from around the world have booked appointments to use this new, most advanced tool in observing the universe.

The following is a glimpse of two projects that the telescope, through its highly capable instruments, will undertake in the initial stages:

The first stars and galaxies

Among the most important characteristics of James Webb is his ability to study the early stages of the history of the universe's emergence after the Big Bang, which occurred 13.8 billion years ago.

The farther the bodies are from the Earth, the longer it takes for their light to reach us. Looking at the history of the universe means returning to its distant past.

"We are looking at this early stage to observe the first galaxies that were formed at the beginning of the universe," says Dan Cui, an astronomer at the Institute of Space Science Observatories who specializes in the emergence of the universe.

And astronomers were able to complete 97% of the stage back to the period after the Big Bang, but "we only see the small red dots when we look at the very distant galaxies."

The scientist adds: "Thanks to James Webb, we can finally look inside galaxies to learn about their components."

While galaxies currently have spiral and elliptical shapes, those in the early universe were "lumpy and irregular", and James Webb is supposed to reveal the oldest red stars that the Hubble telescope was unable to detect.

The space scientist refers to two projects that James Webb intends to achieve, one of which is to observe MACS0647-JD, one of the most distant galaxies known and contributed to its discovery in 2013, while the telescope will observe in the second project Erendel, the most distant star ever observed and discovered in March.

While humanity was amazed by the first James Webb images taken by the infrared telescope because the light emanating from the distant universe extended to these wavelengths coinciding with the expansion of the universe, but scientists are also paying great attention to the spectroscopy technique.

A spectroscopic analysis of the light of a body would reveal the characteristics of this body, such as its temperature, size, and chemical composition. This technique is then a forensic medicine for astronomy.

Science does not know until today what the universe's first stars look like, which may have begun to form a hundred million years after the Big Bang.

"Maybe we may see dramatically different things when observing the third star population, which is theoretically assumed to be much larger than the sun and composed only of hydrogen and helium," Coy says.

These stars were eventually subjected to a supernova (a massive starburst), contributing to the enrichment of the universe with the chemicals that made up the stars and planets that exist today.

Some astronomers are skeptical about the possibility of discovering the stars of the third mass, but this will not deter specialists and astronomers from working to try to discover them.

livable planets?

The scientists who would run James Webb's science projects were chosen based on a competitive selection process that was open to all, regardless of their career progression.

Among those selected was Olivia Lim, a 25-year-old PhD student at the University of Montreal.

"When he started talking about the telescope, I wasn't even born," she tells AFP.

Lim's goal is to observe rocky planets similar in size to Earth and orbiting a star called TRAPPIST-1.

These planets are so close together that from the surface of one of them the other planets can clearly appear in the sky.

"The TRAPPIST-1 system is unique," Lim says, adding that "the criteria in TRAPPIST-1 are conducive to researching the possibility of life outside our solar system."

Three of the seven TRAPPIST-1 planets are in the habitable zone, not far or very close to the star, which provides suitable temperatures for the presence of water on their surface.

TRAPPIST-1 is only 39 light-years away from Earth, and planets can be seen passing in front of the star, which makes it possible to monitor the decrease in brightness that occurs after the star's transit and use the spectroscopy technique to identify the characteristics of the planets.

It is not yet known whether these planets have atmospheres, which Lim is trying to find out.

And if the planets had atmospheres, the light passing through them would be filtered by the particles in them, sending signals for James Webb to pick up.

As for Olivia Lim's biggest achievement, it will be in monitoring the presence of water vapor, carbon dioxide and ozone on these planets.

TRAPPIST-1 is a target so important that a number of scientific teams have taken the time to monitor it.

Lim explains that finding signs that planets are habitable, if they do exist, will take time.

"But everything we're doing this year are important steps toward achieving the ultimate goal," she adds.

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