There is a distant world where quartz crystals float above a scorching hot, puffy atmosphere. On Wasp-107b, a planet 1,300 light-years away from Earth, the clouds that fill the sky are not water droplets, but evaporated grains of sand.
There is also the sauna planet GJ1214. Eight times the mass of Earth, it orbits its parent star at a distance of one-seventieth of the space between the Earth and the Sun, and appears to be covered by a thick, dense atmosphere containing large amounts of vapor.
Or there are Jupiter-sized giant planets discovered floating freely in space in the Orion Nebula; To the consternation of astronomers, there are rogue worlds that appear to have no connection to any parent star.
These strange, distant planets could not be more diverse or strikingly different from each other; But they share a common feature. Their wonders are now being revealed by the James Webb space telescope (JWST).
The $10 billion robotic observatory, which launched on Christmas Day 2021, is currently transforming our knowledge of the planets in our galaxy. Astrophysicist Dr. from the University of Bristol. “It took six months to position the telescope and ensure its systems were working properly, meaning 2023 is the telescope’s first full calendar year,” said Hannah Wakeford. “The results exceeded all our expectations.”
JWST consists of a 6.5-meter gold-plated mirror; a tennis court-sized canopy; and a series of complex instruments cooled to temperatures just a few degrees above absolute zero. These features allow the telescope to observe the skies with infrared radiation, revealing details of the universe just after the birth of the Big Bang 13.8 billion years ago and images of stars being born in dust clouds.
However, JWST provides another gift to science; It turns out that infrared radiation is also ideal for studying exoplanets, known as extrasolar planets, or worlds that orbit other stars. In doing so, the telescope triggers an astronomical revolution.
For centuries, the only planets humans knew about were the few planets we could see in our solar system. So, were scientists wondering if the Sun’s family was a typical family? Were planets abundant or rare elsewhere in the galaxy? These questions were crucial because the second scenario (a cosmic scarcity of planets) meant that extraterrestrial life would also likely be scarce.
The problem for astronomers was that the stars were very bright, but the planets were much smaller and much fainter and could not be detected next to their bright celestial parents. It was not until the end of the last century that a new generation of highly sensitive cameras installed on telescopes and orbiting observatories succeeded in detecting subtle dimmings of exoplanets passing in front of stars.
After the first few of these transit observations were made, discoveries began to increase dramatically. According to NASA’s exoplanet archive, the total number of exoplanets observed today is 5,566.
A few hundred of the most important ones are relatively close to Earth, and they are now ripe for study with JWST, astronomers say. Wasp-107b and its quartz clouds and the roving worlds of the Orion Nebula are already being studied, along with other exoplanets.
“Having found all these worlds, we are now in the fortunate position of being able to study them in detail, analyze their atmospheres and even map their properties, whereas thirty years ago we were not sure whether they existed.” Prof Jayne Birkby, astrophysicist from Oxford University.
The first target for astronomers using JWST was Trappist-1, a small, cool star of the type known as a red dwarf. Forty light-years from Earth, it has a family of seven small rocky worlds, three of which lie in an area known as the habitable zone. Astrobiologists say that the conditions here are not too hot or too cold to prevent liquid water, which is a basic requirement for the development of life.
But analysis using JWST of two of the star’s innermost planets, Trappist-1b and Trappist-1c, revealed that they either have no atmosphere or a very thin atmosphere. Further JWST work on the remainder of the system is planned. Open University astronomer Dr. “Trappist-1’s system still looks promising if you’re looking for a world that can support life,” Jo Barstow said.
But there is a particular problem affecting studies of stars like Trappist-1. Red dwarfs are spotty. Barstow added that this may not seem like a fatal condition, but it has serious consequences. “Our sun has sunspots associated with intense solar activity, but there are relatively few. By contrast, Trappist-1 has dozens of constantly changing spots, making it very difficult to distinguish them from the properties of a planet’s atmosphere. The Trappist-1 system does not easily reveal its secrets.” “It won’t take it off.”
As a result, astronomers using JWST to search for signs of extraterrestrial life are looking for a set of biomarkers known as the Big Four: oxygen, carbon dioxide, water and methane. Their presence in an exoplanet’s atmosphere could be a strong sign that some form of life exists there.
“However, exact rates may vary,” Birkby said. “Earth has an atmosphere of 21% oxygen, but this would have been very different 2.5 billion years ago when there was very little oxygen. The great oxidation event that occurred when cyanobacteria in the oceans began to produce oxygen through photosynthesis had not yet begun. “But there was still life on Earth at that time.”
It remains to be seen what scientists will make of a world whose atmosphere contains all of the Big Four. “It’s hard not to be excited by today’s Earth-like amounts,” Birkby added.
But others sound a note of caution. “Even if you get a perfect profile of gas and water vapor in the exoplanet’s atmosphere, you’ll still only have made indirect measurements, and based on those it’s hard to say with certainty that you’ve found life,” Barstow said.
“Even if you were 99% sure of the claim, there would still be a nagging doubt that what you observed was due to non-biological events.”
The lifespan of the James Webb space telescope promises to be interesting and long. JWST’s flight aboard the Ariane 5 rocket from the European Space Agency’s Kourou launch pad in French Guiana to its current position in orbit around the sun was nearly flawless. The observatory used very little fuel to maneuver to its exact target position; This means there will be extra fuel that will allow the telescope to steer itself for much longer than expected. Space engineers have calculated that JWST could double its expected 10-year lifespan.
“In many ways this is very good news,” said Professor Stephen Wilkins, an astronomer at the University of Sussex. “We’ll be able to do a lot more science with this now. However, the telescope will deteriorate over the years due to impacts from meteors and cosmic rays. This will gradually degrade its performance, so we must make the most of it when operating in near-optimal conditions.”
Wilkins’ area of expertise is the study of galaxies and black holes. “Still, I think the most exciting science JWST will do is on exoplanets,” he said. “We will learn a lot about the chemistry of their atmospheres and find some very strange and strange worlds out there. This is extremely exciting.”