In with a bang: The James Webb Space Telescope after one year
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Liam Archacki Staff writer
On the evening of July 11, 2022, U.S. President Joe Biden tweeted a photo. Points of orange, blue, and gold light sparkled and swirled against the black vacuum of space. It was our universe viewed through a new lens.
The image was the first from NASA鈥檚 James Webb Space Telescope (JWST), which has been heralded as a major step in the study of the cosmos.
鈥淭he first image from the Webb Space Telescope represents a historic moment for science and technology. For astronomy and space exploration,鈥� Mr. Biden鈥檚 tweet read. 鈥淎nd for America and all humanity.鈥�
Why We Wrote This
A story focused onFrom its first images, the James Webb Space Telescope has delivered breathtaking views of our universe. The range and precision of its observations are also transforming science.
That photo was soon followed by countless more, each as enthralling as the last. But the photos alone, though dazzling, don鈥檛 capture the scientific advances that this successor to the Hubble Space Telescope has already enabled in its first year 鈥� or those on the horizon.
鈥淚t鈥檚 transformational,鈥� John Mather, a senior astrophysicist at NASA, says. 鈥淲e expect that every page of the new astronomy textbooks will be different because of what we鈥檝e found.鈥�
How does the JWST enable new views of space?
This is a larger, more powerful telescope than its predecessors.聽聽
While the Hubble was primarily an imaging telescope, the JWST has a size that allows it to specialize in spectroscopy 鈥� the measurement of light in terms of its wavelength. When it comes to astronomy, spectroscopy can reveal many physical details about a celestial object: its temperature, its age, what it鈥檚 made of, and how fast it鈥檚 moving, for instance.
鈥淭he joke in the community ... is that a picture says a thousand words, but a spectrum is worth a thousand pictures,鈥� says Massimo Stiavelli, mission leader for the telescope, which NASA developed with contributions from the European and Canadian space agencies.
Another distinctive feature of the telescope is its capacity to observe light in the infrared range. As a result, it can see objects that are more distant, those obscured by dust clouds, or those that emit only infrared radiation.
A predecessor, Spitzer, was also primarily an infrared telescope, but the much greater size of the JWST means that it can see farther and produce a sharper resolution. This, paired with its spectroscopy prowess, 鈥渕akes it a completely different machine,鈥� Dr. Stiavelli says.
The impressive size of the JWST鈥檚 mirror 鈥� with a light-collecting area six times that of the Hubble鈥檚 鈥� is made possible by a unique design: It is actually made of 18 smaller mirrors that unfurl to form a monolithic mirror after the telescope鈥檚 launch.
What have been its biggest Year 1 discoveries?
Perhaps the greatest surprise so far is that the earliest galaxies were bigger, brighter, and hotter than scientists had predicted.聽聽
鈥淲e don鈥檛 know what the reason is,鈥� Dr. Mather says. 鈥淚t could be something is weird about the way stars grow. It could be that the early universe is just different enough that we have no idea we missed something. It鈥檚 even conceivable that there are weird things about the expansion [of the universe] itself.鈥�
Observations made with the telescope have also offered hints about what Dr. Stiavelli calls 鈥渒ind of the holy grail of JWST鈥�: population III stars.聽
These are stars composed only of hydrogen and helium 鈥� the elements that physicists say made up the universe after the Big Bang.聽Population III stars, although not yet conclusively observed, have been proposed as a likely breeding ground for the formation of the other, heavier elements聽found in stars like our sun, in planets, and even in human beings.
Some observers have argued that they鈥檝e seen evidence of population III stars with the JWST. 鈥淚t鈥檚 very interesting that we see this鈥� high-energy radiation, says Dr. Stiavelli. Still, he maintains a dose of skepticism, citing other possible explanations, such as black holes.聽
Can the JWST help find life out there?
In addition to distant galaxies, the JWST is also adept at observing planets outside of our solar system, called exoplanets, seen as key to the search for other life in the universe. In particular, the telescope has enabled scientists to聽analyze many more exoplanets using light in the infrared range.聽
鈥淭he infrared is very, very rich for studying little fingerprints of things,鈥� says Nikole Lewis, a Cornell University astronomer who specializes in exoplanets, 鈥渓ike water and carbon dioxide, and methane and carbon monoxide, and various types of what we call aerosols 鈥� clouds and hazes.鈥�
鈥淲e, the exoplanet community, are like kids in a candy shop right now,鈥� she adds.聽
An especially significant discovery was the existence of carbon dioxide in 鈥渉ot Jupiters,鈥� gas giants that are warmer than those in our solar system. This was at odds with what models had predicted.
鈥淩ight now, we鈥檙e going through the process of learning about these planets and their atmospheres, and then having to rapidly adapt all of our theories, which have basically been wrong,鈥� Dr. Lewis says. 鈥淪o that鈥檚 been one of the big transformational things, I think, across the board 鈥� not only for exoplanets 鈥� JWST is really pushing the limits of our theories, and pushing them forward.鈥�
What might come next?
First in the near future may be further discoveries that follow from the telescope鈥檚 early results.聽聽
鈥淲e are on the verge of a major step in understanding in a lot of areas,鈥� says Dr. Stiavelli, pointing in particular to the advances already underway in galaxy and star formation.
There are still other areas where, despite a lack of major advances so far, scientists have reason to anticipate fresh fireworks.
One is 鈥渃osmological tension,鈥� which is how scientists characterize attempts to measure the expansion rate of the universe. Different forms of measurement give different results for what鈥檚 known as the Hubble constant, the unit of measurement that aims to pin down precisely how fast the universe is expanding.
A number of researchers are using the JWST to refine their measurements of this constant. Based on whether or not it corresponds to previous measurements, a result here could provide further evidence that the tension is a genuine problem, or help resolve it.聽
Within the field of exoplanet research, much of the focus is on scientists who are trying to measure the atmosphere of rocky exoplanets, similar to Earth. To date, no rocky exoplanet has been confirmed to have an atmosphere.聽
A result in this area would be a crucial step in the search for other life-forms.聽
鈥淚s JWST going to give us a definitive 鈥楴o, we鈥檙e not alone鈥�? I don鈥檛 know,鈥� Dr. Lewis says. 鈥淏ut it鈥檚 certainly going to teach us a lot about how to look for life beyond our solar system.鈥�
