Let's write about our amazing universe via the James Webb Space Telescope

Echo report published in The New York Times Magazine by Kate LaRue and Daniel Zvereff:

Nearly a million miles away, the James Webb Space Telescope just took a picture. Since transmitting its first data in late 2021, Webb has made stunning discoveries, including a plume of water spanning 6,000 miles in our solar system and a galaxy that formed only 390 million years after the Big Bang, or more than 13 billion years ago.

The telescope is an engineering marvel: Its massive mirror makes it possible to collect light from the faintest objects. It has multiple ways of blocking and dissecting that light, giving us detailed portraits of distant galaxies and close neighbors alike. And its position orbiting the sun allows it to take pictures around the clock, sending us up to 57.2 gigabytes of data — the equivalent of tens of thousands of standard iPhone photos — every day. 

What’s it telling us about our past — and the future of cosmology?

Webb can gather data even in the most distant, violent places, like the areas around massive stars.  In one of its first pictures, Webb photographed the Carina Nebula, home to dozens of giant stars, some of which are 50 to 100 times more massive than our sun.

Carina Nebula

Around them, scientists found previously unseen baby stars and pockets of hydrogen.

We think that our solar system was born in this kind of volatile environment.  Scientists recently used Webb to analyze a similar nebula and found water, carbon dioxide and other complex molecules — the elements that make up terrestrial planets.

“We have proven that it is possible to form an Earthlike planet even in the harshest environments in our galaxy,” says María C. Ramírez-Tannus, an astronomer at the Max Planck Institute for Astronomy. “We now need to know: How often does this happen?”

Space is a dark, dusty place — to the human eyeball. The light that is visible to us represents a tiny slice of the light that’s in the universe. Humans perceive different types of light as colors: violet, indigo, blue, green, yellow, orange and red. Bluer light is more energetic, and when it encounters dust — the tiny, solid particles floating around up there — it scatters, obscuring things from our view. Webb can see light just beyond what we can see, called infrared, that can easily pierce through dust. Animals like goldfish have evolved to see infrared light so they can navigate in murky waters.

In this image of the Eagle Nebula taken by the Hubble telescope in 2014, we see mostly visible light. The dust and gas form giant columns, inspiring the name the Pillars of Creation.

Eagle Nebula

Other layers of dust are illuminated in the infrared giving scientists a more three-dimensional portrait of events like the death of stars known as supernovas. 

Pictured here is Cassiopeia A, a star that exploded more than 10,000 years ago. Webb’s image showed us previously unseen gas and dust in its center.

When stars explode or die, new elements are forged, including the calcium that makes up our bones and the oxygen that we breathe. That’s what Carl Sagan meant when he said, “We’re made of star stuff.

Webb can also see further back in time — a mind-bending thought.

The light from this galaxy traveled through space for 40 million years before reaching Webb’s mirrors, which means we’re seeing it as it looked 40 million years ago.  

In the same photo, there are four other galaxies. The five are known as Stephan’s Quintet.

These four look as if they are close to the first galaxy, but they are 250 million light-years farther away. In one photo we see both tens of millions and hundreds of millions of years into the past. 

“We’re looking at a snapshot in time,” says Macarena García Marín, a project scientist at the Space Telescope Science Institute, which operates Webb. “Who knows what Stephan’s Quintet looks like now? Maybe they became a single big galaxy.”

For centuries, we could record only what was visible to the human eye, first with illustrations, then with photographs. 

Cave drawings, monuments and folklore that have survived for thousands of years show us that early humans had a sophisticated understanding of the cosmos.

In the 1200s, the Maya made records of Venus’s position in the sky on paper made from fig-tree fiber. Hieroglyphics carved into their monuments feature three stones surrounding a fire, a cosmic hearth of creation. Today K’iche’ Maya people in Guatemala understand the constellation of Orion to include those three stones and the fire in the center to be the Orion Nebula.

In the dust and gas that the Maya see as a fire, the Webb telescope  found a molecule that we had never detected before outside our own solar system. Called methyl cation*, it is believed to play a key role in the creation of complex carbon molecules — the molecules that make up all life on Earth.

Perhaps Webb’s greatest power is not to capture light, but to scatter and measure it. In 1789, William Herschel used a handcrafted telescope to discover Enceladus, the sixth-largest of Saturn’s 146 moons. Later, he used a prism to disperse sunlight into a rainbow and, using three thermometers, found that the temperatures of each individual color — and colors beyond those visible — were different. He had discovered infrared radiation and furthered the field of spectroscopy.

On Webb, thermometers and prisms have been replaced with dozens of filters and intricate mechanisms. One tool has a quarter of a million tiny shutters that can be used to gather light from 100 individual objects simultaneously. The spectra that it creates reveal granular details — chemical composition, temperature and mass — of individual stars, planets and galaxies. Recently, Webb trained its instruments on Saturn.

Transient Saturn features that appear to come and go with each yearly Hubble observation. The banding in the northern hemisphere remains pronounced as seen in Hubble's 2019 observations, with several bands slightly changing color from year to year. The ringed planet's atmosphere is mostly hydrogen and helium with traces of ammonia, methane, water vapor, and hydrocarbons that give it a yellowish-brown color.

Saturn, like Earth, experiences seasons. But because of its wide orbit, these seasons each last about seven and a half years.

Data collected using Webb was combined with information from Cassini-Huygens (a Saturn-specific mission) and Hubble to refine our understanding of the seasonal change.

Webb also observed Saturn's moon Enceladus. Scientists think it’s one of our best hopes of finding life in our solar system. Using the modern equivalent of Herschel’s prism technique, scientists analyzed a giant fountain of water vapor gushing from the moon. 
“We were shocked to see water in every single pixel of the data,” says Geronimo Villanueva, lead author of the study. Webb was also able to map the whole feature: The water vapor spanned over 6,000 miles.

In 1995, Robert Williams, director of the Space Telescope Science Institute at the time, pointed Hubble at an empty piece of sky and left it there for 10 days. His approach was risky — normally scientists use their precious telescope time to look at known objects. “Throughout my scientific life, I tended to rely on instinct, probably more than I should,” Williams says. He and his colleagues chose a spot just above the Big Dipper.  

Webb was trained on a similar patch of black sky. Its image shows nearly 94,000 galaxies.

“We live in this beautiful galaxy, the Milky Way,” says Brant Robertson, professor of astronomy and astrophysics at the University of California, Santa Cruz. “We can’t see the Milky Way from inside, and we can’t fly out and see it. But we know that our galaxy developed from other galaxies. By looking at these distant objects, we begin to understand the process by which a galaxy like our own home could come to be.”

Webb is showing us the earliest moment in our universe’s history, fossilized in light.

It’s tempting to decide that all this seeing amounts to knowing. But some of Webb’s observations challenge fundamental assumptions in our timeline of the universe.

For instance, we thought it would take more than a billion years after the Big Bang for enough gas and stars to coalesce into big galaxies like our own, but Webb has found more than a dozen big, bright galaxies that may have started forming in the first hundred million years after the Big Bang.

Six galaxies in particular are so bright that in order to fit into our current thinking about galaxy formation, every single atom in the area that they were forming would have had to become a star. 

‘‘In general, star formation is very inefficient,’’ says Erica Nelson, assistant professor of astrophysics at the University of Colorado Boulder. ‘‘Only like 5 percent of the gas becomes stars, and in these galaxies it’s 100 percent.’’ Astronomers are trying to account for this by tweaking different variables in their standard models of galaxy formation, including reconsidering the role of dark energy and dark matter. In the latest models of cosmology, these unobserved phenomena make up 95 percent of the universe.

Webb helps us know but also to “unknow”: It gives us stunning new discoveries while simultaneously challenging us to rethink and rebuild our understanding of the past.

*A correction was made on November 21, 2023: An earlier version of this article described incorrectly the James Webb Space Telescope's position in space. It is not the case that the telescope uses Earth as a shield. Additionally, the methyl cation molecule found by Webb has been detected elsewhere in our solar system; it is not the case that it had never been detected outside our own planet.