Twenty-six years ago, NASA announced a project to launch a space telescope into orbit a million miles from Earth in order to study deep space and light from the early universe. The James Webb Space Telescope (JWST) transmitted its first images last month, providing a view of the cosmos never seen before.
The images were beautiful and dramatic to the untrained eye — “a new window into the history of our universe,” President Biden called them during the July 11 news conference when the images were first released — but to astronomers, they were even more impressive.
“It’s so surprising,” Dr. Keri Hoadley, assistant professor of astronomy at the University of Iowa, said about the First Deep Field image from JWST. That image showed a tremendous profusion of stars and galaxies in an area that’s “just one little speck of the universe,” as NASA Administrator Bill Nelson described it. It’s an area the Hubble Space Telescope has examined before, but it never revealed what JWST did.
Hubble, launched in 1990, focuses on the visible light spectrum. JWST observes the infrared spectrum, where the wavelengths are longer than those the human eye perceives. JWST can see much further into the universe than Hubble, and because light travels at a set speed, the farther away an object in space is, the further back in time it is.
The Deep Field galaxies aren’t just the most distant ones ever observed, they are also the oldest. That’s particularly interesting to Hoadley, whose research involves the formation of objects in the early universe.
“Some of the galaxies that appear orange-red in the image are clocking in at just 500 million years after the Big Bang,” she told Little Village. “We thought the first galaxies would just be forming then, and now we’re seeing galaxies that are full-fledged galaxies at this age. That’s something we did not expect.”
Astronomers are now having to rethink how galaxies form because of JWST.
There were many times between the announcement of the project in 1996 and last month when it appeared JWST would never get off the ground. It faced budget cuts, cost overruns and on several occasions Republicans in Congress tried to kill its funding entirely, claiming it was a waste of taxpayer money.
There were also numerous engineering challenges as new technologies had to be developed and refined. JWST eventually grew into a joint project between NASA, the Canadian Space Agency and the European Space Agency, costing more than $10 billion.
One enormous challenge was the telescope, which needed to be folded up “origami-style” to fit into the rocket transporting it, unfurling at its destination and deploying “a mirror 21 feet wide, a sunshield the size of a tennis court, and 250,000 tiny shutters, each one smaller than a grain of sand,” as President Biden put it.
JWST finally blasted off on Christmas Day 2021, after more than two years of technical difficulties causing launch delays. It took the telescope just 30 days to travel the one million miles to its fixed location at the second Lagrange Point, where the gravitational pull of the Earth and the sun are in balance. This creates a very stable orbit, meaning JWST doesn’t have to expend much fuel to maintain its orbit.
After six months of calibrating equipment, JWST produced its first set of images, with the infrared signals processed into forms the human eye can understand. So far, the oldest object the telescope has detected is a supernova that exploded 13 billion years ago.
For Hoadley, the most interesting JWST image is the “Cosmic Cliffs,” which shows the ragged-looking edge of a nebula in the constellation of Carina.
“It’s a star-forming region of our own galaxy,” she explained. The nebula is a massive cloud of gas and dust 7,500 lightyears from Earth.
“This is a view we’ve never seen before of this kind of cloud. We’re seeing newborn stars littered inside of this cloud that we’ve never seen before,” Hoadley said. “And based on their colors, we can tell how massive they are, how young or old they are at this point. So we can actually test our ideas of how these clouds form stars and how many they should form in ways that we haven’t been able to before.”
The “cliffs” are actually the edge of a giant gaseous cavity in the nebula. It’s the material that appears to be rising like steam from the cliffs that really interests Hoadley.
It’s part of the cloud that is evaporating “because of the intense light being produced from the most massive stars” in a cluster just outside the frame of the image, she said. Hoadley wants to know “how much of that is leaving and how fast.” The answers should help explain how stars in the nebula form.
“My primary interest is in how things form in the universe: stars, planets and even galaxies,” Hoadley said.
The energy involved in those formative periods excites electromagnetic waves, producing ultraviolet light with shorter wavelengths than the visible light spectrum. But because the universe is continually expanding, by the time that light reaches Earth, the wavelength has stretched out and has passed through the visible spectrum into the infrared, while retaining information from the ultraviolet spectrum. That’s why JWST’s array of infrared instruments could be valuable in Hoadley’s research.
In November, Hoadley and a group of colleagues will submit a research proposal seeking one of the 30-minute blocks of JWST time available to researchers. The project focuses on a stellar remnant known as the Blue Ring Nebula.
“We think it’s a star that has basically collided with, and totally absorbed, a companion star not that long ago,” Hoadley said. For an astronomer, a few thousand years qualifies as “not that long ago.”
Blue Ring Nebula animation — NASA/JPL-Caltech/R. Hurt
Stellar remnants “act super-weird,” Hoadley continued. “And this particular star we found has an interesting ultraviolet nebula that we’ve never seen around anything else, that we call the Blue Ring Nebula.”
Thirty minutes on JWST would produce more useful information than hundreds of hours of observations by Hubble, according to Hoadley.
“It would be unreasonable to ask Hubble to do this.”
Hoadley and her colleagues should know by April if their proposal has been approved.
JWST has an expected lifespan of 20 years. The most important thing it could do during that time, according to Hoadley, is “find really tantalizing signs of life on planets around other stars.”
To do this the telescope will have to locate a small, rocky planet in the “habitable zone,” in which liquid water can exist, and then examine its atmosphere.
“In our solar system, if we compare the rocky planets that have substantial atmospheres — Venus and Earth and Mars — if you look at Venus and Mars, their atmospheric compositions look remarkably similar,” Hoadley said. “Mostly made out of carbon dioxide, little trace elements of other things. There’s virtually no oxygen, very little hydrogen.”
“If you look at Earth, it’s so much different. It’s oxygen, it’s nitrogen, it’s water, it’s a little bit of CO2 and other greenhouse gasses,” she explained. “Earth’s atmosphere is totally a consequence of life being present. If it wasn’t for life, our atmosphere would look like that of Venus and Mars.”
“Finding the clear signatures of an atmosphere of a planet that likely has life on it, I think that would be the most revolutionary thing that it could find.”
Paul Brennan is Little Village’s news director. This article was originally published in Little Village issue 309.
