51��Ʒ��Ƶ astronomers will be among the first to use the latest and greatest NASA telescope

Searching for galactic winds

Before the telescope can start looking for galaxies, it has to launch into space. And that’s just the beginning of its precarious journey: Unlike its predecessor, Webb will revolve around Earth in an orbit so distant that it can’t be serviced by astronauts.

“There are 344 single-point failures,” Bezanson said — as in, 344 different ways the mission could go wrong. “It’s not just in the launch; it has to unfurl five layers of thin films the size of a tennis court.”

But that complexity, along with its distance from Earth and size, is what will lend Webb an unprecedented power and sensitivity to see far-away objects.

Its other superpower is the kind of light it can detect.

In the same way that an ambulance’s siren sounds deeper as it drives away, distant celestial objects look more red than they actually are because the space between them and the Earth is expanding. This effect is even more dramatic for the farthest objects: By the time their light reaches Earth, it’s been stretched past the red part of the light spectrum and into the infrared, invisible to the naked eye. Webb is designed to detect those infrared waves — and because the light from those distant objects has spent billions of years traveling to us, the new telescope will be able to show us regions of space as they existed when the universe was young.

That’s an especially exciting prospect to , an assistant professor in 51��Ʒ��Ƶ’s Department of Physics and Astronomy. “The Milky Way is sort of a nice stable disc; it’s puttering along making one star every year,” she said. “But at much earlier cosmic epochs, everything was way more dramatic.”

The project Schneider is a part of, led by Susan Kassin of the Space Telescope Science Institute, will use Webb to study these early galaxies. Schneider, an expert on the theory of how galaxies evolve over time, is particularly interested in the gas that galaxies shoot out early in their evolution, a feature called galactic winds.

In the past few decades, Schneider said, researchers have come to believe that as galaxies form they constantly shoot out gas due to the force of exploding stars. Armed with both Webb’s power to peer into the early universe and its ability to tease apart light waves into their component parts, researchers will be able to tell how much gas the galaxies were ejecting in their early days. That should let them confirm whether their recent theorizing has been on the right track.

“We think that in really early times, everything was much more chaotic — all of this bursty star formation and feedback was going on,” Schneider said. “But we haven't been able to actually measure these things at early times, because you need a telescope like James Webb to do it.”

The James Webb Space Telescope mirror — The fully unfolded mirror of the James Webb Space Telescope, just after completing its first full-system test at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. (Chris Gunn/NASA)

James Webb Space Telescope stowed — Webb in its “stowed” position with the mirror folded — the form it will take when being launched into space. After this, the telescope was shipped to a site in Kourou, French Guiana, to await its launch. (Northrop Grumman)

‘At the mercy of these exploding stars’

Rather than staring deeply at one patch of space, Department of Physics and Astronomy Associate Professor is part of a project that will sneak in minutes throughout the telescope’s first year. There’s a simple reason for that: They don’t yet know where they’ll need to look.

“A typical supernova explodes in a matter of seconds, and then half a year later, the supernova has faded quite a bit. That is when you want to catch them,” Badenes said.

Badenes studies a poorly understood process that happens when cooled-off stars known as white dwarves explode. By the time one of these explosions has dimmed, it has also spread out enough that a telescope can peer right through it, giving them the moniker “see-through supernova.”

It’s blink-and-you’ll-miss-it astronomy, and a unique chance for scientists to see the inner workings of a stellar phenomenon. Wielding Webb’s ability to split apart light waves, Badenes and his colleagues, led by Saurabh Jha at Rutgers University, will be able to understand the chemical composition of these exploding stars. They’ll even be able to measure how quickly supernovae eject material into their surroundings.

“We know these are exploding white dwarves of some kind, but we don’t understand exactly the why and exactly the how,” Badenes said. Webb will give them a chance to answer those questions. Hopefully.

“We’re all at the mercy of these exploding stars,” Badenes said. “They have to go off. If they don’t, then no luck.”

Other programs in Webb’s first year are less concerned with specific phenomena and more aimed at getting as much mileage out of the telescope as possible — like PRIMER, a project that includes Department of Physics and Astronomy Professor .

“The strategy for PRIMER is to cover as much sky as we can,” Newman said.

One problem with staring into an unknown part of space is that the patch of sky you choose might just be a dud. “If you look at a small area of the universe, you may be lucky or unlucky,” Newman said. “That region may have been a high-density part of the universe or low-density part of the universe.”

Newman’s role in PRIMER is to help determine how best to use Webb, minimizing the chance that they’ll find nothing at all of interest. They’ll look to collect data on a broad cross-section of early galaxies in many different wavelengths of light across two patches of sky. The search will provide a bigger picture of how galaxies looked a when the universe was much younger.

And as researchers pore through the resulting information, they’ll find intriguing objects to follow up on later. “But first, we need to find the interesting ones,” Newman said. “PRIMER is really intended to be the discovery engine that allows us to do that.”

Projects like Bezanson’s and Newman’s are poised to produce so much data that the team’s researchers couldn’t possibly analyze it all themselves. It’s one of the many extremes of science that researchers are pushed to, due to the competitive nature of applications for time with Webb. All are large teams with painstakingly economical plans for using the telescope’s precious minutes, and generous plans for making their data available to the public.

If you want a crack at a state-of-the-art telescope, there’s no room for hoarding what you find.

“This is in the DNA of astrophysics: We share our tools,” said Bezanson. “I’m really interested to see what some other group will do with the same dataset, because the way they ask the questions is inevitably going to be different. That combination gives you a rich understanding.”

And the projects 51��Ʒ��Ƶ scientists are a part of are only a fraction of the science that will happen in the telescope’s first year. Making sense of what Webb beams back to Earth will be a global effort — and one that won’t stop anytime soon.

“These things have longevity because there are just a million questions you can ask once you have lots of imaging,” Bezanson said. “This will set the field up for decades.”

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— Patrick Monahan

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