What astronomers are learning from the James Webb Space Telescope

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It was two years ago on Christmas Day when NASA launched the James Webb Space Telescope, the most powerful space telescope ever. This huge telescope had to unfold itself out in space, and all of its instruments had to be calibrated and tested, a process that took months. That means this year, 2023, was its first full calendar year of actually doing science. NPR's Nell Greenfieldboyce asked astronomers what they learned.

NELL GREENFIELDBOYCE, BYLINE: At the start of the year, astronomers were kind of tired. They'd just been through the first exciting months of getting data from this telescope. Jacob Bean is with the University of Chicago. He says that period was like the beginning of a marathon.

JACOB BEAN: And so, like, you take off - right? - and the surge and everyone's going - right? - and you're following the crowd. And then after a while, you realize, like, hey, we got to run 26 miles. And for JWST, it's like, this thing's going to last for 20 years. So, like, you try to settle into a sustainable pace.

GREENFIELDBOYCE: Even though the initial frenzy has slowed down, he says the telescope keeps delivering, big time. Take his area of astronomy. He studies planets that go around distant stars.

BEAN: Each data set for each planet that we look at is more insightful than almost every other observation we ever did before.

GREENFIELDBOYCE: He says what's clear now is that gas giant planets, even if they're about the same size, can have quite different atmospheres. Nature seems to have different recipes for making them.

BEAN: The diversity of these objects is the surprising thing.

GREENFIELDBOYCE: He says there was one kind of bummer this year when the telescope looked at a star called TRAPPIST-1. It's orbited by seven rocky planets. Astronomers thought this was the system where this telescope had the best chance of spotting a planet capable of supporting life.

BEAN: It's the best one that we know of and really the only one where we're going to be able to do this.

GREENFIELDBOYCE: But observations of the two innermost planets show that they seem to be bare rocks with no atmospheres. The gases might have gotten blown off by the star. That's because the star is more active than our own. It randomly erupts, sending out flares. Bean says that means it's other planets may also be barren. Plus, all that star activity makes it hard to study them. Still, there were plenty of other wins. Garth Illingworth is with the University of California, Santa Cruz. He says when this telescope first switched on, it detected light from unexpectedly bright galaxies in the early universe. Over the last year, scientists have been able to learn more about them.

GARTH ILLINGWORTH: We're finding that a lot of these galaxies have a significant contribution from black holes - from the light from black holes. And so that's part of the reason why they appear so bright.

GREENFIELDBOYCE: The James Webb Space Telescope even found the most distant confirmed black hole ever. Priya Natarajan is at Yale University. She says this black hole is 10 times more massive than the one at the center of our own Milky Way galaxy, and this behemoth existed when the universe was only about 500 million years old.

PRIYA NATARAJAN: In the infant universe, literally, you have this huge black hole and its host galaxy in place. And that's super exciting.

GREENFIELDBOYCE: She says it shows how black holes can form in multiple ways, as it seems to have formed from a huge cloud of collapsing gas rather than from a dying star. Meanwhile, the organization that manages the telescope has gathered proposals for where in the sky to point it during the next round of observations, which start in the summer. Nearly 2,000 proposals came in. That's a record for any space telescope. There's so many proposals, the vast majority won't make the cut. Nell Greenfieldboyce, NPR News.

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