Webb telescope already challenging astronomers’ knowledge

The James Webb Space Telescope, performing splendidly as it examines the universe, has got astronomers scratching their heads. The very distant universe looks a little different than expected.

The telescope, launched eight months ago and orbiting the sun about a million miles from Earth, has been capturing images of extremely faint galaxies that emitted their light in the first billion years or so after the big bang. Observing these “early” galaxies is one of the main missions of the telescope — to see deeper into space, and further back in time, than any previous telescope.

The first scientific results have emerged in recent weeks, and what the telescope has seen in deepest space is a little puzzling. Some of those distant galaxies are strikingly massive. A general assumption had been that early galaxies — which formed not long after the first stars ignited — would be relatively small and misshapen. Instead, some of them are big, bright and nicely structured.

“The models just don’t predict this,” Garth Illingworth, an astronomer at the University of California at Santa Cruz, said of the massive early galaxies. “How do you do this in the universe at such an early time? How do you form so many stars so quickly?”

This isn’t a cosmological crisis. What’s happening is a lot of fast science, conducted “in real time,” as astrophysicist Jeyhan Kartaltepe of the Rochester Institute of Technology puts it. Data from the new telescope is gushing forth, and she is among the legions of astronomers who are spinning out new papers, posting them quickly online in advance of peer review.

The Webb is seeing things no one has ever seen in such sharp detail and at such tremendous distances. Research teams across the planet are looking at publicly released data and racing to spot the most distant galaxies or make other remarkable discoveries. Science often proceeds at a stately pace, advancing knowledge incrementally, but the Webb is dumping truckloads of enticing data on scientists all at once. Preliminary estimates of distances will get refined upon closer examination.

Kartaltepe said she is certainly not worried about any tension between astrophysical theory and what the Webb is seeing: “We might be scratching our heads one day, but a day later, ‘Oh, this all makes sense now’.”

What has surprised astronomer Dan Coe of the Space Telescope Science Institute are the number of nicely shaped, disklike galaxies.

“We thought the early universe was this chaotic place where there’s all these clumps of star formation, and things are all a-jumble,” Coe said.

That assumption about the early universe was due in part to observations by the Hubble Space Telescope, which revealed clumpy, irregularly shaped early galaxies. But Hubble observes in a relatively narrow portion of the electromagnetic spectrum, including “visible” light. Webb observes in the infrared, gathering light outside the range of Hubble. With Hubble, Coe said, “We were missing all the colder stars and the older stars. We were really only seeing the hot young ones.”

What is certain is that, for now, the $10 billion telescope — a joint effort of NASA and the space agencies of Canada and Europe — is delivering novel observations not only of those faraway galaxies but also closerto-home objects like Jupiter, a giant asteroid and a newly discovered comet.

The latest Webb discovery was announced Thursday: Carbon dioxide has been detected in the atmosphere of a distant, giant planet named WASP-39 b. It is “the first definitive detection of carbon dioxide in the atmosphere of an exoplanet,” according to Knicole Colon, a Webb project scientist at NASA. Although WASP-39 b is considered far too hot to be habitable, the successful detection of carbon dioxide demonstrates the acuity of Webb’s vision and holds promise for future examination of distant planets that might harbor life.