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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 Webb telescope is astonishing. But the universe is even more so.
“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’.”
NASA unveils first images from James Webb Space Telescope
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.”
The easiest explanation for those surprisingly massive galaxies is that, at least for some of them, there’s been a miscalculation — perhaps due to a trick of light.
The distant galaxies are very red. They are, in astronomical lingo, “redshifted.” The wavelengths of light from these objects have been stretched by the expansion of the universe. The ones that look the reddest — that have the highest redshift — are presumed to be the farthest away.
But dust can be throwing off the calculations. Dust can absorb blue light, and redden the object. It could be that some of these very distant, highly red-shifted galaxies are just very dusty, and not actually as far away (and as “young”) as they appear. That would realign the observations with what astronomers expected.
Or some other explanation could surface. 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 closer-to-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.
The telescope is controlled by engineers at the Space Telescope Science Institute in Baltimore. The Mission Operations Center is on the second floor of the institute, which is on the edge of the Johns Hopkins University campus.
On a recent morning, only three people were staffing the flight control room: operations controller Irma Aracely Quispe-Neira, ground systems engineer Evan Adams and command controller Kayla Yates. They sat at a row of work stations with large monitors laden with data from the telescope.
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“We don’t typically live-command the action,” Yates said. In other words, no one is controlling the telescope with a joystick or anything of the sort. It functions largely autonomously, fulfilling an observation schedule uploaded about once a week. A command is sent from the flight control room to NASA’s Goddard Space Flight Center in Greenbelt, Md. From there the command travels to the NASA Jet Propulsion Laboratory in Pasadena, Calif., and then to the Deep Space Network — radio antennas near Barstow, Calif., Madrid and Canberra, Australia. Depending on the Earth’s rotation, one of those antennas can beam the command to the telescope.
Long gone from the mission operations center in Baltimore are the crowds of people who were on hand on the morning of the telescope’s launch last Christmas.
“It’s a testament to how well it works that we can go from several hundred people to just three of us,” Adams said.
The observing schedule is largely determined by the desire to be efficient, and that often means looking at things that appear close to each other in the sky even if they’re billions of light-years distant from one another.
A visitor will be disappointed to realize that the flight control team does not see what the telescope sees. There is no big screen showing, for example, a comet, or a galaxy, or the Dawn of Time. But the flight control team can read out data describing the orientation of the telescope — for example, “32 degrees right ascension, 12 degrees declination.” And then consult a star chart to see where the telescope is pointing.
“It’s between Andromeda and whatever that other constellation is,” Adams said.
‘Incredible’ Jupiter images revealed by NASA’s James Webb telescope
Here’s a sample of some Webb observations, which should yield new images, as well as scientific reports, in the months ahead:
The Cartwheel Galaxy: A strikingly beautiful and rare “ring” galaxy about 500 million light-years away. Its unusual structure is due to a collision with another galaxy. This had been one of the first images processed by the Webb team to showcase what the telescope can do.
M16, the Eagle Nebula: This is a “planetary nebula” within our own galaxy that is famously the home of a structure nicknamed the “Pillars of Creation” that was imaged by the Hubble Space Telescope. It became one of the most famous Hubble images, showing three towering pillars of dust illuminated by hot, young stars outside the frame of the image, all of it oriented by NASA to produce what to the human eye looks like a terrestrial landscape. The Webb will presumably produce a similarly framed image but with new resolution and details, thanks to the ability to gather light in the infrared wavelengths inaccessible to the Hubble.
Ganymede, Jupiter’s largest moon: It’s the largest moon in the solar system and is bigger even than the planet Mercury. Scientists believe it has a subsurface ocean with more water than all the oceans on Earth. Webb project scientist Klaus Pontopiddan said the telescope will be looking for plumes — geysers akin to what have been spotted on Jupiter’s moon Europa and Saturn’s moon Enceladus.
C/2017 K2 comet: Discovered in 2017, this is an unusually large comet with a tail 500,000 miles long, heading toward the sun.
The Great Barred Spiral Galaxy: Officially “NGC-1365,″ this is a classic, gorgeous “barred” galaxy — a spiral with a central bar of stars that links two prominent, curving arms. It’s about 56 million light-years away.
Trappist-1 planetary system: Seven planets orbit this star, and several are in the “habitable zone,” meaning they are at a distance from the star where water could be liquid at the surface. Astronomers want to know if these planets have atmospheres.
Draco and Sculptor: These are dwarf spheroidal galaxies close to the Milky Way. By studying their motion over a long period of time, astronomers hope to learn more about the presence of dark matter — which is invisible but has a gravitational signature.
That’s just a partial list. There’s a lot to see out there.
“It’s nonstop, 24-7, just science pouring back,” said Heidi Hammel, a planetary astronomer and vice president for science for the Association of Universities for Research in Astronomy. “And it’s a huge diversity of science. I saw Jupiter’s great red spot — but then two hours later, now we’re looking at M33, this spiral galaxy. Two hours later, now we’re looking an exoplanet that I actually know by name. It’s very cool to watch that.”