The Webb Telescope has just started
The Webb Telescope has just started
BALTIMORE – Until now, it’s been eye candy in the sky: the black vastness of space filled with enigmatic, unfathomable specks of light. Ghostly portraits of Neptune, Jupiter and other neighbors we thought we already knew. Nebulas and galaxies made visible by the penetrating infrared eyes of the James Webb Space Telescope.
The telescope, named after James Webb, NASA’s administrator during the run-up to the Apollo moon landings, is a joint project of NASA, the European Space Agency and the Canadian Space Agency. It launched on Christmas a year ago, after two decades of trouble and $10 billion, on a mission to observe the universe at wavelengths no human eye can see. With a 21-foot-wide primary mirror, Webb is seven times more powerful than its predecessor, the Hubble Space Telescope. Depending on how you do the math, an hour of observing time at the telescope can cost NASA $19,000 or more.
But neither NASA nor the astronomers paid all that money and political capital just for pretty pictures, not that anyone is complaining.
“The first images were just the beginning,” said Nancy Levenson, interim director of the Space Telescope Science Institute, which manages both Webb and Hubble. “More is needed to turn them into real science.”
A bright future (infrared).
For three days in December, about 200 astronomers filled an auditorium at the institute to hear and discuss the telescope’s first results. About 300 more have been viewed online, according to organizers. The event served as a belated celebration of the Webb’s successful launch and inauguration and a preview of its bright future.
One by one, the astronomers marched to the podium and, speaking quickly to obey the 12-minute limit, went through a cosmos of discovery. Galaxies that, even in their relative youth, had already spawned supermassive black holes. Atmospheric studies of some of the seven rocky exoplanets orbiting Trappist 1, a red dwarf star that could host habitable planets. (The data suggest that at least two of the exoplanets lack the voluminous atmospheres of primordial hydrogen that would suffocate life as we know it, but may have sparse atmospheres of denser molecules such as water or carbon dioxide.)
“We’re in business,” declared Bjorn Benneke of the University of Montreal as he presented data from one of the exoplanets.
Megan Reiter of Rice University led her colleagues on a “deep dive” through the Cosmic Cliffs, a cloudy fire of star formation in the constellation Carina, which was a of heaven’s first favorite sweets. It is tracing how jets of new stars, shock waves and ionizing radiation from nearby more massive stars that were born boiling are constantly reshaping the cosmic geography and triggering the formation of new stars.
“This could be a template for what happened to our sun when it formed,” Dr. Reiter said in an interview.
Between presentations, on the sidelines and in the corridors, senior astronomers who were present in 1989 when the idea for the Webb Telescope was first mooted congratulated each other and traded war stories about the telescope’s development. They gasped audibly as the youngsters displayed data that surpassed their own Hubble achievements.
Jane Rigby, the project scientist for the telescope’s operations, recalled her emotional turmoil a year ago as the telescope finally neared its launch. The instrument had been designed to be deployed in space, a complex process with 344 potential ‘single point failures’, and Dr Rigby could only count them over and over.
“I was in the denial stage,” he said in Baltimore. But the launch and deployment went perfectly. Now, he said, “I’m living the dream.”
Garth Illingworth, an astronomer at the University of California, Santa Cruz, who in 1989 chaired a key meeting at the Space Telescope Science Institute that eventually led to the Webb, said simply, “I’m blown away.”
At a reception after the meeting’s first day, John Mather of NASA’s Goddard Space Flight Center and Webb’s senior project scientist from the beginning raised a glass to the 20,000 people who built the telescope, the 600 astronomers who they had tested it in space and the new generation of scientists who would use it.
“Some of you weren’t even born when we started planning this,” he said. “Do it!”
A return machine
So far, the telescope, packed with cameras, spectroscopes and other instruments, is exceeding expectations. (Its resolving power is twice as advertised.) The telescope’s flawless launch, reported Dr. Rigby, has left it with enough maneuvering fuel to keep it running for 26 years or more.
“Those are happy numbers,” she said, as she and her colleagues rattled off performance statistics for their instruments. Dr Rigby cautioned that the telescope’s instruments were still being calibrated, so the numbers could still change. Get ready to recalculate your results at the push of a button, he told a group of astronomers in the lobby: “Otherwise, you’re going to hate your life.”
Perhaps the Webb Telescope’s biggest surprise yet involves events from the early millennia of the universe. Galaxies appear to have been forming, spawning and nurturing stars faster than battle-tested cosmological models estimated.
“How did galaxies get so old so fast?” asked Adam Riess, a Nobel laureate in physics and Johns Hopkins University cosmologist who spent the day.
Exploring this province, “cosmic spring”, as one astronomer called it, is the goal of several international collaborations with agile acronyms such as JADES (JWST Advanced Deep Extragalactic Survey), CEERS (Cosmic Evolution Early Release Science), GLASS ( Grism Lens-Amplified). Survey From Space) and PEARLS (Thin Extragalactic Areas for Reionization and Lensing Science).
Webb’s infrared vision is critical to these efforts. As the universe expands, galaxies and other distant celestial objects are moving away from Earth so rapidly that their light has been stretched and shifted to invisible infrared wavelengths. Beyond a certain point, the most distant galaxies recede so quickly and their light is so spread out in wavelength that they are invisible even to the Hubble telescope.
The Webb Telescope was designed to expose and explore these regions, which represent the universe just a billion years old, when the first galaxies began to bloom with stars.
“Matter needs time to cool and become dense enough to ignite stars,” said Emma Curtis-Lake of the University of Hertfordshire and a member of the JADES team. The rate of star formation peaked when the universe was four billion years old, he added, and has been declining since then. The cosmos is now 13.8 billion years old.
Astronomers measure cosmic distances with a parameter called redshift, which indicates how much light from a distant object has been stretched. Just a few months ago a redshift of 8, which corresponds to a time when the universe was about 646 million years old, was considered high redshift. Thanks to Dr. Curtis-Lake and her colleagues, the redshift record is now 13.2, which corresponds to when the universe was only 325 million years old.
Dr. Curtis-Lake and her team had pointed the telescope at a patch of sky called GOODS South, looking for galaxies that Hubble had failed to detect. Sure enough, there were four of them, specters in the heat haze of creation. Subsequent measurements confirmed that they were indeed back in time.
“We didn’t want to say we believed it, publicly,” said Brant Robertson, a JADES fellow at the University of California, Santa Cruz.
The record is not expected to last long. The CEERS collaboration has reported a candidate galaxy which could have a redshift of 16from when the universe was only 250 million years old.
Experts are already debating whether these excess galaxies reveal something fundamental, and overlooked, in current theories of the early universe. Perhaps some field or effect squeezed out gravity then and accelerated the growth of galaxies and black holes. Or perhaps the discrepancies merely reflect scientific uncertainties about the messy details—the “gastrophysics”—of star formation.
Over the past 20 years, astronomers have refined a solid “standard model” of a universe composed of dark energy, dark matter, and some atomic matter. It’s too early to break that model, Dr. Curtis-Lake said in an interview; Webb has perhaps three decades of observation ahead of him. “We’re in the early stages,” he said.
The closing talk went to Dr. Mather. He told the history of the telescope and gave a shout-out to Barbara Mikulski, the former senator from Maryland, who supported the project in 2011 when it was in danger of being canceled. He also envisioned NASA’s next big thing: a 12-meter space telescope called the Habitable Worlds Observatory that would search for planets and study them.
“Everything we’ve done has been worth it,” he said. “So here we are: this is a celebratory party, getting a first look at what’s here. It’s not the last we’ll be doing.”
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