Five Massachusetts researchers will soon begin experiments using a telescope that is floating in space nearly a million miles away.
The James Webb Space Telescope, which was launched from French Guiana on Dec. 25, is NASA’s largest telescope in space, with its primary mirror measuring 21.3 feet, according to the agency. As of Jan. 24, Webb is orbiting the sun at the second Lagrange point, or L2, which is one of five points where the Sun and Earth’s gravity balances a satellite’s orbital motion.
“It’s really marvelous how much effort went into this,” said Daniel Eisenstein, chairman of the astronomy department at Harvard University. “It’s great to look ahead at what it’s going to do, but it’s also really great to look back at what’s been accomplished already.”
Eisenstein said he’s interested in how galaxies have formed and how they “build up over time,” comparing galaxies to understand their evolution. For days at a time, he said, as part of his research, the telescope will point at certain points in the sky “to build up the signal to be able to observe very faint objects.”
Researchers have hailed Webb as a successor to the groundbreaking Hubble Telescope. The key difference between the two telescopes is that Webb will capture information through infrared light, rather than visible light, and will allow researchers to collect information at greater sensitivity.
NASA says the telescope will actually be able to see further back in time because ultraviolet and visible light emitted during the epoch when the very first galaxies formed is now arriving in the form of infrared light, after being stretched or “red-shifted” by the expansion of the universe.
“Different telescopes are designed to look at different parts of the spectrum,” said Edo Berger, a professor of astronomy at Harvard University. Webb “is significantly bigger than Hubble, and it’s optimized for observations, very detailed observations” in the infrared spectrum, rather than the visible spectrum.
Berger plans to use the telescope to study kilonova explosions, which are collisions of neutron stars. He explained that neutron stars are dense objects that “weigh about one and a half times the mass of the sun but packed into a sphere that’s about the size of the city of Boston.”
“What James Webb will do for us, in particular, is that it will allow us to study these collisions in much greater detail and [at] much larger distances than they have been able to do in the past,” he said.
Two other scientists in separate projects are going to use the telescope to study exoplanets — planets that orbit stars other than the sun — and their atmospheres.
Sara Seager, professor of physics and planetary science at the Massachusetts Institute of Technology, said she will use the telescope to compare when an exoplanet is in front of a star and when it isn’t.
“By comparing those two measurements, they’re going to be a tiny bit different because when the planet ... in front of the star is blocking some of the starlight, in particular, the atmosphere blocks some of the starlight, and so we can tell what’s in the planet atmosphere,” said Seager, whose team is studying three exoplanets.
Mercedes López-Morales, an astrophysicist at the Center for Astrophysics/Harvard & Smithsonian, will use spectrography to gain more insight into exoplanets’ atmospheres.
“Basically, if you have a molecule of water, that water molecule is going to not let [it] go through the light of a given color. ... What we do is when we receive that light, we look at the different colors, and we look for the ones that are missing,” López-Morales said. “That’s exactly how we know what molecules ... the atmosphere of the planet has.”
Karin Öberg, a professor of astronomy at Harvard, will use the telescope to identify specific molecules in five planet-forming “discs” around young stars.
Researchers will start their work once the telescope is fully operational — in about five months or so, Berger said.
López-Morales said she’s excited about the potential to learn new and important information about the universe.
“I don’t know what [our observations] will show us right now — because we don’t have them yet,” she said. “But they might show us things that we weren’t even thinking about, and that [in] itself — that’s how scientific breakthroughs happen.”