A rendering of the James Webb Space Telescope fully deployed.

Dale Kocevski and Elizabeth McGrath, assistant professors of physics and astronomy at Colby, will be among the first astronomers to use the new James Webb Space Telescope as part of NASA’s Early Release Science Program, the space agency recently announced. McGrath and Kocevski were granted initial access to the instrument to test its capabilities as part of the Cosmic Evolution Early Release Science (CEERS) Survey team, chosen as one of just 13 projects to use the orbiting telescope during its first five months of operation.

The tennis court-sized James Webb Space Telescope (JWST), the largest ever put into space and scheduled to launch in spring 2019, will allow astronomers to see 13.5 billion years into the past, farther than any previous telescope, including the Hubble Space Telescope. Instead of making observations in visible light, however, the JWST will study infrared light, which is invisible to the human eye.

“I’ve been waiting for some of the capabilities of James Webb since I was a grad student,” said McGrath, the Clare Boothe Luce Assistant Professor of Physics and Astronomy. McGrath needs spectroscopic data of long wavelengths of light, such as infrared light, to further her research on galaxy evolution.

Watch Kocevski and McGrath discuss the impact of JWST.

The $8-billion telescope, with a segmented parabolic mirror 21.6 feet (6.5 meters) in diameter, will have sensitivity and resolution similar to the Hubble Space Telescope, Kocevski said. But the real power of the JWST is that it will allow the CEERS team to study the most distant galaxies, which existed as soon as 200 million years after the Big Bang.

“CEERS is going to be the premier extragalactic survey that JWST will carry out,” Kocevski said. “Our survey will focus on trying to find the earliest, or most distant, galaxies in the universe then studying how galaxies evolve over cosmic time from those early times to the present day.”

The Colby astronomers, who have both done research using the Hubble, bring specific expertise to the CEERS team of 17 international scientists. Kocevski studies super-massive black holes that reside in the center of galaxies; he will try to understand how those black holes affect overall galaxy formation. McGrath, who studies the evolution of the structure of galaxies, will conduct modeling to determine how images of galaxies are blurred and whether the blurring is due to optics or to the galaxies actually changing shape.

The Hubble Space Telescope (top left) and James Webb Space Telescope (top right) showing the relative size of the telescopes, the size of their mirrors, and their respective spectra of light. (Image courtesy the Hubble 25th anniversary website) Click to enlarge.

The CEERS team will be expected to analyze its data relatively quickly and report its findings to the astronomical community. That’s where Colby students come in. Kocevski and McGrath will directly involve students by training them to identify different types of galaxies by studying images from the JWST. “The human eye is a fantastic pattern recognizer,” Kocevski said. “So students trained in a matter of weeks can then start classifying hundreds of galaxies per hour.”

When the telescope begins sending back its first data in about two years, scientists hope it will help answer big questions. “We’ll be pushing back to the earliest galaxies that formed in our universe and trying to understand those fundamental questions of how we got to be here,” McGrath said.

By allowing humans to see farther than they’ve seen before, Kocevski said, the James Webb Space Telescope will drive science forward by looking into the past.


The James Webb Space Telescope is operated by the Space Telescope Science Institute in collaboration with the European Space Agency and the Canadian Space Agency. The telescope is named after James Webb, NASA’s second administrator, who led the Apollo lunar program and other space science initiatives.