NASA has launched the ultimate time machine into space.
The long-awaited James Webb Space Telescope will unveil the faraway universe in unprecedented detail. We’ll see galaxies being born. We’ll watch planets being born. We’ll seek potentially habitable worlds by finding out about the atmospheres of planets outside our solar system. Scientists will trace our own planet’s origin story — and how it fits into the cosmos surrounding us.
After Webb launched on a European Ariane 5 rocket from French Guiana on Christmas Day 2021, the telescope began a long journey to a relatively stable location in space called a Lagrange point, 1.5 million kilometres away from Earth. It will unfurl its golden mirrors, then orient itself for test observations with a Canadian fine guidance sensor (see more details on Webb’s components by clicking/tapping on the + symbols in the image below). The pointing sensor will let Webb find and measure the position of stars and take the sharpest possible images of them, says René Doyon, principal investigator of the fine guidance sensor and an exoplanet researcher at Université de Montréal.
“FGS can detect the movement of the thickness of a human hair at one kilometre away, so this is very, very accurate,” he says. “There’s no other guidance system that has been this exact before.”
Doyon also led work on a scientific instrument called a near-infrared imager and slitless spectrograph, which shows researchers the composition of galaxies and atmospheres and helps distinguish between objects that are hard to separate in visual wavelengths. Infrared wavelengths are also sensitive to heat, allowing the device to peer through galactic dust to see stars being born.
Getting those Canadian instruments working was crucial for Doyon’s science program, which includes 450 hours of observations on the instruments. Half of that time will be spent studying the most distant galaxies, even more remote than the Hubble Space Telescope’s “eXtreme Deep Field” image of 2012. The Hubble collection of images zoomed in on a spot only a fraction of the angular diameter of the full moon (angular diameter being the size an object appears to an observer — so a fraction of the angular diameter of the moon would be a very small space). Hubble allowed researchers to view large and fuzzy “red” galaxies where star formation stopped long ago, shedding insights on star evolution that Webb hopes to expand on.
The rest of Doyon’s time will be spent examining a range of planets, from hot Jupiter-like planets that orbit closely around their parental star to potentially habitable Earth-sized rocky planets, including the famous set of seven worlds the Transiting Planets and Planetesimals Small Telescope found.
“Those will be our prime targets,” Doyon says of the seven worlds his team will study. “Do they have an atmosphere? We don’t know yet, but we’ll give the answer… Then the next biggest question is, do they have water? Webb’s instruments will have the capability to answer that question.”
Webb will observe for at least five to 10 years, depending on how much fuel is available, how healthy its instruments remain and how much funding comes for the telescope’s program.