When thinking of space telescopes, the name Hubble may rise to the top. The Hubble Space Telescope has been bringing images, like the one below, to scientists on Earth since the 1990s.
Now, the next generation space telescope is ready to be launched. On Dec. 25, 2021, the James Webb Space Telescope will lift off into space.
Webb is not a replacement for Hubble, it's a separate telescope that will provide different types of images with the ability to look farther away, and farther back in time.
"The Hubble physics could be looking at things in the 2, 3, 4 billion years [ago], whereas the Webb physics is going to be looking at physics that happened 10, 12, 13 billion years ago," said Phil Stahl, Senior Optical Physicist for NASA.
Hubble will continue to collect images and provide critical data about space, likely into the 2030s.
The James Webb Telescope contains multiple instruments that will allow scientists and researchers to look at space and time like never before.
"Webb will fundamentally alter our understanding of the universe. It can observe all of the cosmos, from planets to stars to nebulae to galaxies and beyond – helping scientists uncover secrets of the distant universe as well as exoplanets closer to home," says NASA.
The telescope will be able to see back to when some of the first stars and galaxies formed around 13.5 billion years ago. This telescope can see a different section of the electromagnetic spectrum than previous space telescopes. Its view of the not-previously explored infrared light allows scientists to see light more clearly.
"The primary mission goal for Webb is to image the first light of the universe, or actually more precisely the first objects in the universe that emitted light," Stahl explained.
Looking specifically at the instrumentation, Webb has two cameras (a near-infrared and mid-infrared camera), a spectrograph (which can break light into different wavelengths, allowing for analysis), and a coronagraph (which blocks starlight, allowing for better observation of nearby planets).
Webb is the largest telescope ever launched into space. Webb weighs about as much as a full-sized school bus, approximately 13,700 pounds. It will be compacted for launch but unfold to be about the size of a tennis court.
See a video of the deployment sequence here.
The large size is a critical part of the objective.
"When we're looking at stars, we're not looking at the light that's emitted from the star right now, we're looking at the light that was emitted from the star 50 years ago, 100 years ago, a million years ago, a billion years ago... But the light that we're seeing is very old and, again, the further away it is, the dimmer it is. Therefore, we need a really big aperture to see it," Stahl said.
"When we're looking at stars, we're not looking at the light that's emitted from the star right now, we're looking at the light that was emitted from the star 50 years ago, 100 years ago, a million years ago, a billion years ago... But the light that we're seeing is very old and, again, the further away it is, the dimmer it is. Therefore, we need a really big aperture to see it," Stahl said.
The launch will take place near Kourou, French Guiana from the Guiana Space Center. From there, Webb will travel to its new home, about a million miles from Earth.
This project has been in the works for more than two decades and has been worked on by thousands of people from 14 different counties. It's estimated that 40-million total hours have been spent building Webb. Multiple companies have contributed to the project, including one company from right here in Southeast Wisconsin. Ellsworth Adhesive in Germantown provided some of the epoxy and adhesives.
"Thousands and thousands of people have made this mission possible, and everybody's contribution is important," added Stahl.
It will take some time before we start to see images and observations from Webb. The telescope must be unfolded, cooled, calibrated, and the components aligned VERY specifically before it can get to work. Right now, it's expected to take four to six months to start seeing images from Webb.
Fun Facts from NASA:
