The What and Why of JWST

The What and Why of JWST
James Webb Space Telescope with its gold-plated mirrors

If all goes as planned, Christmas Eve will see the launch of the James Webb Space Telescope (JWST or WEBB). It has been a long time in the making with many delays and cost overruns, but it seems that the time has finally arrived. The JWST was supposed to launch in 2007 at the cost of $1 billion. Now it is launching at the end of 2021, and the price has escalated to $10 billion. Let’s examine the what and why of JWST.

First, the what of JWST. The James Webb Space Telescope is a successor to the Hubble Space Telescope (HST or Hubble). It is intended to be a space observatory with capabilities far beyond HST, which was launched in 1990. NASA designed the JWST, and Northrop Grumman built it in California. The European Space Agency will launch it from their launch site in French Guiana, South America.

The why of JWST is that scientists expect it to revolutionize astronomy and expand our knowledge of the universe. Science and technology have made great strides since Hubble was launched and even since astronauts repaired and updated it, most recently in 2009. JWST will observe the universe in infrared light, while HST is limited to visible light. Because galaxies farther away are retreating at increasing speeds, their light shifts toward the red or infrared spectrum. Scientists hope that JWST can observe farther back toward the cosmic creation event known as the big bang. Because of that, astronomers expect to learn more about the formation of stars and galaxies.

Earth-based telescopes must always observe the universe through our atmosphere with particles, pollution, and moisture. That limits their ability to obtain sharp, precise images. Space-based telescopes, like Hubble, eliminate that problem. Webb will give much sharper images with its mirror made of beryllium coated with gold and a diameter more than 2.5 times as wide as Hubble’s.

JWST will locate itself at the Lagrange point where the gravity of Earth and Sun balance each other. That is 930,000 miles (1.5 million km) from Earth. Repairs or upgrades such as those performed on Hubble will not be possible at that distance. That means everything will have to perform flawlessly when the telescope reaches its destination. Deploying the mirror, sun-shield, super-cooling equipment, and telemetry equipment will take a month, which NASA has called “29 days on the edge.”

Another thing that astronomers hope to study with JWST is dark matter, the stuff that’s out there but cannot be seen or detected by any means science has discovered. The way they know dark matter must be there is that it holds the galaxies together. Physics cannot explain why spinning, spiral galaxies, such as the Milky Way, do not fly apart because of centrifugal force. Astronomers hope that JWST’s high-definition images can at least show us where the dark matter is by what they call “gravitational lensing.”

So that is the what and why of JWST. We are excited to see the new images of the universe the James Webb Space Telescope will capture. As we learn about the formation of stars and galaxies, it opens the door to knowledge of God’s handiwork, allowing us to say, “So that’s how God did it!

— Roland Earnst © 2021

Reference: You can find much more about the James Webb Space Telescope at NASA’s fact sheet at THIS LINK.