The James Webb Telescope

What is the James Webb Telescope

With technology developing exponentially, scientists' opportunities to see more and do more increase. Attempting to replace the Hubble Telescope, the JWST will be used to look at deep space objects which will give us even a further look into the past. The infrared observatory is better than Hubble because of its increased depth in view and improved sensitivity. Named after the famous James Webb (the second administrator of NASA in the 1960s), the JWST's size can be split into two parts, the base, and the sun-shield. According to sciencfocus.com, "Billed as the successor to the Hubble Space Telescope, the JWST is the largest space observatory ever built. Its gigantic sun shield base measures a massive 22m by 12m, roughly the same size as a tennis court. Although nearly twice as big as Hubble (which is only 13m long), the JWST is almost half the weight at 6,500kg. The JWST’s gold-plated mirrors have a total diameter of 6.5m, much larger than Hubble’s 2.4m diameter plate. Overall, the JWST will have approximately a 15 times wider view than Hubble." ( taken from https://www.sciencefocus.com/space/james-webb-space-telescope/ )  Finally, its main missions are to, study galaxy evolution, see the first in the universe and the first objects after the big bang, study the atmosphere of planets, and find dark matter.​

JWST deployed in space.

How far JWST can see in comparison to other telescopes.

How does the JWST work?

JWST parts labeled with their purposes.

The infrared observatory will be able to see objects 13.6 billion years ago which is nearly 200 million years after the big bang. Infrared light is not visible to the human eye but we encounter it every day when we heat food. JWST uses infrared light rather than UV light and regular light (Hubble used UV) because it has a longer wavelength and can go through objects in space that another light can't, an example of this is dust or gas. This will help astronomers peak into early star formation clouds and be able to look through them. To pick up the smallest heat signatures, the JWST must be kept at extremely cold temperatures and that is the sunshield's purpose. As for how the mirrors work, it is used as part of the observation process and is required to be large for the telescope to reach its astounding depth in view. The mirror segments also had to be hexagonal, NASA perfectly explains why in this paragraph, "The hexagonal shape allows for a roughly circular, segmented mirror with "high filling factor and six-fold symmetry." The high filling factor means the segments fit together without gaps. If the segments were circular, there would be gaps between them. Symmetry is good because there need only be 3 different optical prescriptions for 18 segments, 6 of each (see above right diagram). Finally, a roughly circular overall mirror shape is desired because that focuses the light into the most compact region on the detectors. An oval mirror, for example, would give images that are elongated in one direction. A square mirror would send a lot of the light out of the central region." ( taken from         https://webb.nasa.gov/content/observatory/ote/mirrors/index.html ).

Image of JWST's positioning (it's currently approaching L2).

Final Thoughts

Images from the JWST should be available in May of this year which is extremely exciting, I honestly cannot wait. After launching in Christmas Day (December 25), JWST is now approaching the position known as L2 (image above for reference), I wish all the scientists that are currently participating in the JWST's deployment luck, thank you, and stay safe.​