The James Webb Space Telescope (JWST), previously known as the Next Generation Space Telescope (NGST), is a revolutionary piece of space exploration technology set to launch in 2021.
It will be the world’s most powerful space telescope, an infrared-optimized observatory that will peer into the early universe, enabling unprecedented explorations of galaxies, stars and planets beyond our Solar System. Developed jointly by NASA, the European Space Agency (ESA), and the Canadian Space Agency, JWST will provide astronomers with higher-quality images, more accurate measurements and a better understanding of the history and contents of the universe.
Here, we’ll take a closer look at what makes the Webb Telescope so special and explain why its discoveries will open up new frontiers of scientific knowledge.
What the Webb Telescope Will Do
The objectives of the Webb Telescope are to look further into space and time than was ever possible before. Its ambitious goals include:
• Analyzing the first galaxies formed following the Big Bang;
• Uncovering new information about the formation of our own Solar System;
• Detecting atmospheres of other planets in our own system, as well as extra-solar planets;
• Investigating molecules associated with the formation of stars, planets and galaxies;
• Studying star formation and death in a variety of environmental settings;
• Exploring the physics behind various classes of astronomical objects; and
• To service as a general science archive.
How the Webb Telescope Differs From Its Predecessors
What sets the JWST apart from other space telescopes – such as the Hubble – is its ability to take advantage of infrared light. The relativistically expanding universe (as well as other physical effects) cause the light from very distant objects to become redshifted, or shifted toward the red part of the spectrum. By observing in the infrared spectrum, the JWST will be able to look farther back in time and observe objects that are too far away to be seen in visible light.
Another way in which the Webb Telescope has an improved capability compared to its predecessors is its larger size. At 6.5 meters in diameter – approximately one-and-a-half times the size of the Hubble –it will be able to gather more light and produce more highly detailed images.
In addition, its improved sensitivity will enable more accurate measurements of the faint astronomical sources that could be revealed by the JWST, and the greater spectral range (30 – 300 micrometers) will extend the range of observations to the very edges of space and time.
Design and Construction of the Webb Telescope
The design of the Webb Telescope is based around the concepts of ultra-lightweight mirrors and the “segmented” mirror system.
This segmented mirror technology is the same type of mirror used in larger optical telescopes, but applied to much larger mirror surfaces through the use of single-piece, lightweight substrates, each of which can be bent like an eggshell. These mirror segments are connected together to form one large mirror, resulting in a much larger aperture thereby allowing for more accurate images.
A secondary mirror system is also included to redirect the collected light towards a series of scientific instruments, which will provide unparalleled capabilities for infrared astronomy.
In addition to its mirrors, the Webb Telescope is outfitted with a variety of highly advanced instruments, such as:
• The Near-Infrared Camera (NIRCam), which will provide imaging in the light from 0.6 to 5 microns;
• The Near-Infrared Spectrograph (NIRSpec), which will be used to study spectral information of astronomical objects;
• The Mid-Infrared Instrument (MIRI), which will be equipped with a coronagraph designed to block the light from stars to create clearer images of the planets around them;
• The Fine Guidance Sensor/Near Infrared Imager (FGS/NIRISS), which will be used to detect the motions of stars and measure the properties of extra-solar planets.
Launch of the Webb Telescope
The Webb Telescope will be launched by an Ariane 5 ECA rocket from the Kourou Spaceport in French Guiana. The launch is currently planned for October 2021, with deployment of the telescope slated for March 2022 and the commencement of operations to follow shortly thereafter.
In preparation for the launch, a variety of pre-launch activities are taking place, including the testing of all the integrated components as well as the calibration of the telescope’s systems. The launch and deployment of the Webb Telescope is a complex procedure, as all components must fit together in a certain way and the projectile trajectory must be precisely calculated.
Capabilities of the Webb Telescope
The Webb Telescope’s capabilities extend far beyond those of other space-based observatories. Its larger mirror, coupled with its infrared sensitivity, enables it to resolve objects that appear as a single point of light with other telescopes and to study galaxies at much earlier stages of cosmic history. Taylor et. al 2017)
In addition, its improved angular resolution, enabled by the higher number of mirror segments, will allow us to study smaller and more distant subject matter than ever before.
The Webb Telescope is equipped with detectors that can measure very faint sources of light and measure the exact position of the stellar sources observed by the telescope. These have been designed to have the ability to detect individual photons. This means that the Webb Telescope will be able to distinguish between two or more stars close together, which would not be possible with other telescopes.
Finally, the Webb Telescope will also be able to measure the temperatures of distant galaxies and stars and to study the distribution of dust in space.
Proposed Discoveries Through the Use of the Webb Telescope
The number of potential discoveries that the Webb Telescope is capable of making is immense. Scientists hope to uncover the mysteries of star formation, probe the atmospheres of distant planets, and peer deep into the history of the universe by peering back to the initial phases of cosmic expansion.
In addition, the Webb Telescope will be able to pick up on the first stars and galaxies to have emerged following the Big Bang, paving the way for groundbreaking discoveries through the study of cosmic evolution. It will also offer improved investigations into dark matter and dark energy, both of which remain largely mysterious and are believed to play a key role in the formation of the universe.
The Webb Telescope’s ability to measure the temperatures of individual galaxies enables us to better understand the physics that govern their evolution, providing us with a more detailed understanding of the universe’s early history. It will also deepen our understanding of stars and their properties, as well as the material from which planets are generated.
As the first space telescope to be optimized in the infrared spectrum and build with ultra-lightweight mirrors, the James Webb Space Telescope is set to revolutionize our understanding of the universe, its contents and its history. Through the detection of faint light sources and the measurement of exact positions of stars and galaxies, the Webb Telescope will reveal unprecedented insights into the most distant reaches of space and time.
The results from its observations are certain to astound us, and come 2021, we may be looking at a window to the past that is near-infinitely beyond our comprehension.
