[Model Answer QP2022 GS3] Launched on 25th December, 2021, James Webb Space Telescope has been much in news since then. What are its unique features which make it superior to its predecessor Space Telescopes? What are the key goals of this mission? What potential benefits does it hold for the human race?

The James Webb Telescope, often just referred to as the Webb telescope or JWST, is an orbiting infrared observatory that was launched as part of an international program between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA) to complement and extend the discoveries of the Hubble Space Telescope
The Webb telescope operates from space and orbits the Sun 1.5 million kilometres away from Earth, called the second Lagrange point. This is a major difference from the Hubble telescope which orbits the Earth in low-orbit. 
The telescope views the world at infrared wavelengths, allowing for a deeper look into space to see the earliest stars and galaxies in the universe that formed after the Big Bang. The infrared light also makes visible stars and planetary systems forming inside clouds of dust visible which would otherwise be opaque. The telescope will help scientists search for the first galaxies formed after the universe was created and study these galaxies’ evolutions.

Differences between James Webb and Hubble (its predecessor) Telescope

James Webb Space TelescopeHubble Telescope
It will orbit the sun 1.5 million kilometres (1 million miles) away from the Earth at what is called the second Lagrange point or L2The Hubble Space Telescope orbits around the Earth at an altitude of ~570 km above it.
The James Webb telescope was always meant for long-term exposure and deep space capturing with hopes of retrieving data on galaxies set apart by lightyears upon lightyears.While the Hubble Telescope’s goal is to capture distant stars and galaxies, it remains close—in the earth’s orbit.
The James Webb telescope specialises in infrared wavelength The Hubble telescope specialises in ultra-violet wavelength
The James Webb telescope’s mirror, however, is composed mostly of beryllium, a light but long-lasting substance, making the mirror much lighter. (around 21 kgs)The Hubble telescope’s mirror is made of glass and coated in aluminium. (Around 830 kgs)
Because of its low-earth orbit, the Hubble has been serviced by astronauts while still in orbit.The James Webb is built in such a way that it does not require frequent servicing, and therefore does not need to stop its orbit in order to be updated.
A key feature of Webb’s design is that it has a “cold side” and a “hot side.” The cold side is the one that does the observing, while the hot side carries the spacecraft’s solar panels and an antenna for two-way communication with EarthBut this arrangement only works if the sun and Earth are always facing in the same direction from the spacecraft’s point of view. Hence not possible in Hubble as it orbits the earth. 

Goals of the Mission

  1. Search for the first galaxies or luminous objects formed after the Big Bang.
  2. Determine how galaxies evolved from their formation until now.
  3. Observe the formation of stars from the first stages to the formation of planetary systems.
  4. Measure the physical and chemical properties of planetary systems, including our own Solar System, and investigate the potential for life in those systems.

Potential benefits does it hold for the human race

  1. James Webb’s photos are essentially a step farther back in time; the farther the telescope can see, the older the light of a star or galaxy it finds is. Hence James Webb is believed by NASA to have the ability to see some of the first galaxies and stars in existence. This is both a result of its mammoth mirror and light-capturing abilities, as well as its duration in space. This allows humanity’s eyes into the past by understanding the Big Bang. 
  2. Compare the galaxies of the distant past with those of the present (in the second phase of the mission)
  3. Explore regions of the universe where stars and planetary systems are forming so scientists can study them.
  4. Study the atmospheres of planets outside our solar system in the hope of discovering the elements necessary for life – as we know it – elsewhere in the cosmos. It will also examine objects in our own solar system.

Every image is a new discovery,” said NASA administrator Bill Nelson. “Each will give humanity a view of the universe that we’ve never seen before.

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