As James Webb Space Telescope readies for its 1st image, here are some lesser-known facts

The James Webb Space Telescope is weeks away from releasing its first-ever colour image of the universe. The National Aeronautics and Space Administration (NASA) recently urged netizens to save the date as the picture will be released on July 12. However, the contents of the photo are still a secret. Since there is still time before the historic moment, let us take a look at some of the key facts you must know about the world’s most powerful observatory. 

About the Webb telescope

The Webb telescope has been developed by teams from NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA). Webb, which is a decades-old idea, was initially named the "Next Generation Space Telescope" (NGST) but was renamed in September 2002 after former NASA administrator, James Webb. Its development first began in the mid-1990s but several delays and roadblocks in the construction delayed its launch to December 25, 2021, and the construction cost inflated to about $10 billion. 

Where is the Webb telescope?

Unlike the Hubble Space Telescope, which orbits the Earth at an altitude of about 547 kilometres, the Webb telescope is located at the second Lagrange point (L2), which is 15 lakh kilometres away from our planet. There are a total of five Lagrange points encircling the Earth and the sun and, according to NASA, these locations are gravitationally stable which enables a spacecraft to remain stable and use its fuel more efficiently. 

(Lagrange points around the Sun and the Earth; Image: NASA)

On a side note, ESA's Gaia telescope, which was launched in 2013 to map the entire Milky Way, is also located at the second Lagrange point. Besides, the Euclid mission is also headed to L2.

Webb's components

The telescope has a total of four instruments which would help it make unprecedented discoveries about the universe. The four instruments are the Mid-Infrared Imaging (MIRI), Near-Infrared Camera (NIRCam), Near-Infrared Spectrograph (NIRSpec), and Fine Guidance Sensor/Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS). Another important component of the telescope is its primary mirror, which comprises 18 small hexagonal mirrors.

Interestingly, Webb's mirrors have a thin plating of gold as the element will ensure the highest reflection of the infrared light to Webb's instruments. Our everyday mirrors normally have silver or aluminum in them but they are unsuitable owing to their inferior reflecting properties. Silver reflects 95% of the infrared light whereas aluminum reflects only 85% of the same in comparison to gold, which reflects 99% of all the infrared light that it encounters. 

Webb's capabilities

The telescope is extremely sensitive to infrared light, the kind which is not visible to us but can be felt in the form of heat energy. A light beam becomes infrared when its wavelength gets stretched after travelling billions of light-years. Scientists believe that infrared is the key to understanding the origin of our universe as the first beam of light, which emerged after the big bang, could be detected by Webb and broken down to extract the information embedded in it. Once operational in a couple of months, Webb will be able to detect atmospheres of exoplanets, peer through thick dust clouds and reveal information about black holes and other mystery objects in our universe.