James Webb Space Telescope

We all know that the road from JWST’s proposal to its launch has been a roller coaster ride. The James Webb Space Telescope (JWST) took 30 years and $10 billion to build and is regarded as one of the great scientific achievements of the twenty-first century.


1) What is the James Webb Space Telescope?


JWST is a massive, space-based observatory with infrared wavelengths that will complement and augment the Hubble Space Telescope’s discoveries. Webb will be able to search further back in time to identify the first galaxies that formed over 13.5 billion years ago, as well as gaze inside dust clouds where stars and planetary systems are developing now, thanks to its longer wavelength coverage and considerably enhanced sensitivity.


JWST at NASA | Credit: NASA


NASA’s Webb space telescope is the most powerful and largest space research telescope yet built. Webb’s massive size and low working temperature provide a huge technical challenge. After its launch from Ariane 5, the Observatory will reach a million-mile orbit and will spend six months in space during these six months it will configure its mirrors, sun-shield, and other small components, as well as cooling, alignment, and calibration.


Astronomers around the world will be able to perform scientific observations, which will help us learn more about the universe. Webb will also add to the science that has already been achieved by other NASA missions. Webb is a joint venture between NASA, the European Space Agency, and the Canadian Space Agency. Thousands of engineers and hundreds of scientists, as well as over 300 colleges, and businesses from 29 states and 14 countries, collaborated to make Webb a reality.

 

2) Research Goal of Webb


NASA’s James Webb Space Telescope, which will peer deep into a patch of sky, the size of three full Moons, will embark on an ambitious quest to examine half a million galaxies. One of the initial missions of NASA’s James Webb Space Telescope, which will launch in 2022, will be to record the universe’s oldest structures.


The main project Webb will conduct during its first year is COSMOS-Webb, a wide and deep survey of half-a-million galaxies. Because of the universe’s constant expansion, the ultraviolet and visible light emitted by the initial brilliant objects has been stretched or ‘redshifted,’ resulting in the infrared light we see today. Webb has been designed to perceive infrared light with unparalleled sensitivity and detail. It will build on previous discoveries and make advances in three areas of research with more than 200 hours of observation time.


The main research goals of Webb include:


a) Understand the formation of the first galaxy and stars after Big Bang which will give us insights into our history.


b) The nature of dark matter by measuring the mass function of sub-halos around massive galaxies and the nature of dark energy by measuring time-delay distances.


c) Study of exoplanets.


2.1 Formation of first galaxy and star after Big-Bang


When NASA’s James Webb Space Telescope will start its scientific operation in 2022, one of its first tasks will be an ambitious program that maps the earliest structures in the universe.


This extensive and detailed survey of 500,000 galaxies, called COSMOS Webb, is Webb’s largest project in its first year. With an observation time of over 200 hours, COSMOS Webb will make use of a near-infrared camera (NIRCam) to measure most of the sky (0.6 square degrees). It is the size of three full moons. At the same time, it will use the Mid-Infrared Instrument (MIRI) to map smaller areas. With such a wide range of coverage, we can see the large-scale structures in the early stages of galaxy formation. Also, look for some of the rarest galaxies that existed in the early days.


COSMOS Webb will utilize its near-infrared, high-resolution multi-band imaging to study 500,000 galaxies and mid-infrared to unprecedented 32,000 galaxies. As soon as the data is released, the study will be the leading legacy Webb dataset for scientists around the world studying galaxies across the Milky Way.


JWST in space | Credit: NASA


COSMOS Webb will search for a fully evolved galaxy that formed in the first 2 billion years after the Big Bang and then ceased forming stars. Only a few of these galaxies have been spotted by Hubble, and they contradict existing explanations of the universe’s formation. Scientists are having a hard time explaining how these galaxies have old stars and are unable to form new stars earlier in the history of the universe. Many of these uncommon galaxies will be discovered in a massive survey like COSMOS Webb. They intend to investigate these galaxies in-depth to learn how they evolved quickly and ended star creation early. We don’t know when or how the universe began to produce the first stars and galaxies. JWST will assist in answering this question.


2.2 Study of Dark Matter and its effect on the Universe


The survey conducted by COSMOS-Webb of a large patch of sky- 0.6 square degrees will provide scientists with a previously unexplored unprecedented resolution of the cosmos. Through this, scientists aim to gather a comprehensive insight into the inner workings of dark matter.


The Universe is composed of two types of matter: baryonic matter (stars and galaxies) and invisible dark matter. Analysis of the observational data suggests that Universe is composed of 27 % dark matter and 5 % baryonic matter. Due to its unexplainable abundance in the Universe, the existence of the latter has resulted in the formation and evolution of galaxies to be concentrated about some filament-type structures. Therefore, the interaction between baryonic and dark matter plays a keen role in shaping the Universe as we see it.


COSMOS-Webb will help scientists understand these trivial processes by direct surveillance of the dark matter halos through gravitational lensing. The existence of this is implied by the presence of high mass gravitation systems which can distort and bend photons coming from other galaxies.


Data collected from the COSMOS-Webb survey will help scientists calculate the mass of these halos and shed some light on the mysterious nature of dark matter.


2.3 Study of Exoplanets

Exoplanet atmospheres will be studied as part of the James Webb Space Telescope’s hunt for the building elements of life elsewhere in the cosmos. Webb will employ the transit method to research exoplanets, which means it will look for the dimming of a star’s light as its planet passes between us and the star. Collaboration with ground-based observatories can help us establish the mass of the planets using the radial velocity technique, which involves detecting the star wobble induced by a planet’s gravitational tug. Webb will next perform spectroscopy of the planet’s atmosphere.


How will Spectroscopy be helpful: The science of measuring the intensity of light at different wavelengths is known as spectroscopy. Spectra are graphical representations of these measurements that are crucial to understanding the composition of extraterrestrial atmospheres.