The marvel that James Webb Space Telescope is

Astronomers are keeping their fingers crossed as the James Webb Space Telescope (JWST), recently launched, is speeding towards its parking slot, L2, in deep space. It aims to eye at the early universe, a few hundred million years after the Big Bang. It was an era when the first stars fused the hydrogen atoms into more helium in thermonuclear fusion and radiated the first starlight. The Webb is the successor to the Hubble space telescope. The Hubble was about the size of a school bus, whereas the Webb is about half as big as a jumbo 737 aircraft. With its razor-sharp resolving power (ability to discern fine details), it can show us the first few chapters in the universe's evolution and perhaps identify exoplanets hosting alien life.

Largest space telescope in history

A galaxy might shine with the brilliance of a billion suns. Nevertheless, the brightness decreases so rapidly that a galaxy at a distance of one billion light-year years will appear as bright as the headlamp of a car 10,000 kilometres away. Now, imagine trying to spot a stellar object at a distance of 10 billion light-years; the challenge gets a hundred times harder. Some 10-15 billion light-years away to look deep into space, we need a telescope that can detect faint stellar objects. The telescope must see things that are 10 billion times fainter than the faintest stars visible to the naked eye, or ten to a hundred times fainter than what the Hubble space telescope can see. As an add on, it is welcome if the telescope could discover Earth-like distant exoplanets or extrasolar planets that orbit other stars.