With Webb, scientists should be able to tell whether other planets contain molecules like water vapour, carbon monoxide and methane.

Soon to offer a better look at these so-called exoplanets is NASA's new James Webb telescope, which is set to launch this month and become the largest and most powerful observatory in orbit.

One of its major missions is to look for conditions that could sustain life outside our solar system, where scientists have only recently been able to look for it.

James Webb: The Hubble Telescope Successor

Detecting biological activity

Equipped with a new piece of technology called the Mid-Infrared Instrument (MIRI), the telescope will use a camera and a spectrograph to see light in the mid-infrared region of the electromagnetic spectrum, invisible to the human eye.

Webb will soon meet its rocket. 🚀
Having been moved to the final assembly building at Europe’s Spaceport, next Webb will be connected to the @ariane5's upper stage & encapsulated within the fairing. Launch is on Dec. 22: https://t.co/FfXhuH8TVX
Credits: © ESA-CNES-Arianespace pic.twitter.com/ZBKmA4D5kL
— NASA Webb Telescope (@NASAWebb) December 9, 2021

Pierre Ferruit, a Webb project scientist at the European Space Agency, told AFP "scientists should be able to tell whether other planets contain molecules like water vapour, carbon monoxide and methane."

Those three substances are present in Earth's atmosphere and could potentially signal biological activity on a planet's surface.

Webb "Answering the biggest questions"

In a recent Tweet chat, cosmologist and astrophysicist John Mather, who co-founded the Webb project, described the telescope's unprecedented sensitivity.

"#JWST can see the heat signature of a bumblebee at the distance of the Moon," he tweeted.

NASA's Hubble telescope is capable of observing events that happened in space some 500 million years after the Big Bang, while Webb can go back even further to around 200 million years after that event.

"This telescope is designed to answer the biggest questions in astronomy today," NASA astrophysicist Amber Straughn said in a 2017 TED talk.

"With Webb we hope to see these infant galaxies," she said, "and learn how galaxies grow over time."

Developed and constructed over more than 30 years, #Webb is a remarkable feat of engineering and technology.
Learn more in this new video featuring @esa experts @markmccaughrean, @kainoeske and Giovanna Giardino👉 https://t.co/rnmxuVBuqe #WebbSeesFarther #WebbFliesAriane #JWST pic.twitter.com/TFIoPOF2c7
— ESA Webb Telescope (@ESA_Webb) December 7, 2021

Launching delay

The NASA project, launched in 1989, was originally expected to deploy in the early 2000s.

But multiple problems forced delays alongside a tripling of the telescope's original budget with a final price tag of nearly 10 billion dollars (8.8 billion euros).

Webb was built in the US and transported to its launch site in Kourou in French Guyana this year.

Its original launch date of December 18 was delayed after an accident in late November.

On Tuesday, #Webb was moved to meet its @ariane5 in the final assembly building @EuropeSpacePort 🤩🚀
Next up: Webb will be integrated on the rocket's upper stage and encapsulated inside the fairing 👉https://t.co/3ucO3rUkQx #WebbFliesAriane #WebbSeesFarther #JWST pic.twitter.com/sBnikNVN9i
— ESA Webb Telescope (@ESA_Webb) December 9, 2021

An Ariane 5 rocket is now set to carry it into space on December 22, and it is estimated that it will take a month to reach its point of orbit.

"All that's left is to fill up the gas tanks!" said ESA's Pierre Ferruit.