The ultra-high-tech successor to the ageing Hubble Telescope will open an exciting new window on the cosmos, exploring unseen realms – some of which might harbour life, albeit not necessarily as we know it.
NASA engineers have revealed the James Webb Space Telescope, the largest of its kind ever built, has an eight-metre gold-coated mirror, seven times bigger than Hubble's. Fully deployed, the whole telescope will be as wide and long as a tennis court and about four storeys tall.
Scientists say it will be the world's premier observatory for the next decade, serving thousands of astronomers worldwide, including hundreds in Australia.
Under construction at NASA's Goddard Space Flight Centre in Maryland, the $10 billion space-based telescope is a joint venture between the US, European and Canadian space agencies.
After being launched on an Ariane 5 rocket from French Guiana in October 2018, it will study every phase in our universe's history, ranging from the first luminous glows after the Big Bang to the formation of remote solar systems capable of supporting life on planets like Earth.
The monster scope, known affectionately as Webb, will follow Earth's path around the Sun, from a distance of 1.5 million kilometres - far enough away to be undisturbed by our planet's light and heat.
"Webb is designed to observe in the infrared because the most distant galaxies in the universe are only detectable in that band," said ICRAR-Curtin University astrophysicist Dr Rob Soria.
So, all being well, it should shed light on the nature of dark matter – and even dark energy, a mysterious force driving the universe's accelerating expansion.
"Webb's bigger mirror means it will find much fainter objects than Hubble could in the colours it can detect," Dr Soria explained. "So, its primary mission is to study very distant galaxies, formed during the universe's first billion years."
"By studying those faint, distant galaxies, astronomers hope to understand when the first stars began to form and what the first galaxies were like," Dr Soria explained. "Using the new scope, scientists can gauge how quickly the earliest galaxies formed, pulled together by gravity."
For the first time, Webb has special devices, called coronagraphs, that will block the light of nearby stars to help search for planets around them.
"Also, it will be able to study regions where stars formed in nearby galaxies, still surrounded by lots of cold gas and dust - before the newly formed stars blew them away. Then it will be up to theoreticians to interpret those new observations with better models of dark matter and dark energy, or with better theories of gravity."
"It is from these discs that planets form," said Swinburne University astrophysicist Dr Kurt Liffman. "So it will provide more information on star and planet formation - helping us to understand the very earliest formation processes of our solar system."
Airbus Defence and Space built and successfully tested two of the key instruments. First, a near-infrared spectrograph will measure the spectra of up to one hundred objects simultaneously.
"It will observe large samples of galaxies and stars at unprecedented depths across large swathes of the universe and far back in time," said François Auque, the head of space systems.
And, second, a combined camera and spectrograph will extend Webb's observation capabilities to longer wavelengths than those covered by other instruments. "The apparatus will study light from objects in the early universe and will peer inside dust clouds where stars and planetary systems are forming," Mr Auque explained.
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