Sat, Dec 11, 2021 page6

• Telescope aims to answer astronmy’s ‘big’ questions

  • AFP, PARIS
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  It has been three decades in the making: The largest and most powerful telescope ever to be launched into space is finally ready to take up its orbit and beam back new clues to the origins of the universe and Earth-like planets beyond the solar system.

  NASA’s James Webb Space Telescope, named for a former director of the US space agency, follows in the footsteps of the legendary Hubble — but intends to show humans what the universe looked like even closer to its birth nearly 14 billion years ago.

  Cosmologist and astrophysicist John Mather, who cofounded the Webb project, on Twitter wrote that the telescope “can see the heat signature of a bumblebee at the distance of the MOON.”

  

  NASA technicians lift the James Webb Space Telescope using a crane and move it inside a clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in an undated photograph.

  Photo: EPA-EFE / NASA / Desiree Stover

  All that power is needed to detect the weak glow emitted billions of years ago by the first galaxies to exist and the first stars being formed.

  Hubble is capable of observing events that happened in space about 500 million years after the Big Bang, and Webb can go back even further to about 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, and learn how galaxies grow over time,” she said.

  It would also give new information about nearly 5,000 exoplanets. The ultimate goal is to find out whether Earth is unique or whether there are similar planets that could give rise to life.

  “There’s a lot of excitement — we’ve been waiting for this moment for a long time,” European Space Agency (ESA) project scientist Pierre Ferruit said.

  The ESA and the Canadian Space Agency collaborated on Webb, and Ferruit, like thousands of his colleagues, has been working on it for most of his career. Researchers are already competing for access, he said.

  “Observation time is in very high demand. The ESA has received over a thousand applications for just the first year of operation,” he said.

  “Even after 20 years, the questions Webb was made to answer are still just as pressing,” he added.

  The telescope is unequaled in size and complexity. Its mirror measures 6.5m in diameter — three times the size of the one on the Hubble telescope — and is made of 18 hexagonal sections.

  It is so large that it had to be folded to fit into the Ariane 5 rocket that is to carry it to its orbit on Dec. 22.

  Once the telescope is in place, the challenge would be to fully deploy the mirror and a tennis-court-sized sun shield — a process that would take two weeks.

  Its orbit around the sun would be 1.5 million kilometers from Earth, much farther away than Hubble, which has been 600km above Earth since 1990.

  The location of Webb’s orbit is called the Lagrange 2 point and was chosen in part because it would keep the Earth, the sun and the moon all on the same side of its sun shield.

  “This will put it in darkness and in extreme cold,” conditions which would allow the telescope’s infrared sensors to “see” without interference — a kind of observation of which the Hubble was incapable, Ferruit said.

  The NASA project, launched in 1989, was originally expected to deploy in the early 2000s, but multiple problems forced delays and a tripling of the telescope’s original budget with a final price tag of nearly US$10 billion.

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

  “All that’s left is to fill up the gas tanks,” Ferruit said.
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