প্রকাশ: 10/07/2022
Drawing back the curtain to a photo gallery unlike any other, NASA will
soon present the first full-color images from its James Webb Space Telescope, a
revolutionary apparatus designed to peer through the cosmos to the dawn of the
universe.
The highly
anticipated 12 July unveiling of pictures and spectroscopic data from the newly
operational observatory follows a six-month process of remotely unfurling
various components, aligning its mirrors and calibrating instruments.
With Webb
now finely tuned and fully focused, astronomers will embark on a competitively
selected list of science projects exploring the evolution of galaxies, the life
cycles of stars, the atmospheres of distant exoplanets and the moons of our outer
solar system.
The first
batch of photos, which have taken weeks to process from raw telescope data, are
expected to offer a compelling glimpse at what Webb will capture on the science
missions that lie ahead.
NASA on
Friday posted a list of the five celestial subjects chosen for its showcase
debut of Webb, built for the U.S. space agency by aerospace giant Northrop
Grumman Corp.
Among them
are two nebulae - enormous clouds of gas and dust blasted into space by stellar
explosions that form nurseries for new stars - and two sets of galaxy clusters.
One of
those, according to NASA, features objects in the foreground so massive that
they act as "gravitational lenses," a visual distortion of space that
greatly magnifies the light coming from behind them to expose even fainter
objects farther away and further back in time. How far back and what showed up
on camera remains to be seen.
NASA will
also publish Webb's first spectrographic analysis of an exoplanet, revealing
the molecular signatures from patterns of filtered light passing through its
atmosphere. The exoplanet in this case, roughly half the mass of Jupiter, is
more than 1,100 light years away. A light year is the distance light travels in
a year - 5.9 trillion miles (9.5 trillion km).
'MOVED
ME AS A SCIENTIST ... AS A HUMAN BEING'
All five
of the Webb's introductory targets were previously known to scientists. One of
them, the galaxy group 290 million light-years from Earth known as Stephan's
Quintet, was first discovered in 1877.
But NASA
officials promise Webb's imagery captures its subjects in an entirely new
light, literally.
"What
I have seen moved me as a scientist, as an engineer and as a human being,"
NASA deputy administrator Pam Melroy, who has reviewed the images, told reporters
during a June 29 news briefing.
Klaus
Pontoppidan, a Webb project scientist at the Space Telescope Science Institute
in Baltimore, where mission control engineers operate the telescope, has
promised the first pictures would "deliver a long-awaited 'wow' for
astronomers and the public."
The $9
billion infrared telescope, the largest and most complex astronomical
observatory ever sent to space, was launched on Christmas Day from French
Guiana, on the northeastern coast of South America.
A month
later, the 14,000-pound (6,350-kg) instrument reached its gravitational parking
spot in solar orbit, circling the sun in tandem with Earth nearly 1 million
miles from home.
Webb,
which views its subjects chiefly in the infrared spectrum, is about 100 times
more sensitive than its 30-year-old predecessor, the Hubble Space Telescope,
which orbits Earth from 340 miles (547 km) away and operates mainly at optical
and ultraviolet wavelengths.
The larger
light-collecting surface of Webb's primary mirror - an array of 18 hexagonal
segments of gold-coated beryllium metal - enables it to observe objects at
greater distances, thus further back in time, than Hubble or any other
telescope.
Its
infrared sensitivity allows it to detect light sources that would otherwise be
hidden in the visible spectrum by dust and gas.
Taken
together, these features are expected to transform astronomy, providing the
first glimpse of infant galaxies dating to just 100 million years after the Big
Bang, the theoretical flashpoint that set the expansion of the known universe
in motion an estimated 13.8 billion years ago.
Webb's
instruments also make it ideal to search for signs of potentially
life-supporting atmospheres around scores of newly documented plants orbiting
distant stars and to observe worlds much closer to home, such as Mars and
Saturn's icy moon Titan.
Besides a
host of studies already lined up for Webb, the telescope's most revolutionary
findings may prove to be those that have yet to be anticipated.
Such was
the case in Hubble's surprising discovery, through observations of distant
supernovas, that the expansion of the universe is accelerating, rather than
slowing down, opening a new field of astrophysics devoted to a mysterious
phenomenon scientists call dark energy.
The Webb
telescope is an international collaboration led by NASA in partnership with the
European and Canadian space agencies.
- Reuters
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