The James Webb space telescope, a $10 billion observatory that successfully launched into
space on Christmas Day last year. Ever since it launched, the world has been waiting to
see its first images, images that according to NASA, will deliver us a new view of the cosmos.
Although we have still got a few months to wait until we start to see these
unprecedented views, recently, NASA released Webb's first "in focus" image of a single
bright star captured as part of a mirror alignment process.
But in the background of this image, if you look carefully, you will see something even
more interesting, a "taster", if you like, of what this extraordinary telescope is capable of.
While some of the largest ground based telescopes on Earth use segmented primary mirrors, Webb is
the first telescope in space to use this design. The 21 foot or 6.5 metre gold covered mirror was
far too big to fit inside of a rocket fairing, however, and so it had to be folded up for launch.
After Webb successfully made it into space, the 18 hexagonal beryllium mirror segments that
make up the primary mirror then unfolded, but for the telescope to work properly,
all of these segments have to be aligned with extraordinary precision.
Aligning each segment into one smooth reflecting surface was one of the most
important tasks the Webb control team had to tackle since the telescope launched.
According to NASA's recent news conference, however, the primary mirror is now fully
aligned within a fraction of the width of a human hair and performing even better than expected.
Although many other alignment steps and tests need completing before Webb ultimately delivers its new
view of the cosmos, this fully focused image is the highest resolution infrared image ever
taken from space, providing us with a tiny glimpse of how powerful Webb is.
The star at the centre is called 2MASS J17554042+6551277, and although it is the
brightest thing in the image, emanating streams of light across the universe, it is nothing
particularly special. It is just a generic, anonymous star with the right level of brightness
used to make sure that the mirror alignment is precise enough. A test star if you like.
It's what is surrounding the star that is interesting. The spray of tiny dots,
scattered across the background. Because these specks are distant
galaxies billions of light years away that have never been observed before.
These mysterious, distant galaxies make this crystal clear image a so called deep field image,
which is an image that has captured the most distant objects in the universe. The Hubble
space telescope required days, sometimes weeks to obtain some of its most famous deep fields,
such as this one. Whereas Webb will be able to accomplish the same results in just hours.
The James Webb space telescope is designed to be 100 times more sensitive than Hubble,
but the two observatories do not image in the same wavelengths. Hubble is an expert
in mainly visible and ultraviolet radiation, while Webb operates in the realms of infrared.
It's important to remember, however, that this is only a
test image. The glorious vistas, such as those captured by Hubble over the last
30 years or so will come later, once the observatory is fully operational.
But even though it is a test, it represents the beginning of what we will soon be observing.
The James Webb space telescope will allow us to peer back in time
and capture the first galaxies that formed only a few hundred million years after the Big Bang.
Potentially transforming our understanding of the cosmos. And I for one, cannot wait.
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universe even more then why not check out this video, where we fly faster than the speed of light
into the centre of the Milky Way Galaxy. Thanks again for watching and I'll see you next time.