Look Back in Time

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Nasa’s James Webb Space Telescope is designed to peer back to the dawn of time.

This week the solid state video recorder that will store the images, a sort of cosmic Sky HD box, was delivered to the team building it at Nasa’s Goddard Space Flight Center in Maryland.

Built by Colorado-based Seakr Engineering, it’s been hailed as the most reliable ever made.

And it has to be, because it will operate in the most hostile conditions imaginable.
The telescope is being sent to a point in the solar system called the ‘Earth-Sun L2 Lagrange point’, a million miles away.

It won’t be possible to make repairs to it out there, so there will be a lot of fingers crossed back at mission control.

By contrast Hubble sits in orbit a mere 350 miles above the Earth.

Out at the Lagrange point, temperatures can plummet to as low as -411F (-210C).

However, Seakr are bullish about their bit of kit and claim that it’s so reliable there’s no need to include a back-up.

Unlike the Hubble, Webb, which is almost as big as a 737, will use infrared instruments to scan the skies.

What’s more, Webb will have a 6.5 meter diameter primary mirror, which would give it a significantly larger collecting area than the mirrors available on the current generation of space telescopes.

Hubble’s mirror is a much smaller 2.4 meters in diameter.

This will mean that where Hubble can see the equivalent of ‘toddler galaxies’, Webb Telescope will be able see ‘baby galaxies’.

The Big Bang caused the universe (and thus the galaxies in it) to expand, so most galaxies are moving away from each other.

The most distant (and thus youngest) galaxies are moving away so quickly that the light they emit gets shifted towards the red end of the spectrum.

This is very similar to listening to a train whistle shifting from higher to lower frequency as it passes by.

Because visible light from faraway is shifted to the infrared, infrared telescopes, like Webb, are ideal for observing these early galaxies.

Attribution: Mail Online, NASA

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