Cool Running - The James Webb Space Telescope

10 August 2008

Interview with

Dr John Mather, James Webb Space Telescope

Chris - What are the big questions that are out there that we want to answer with the next generation of space telescope?

John - I think the number one question is how did we get here and are we alone?  Astronomers can tackle some pieces of this question by looking at the first objects that formed after the Big Bang, looking to see how galaxies are made, how stars and planets are formed from their gas clouds and finally how did the Earth come to be like it is?

Artists impression of the James Webb Space TelescopeChris - How are you hoping to answer those things?

John - We have in mind a telescope which will be much larger and more powerful than the Hubble space telescope and would be launched in 2013 into deep space by a consortium of NASA leading the partnership with European and Canadian space agencies; pieces from around the world coming together to make this happen.  Launch in 2013 on the Ariane rocket from French Guyana, near the equator.

Chris - When you say deep space, why can we not just put it in orbit around the Earth?

John - We need to put the telescope far from Earth so that it can cool down to a lower temperature so that it can detect the infrared radiation that is now the new frontier in space astronomy.

Chris - That's interesting.  Why do you want to look at infra red?  It seems paradoxical to look at light that we, as humans, can't see.  I suppose that we as humans get used to seeing things we can see rather than some things like infra red we can't.

John - Yes, the new technology has opened up a new window for us.  Infra red light comes to us from the most distant parts of the universe because of the expansion which causes something we call a red shift.  Also we get to look inside clouds of dust and gas where things are cooler.  Where they're not warm enough to emit radiation that we can see with our eyes but they still put out immense amounts of heat radiation.  If you wanted to see yourself at a great distance you might use an infrared telescope.

Chris - Where will this telescope actually go?  How far from Earth have you got to put it out there?

John - It's put out at 1.5 million kilometres from Earth, a place called Lagrange point 2 which orbits the sun along with the Earth every year.

Chris - How's it powered, solar?

John - It does receive power from the sun with solar cells.

Chris - What major experiments will it be doing as a telescope?

Infra-red view of the solar systemJohn - It has four instruments on it, cameras and spectrographs to cover the entire range of wavelengths from 0.6 microns which is red light that you can see with your eye way out into the near and mid-infrared.  These four instruments will be able to look at distant galaxies, stars, planets, clouds of gas where they've been made and even little objects in the outer solar system.

Chris - Dare I ask what's the price tag?

John - The lifecycle cost from the first day to the very last is four and a half billion dollars, which is actually less than the similar tag for the Hubble space telescope even though the telescope is much more powerful.

Chris - And when you say lifetime cost how long do you anticipate you'll be able to use this?

John - It'll take about another five and a half years to get it to launch and then we expect to run it for ten years.

Chris - That's quite cheap really, isn't it?  On a ten year running cycle that's not bad.

John - For what it can do it's quite cheap.  It's so spectacular in its capabilities that we expect miracles to be found, surprises to abound in the data and beautiful pictures as well.

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