Nobel physicist focuses on Hubble’s heir

Could the Webb telescope be used in any way to look for life outside our solar system?

We certainly hope to look for life outside the solar system, in a couple of ways. One is, we already know some planets around other stars go in front of those stars or behind those stars. We can't actually see separate images of those planets yet, but we can tell something about the light that came from the planet.

When it's blocked by the star, and you can see the difference, you can tell how much light did come from the planet. And when it goes in front of the star, it blocks some of the starlight, and you can also tell something about the planet from that. So we have hopes of detecting the chemical composition of atmospheres of planets around other stars by this method.

We also are pretty sure there's a planet that could be detected directly, around a star called Fomalhaut. It's got a big cloud of dust around it which is organized in a ring.  This ring is probably due to the gravitational force of a planet that's also orbiting that same star. So we think we know more or less where to look for that planet, and that it should be big enough to see directly. But it's more like Jupiter than like Earth. So we'll be getting some clues about the possibilities for life elsewhere from all of this.

This doesn't launch until 2013. I'm wondering what it's like to commit to a design, then see advances in technology come along that you'd want. Can you incorporate new technology into this project?

Right now we are committing to the design technologies that we have now. We have just finished the 10 main inventions that we had to make. Since those are now complete, we're ready to go on to the next stage of finishing the engineering and building the telescope. So we do indeed have to commit to the particular situation right now in order to go forward. And yes, better things will be invented, but those will be for the next mission to use.

When people see that there's a new space telescope coming up, they may ask why we can't just keep the Hubble telescope going forever. Why not just put new instruments on that? Or they may hear that there's already an infrared telescope called Spitzer. Why build another infrared space telescope? Could you explain how all these telescopes fit together?

Well, to begin with, we are servicing the Hubble Space Telescope one more time, and putting in a marvelous new instrument package that will make it 10 or 100 times more powerful than it is today, and which is already far more powerful than when it was launched. So we've been very successful in putting new instruments with new technology into the Hubble. But we're not that far from perfection on the Hubble instrument package, so it seems that the best expenditure of effort now is to open up a new territory in the infrared. It demands a bigger telescope, new instrument technologies, new kinds of detectors.

The Spitzer Space Telescope also has done marvelous things. It's shown quite clearly that the infrared radiation that it measures comes from very distant things in the early universe. It's also shown us that we can see into the hearts of places where stars and planets are being made. They've even been able to see planets going around other stars. They've proven how important the infrared is.

But our new telescope will be huge by comparison. Spitzer has an aperture diameter of about 3 feet. The new telescope has an aperture which is about 20 feet. So it collects a vast amount more light and will give us much sharper images of things we are looking for.

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