One of NASA’s next big space telescope projects could be an orbiter designed to search for planets as small as Earth orbiting other stars. Sometime around 2015, scientists want to launch a major space observatory on the scale of the Hubble Space Telescope.
But it won’t be looking at stars. In fact, it’ll be designed to block out starlight. It’s called the Terrestrial Planet Finder — and it’ll search for earthlike planets around nearby stars. Stephen Unwin is the deputy project scientist for the mission. He says the major challenge is seeing a planet through the glare of its parent star.
Stephen Unwin: We’d expect the planet to be about 10 billion times fainter than the star that’s right next to. So this is like looking at a firefly right next to a searchlight that’s pointing straight at you.
Scientists are now studying two competing design concepts. One uses a very large telescope with a coronograph — a kind of mask that blocks starlight. The other combines images from several small infrared detectors in a way that erases the starlight, but not the planet-light. Unwin says that either design could reveal whether earthlike planets exist.
Stephen Unwin: We’d like very much to know whether our solar system is unique, or whether it’s a pattern which is followed around many stars. We just simply don’t know.
The Terrestrial Planet Finder
The Terrestrial Planet Finder has particular interest for me since, with a few other colleagues, I’m preparing a database on Nearby Stars (“NStars”) to help provide a target list for (it). Also, earthshine studies are being done at our VATT telescope to determine the spectroscopic signature of a life-bearing earthlike planet.
The text below is fine as far as it goes. However I’d like to see some mention that it is hoped the Terrestrial Planet Finder will be able give us spectra of the earthlike planet’s atmosphere, so we can see if it contains signs of gases, such as oxygen, which can (we think) only be produced by life . . . that is the really exciting part of TPF for me.
Excerpts from Unwin Interview:
“… ultimately its human curiosity. We’d like to know if we’re alone in the universe. Whether there’s life out there that we don’t know about yet. Umm, It’s a very basic human question and science, in principle has the answer to that because we have the technology to actually detect planets like our own. And we think that from our limited understanding that planets that have water on their surface and oxygen in their atmosphere. could well support life. We don’t know the processes by which it actually takes place, but those are the . . . ”
“This technology has been developed in the classified world for use on military instruments. But the technique has been used in astronomy for at least a decade now. What’s changed is the recognition that we can build very smooth mirrors and combine them with adaptive optics, plus going to space and the combination of those allows us to get into the regime where we believe that we can actually build the terrestrial planet finder and have a good shot at detecting planets like our own.”
“But this is the start of a very broad field. Our understanding of the universe on scales of solar systems is very poor right now. We only have our own solar system as a template and so I would foresee a big research area once we discover other planetary systems and learn about those planets.”
“… and I’m excited to be involved because as an astronomer I like to learn as much as possible about the universe and we’re really in the early stages of learning some pretty fundamental things about our local corner of the universe.”