Planting the Thirty-Meter Telescope

Dave on Earth (4:07:25 PM) Hello, this is Dave Mosher from Discovery.com.
How are you doing today Dr. Stone - or should I call you Ed?

EdLovesAstronomy (4:10:50 PM) Hello Dave! Ed is fine, and I'm doing very well.

Dave on Earth (4:11 PM) Great! Where are you chatting from today?

EdLovesAstronomy (4:12 PM) I'm in my office at Caltech in Pasadena, California. What about you?

Dave on Earth (4:13 PM) I'm in New York City - thanks for asking.
So I hear you're working on something big these days...

EdLovesAstronomy (4:14 PM) You'd be right. One of the current projects I'm involved with is the Thirty Meter Telescope, or TMT for short.

Dave on Earth (4:15 PM) What would you need a telescope that big for?

EdLovesAstronomy (4:19 PM) We want to look deep into space, which means looking back in time to about 400 million years after the Big Bang.
That's when first galaxies formed, so we could study how they evolved into the diversity of galaxies that we see today.

Dave on Earth (4:21 PM) So the Thirty Meter Telescope will look back in time.
How does that work?

EdLovesAstronomy (4:25 PM) Yes, nature provides us with a convenient time machine because light travels at a finite speed.
So if an object is 10 billion light years away, the light we are seeing today left the object 10 billion years ago.
It's like we are seeing the object as it existed 10 billion years in the past.

Dave on Earth (4:27 PM) Right. Isn't it harder to see distant objects, though?

EdLovesAstronomy (4:27 PM) Of course, there is a price to pay, because the farther away an object is, the fainter it is.
So you need larger telescopes to collect enough light to detect the more distant objects.
Even the two Keck telescopes, each having mirrors 10 meters in diameter, can't collect enough light to study galaxies 13.3 billion light years away, when it is thought they first formed.

Dave on Earth (4:29 PM) I see... so a huge mirror - as wide as a 10-story building is tall - could gather more light than any telescope out there, making even the faintest objects seem bright.
I'm wondering, Ed, how did you get involved with this project?

EdLovesAstronomy (4:35 PM) Well, I've been involved with a number of space missions, including the two Voyager spacecraft that were launched in 1977.
They flew by Jupiter, Saturn, Uranus, and Neptune and are now exploring the final frontier of the solar system on their journey to interstellar space.

Dave on Earth (4:35 PM) Far out. You mentioned the Keck telescopes earlier - didn't you have a hand in those, too?

EdLovesAstronomy (4:38 PM) Yes. I've also overseen the development and operation of the two Keck telescopes since 1985.
They were the first large telescopes in which the primary mirror was made of hexagonal segments (36 to be exact) and where adaptive optics is used to correct for the blurring of the atmosphere.

Dave on Earth (4:38 PM) TMT's main mirror is also going to be made of pieces. How will it measure up?

EdLovesAstronomy (4:39 PM) TMT has a similar design with 492 segments and adaptive optics. So many more mirrors.

Dave on Earth (4:40 PM) Impressive. So what would you say is your favorite, if you had to pick between Voyager and Keck?

EdLovesAstronomy (4:41 PM) I've been lucky to have been involved with many great projects, but if I have to choose one... it would be Voyager.

Dave on Earth (4:42 PM) If you don't mind my asking, why Voyager?

EdLovesAstronomy (4:44 PM) I've been directly involved with many of the discoveries that Voyager has made, and I'm still learning so much about the solar system to this day from them.

Dave on Earth (4:45 PM) Here's another "favorite" question: What's your favorite planet?
And the follow-up: Why?

EdLovesAstronomy (4:48 PM) I would pick Jupiter.
It was the first stop on the Voyager journey, and it's where the spacecraft made many unexpected discoveries that revealed how diverse the bodies in the solar system are.

Dave on Earth (4:49 PM) What sorts of unexpected things did you discover out there?

EdLovesAstronomy (4:51 PM) Perhaps the biggest surprise was the discovery of eight active volcanoes on Io, a moon of Jupiter that has 100 time the volcanic activity of Earth.
It's interesting to note, though, that with adaptive optics on the Keck telescopes, many of those volcanic features on Io can now be seen from Earth.

Dave on Earth (4:53 PM) So we can now see from Earth what only a spacecraft could see before... Amazing.
But I'm sidetracking us here - we were talking about the Thirty-Meter Telescope! I heard you have been looking for good sites to build this thing.
What makes a primo spot?

EdLovesAstronomy (4:57 PM) The best place to site a telescope is on a high mountain where the air is least turbulent, such as near to or in the middle of an ocean.

Dave on Earth (4:57 PM) That narrows it down a bit, I suppose. How did you pick the best sites?

EdLovesAstronomy (4:59 PM) Right.
So we set up observing stations at five sites and monitored the stability and other characteristics of the atmosphere over the last three to four years.
All were excellent sites, but we've recently selected two sites for further study in the next year, with a plan to select the final site in June 2009. We expect to be operational by 2018.

Dave on Earth (5:00 PM) Which sites made it to the top two?

EdLovesAstronomy (5:03 PM) One is the Cerro Armazones, which is in the middle of a big Chilean desert called the Atacama. The other is Mauna Kea in Hawaii.

Dave on Earth (5:03 PM) So it's the driest desert in the world, or a tropical island mountain.
Hawaii seems like a suspiciously nice site to work from as an astronomer. Great beaches and beautiful scenery...

EdLovesAstronomy (5:05 PM) Fortunately, it also a great site for astronomy!
Well Dave, I've enjoyed the chat but have to sign off for now. Let's chat again soon!

Dave on Earth (5:06 PM) Thanks Ed, and great chatting with you.

MORE EXPERTS