Finding An Earthly Home For The Thirty Meter Telescope
Named for the diameter of its mirror, the Thirty Meter Telescope (TMT, for short) will some day see 10 to 100 times farther in the sky than existing telescopes — far enough, scientists hope, to glimpse exoplanets and some of the oldest objects in the universe.
The powerful telescope is being developed as a partnership between the United States, Canada, Japan, China and India. But for the moment, it’s still just a twinkle in the eyes of international astronomers — because as it turns out, finding an Earthly home for TMT has been harder than anyone counted on.Originally, the telescope was to be built on Hawaii’s Mauna Kea, but construction halted in 2015 after Native Hawaiians sued — the volcano is one of the most sacred spots in the Hawaiian Islands.
The TMT team has a backup location in Spain’s Canary Islands, and in mid-May, a group of Canadian scientists issued a report examining the costs of switching sites. As Space.com senior writer Michael Wall explains, the substitute spot isn’t a clear win, either — it’s considerably lower in elevation than Mauna Kea.
“It’s about 6,000 feet lower, actually,” he says, “which means that if you build the telescope there it has to peer up through a lot more atmosphere, and that makes it a lot harder to actually see into space.”
If the telescope is built in the Canary Islands, scientists could install adaptive optics to lessen the blurring caused by all that extra atmosphere, he explains. But even then, success isn’t a sure thing: “It’s still possible that … won’t be able to totally counteract the atmospheric effects,” he says. “There’s a reason why the Hawaii place was a scientifically preferred site in the first place, and so they would still hope to build it there.”
Given the telescope’s requirements, the dry, high elevations of the Chilean Andes would be another option — but two gigantic telescopes, the European Extremely Large Telescope and the Giant Magellan Telescope, are already being built in the area.
“What they’d really like is [to] have one in the Northern Hemisphere, which will be able to do different parts of the sky and therefore different objects,” Wall says, “and also link up with a bunch of the Northern Hemisphere telescopes, so that they can perform similar studies on similar parts of the sky.”
“They don’t want to put all of the giant megascopes on Earth in the same little patch of Southern Hemisphere to look at the same part of the sky.”
Given the variables, it could be a while yet before the telescope finds its footing. “We’re expecting to hear a new ruling about whether [Mauna Kea] construction can actually go forward in the next couple of months,” Wall says. “But nobody really knows, and nobody knows if there will be a challenge after that judgment is handed down.”
Soon, however, the Thirty Meter Telescope will simply need a home — wherever that may be. “They would ideally like to start construction by spring of 2018,” Wall says.
Michael Wall is a senior writer with Space.com. He’s based in San Francisco, California.
IRA FLATOW: And now it’s time to play Good Thing, Bad Thing. Because every story has a flip side. The scientists behind the 30-meter telescope have some lofty goals to see some of the oldest objects in the universe, take a closer look at exoplanets, maybe even help us find evidence of life. But it has been complicated getting the telescope built. They lost their building permit at Hawaii’s Mauna Kea mountaintop in 2015, after a native Hawaiian sued. Mauna Kea, it turns out, is one of the most sacred spots in the Hawaiian archipelago.
The good news, the 30-meter telescope team has a backup site on the Canary Islands in Spain. But as you’ll soon hear, switching sites– well, it would not come without costs. Michael Wall, senior writer for space.com is with us. He’s based in San Francisco. Welcome, Michael.
MICHAEL WALL: Thanks for having me.
IRA FLATOW: Well, it’s good to hear that there’s another site for the telescope. Now we can be sure the telescope will be built?
MICHAEL WALL: Yeah. Yeah. I mean, it certainly looks that way. They would still like to build it in Hawaii, if at all possible. That’s the main site. But now they do have a backup site. So they do have a path forward if Hawaii doesn’t work out.
IRA FLATOW: So that’s the good news, then.
MICHAEL WALL: Yes. But there is bad news, and that’s that the Canary Islands site, which is the backup site they decided on, is considerably lower in elevation. It’s about 6,000 feet lower, actually, which means that if you build the telescope there, it has to peer up through a lot more atmosphere. And that makes it a lot harder to actually see into space.
IRA FLATOW: Oh, that is not a good thing. (LAUGHING) It’s not a good thing. Because you want to get it as high as possible without the atmosphere.
MICHAEL WALL: Right, right. Yeah, and they could take mitigating moves to actually kind of get over that. But they would require putting some more adaptive optics on the Canary Islands scope, which basically means they would have to add a little bit more [INAUDIBLE] to kind of correct for the sort of blurring effects of that much more atmosphere. And it’s still possible that that won’t still be able to totally counteract the atmospheric effect. So yeah, there’s a reason why the Hawaii site was the scientifically preferred site in the first place. And yeah, and so they would still hope to build it there.
IRA FLATOW: Well, aren’t there any other sites out there that could be just as good as Mauna Kea? Maybe in Chile? Isn’t there a telescope already in Chile? Maybe piggy back on that?
MICHAEL WALL: Yeah, there are a lot of telescopes being built down there, you know. That’s a great site. It’s really high up, and it’s got really, really dry air.
But they actually want to build this one in the northern hemisphere, because there are already two giant telescopes that are going to be sort of similar that are already going up down in the Chilean Andes. So what they’d really like is to have one in the northern hemisphere which will be able to see different parts of the sky, and therefore different objects, and also kind of link up with a bunch of the northern hemisphere telescopes, so that they can perform similar studies on similar parts of the sky. They don’t want to put all of the giant megascopes on earth in like the same little patch of southern hemisphere to look at the same part of the sky. So yeah, that’s kind of part of the reason why they chose Hawaii in the first place, was to give us better coverage for these giant scopes.
IRA FLATOW: Why not just upgrade Mount Palomar out there in California?
MICHAEL WALL: [LAUGHING] Yeah, well that’s got pros and cons too. We could talk about that. But you know, it’s close to some bigger cities. It’s not quite so high up. You got some California smog coming into play there too.
IRA FLATOW: Yeah. Well, it’s a wonderful telescope, has been an icon for decades. But let’s get back to the ending to this. How much longer will it take to know whether the 30-meter telescope– and where we’ll end up?
MICHAEL WALL: Well, that’s sort of the thing, is it’s still up in the air sort of. I mean, like, we’re expecting to hear a new ruling about whether construction can actually go forward in the next– I don’t know– couple months or so. But like, nobody really knows, and nobody knows if there will be a challenge after that [INAUDIBLE], after that judgment is handed down.
So yeah, we’re still waiting. They would ideally like to start construction by spring of 2018. So I mean, something’s probably going to happen within the next– I don’t know– seven, eight months, where we get something wrapped up, and there’s a final decision made. But yeah, we don’t really know when that’s going to happen exactly, or what that decision’s going to be. So we just wait and see.
IRA FLATOW: All right, we’ll have you back when they make that decision, Michael. Thank you for taking time to be with us today.
MICHAEL WALL: Sure, thank you.
IRA FLATOW: Michael Wall, senior writer for space.com, based in San Francisco.