What would Dr. Evil do with a giant laser and deformable 30-meter mirror? Hold the planet for ransom, no doubt. The billion-dollar Thirty Meter Telescope (TMT) project, on the other hand, will assemble these components into a state-of-the-art optical telescope on the lip of a giant volcano and peer into the depths of space and time. (Astronomers. No ambition.)
The Hawaiian Board of Land and Natural Resources (BLNR) recently granted the TMT a building permit on Mauna Kea. After gaining final approval by Department of Land and Natural Resources (DLNR), the team hopes to begin preparing ground later this year for the start of construction in April, 2014.
We’ve recently covered a few big radio telescope projects made possible by accelerating computing power—the Atacama Large Millimeter Array and the Australian Square Kilometer Array Pathfinder. Likewise, digital age optical telescopes are getting bigger and badder too.
TMT’s primary segmented mirror will be made up of 492 smaller mirrors and measure thirty meters across—three times the diameter and nine times the collecting area of the giant Keck Telescope. Once considered inferior to space-based telescopes like Hubble, ground-based optical telescopes are rapidly overtaking their space-based brethren. TMT will deliver images 12 times sharper than those taken by Hubble.
How’s that possible? The first ground-based strategy is to locate in a remote place to minimize pollution (light and air) and high up to minimize cloud cover. Hawaii’s Mauna Kea is an ideal spot, and its slopes are already dotted with observatories.
But the atmosphere itself, no matter how clear or free of pollution, deforms light waves. Computer-powered adaptive optics correct that distortion by studying a laser-projected artificial “guide star” near the point of observation in the upper reaches of Earth’s atmosphere. The telescope’s computer notes how the layers of air distort the guide star’s light and uses actuators to shift segments of the primary mirror, correcting the observed wave pattern.
Adaptive optics allow space-like observations without space-like costs. Ground-based scopes are easier to maintain, repair, and upgrade. And researchers can build them as large as the technology will allow. In comparison to TMT’s 30-meter diameter, Hubble measures only 2.4 meters and even the next-generation James Webb Space Telescope will be but 6.5 meters.
Beyond being an awesome machine, TMT will do some awe-inspiring science too. The scope will look back to the edge of the cosmological “Dark Ages” when the earliest stars ignited and formed the first heavy elements. TMT will study relativistic effects near the supermassive black hole at the center of our galaxy and resolve supermassive black hole accretion disks (matter spiralling into active black holes) as far out as the Virgo Cluster of galaxies 60 million light years away.
But maybe coolest of all, TMT will directly observe extrasolar planets in reflected and emitted light and study the spectral make-up of their atmospheres. Instead of identifying Earth-like planets by their mass and orbit alone, as we do now, researchers will catalogue their chemical composition too. Once we’ve got our list of habitable worlds, all we need to do is figure out how to get to them.
Image Credit: Thirty Meter Telescope
