Thirty Meter Telescope to see cosmos on micro scale
Canada to fund international telescope with up to $243.5M over next decade
Less is more.
That's one way to see things when it comes to the Thirty Meter Telescope, a project that received more than $240-million in funding from Canada on Monday. It's billed as the most powerful optical instrument on Earth for viewing the cosmos.
Named for the diameter of the aperture it will use to gather light, the Thirty Meter Telescope is designed to offer astronomers the most detailed glimpses of the known universe that they can get from the ground.
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Whereas the most advanced radio telescopes present a macro overview of the skies, the new TMT is all about viewing the universe at "relatively small scales," says Raymond Carlberg, the international project's Canadian director.
Even a granular look at a snapshot of the universe could help scientists understand how the first stars in our universe formed.
"Those first stars produced carbon, oxygen, nickel, iron, and that got subsequent stars going. That's what makes up the Earth; that's what makes up us. And we want to understand how that process got going," said Carlberg, an astronomy professor at the University of Toronto.
Imaging 3 times sharper
The TMT is being built in Hawaii at the summit of the dormant volcano Mauna Kea, and is slated for completion in 2022.
Canada announced plans April 6 to provide up to $243.5 million over the next decade towards the TMT. The U.S., Japan, India and China have already committed funding to the telescope.
The project has generated opposition from Hawaiians who consider the site to be sacred ground, however, resulting in recent demonstrations and arrests. A day after the Canadian funding announcement, Hawaii Gov. David Ige said the company building the telescope has agreed to his request to halt construction for a week so the project's backers and the protestors can meet.
The TMT's imaging capabilities are expected to be three times sharper than any other optical telescope on Earth, matching resolutions that could be obtained from space. It will also gather more light, boosting the brightness factor beyond the current largest telescope, the 10.4-metre Gran telescope on the Canary Islands.
Carlberg said the completed telescope would typically have a sharpness of about three milliarcseconds, or one-millionth of an angular degree.
If a coin were to be set at a distance of 1,000 kilometres away, for instance, the TMT would be able to spot it as a distinct object.
According to the telescope's California-based research scientist, Warren Skidmore, the TMT is the only telescope in its class capable of quickly changing targets to observe sudden "morphology" of objects such as gamma-ray bursts or supernovae.
"Gathering observations of these targets in the early stages after detection of the explosion is key to understanding the physics that is happening," Skidmore said.
But there are limitations to the technology.
Whether or not the TMT would be able to see anything at all depends on atmospheric conditions such as rain or cloudy skies — a drawback for all optical telescopes.
Digital radio telescopes such as the Canadian Hydrogen Intensity Mapping Experiment, which is still under construction in B.C., harness the radio band's longer wavelengths to create a large-scale 3D structure of the observable universe.
"With radio telescopes, you can use them during the day, the night, when it's cloudy, whenever," said Randy Attwood, executive director of the Royal Astronomical Society of Canada. "Radio waves just penetrate all that stuff."
Radio telescopes also capture images of the sky that are thousands of times more complete. The trade-off is the images are blurry.
Space telescopes can see at different wavelengths, but they're expensive to operate and difficult to repair.
If you want to measure properties of stars or the stellar population of galaxies, their chemistry, and their motions, then you want to do that in the optical.- Christine Wilson, president of the Canadian Astronomical Society
The TMT's ability to collect more light than current optical telescopes means it can bring faint objects into much better focus than when they're captured by other imaging systems.
Astronomers are interested in more than just the visible light, Attwood said.
"Radio waves, microwaves, X-rays, gamma-rays, heat, ultraviolet — they're all part of the electromagnetic spectrum," he said.
"Astronomers want to receive and analyze it all."
European telescope will be larger
Astronomers need different telescopes to operate on different wavelengths so researchers can cross-reference data towards building a profile of the universe.
The wavelength range in which an object is brightest relates to the temperatures of the object, said Christine Wilson, president of the Canadian Astronomical Society.
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Stars and galaxies made up of stars emit temperatures reaching thousands of kelvins, meaning they produce a lot of energy.
"So if you want to measure properties of stars or the stellar population of galaxies, their chemistry and their motions, then you want to do that in the optical [spectrum]," Wilson explained.
"If you want to look at something that's cold, like the gas and the dust in regions of star formation in our galaxy or other galaxies, that might just be a few tens to hundreds degrees kelvin, and that produces radiation in the radiation level of the spectrum."
Attwood said scientists often take the lower-resolution radio telescope images of a region of the sky and "overlay" that against a picture taken from an optical telescope.
Plans for the TMT to be the biggest of its kind in the world wouldn't last long. The European Extremely Large Telescope would take that title by its first light, scheduled for 2024.
The European project's 39-metre-diameter "segmented mirror" would also be larger than the TMT's 30-metre aperture comprising an array of 600 hexagonal mirrors.
Even so, Wilson said the Canadian-backed telescope is expected to remain more powerful, owing to its adaptive optics system, which would allow the aperture to finely focus more light.
Guy Nelson, CEO of Vancouver's Dynamic Structures, which designed the enclosure and telescope structure, said the project should advance Canadian cosmological research for years to come.
"Canadian astronomers rank among the best in the world, and to stay at the best of the world, we need the best instruments to keep at the top of our game," he said.
- This story originally said that, "stars and galaxies made up of stars emit temperatures reaching thousands of degrees kelvin, meaning they produce a lot of energy." The Kelvin Scale is not measured in degrees - the story has been updated to read "thousands of kelvins."Apr 09, 2015 8:34 AM ET