Protesters are in the fifth week of blocking the start of construction to build the world’s most powerful telescope on the slopes of Mauna Kea, which many Native Hawaiians consider sacred. Among the activists, known as protectors, there are so far no indications of weakening in their vow to thwart the project.
At risk in the clash over Mauna Kea’s future as a hub for world class astronomy is the fate of the giant Thirty Meter Telescope, which is expected to revolutionize the next generation of ground-based celestial study. Named for its unprecedented 30-meter diameter mirror, the proposed telescope would be able to access roughly half the sky at a resolution 12 times sharper than the Hubble Space Telescope.
When combined with the complementary 20-meter Giant Magellan Telescope under construction in Chile, the TMT and its southern counterpart would be able to observe the entire universe in far greater detail than possible with the current suite of 8 to 10-meter telescopes available to astronomers. Pillars of the U.S. Extremely Large Telescope Program, these dual optics in either hemisphere are expected to help scientists demystify the awakening of the universe — a period when, out of the dark ages, the first stars, planets and galaxies were born.
Whether life is a unique feature of Earth or widespread in the galaxy is one of the fundamental questions astronomers hope to come closer to answering with this new technology.
This upcoming class of giant telescopes, including TMT, has been at the top of astronomers’ wish lists for nearly two decades.
Years before these telescopes are projected to be ready for operation, scientists around the world are already jockeying for time slots to utilize their enhanced optics to further studies related to the genesis of stars, planets, black holes and galaxies, as well as other yet-to-be imagined areas of research.
The international consortium behind the TMT still plans to build the telescope on Mauna Kea, Hawaii’s tallest peak. The mountain’s favorable atmospheric conditions make it one of the best locations in the world from which to view the night sky.
But if the project is stopped, they have an alternate option. A site in Spain’s Canary Islands remains a backup location for the $1.4 billion telescope in the event that construction on Mauna Kea becomes impossible.
Amid this period of uncertainty over the telescope’s future, Civil Beat reviewed more than a dozen scientific proposals for projects that require the advanced optics of a giant telescope such as the TMT and interviewed two scientists about the most pressing questions they would like to explore.
At the University of Texas, astrophysicist J. Craig Wheeler is the lead author of a science proposal that depends on the bigger lenses and much larger mirrors of a giant telescope to uncover what makes a star explode.
An expert in the study of luminous star explosions known as supernovae, Wheeler said the next generation of telescopes will allow scientists to view these explosions in greater detail and at farther distances.
He is competing for time to make observations on the GMT in Chile, but this proposed science could also be conducted by the TMT on Mauna Kea.
A 30-meter class telescope could answer questions about what kinds of elements are blown out into space during a star explosion and how those elements form new stars and planets, including Earth-like planets that may support life.
The answers to these questions could revolutionize humankind’s understanding of the evolution of the galaxy, Wheeler said.
“A supernova is hot and young and bright, which is exciting to see, but then it fades away, and as it gets dimmer and dimmer and dimmer it gets harder to observe,” Wheeler explained.
“With a bigger telescope, you can follow a supernova as it gets fainter and fainter and fainter and you can see deep down into the guts of the supernova in ways that we can’t yet see with our current telescopes. There’s a zoo of things we can learn from that because it’s part of the cycle of life.”
For example, images from NASA’s Chandra X-ray Observatory show the explosion of a massive star called Cassiopeia A, also known as Cas A, about 340 years after the blast. The image shows elements blown out in different directions from the supernova’s center, including oxygen, silicon, calcium and iron, which are necessary to form planets and life.
The image also shows what appears to be a neutron star near the center of the explosion.
“We are still endeavoring to understand what happens at the end of the life of a massive star when its innards collapse to form the neutron star and the energy of collapse blasts the remaining material into space,” Wheeler said. “Supernovae are part of the wondrous cosmological ecology that turned the expanding universe after the Big Bang into the stars and galaxies that fill it today.”
More sensitive instrumentation afforded by the news class of telescopes could also aid the study of stars ripped apart by supermassive black holes.
In another proposal authored by Wheeler, a larger telescope is pegged as key to understanding these so-called tidal eruption events, which occur when a star passes by a supermassive black hole and the force of gravity. These events, which are stronger on the side of the star that’s closer to the black hole and weaker on the side of the star that’s farther away from the black hole, stretch the star to the point where it’s torn apart.
“We have anticipated that such things could occur for many years, and finally in the last few years we’ve discovered that they do,” Wheeler said. “But they’re kind of dim and they’re far away and they don’t appear to behave exactly the way we thought they would, so there’s a whole raft of things we would like to look at with a larger telescope.”
Wheeler characterizes his science proposals for the next generation of telescopes as probes aimed at helping humankind better understand its place in the universe.
“In the last 100 years we’ve gone from thinking that we’re kind of in the center of the sky around us to understanding that that’s not true, there’s a whole vast universe out there full of galaxies and probably full of planets,” Wheeler said. “We’ve catalogued the universe to a great extent, but there are still some huge unanswered questions of how we got here and where we’re going.”
He added, “Does that affect how you go about your business in a 9-to-5 job? Well, not directly. But it does kind of permeate into the whole cultural scheme of how we think of ourselves as people of this planet.”
Ben Mazin, a physics professor at the University of California, Santa Barbara, wants to use the new class of giant telescopes to find Earth-like planets in other solar systems.
Mazin said he specifically wants to use the TMT to further his science, and he said he would prefer that the telescope be built on Mauna Kea over the Canary Islands because of the Hawaii site’s elite weather and atmospheric conditions.
Earth-like planets are difficult to detect with the current suite of telescopes because they orbit so closely to their stars that they can’t be seen through the bright light.
The more sensitive optics of a 30-meter telescope, however, are expected to help scientists peer in closer to distinguish between the star and these potentially habitable planets.
“It’s like using your eyes to see something small and then, with the TMT, it’s like now you’re getting to use a microscope,” Mazin explains. “Whereas on an 8-meter telescope we’re looking at gas giant planets far from their star, the hope is that TMT will be able to peer into the inner solar systems of some of the nearest stars to us so that we’ll actually be able to zoom in and look at rocky, Earth-like planets in the habitable zone.”
Astronomers can then probe images of those planets to look for signs of life that alter the chemistry of the atmosphere.
“That’s really our goal: finding life outside our solar system,” Mazin said.
Scientists have so far discovered about 4,000 planets outside our solar system. But with hundreds of billions of stars in the Milky Way, there are likely to be more planets, some of which could be similar to Earth in their ability to host life.
“It’s very hard to discover these planets with current techniques,” Mazin said. “That’s why we need the TMT.”
Mazin said scientists have identified at least a half dozen planets that appear to be good targets to probe with the TMT for signs of life. One of them is Proxima Centauri b, which orbits the closest star to the sun.
Scientists plan to use giant telescopes to assess whether Proxima Centauri b’s atmosphere allows its planetary surface to maintain water.
“We know these Earth-like planets are pretty common at this point,” Mazin said. “What we don’t know is whether they have life on them — that’s our longterm goal. And when I say life, I mean that we would be happy with pond scum.”
“I do think it’s one of the most important questions that humans can answer: Are we alone? It’s a really important question that could change the way we look at our planet.”
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