December 30, 2003 Astronomy's New Grail: The $1 Billion Telescope By DENNIS OVERBYE n the quest for some understanding of our twinkling existence, astronomers have built ever larger telescopes capable of catching and pooling the rare light of remote stars and galaxies.
Over the decades the torch of awe has been passed from mountaintop to mountaintop, from Mount Wilson, from where the expansion of the universe was discovered, to Palomar, home of the famous 200-inch reflector, which reigned supreme for almost half a century, to the cinder cones of Mauna Kea in Hawaii, where the twin 400-inch-diameter Keck Telescopes lord it over 13 others.
And even to space, where the Hubble Space Telescope is a peerless time machine.
Now the torch may be passed again.
Emboldened by the advances of the last two decades, groups of universities, observatories, nations and other research organizations are pondering plans for radical new telescopes that will dwarf even the giants on Mauna Kea and reach even farther into space and further back in time.
The proposals sport Brobdingnagian names like the California Extremely Large Telescope, or CELT; Giant Magellan; or the Overwhelming Large Telescope, OWL, a 100-meter-diameter behemoth being contemplated by a collaboration of European nations. And their proponents promise appropriately outsized scientific results.
The new telescopes, they say, will be able to deliver images sharper than the Hubble's, while gathering much more light, bringing into focus the blobs of primeval stars and gas from which galaxies were assembling themselves 10 billion years ago, or glimpses of planets around distant stars.
"With such a telescope you can for the first time really trace the connections between the first seconds of the Big Bang and the formation of life in the universe," said Dr. Rolf-Peter Kudritzki, director of the Institute for Astronomy at the University of Hawaii.
Astronomers say such a telescope will be needed to follow up and investigate the discoveries of the James Webb Space Telescope, scheduled for a 2011 launching, and the Atacama Large Millimeter Array, a radio telescope being built by the United States and Europe in Chile. In a report published in 2000, a committee of the National Academy of Sciences ranked a 30-meter telescope first on a wish list of new instruments for the coming decade.
But such a telescope also comes with a Brobdingnagian price tag — roughly a billion dollars to build, equip and operate for 20 years. That is more than the most recent generation of large telescopes cost altogether, according to a survey in Physics Today.
"We are really going to have a hard time building even one of these," said Dr. Richard Ellis, an astronomer at the California Institute of Technology, and one of the leaders of the effort to build the California telescope. Paying for such a telescope will require a merger of private and public sources of financing that is rare in astronomy, he said. Many large ground-based innovative telescopes in the United States, like Palomar and the Kecks have been built by private observatories and universities — not the taxpayer.
Dr. Ellis and his colleagues at Caltech and the University of California working on the California telescope have taken the first steps into this new era. This year the Associated Universities for Research in Astronomy, or AURA, agreed to join the California effort, which was renamed the 30-Meter Telescope. Subsequently the Gordon and Betty Moore Foundation granted Caltech and California $17.5 million each to help pay the cost of designing the telescope. AURA, which has no money of its own, has applied to the National Science Foundation for its share of the design cost.
But the 30-Meter Telescope has competitors, in particular the Giant Magellan, an effort led by the Carnegie Observatories in Pasadena, Calif., to build a 20-meter telescope in Chile.
AURA is a consortium of 36 educational and other institutions, which operates a network of national observatories for American astronomers. In an interview, the consortium president, Dr. William Smith, said it was important to move ahead in order to have a telescope by the time the Webb telescope was launched.
But the consortium's move to join the California effort dismayed some of its members, some of them involved in rival projects. They say that it is too soon to know yet what is involved in building a giant telescope or what is at stake scientifically in choosing one design over another.
In a letter to the National Science Foundation, 18 astronomers said in November that the agreement between AURA and CELT "may violate the principle of open competition." They included Dr. Peter Strittmatter, director of the University of Arizona's Steward Observatory; Dr. Irwin Shapiro, director of the Harvard-Smithsonian Center for Astrophysics; and Dr. Wendy Freedman, director of the Carnegie Obseratories. They urged the science foundation to hold an open competition to develop the best strategy for a giant telescope.
Dr. Michael Turner, the foundation's assistant director for mathematics and physical sciences, said all options were still open.
In statements and at meetings recently, he and Dr. Wayne Van Citters, director of astronomical sciences at the science foundation, have been circumspect, emphasizing the need for strategic planning before locking in a specific design. "The science that a Really Big Telescope can do has everyone excited," Dr. Turner said in an e-mail message. "We just have to figure out the best way to get there."
The road once ended at Palomar.
Palomar's Hale reflector, finished in 1948, was long considered the limit for ground-based telescopes. Bigger mirrors would just be too heavy.
But in the 1990's, technological advances made it possible to build thin, lightweight mirrors as large as 8 meters (about 26 feet) in diameter that relied on computer adjusted supports to keep the mirrors from sagging under their own weight.
The largest of the new breed were the Kecks, built by Caltech and California on Mauna Kea. Instead of being monolithic slabs of glass, their 10-meter-diameter mirrors are composed of 36 small hexagons warped and fitted together. The design was the brainchild of Dr. Jerry Nelson, a former particle physicist at the University of California at Santa Cruz.
The first Keck went into operation in 1993. By the end of the decade Dr. Ellis and his colleagues had already begun to study how to scale up the Keck idea. Last year they published a 300-page "conceptual design" for a 30-meter telescope with a mirror made of some thousand hexagons.
The new Moore Foundation grant, he said, will enable the California group to refine their design and study the trade-offs between size, cost and performance of a telescope.
In the meantime, they have also begun testing sites for the telescope in Chile; Baja, Mexico; and Mauna Kea in Hawaii.
Only when the design is finished, will the 30-Meter partners, which Dr. Ellis hopes will soon include the Association of Canadian Universities for Research in Astronomy, or Acura, be able to decide whether to proceed with building the telescope and with raising the serious money it will require.
With no "hiccups," Dr. Ellis said, the telescope could be ready in 2012.
While the California telescope will consist of many small pieces, the 20-meter Giant Magellan is to have only a few very large ones. Its main mirror will have only six circular segments surrounding a central one.
The project grew out of the twin 6.5-meter Magellan telescopes that have recently been built at Carnegie's Las Campanas Observatory in Chile by a partnership that includes the Universities of Michigan and Arizona, the Harvard-Smithsonian Center for Astrophysics, and the Massachusetts Institute of Technology, as well as Carnegie.
The plan capitalizes on the expertise of Dr. Roger Angel and his colleagues at the Optical Sciences Center at the University of Arizona, who have mastered the art of casting giant mirror blanks in a rotating furnace and then polishing them into shape. Each of the seven mirror segments is to be 8.4 meters in diameter, which is the biggest size his furnace can handle.
The telescope could be ready by 2015, if all goes well, the Magellan partners say.
Dr. Freedman, Carnegie's director, said she was optimistic that there would be resources and room on the planet for both the 30-Meter and the Giant Magellan, and that they could complement each other.
"We're all moving forward," she said after a recent meeting on telescopes at the National Academy of Sciences in Irvine, Calif. "We will succeed because the science is exciting."
Looming over these and other efforts is the prospect of a European giant.
That is the 100-meter Overwhelmingly Large Telescope contemplated by the European Southern Observatory, a multinational consortium that operates the world's largest array, the Very Large Telescope, on Cerro Paranal in Chile.
Dr. Robert Gilmozzi, an astronomer at the European Southern Observatory, said 100 meters was the minimum size needed to peruse Earth-like planets around nearby stars for signs of life.
The mirror for the proposed telescope has a novel spherical design that will allow it to be enlarged, or built in stages, said Dr. Guy Monnet, an astronomer at the European Southern Observatory and the project manager for OWL.
This means, Dr. Monnet said, that every segment of the primary mirror will be identical, simplifying the construction. It also means that the the European Southern astronomers can build a 60-meter telescope and see if it works, and then expand the mirror by filling out the sphere with more segments to make a 100-meter telescope. Such a telescope will be more likely if Americans participate, he added.
In order to realize their full potential the new telescopes will have to make maximum use of a new technology that undoes the blurring effects of the atmosphere.
In principle the resolving power of a telescope depends on its diameter — a bigger one can see finer detail — but in practice atmospheric turbulence, the same effect that makes stars appear to twinkle, blurs the stars and erases fine detail. This is why the Hubble, even though it is not large, only about 2.4 meters (96 inches), compared with the new giants on the ground, can do breathtaking work.
Lately astronomers have begun to learn how to tune out some of the blurring by monitoring the image of a bright star near the target of observation and continually adjusting a mirror inside the telescope. But these so-called "adaptive optics" systems have been added after the fact to existing telescopes.
The new big telescopes will be the first telescopes to have adaptive optics built in from the start, Dr. Ellis said.
What can you see with such a telescope?
Extraterrestrial planets are on the top of many astronomers' lists.
In the last decade more than 100 planets have been detected around nearby stars by their gravitational effects. These have all been very massive objects, at least as big as Jupiter, but the discoveries have fueled hopes that full-fledged systems with planets more like Earth, possible abodes of life, may eventually be found.
A giant mirror that could focus starlight into the smallest tiny point would be particularly well-suited to detecting planets. Masking out the bright star might bring the much fainter light of a planet otherwise lost in the glare.
Most of these would be the Jupiter-size planets, but Dr. Angel said 20- or 30-meter telescopes could be on the threshold of being able to detect Earth-like planets. A 100-meter telescope, with another tenfold increase in light-gathering power and even sharper images, he said, would be "extremely powerful." It would allow spectroscopy of Earth-like planets, he said, allowing astronomers to examine its atmosphere and perhaps rudimentary signs of life.
At the other end of creation, a really big telescope will be able to study what happened about 11 billion or 12 billion years ago when the universe was undergoing a rush of construction. Clouds of gas and dust collapsed and lit up as stars, which in turn began to transform the universe from primordial hydrogen and helium into the rich mix of elements like carbon and oxygen that have seeded life and wonder today. Meanwhile, clusters of stars were condensing into the first gawky-looking galaxies, ancestors of the milky spirals and bulging smooth clouds that now rule space.
But, Dr. Patrick McCarthy of Carnegie explained, "a large telescope will be able to see all the bits and pieces that coalesce into galaxies. That's where the physics is."
Is Saturn the very bright object in the east about 11 pm? I thought that was Jupiter, I know Jupiter was in that neck of the woods a few years back.
Saturn is yellowish compared to Jupiter. The hard naked-eye planet is Mercury. Generally one has to go outdoors with the deliberate and planned intent to observe Mercury or one will never see Mercury, not in a lifetime.
OK, thanks. I'll take a look. This is hugh. Not to mention Sirius! (Also, very prominent now!)
I did that for one express purpose once, although not Mercury (which I have never spotted).
A few years back, Venus was totally stunning right after sunset. So I went each day to the same place, earlier each night, with some telephone poles and wires in the foreground. Finally, after about five days, it worked. I saw it in the sky, very faint. Before sunset.
You saw Mercury? Or Venus? Mercury is bright enough, but it is so close to the sun at best that there is still twilight when you see the planet. There are only a few minutes between when you can make out the planet in twilight and when it sets.
Venus. During the day, before sunset. I had heard long ago it was possible. It's very, very faint, but if you know exactly where to look, you can see it.
Yes, Venus is possible in daylight if the sky is very clear. So is the moon, but I would bet that few have noticed the moon in daylight.
Why not use the moon as a platform for a 100 or more meters telescope, where there is no atmospheric and very little gravitational and thermal( on the dark side) distortion effects. This of course assumes the colonization of the moon.
Saw the moon one morning very close to sunrise in the dead of winter, it was within a day of the new moon. There was a ring around it, almost like an annular eclipse, and a ghostly glow. Very beautiful sight.
