Editor’s note: To mark the International Year of Astronomy, Mālamalama looks at an innovative, international University of Hawaiʻi–led effort to survey the sky.
Somewhere out there lurks a killer asteroid on a collision course with Earth. Perhaps one of 10,000 uncharted near Earth objects orbiting the Sun, its cataclysmic impact could equal that of the asteroid that wiped out the dinosaurs and 95 percent of all other species on Earth.
Now that I have your attention…
Most of the headlines to date about Pan-STARRS have focused on the panoramic 4-telescope project’s mission to survey the sky for early detection of any incoming threats.
But to the University of Hawaiʻi at Mānoa scientists and engineers involved in building the unprecedented prototype instrument, Pan-STARRS Telescope #1, or PS1, the real story is the radical new approach to science that the wide-field imaging facility represents.
Indeed Pan-STARRS (the name stands for Panoramic Survey Telescope and Rapid Response System) is an ambitious, even audacious undertaking. Consider—
- It is more powerful for survey work than all existing telescopes combined. Where others focus in on a pinprick in the sky, PS1 will image an area 30–35 times the diameter of the full moon, repeating the task over and over in 30-second intervals to cover the entire sky.
- It uses the world’s largest, most sophisticated camera, with built-in ability to compensate for image motion from turbulence in Earth’s atmosphere. (In traditional telescopes, the mirrors must be adjusted to compensate for atmospheric disturbances.) And talk about mega-pixels, viewing the 1.4 billion pixel image that Pan-STARRS captures would require a wall of monitors half the size of a basketball court, never mind zooming in on any detail or comparing one night’s image with another to identify changes in position or intensity.
- Handling all that data (several terabytes per night) requires the power of a specialized supercomputer hosted at UH’s Maui High Performance Computing Center and innovative new software. Picture Lucille Ball on the candy-wrapping assembly line: the computers must create a composite image from numerous charge-coupled device arrays on multiple silicon chips, analyze the image and extract the most important information for archiving, all in about a minute to keep new Pan-STARRS images from piling up. “We can’t afford to do this by brute force, so we have to be clever,” says Kenneth Chambers, associate astronomer at UH’s Institute for Astronomy who serves as director and principal investigator for the PS1 Science Consortium, an international group of academic institutions supporting the initial sky surveys with PS1.
- Pan-STARRS represents a new model in how an astronomic instrument is conceived, built and used. “It is really a home-grown project,” observes IfA Director Rolf Kudritzki—shepherded by IfA staff from the initial concept (credit Pan-STARRS Project Principle Investigator Nicholas Kaiser) through development to start of operations. Instead of telescope time allotted to a specific astronomer to obtain particular observations, data fromthe remotely operated Pan-STARRS’ nightly sky-wide surveys will go to more than 350 scientists in the consortium and eventually will be available anyone online.
“We’re really doing astronomy in a fundamentally different way,” says Chambers. “We can do a very, very broad wealth of science all the way across astronomy. We’re mapping the universe at the same time we are take a census of what lurks in our own backyard.”
The tools of big science typically require national agency sponsorship, but Pan-STARRS wasn’t on their horizon when budgets were planned, so UH pulled together an international group of partners. Universities from Edinburgh to Taiwan are part of the PS1 consortium, along with independent research organizations from the Max Planck Society to Las Cumbres Observatory and U.S. astronomy groups from Harvard, Johns Hopkins and Durham Universities.
The consortium is contributing $13 million for operating PS1, the prototype telescope, on the site of the south dome of the 35-year-old LURE (Lunar Ranging Experiment) Observatory near the summit of Haleakalā on Maui. After paying the utility bill for cooling the equipment, including telescope and computers, most of that money goes into salaries, and thus into the local economy, Chambers notes.
There is a sizeable IfA team affiliated with the project. Astronomer John Tonry led the camera design. Jeffrey Morgan is senior supervising engineer. Gene Magnier heads the image processing software; Jim Heasley, the enormous relational database; and Rob Jedicke, the software group that searches for asteroids. Bob Calder is operations manager.
Others include astronomers, software engineers, information technology specialists, telescope operators and observers and support staff.
Three additional telescopes are planned, with PS2 expected to come online at the end of the PS1’s first three and half years of operation.
In addition to a census of the inner and outer solar system, PS1 will identify new comets and planets. It will shed light on the properties and objects of nearby solar systems, document the activity of stars and black holes, analyze the structure of the Milky Way galaxy and characterize billions of other galaxies. By looking deeper into space, it will look further back in time to help explain the processes that formed the structure in the universe.
In addition, it may unravel mysteries such as how water got to Earth, determine the nature and role of “dark matter” (seen only by its gravitational impact on other objects) and quantify the magnitude of hypothesized “dark energy.”
“And then there’s the serendipitous stuff,” says Chambers. “We’ll make discoveries we’re not expecting.”
Although not yet fully operational, PS1 has produced some exciting early images and discovered its first confirmed supernova during limited operations.
“The science we can do with it is spectacular,” enthuses Kudritzki.
So what about that asteroid threat?
An asteroid large enough to be catastrophic could strike Earth next week or not for another 65 million years, Chambers says. “I don’t lose any sleep about it.”
Some scientists calculate that the risk of dying from an asteroid strike is about the same as that of dying in a plane crash. Astronomers know of 1,000 potentially hazardous asteroids in orbits that come close to Earth. They also know there are about 10,000 out there whose orbits aren’t known.
“We’d like to map those for obvious reasons”, he says. “It’s like an insurance policy.”
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