The solar eclipse Thursday will put more people under the moon`s shadow than any eclipse in history.
”It`s almost as if somebody wrote a script for this,” said astronomer Barry LaBonte of the University of Hawaii`s Institute for Astronomy in Honolulu.
”It is happening at the best site,” he said. ”It is even happening at the right time of day.”
The eclipse will give astronomers at the Mauna Kea Observatories in Hawaii an unprecedented chance to learn more about the sun`s temperature, composition and magnetic fields, using the best technology available.
”It`s like a window into the future,” LaBonte said. ”It`s a picture of what science might be like 50 years into the future when there`s a big telescope in space.”
LaBonte will lead one of the nine experiments planned at Mauna Kea.
”If these pictures turn out well, that`s a really strong argument for building a telescope in space,” he said.
The eclipse comes at a time when images of the sun`s outer halo, or corona, are hard to come by. Satellites once were often equipped with coronagraphs-telescopes that create artificial eclipses-to allow observation of the corona, which is obscured by the sun`s brightness under normal conditions.
But there are no operating solar satellites now, because of federal budget constraints, said Steve Maran, an astronomer at the National Aeronautics and Space Administration`s Goddard Space Flight Center in Maryland.
Most eclipses fall in inconvenient places where visibility is poor. But this one will offer a once-in-a-lifetime chance for professional and non-professional stargazers.
Totality, the phase when the sun`s disc is completely blotted out by the moon, will last 6 minutes 53.5 seconds at the midpoint of the eclipse path. That is only 10 seconds short of the longest solar eclipse of the 20th Century and 33 seconds short of the theoretical maximum.
Eclipse watchers will have to wait until 2132 to spend a longer time in the moon`s shadow.
When the eclipse passes over Mexico City, with a population of more than 20 million, more people will stand under the moon`s shadow at once than ever before, scientists say.
In particular, astronomers hope the eclipse will help unravel the mystery of why the corona is at least 1,000 times hotter than the sun itself.
This has long puzzled scientists. Common sense would suggest that the encircling corona would be cooler than the sun`s inner layers, which fuel the corona with energy. A number of Mauna Kea experiments are designed to help astronomers better understand the engine that heats the corona.
