US, Japan astrophysicists win Nobel prize
The Royal Swedish Academy of Sciences said Davis, 87, and Koshiba, 76, would share half of the one million dollars prize for their pioneering work in astrophysics, which laid the foundations for a new field of science called neutrino astronomy.
Italian-born Giacconi, 71, would receive the other half of the coveted award for work that helped launch X-ray astronomy.
“This year’s Nobel laureates in physics have used (the) very smallest components of the universe to increase our understanding of the very largest: the sun, stars, galaxies and supernovae,” the academy said in a statement. “The new knowledge has changed the way we look upon the universe.”
Davis and Koshiba proved the existence of tiny particles coming from the sun — solar neutrinos — created in a nuclear reaction transforming hydrogen into helium, confirming the theory that this reaction was the source of the sun’s energy.
Thousands of billions of solar neutrinos are estimated to pass through our bodies every second without our noticing them, because the tiny particles react weakly with matter. It is therefore very difficult to capture them.
CLEANING FLUID: Davis, who has Alzheimer’s disease according to the University of Pennsylvania where he is emeritus professor, took a 615-ton tank of the chemical used for dry-cleaning clothes and placed it 1.6kms below the Earth’s surface in a South Dakota gold mine to keep out sun rays.
The 30-year study allowed him to measure neutrinos produced by nuclear fusion reactions at the sun’s core as they turned atoms of chlorine in the cleaning liquid into atoms of argon.
Davis came up with a method of counting the argon atoms — “an achievement considerably more difficult than finding a particular grain of sand in the whole of the Sahara desert,” the academy said.
As a result, he not only solved a century-old mystery surrounding solar energy generation but gained important new insights into the underlying makeup of the universe.
Koshiba, in a separate experiment using a water tank in a mine in Japan, recorded the small flashes of light created when a neutrino interacts with atomic nuclei in water.
By registering the speed and direction of the particles, Koshiba was able to prove that neutrinos come from the sun.
Giacconi, born in the Italian city of Genoa, constructed a telescope detecting X-ray radiation from outside the Earth, making it possible to see distant stars.
“I feel a little numb,” he told Reuters from his home in Maryland. “I didn’t even think about it and then at about 5.30 a.m. this morning I got woken up by the president of the Royal Academy of Sweden and I haven’t been off the phone since.”
In 1979 an X-ray telescope was first employed on the satellite Einstein, helping detect millions of radiation sources.
“These sources could be weaker, so it could be normal stars, or it could be very far away like quasars. So now X-ray astronomy encompasses the field of astronomy as a whole,” Giacconi told Reuters.
The X-ray astronomy Giacconi pioneered gave the strongest evidence so far of the existence of black holes — stars of small size but enormous mass that attract everything around them, including light.
“The work of all three has also improved the sensitivity and range of such equipment as airport luggage scanners, or machines used by banks to detect counterfeit banknotes,” said Finnish theoretical physicist Stig-Erik Starck.
Koshiba appeared on Japan’s NHK state television shortly after the news came out.
“Thank you very much,” the grey-haired scientist said, beaming and bowing to reporters on being congratulated. “Of course I’m happy.” When asked how he felt when the call came through, he said, “Ah, here it is.”—Reuters