Posted on 12/18/2001 2:08:49 PM PST by E. Pluribus Unum
| A University of B.C. research team has recreated the death of a star and subsequent birth of elements that form the universe, the first time this has been done by mankind. "Canada is now the world leader in this research," TRIUMF director Alan Shotter said after the breakthrough experiment, which puts UBC ahead of the only other facility of its kind, in Geneva, Switzerland. "We are pushing this technology to the absolute limits of what's possible." The achievement moves science a step closer to understanding the creation of the elements. "By understanding what happens to matter during a supernova we gain a better understanding of how the basic building materials of our universe are created and distributed throughout space," said Shotter. Project director Paul Schmor noted, "We have satellite detectors in space called observatories, studying the effects [of stellar explosions] long after the event. "Now we can re-create the event itself." Noting that TRIUMF researchers first proposed the project nearly 18 years ago, Shotter said "to see it come to fruition now is very fulfilling." The project was done at UBC's ISAC facility (Isotope Separator and ACcelerator). Using a proton beam from the university's TRIUMF cyclotron directed by giant electromagnets, the team accelerated the radioactive isotope sodium 21 in a recreation of the explosive death of a star eight times the size of our own sun. (An isotope is one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic masses and physical properties.) In this instance, the sodium 21 was transmuted into magnesium 22, which decays into the radioactive isotope sodium 22. This sequence of changes is of great interest to astrophysicists and astronomers who study the rays given off by the latter substance. Stars are composed primarily of hydrogen and helium; after a birth in which they coalesce from gases and dust they mature to become massive fusion reactors until, in their death throes, the tremendous energy generated -- temperatures in the hundreds of millions of degrees -- explodes outward, carrying the unstable isotopes created by the event into space. The Big Bang is believed to have created only hydrogen and helium, from which stars formed and, a billion years later, became the first novas and supernovas to explode. From this debris, literally the ashes of dead stars, all the heavy elements were created, a slow process still going on; the universe is even now 98 per cent hydrogen and helium. With the completion of ISAC in 1999, TRIUMF became unequalled in the world in its ability to study nuclear astrophysics and element synthesis in the universe. The only other facility of its kind, in Geneva, sent congratulations Monday to the ISAC team that beat it to the finish line. The UBC cyclotron generates a 500 MeV (megavolt) proton beam which produces the isotopes under study. Ions from the isotope are "aimed" by the TRIUMF electromagnets and focused into a beam. ISAC's radiofrequency linear accelerator kicks them up to speed consistent with stellar events and, as Shotter says, what happens next is "something actually beyond our abilities to theorize about these sorts of processes. No one has ever seen this before." Next for the lab is what Shotter describes as one of the thorniest problems for nuclear astrophysicists, duplicating the reaction of the isotope oxygen 15, which is believed to be the spark that ignites nova explosions and x-ray bursts. The researchers will largely be racing themselves this time. "The Americans are planning a similar facility and they expect it to cost $800 million US and take 10 years to build. So we're 10 years ahead," Schmor said. "Canada is now leading the world in the field of nuclear astrophysics. "We have bragging rights." |
Today Saskatoon, tomorrow...???
... that team members were shocked to discover that supernovas generate huge masses of graham crackers, chocolate, and marshmallow.....
Interesting artice...thanks for posting.
Reminds me of the joke about scientists and God. The punchline was: "No, first you have to create your own dirt."
(An isotope is one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic masses and physical properties.)
Possibly the lamest definition of "isotope" I've ever seen. The only thing journalists do worse than science is economics.
Project director Paul Schmor noted, "We have satellite detectors in space called observatories, studying the effects [of stellar explosions] long after the event.
Oh. I thought they were called "dog sleds," or perhaps "caribou pies."
You forgot journalism......
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