NIST study may solve ‘universe’s expansion mystery’

WASHINGTON - Astrophysicists may finally be able to solve the mystery of the unending expansion of our universe, thanks to a telescope calibrated by scientists from the National Institute of Standards and Technology (NIST), Harvard University and the University of Hawaii.

The team travelled to the summit of Haleakala volcano in Hawaii to fine-tune the operation of the Pan-STARRS telescope, which scans the heavens for Type IA supernovae.

These dying stars always shine with the same luminosity as other Type IA supernovae, creating a standard for judging distance in the universe.

Any apparent shift in the supernova’s spectrum gives a measure of how the universe has expanded (or contracted) as the light travelled from the supernova to Earth.

To get a clear and accurate picture, astrophysicists need a telescope that will return consistent information about supernovae regardless of which of the roughly 1,400,000,000 pixels of its collector spots it.

“We specialize in measurement, and they needed to calibrate the telescope in a way that has never been done before,” said NIST’s John Woodward.

The team used a special laser whose wavelength can be tuned to any value in that range, and spent three days testing the telescope’s huge 1.4-gigapixel camera-the largest in the world, Woodward said.

“Pan-STARRS will scan the same areas of the sky repeatedly over many months. It was designed to look for near-Earth objects like asteroids, and it also pulls double duty as a supernova hunter. But for both jobs, observers need to be sure they can usefully compare what they see from one image to the next,” Woodward said.

The performance of the telescope will be used by his team to calibrate a much larger telescope-the Large Synoptic Survey Telescope, planned for construction in Chile. (ANI)