Astronomers have used careful measurements of star brightness originally gathered for spotting planets for a new purpose: guessing the age of our galaxy. After tracking “star-quakes,” they believe a more accurate estimate is that the Milky Way is 10 billion years old.
When NASA’s Kepler satellite was scouring the skies for exoplanets, it found them by carefully watching a star’s brightness for the telltale dimming caused by a planet passing in front of it. While Kepler’s mission is complete, the data it collected keeps on giving: a team of scientists led by researchers at the Sydney-based ARC Centre of Excellence for All Sky Astrophysics in Three Dimensions (ASTRO-3-D) have used the data to estimate star ages, and thus the galaxy’s birthdate, too.
“This finding clears up a mystery,” lead author Dr. Sanjib Sharma from ASTRO-3-D and Australia’s University of Sydney told Phys.org. “Earlier data about the age distribution of stars in the disc didn’t agree with the models constructed to describe it, but no one knew where the error lay – in the data or the models. Now we’re pretty sure we’ve found it.”
Where they found it was in neutron stars, the ultra-dense cores of collapsed stars, and the violent periodical corrections to their wildly powerful magnetic fields.
The largest star-quake ever recorded, seen in the neutron star SGR 1806-20 on December 27, 2004, had a frequency of 94.5 Hertz – a slightly flat F sharp, equivalent to the 22nd key on a piano, Space.com reported. In that moment, an intense flash of energy lasting one-tenth of a second released more energy than our Sun emits in 150,000 years.
Sourse: sputniknews.com
