Washington, April 11 :
Applying a novel technique that can yield new insight into dark energy in space, astronomers can now precisely measure the distance of stars up to 10,000 light-years away – 10 times farther than previously possible.
Astronomers used the 24-year-old NASA’s Hubble space telescope by employing a technique called spatial scanning that dramatically improves Hubble’s accuracy for making precision distance measurements 10 times farther into our galaxy.
“This new capability is expected to yield new insight into the nature of dark energy, a mysterious component of space that is pushing the universe apart at an ever-faster rate,” explained Noble laureate Adam Riess of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.
This new long-range precision was proven when scientists successfully used Hubble to measure the distance of a special class of bright stars called Cepheid variables, approximately 7,500 light-years away in the northern constellation Auriga.
The technique worked so well that they are now using Hubble to measure the distances of other far-flung Cepheids.
Such measurements would be used to provide firmer footing for the so-called cosmic “distance ladder”.
This ladder’s “bottom rung” is built on measurements to Cepheid variable stars that, because of their known brightness, have been used for more than a century to gauge the size of the observable universe.
They are the first step in calibrating far more distant extra-galactic milepost markers such as Type Ia supernovae, the astronomers added.
Riess shares the 2011 Nobel Prize in Physics with another team for his leadership in the 1998 discovery that the expansion rate of the universe is accelerating – a phenomenon widely attributed to a mysterious, unexplained dark energy filling the universe.