Hubble Space Telescope Used to Measure Stars 10 Times Farther Than Before
NASA's Hubble Space Telescope may be aging, but it regularly delivers images of astronomical wonders, and now its operators have come up with a novel new trick to get the telescope to measure stars at a distance up to 10 times farther than previously possible.
According to NASA, this new technique - called spatial sprawling - enables the Hubble to measure the distance of stars up to 10,000 light years away.
"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," said Adam Riess of the Space Telescope Science Institute in Baltimore, Md.
The extra distance is gained by applying spatial sprawling to an trigonometric technique for gauging distances called astronomical parallax, which is an old, but reliable way of making astronomical distance measurements.
Land surveyors here on Earth also use this technique. For astronomers, the diameter of the Earth's orbit is used as the base of a the triangle in the equation. A distant star is used as the apex where the triangle's side meet. The length of those sides is calculated by measuring the three angles of the resulting triangle.
This method is effective for measuring stars up to a few hundred light years away, but for more distance stars, the angles of the triangle become difficult to measure.
The new spatial sprawling method was proven successful after measuring the distance of a special class of bright stars called Cepheid variables, approximately 7,500 light-years away.
"Such measurements will be used to provide firmer footing for the so-called cosmic 'distance ladder,' " NASA said in a statement. "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."
This new, highly precise distance-measuring system will also allow researchers to gauge just how much the universe is stretching, NASA said.