Astronomers have come with a new use of NASA's Hubble Space Telescope, even though it is 24 years old.
The innovative technique improves Hubble's observing accuracy to the point where rock-solid distance measurements can be made to Milky Way stars 10 times farther away than ever accomplished before.
To do this, Hubble observations and subsequent analysis were fine-tuned to make angular measurements (needed for estimating distances) that are so fine that if your eyes had a similar capability you could read a car's license plate located as far away as the Moon!
This new capability allows astronomers to use even more distant stars as yardsticks to refine estimates. In addition, it 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.
As proof of concept for this new long-range precision, Hubble was used to measure the distance to a bright star of a special class (called Cepheid variables) that is located approximately 7,500 light-years away in the northern constellation Auriga. The technique worked so well that additional Hubble distance measurements to other far-flung Cepheids are being measured.
Noble Laureate Adam Riess of the Space Telescope Science Institute (STScI) and the Johns Hopkins University in Baltimore, Md., in collaboration with Stefano Casertano of STScI, developed the ingenious technique to use Hubble to make measurements as fine as five-billionths of a degree on the sky. (A degree is twice the angular width of the full Moon.
