Scientists have found a way to use the Hubble Space Telescope as an extremely precise galactic tape measure, multiplying our previous capabilities by 10. This increase will result in a more accurate understanding of the size of the observable Universe. plus new insight into the mysterious force known as dark energy.
The new technique is called spatial scanning and it extends our star distance measurement capability up to 10,000 light-years away — with a precision of five-billionths of a degree.
Spatial scanning will be applied to an ancient method of measuring the distance to stars called astronomical parallax. This calculation relies on perspective. As Earth moves around the sun, the apparent position of close stars change in relation to the background of faraway galaxies. Since we know the radius of Earth’s orbit around the sun, we can calculate the angles and the distance to the star by measuring how the apparent position changes within a six-month period.
The lengths of the sides are calculated by accurately measuring the three angles of the resulting triangle.
The increase in measurement capability doesn’t seem like much when you consider that the Milky Way is 100,000 light years in diameter, but — according to Noble laureate and co-inventor of spatial scanning Adam Riess, of the Space Telescope Science Institute (STScI) in Baltimore, Maryland — it can help us look into the nature of dark energy:
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.
The increased precision will affect our idea of the entire scale of the Universe, according to NASA:
Such measurements will 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.