Astronomers measure distance to far side of our galaxy
Researchers have taken a direct measurement of an object far past the Milky Way's centre – doubling the previous record
Astronomers have directly measured the distance to a starforming region on the opposite side of our galaxy from the Sun, meaning they are now in a position to accurately map the entire extent of the Milky Way.
Using the National Science Foundation's Very Long Baseline Array – a system of ten radio telescopes in New Mexico – they have been able to measure a distance of more than 66,000 light years to a star-forming region called G007.47+00.05. This is well past the centre of the Milky Way, and roughly twice the previous record of 36,000 light years.
To gain this direct measurement, the astronomers used a technique called trigonometric parallax, which depends on the apparent motion of nearby stars compared to more distant stars. Such a method is crucial because of the positioning of our Solar System, which is on one of the Milky Way's spiral arms. This ensures the only view we get is side on, and it means we can only map the galaxy by measuring the distances between objects.
"Most of the stars and gas in our galaxy are within this newly measured distance from the
Sun," said Alberto Sanna, of the
Max Planck Institute for Radio Astronomy in Bonn, Germany.
“With the VLBA, we now have the capability to measure enough distances to accurately trace the Galaxy’s spiral arms and learn their true shapes.”
The aim now is to get a fairly complete picture of what our galaxy looks like if we could view it face on instead of along the plane of its disc.