Parallax pinpoints Milky Way’s far side
The longest distance measurement ever taken within our Galaxy has been achieved by the Very Long Baseline Array (VLBA), a network of 10 radio antennas across the globe to create one giant scope.
The readings pinpointed that a star-forming region on a distant spiral arm is 66,000 lightyears away. Astronomers used parallax measurements, calculating distance by measuring the apparent shift in sky position of a celestial object when observed from different locations on Earth. “This means that, using the VLBA, we can now accurately map the whole extent of our Galaxy,” says Alberto Sanna, of the Max-Planck Institute for Radio Astronomy.
Previous efforts to map the Milky Way have been hampered by difficulties in measuring the location of objects on the far side of our Galaxy.
“Most of the stars and gas in our Galaxy are within this newly-measured distance from the Sun. 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,” says Sanna. https://science.nrao.edu/facilities/vlba
Star-forming region The Sun The star-forming region measured is about as far away from the Solar System as you could get