Earth 16,000 MPH faster, 2,000 light years closer to the supermassive black hole at the center of the Milky Way

Earth has just become 7 km / s (~ 16,000 mph) faster and about 2,000 light-years closer to the supermassive. prison in the center of Milky Way Galaxy. But don’t worry, this doesn’t mean our planet is sinking into the black hole. Instead, the changes are the result of a better model of the Milky Way based on new observational data, including a catalog of objects observed for more than 15 years by the Japanese radio astronomy project VERA.

VERA (VLBI Radio Astrometry Scan, from the way “VLBI” stands for Very Long Baseline Interferometry) began in 2000 to map three-dimensional velocity and spatial structures in the Milky Way. VERA uses a technique known as interferometry to combine data from radio telescopes scattered across the Japanese archipelago in order to achieve the same resolution as a 2300 km diameter telescope. Measurement precision achieved at this resolution, 10 arc microseconds, is sharp enough in theory to resolve an American penny placed on the surface of the Moon.

Since the Earth is located inside the Milky Way, we cannot take a step back and see what the Galaxy looks like from the outside. Astrometry, the precise measurement of the positions and movements of objects, is a fundamental tool for understanding the general structure of the galaxy and our place in it. This year, the first VERA astrometric catalog was published containing data from 99 objects.

Based on the VERA Catalog of Astrometry and recent observations by other groups, the astronomers constructed a map of position and velocity. From this map they calculated the center of the Galaxy, the point around which everything revolves. The map suggests that the center of the galaxy and the supermassive black hole that resides there are 25,800 light-years from Earth. This is closer than the official value of 27,700 light years adopted by the International Astronomical Union in 1985. The velocity component of the map indicates that the Earth is traveling at 227 km / s as it orbits the Galactic Center. This is faster than the official value of 220 km / s.

Now, VERA hopes to observe more objects, particularly those near the central supermassive black hole, to better characterize the Galaxy’s structure and motion. As part of these efforts, VERA will participate in the East Asian VLBI Network (EAVN) consisting of radio telescopes located in Japan, South Korea and China. By increasing the number of telescopes and the maximum distance between telescopes, EAVN can achieve even greater accuracy.

“The first VERA astrometric catalog” from the collaboration of VERA et al. appeared in the publications of the Astronomical Society of Japan in August 2020.