Earth is 2000 light-years closer to a supermassive black hole than scientists realised

Adam Smith
·2-min read
<p>An artist’s impression of a black hole</p> (NASA/Swift/Aurore Simonnet, Sonoma State Univ)

An artist’s impression of a black hole

(NASA/Swift/Aurore Simonnet, Sonoma State Univ)

The Earth is 2000 light-years closer to a black hole than we previously thought, new research has revealed.

The finding comes from the Japanese radio astronomy project VERA (VLBI Exploration of Radio Astrometry), which has been mapping three-dimensional velocity and special structures in the Milky Way since 2000.

The scientists used a technique called interferometry – which combines the interference of light, radio, or sound waves from two or more telescopes to get a detailed picture of the sky – on information gathered by from radio telescopes across Japan.

This means that it can map with the same resolution as a 2300km diameter telescope would have; for comparison that resolution (10 micro-arcseconds) is enough to resolve a penny that has been placed on the moon.

Based on this catalogue, and recent observations from other astronomers, the scientists constructed a position and velocity map and calculated the centre of the galaxy – home to the supermassive black hole Sagitterius A*.

The map suggests that the centre of the galaxy is located 25,800 light-years from Earth, rather than the official value of 27,700 light-years that has been used by the International Astronomical Union since 1985.

This new data also indicates that the Earth is travelling faster than previously thought, moving at 227 km/s (kilometres per second) around the Galactic Center rather than the official value of 220 km/s.

This new research, called “The First VERA Astrometry Catalog”, is available in Publications of the Astronomical Society of Japan.

VERA hopes to now monitor more objects to better characterise the structure and motion of the galaxy, using data from EAVN (the East Asian VLBI Network).

EAVN uses radio telescope data from Japan, South Korea, and China, which would make its readings even more accurate and provide more valuable data for scientists studying the cosmos.

Sagitterius A* triggered a “cataclysmic” explosion recently enough to occur as our earliest ancestors walked the Earth, scientists believe, and last year was found to be sending out strange, unexplained flashes.

It is one of potentially thousands of supermassive bodies at the heart of the Milky Way.

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