The supermassive black hole that hides in the center of our galaxy is much closer to Earth, about 2,000 light-years closer than scientists thought, according to new research in Japan.
Not only that, but ours as well solar system it moves faster than previously thought as it orbits this galactic center.
All this does not mean that you have to worry that the Earth is approaching the central monster or that we will be sucked into the gravitational monster, the researchers observed. We are still quite far from the black hole, called Sagittarius A * (Sgr A *): 25,800 light-years, where a light-year is about 6 trillion miles (9.5 trillion kilometers).
Related: The greatest discoveries of the black hole
The study is part of the VERA Experiment or VLBI Exploration of Radio Astrometry, whose purpose is to explore the three-dimensional structure of the Milky Way. Because we live in the Milky Way, scientists can’t just take a snapshot to figure out its structure. Instead, they take accurate measurements of star size, position, and orbital velocity — how fast it surrounds the galactic center — in a scientific field called astrometry. The resulting maps can shed light on the details of the Milky Way, the stars in it, and possibly the universe.
Researchers can now “measure the distances of stars 30,000 light-years away from our solar system,” said Tomoya Hirota, a professor in the Astronomy Department at SOKENDAI and the leader of the VERA data analysis team.
Measuring a monster
How do you measure the distance to a black hole as monstrous as Sgr A *, weighing 4.2 million times the mass of the sun? Very accurate.
To do this, researchers with VERA used four very long Basic Interferometry Telescopes (VLBI) in Japan. These observatories work together to achieve results comparable to a telescope with a diameter of about 2,300 km. The resolution is so clear that, compared to human sight, it would be like seeing a penny on the surface of the moon. However, VERA is designed to see things that are far beyond the Moon. For example, VERA can distinguish the annual positional change of a star within 10 micro-arcs, which is an angle of 1 / 360,000,000 of the distance between two check marks on a protractor.
Using the four telescopes, the researchers were able to measure the exact positions, dimensions and orbital speed of the stars in the Milky Way. VERA has published a catalog of 99 Milky Way objects. From the cataloged information, they built a map of position and speed. This map helped them project orbits around the galactic center and, in turn, materialize in its location. With this new location, they discovered the more accurate speed of the solar system.
They used this information to reveal our location in the Milky Way and to determine the three-dimensional speed and spatial structure of the galaxy, which is a spiral of bars.
They discovered that Sagittarius A * is 2,000 light-years closer to Earth than the International Astronomical Union (IAU) established in 1985. In addition, our solar system travels 227 km / s, 510,000 mph, which is faster than the official speed previously recorded. VERA measurements are considered to be more accurate than in the past, as the group used more advanced technology and corrected how the Earth’s atmosphere blurred previous measurements.
The new discovery also agrees with the measurement of distance reported in the journal Astronomy & Astrophysics in 2019, which put the Earth about 26,660 light-years from Sgr. A *, Nicholas Suntzeff, a professor and director of the astronomy program at the University of Texas A&M, told Live Science. As such, Suntzeff wondered why the team compared its results primarily with 1985 data, rather than this more recent measurement, in an experiment called GRAVITY, which involves the GRAVITY instrument attached to the Observatory’s very large telescope (VLT) Southern European (ESO) Chile.
Hirota agreed that VERA’s results should be compared to GRAVITY. “An important point is that we estimate the same parameters independently of the GRAVITY results, using a different method.”
The new discoveries have implications for solving some of the most enduring mysteries in astronomy.
“These results can be used to estimate other astronomical parameters, such as the distribution of dark matter and its density around the solar system, and could even help scientists predict how often we should see hypothetical dark matter particles, if they exist, ”said Hirota, whose group has been working to improve astrometry techniques and accuracy for more than 15 years. Many searches for dark matter are based on a “wind” of dark matter blowing through the solar system. It is believed that some of the dark matter will interact with Earth-based detectors. Faster dark matter will produce larger signals. If the VERA experiment is correct and the solar system moves faster, dark matter may be easier to detect than scientists currently believe.
In their next collaboration, VERA researchers will look at objects even closer to the heart of the Milky Way. With each measurement, we will get to know our place in the universe better.