A new map of the Milky Way offered by the Astronomical Society of Japan suggests that the solar system is actually closer to the galactic center – and the supermassive hole that s found there – what we thought. It's also moving around at a faster rate than expected.
In our Galaxy, as in the rest of the Universe, everything is in motion. If it remains relatively easy to map the two-dimensional coordinates of the objects present inside the Milky Way, defining the distances between each object (astrometry) is on the other hand much more difficult insofar as we evolve inside the Milky Way itself. this galaxy. Calculating these distances is very important if we want to understand the nature of the different objects that are there.
Bételgeuse is the perfect example. A recent study has indeed confirmed to us that this star is actually closer than previous measurements had suggested. That means it's not as big or as bright as we thought.
That said, the Japanese VERA survey (for VLBI – Very Long Baseline Interferometry- Exploration of Radio Astrometry ) aims to refine all these measures. It has been underway since the early 2000s. With this in mind, researchers rely on a number of radio telescopes scattered across the Japanese archipelago. They then combine their data to produce the same resolution as a telescope 2300 kilometers in diameter .
You will have understood it, it is the same principle as the Event Horizon Telescope program, the network of terrestrial radio telescopes which allowed last year to photograph the horizon of a black hole for the first time.
The VERA experiment is designed in such a way that it calculates the distances of different stellar radio sources by calculating their parallax. Concretely, this giant radio telescope observes certain stars for more than a year and determines their changes in position compared to stars much more distant. These changes can then be used to calculate the distance between these stars and Earth.
As part of recent work, Japanese astronomers have therefore relied on this approach to refine the position of our solar system in the Milky Way. They then determined that our star evolves only 25,800 light-years from the galactic center . For your information, in 1985, the International Astronomical Union defined the distance from the galactic center to 27,700 light-years of the earth. Last year, the GRAVITY collaboration brought it closer to just 26,673 light-years .
Finally, these new measurements also allowed astronomers to estimate the orbital speed of the solar system at 227 kilometers per second . Again, this is faster than expected. Previously, we thought our star was moving at about 220 kilometers per second around the galactic center.
