It looks like the Earth has been lost.
According to a new map of the Milky Way galaxy, the position of the Solar System is not where we thought it was. Not only is it closer to the galactic center – and the supermassive hole in it, Sagittarius A * – it is orbiting in a faster clip.
There is nothing to worry about; we are not really moving closer to Sgr A * and we are not in danger of being sucked. Instead, our map of the Milky Way has been adjusted, more accurately identifying where we have been all along.
And the research beautifully demonstrates how complicated it is to map a galaxy in three dimensions from within it.
It is a problem that has long devoured our understanding of space phenomena. It is relatively easy to map the two-dimensional coordinates of stars and other cosmic objects, but the distances to these objects are much more difficult to calculate.
And distances are important – they help us determine the intrinsic brightness of objects. A good recent example of this is the red giant star Betelgeuse, which ended up getting closer to Earth than previous measurements suggested. This means that it is not as big or as bright as we thought.
Another is the object CK Vulpeculae, a star that exploded 350 years ago. In fact, it is much further away, which means that the explosion was brighter and more energetic, and requires a new explanation, since previous analyzes were carried out under the assumption that the energy was relatively low.
But we are improving the calculation of these distances, with research using the best technologies and techniques available, working hard to refine our three-dimensional maps of the Milky Way, a field known as astrometry. And one of them is the VERA radio astronomy research, conducted by Japanese collaboration VERA.
VERA stands for VLBI (Very Long Baseline Interferometry) Exploration of Radio Astrometry, and uses a series of radio telescopes across the Japanese archipelago, combining its data to effectively produce the same resolution as a 2,300 kilometer- (1,430-mile) dish telescope in diameter . It’s the same principle behind the Event Horizon Telescope that produced our first direct image of a black hole’s shadow.
VERA, which we started observing in 2000, is designed to help us calculate distances to radio stars by calculating their parallax. With his incredible resolution, he watches these stars for more than a year and watches how their position changes relative to stars that are much more distant when the Earth orbits the sun.
This change in position can then be used to calculate how far a star is from Earth, but not all parallax observations are created equal. VLBI can produce images of much higher resolution; VERA has a breathtaking angular resolution of 10 millionths of a second of arc, which should produce astronomical measurements of extraordinary precision.
And that is what astronomers used to refine the position of our Solar System in the Milky Way. Based on the first VERA Astrometry Catalog from 99 objects launched earlier this year, as well as other observations, astronomers have created a map of the position and speed of these objects.
From this map, they calculated the position of the galactic center.
In 1985, the International Astronomical Union defined the distance to the galactic center as 27,700 light years. Last year, the GRAVITY collaboration recalculated and found it closer, just 26,673 light years away.
VERA-based measurements bring it even closer, at a distance of just 25,800 light years. And the Solar System’s orbital speed is also faster – 227 kilometers (141 miles) per second, instead of the official speed of 220 kilometers (137 miles) per second.
This change may not seem like much, but it can have an impact on how we measure and interpret activity at the center of the galaxy – ultimately, hopefully, leading to a more accurate picture of the complex interactions around Sgr A *.
Meanwhile, VERA collaboration is advancing. Not only continues to make observations of objects in the Milky Way, but also joins an even bigger project, the East Asian VLBI Network. Together, astronomers hope, the telescopes involved in this project can provide unprecedented precision measurements.
The Vera Astrometry Catalog was published in Astronomical Society of Japan publications.