We know that the Milky Way is our galaxy and that it is a collection of billions of stars orbiting around something. Scientists have long wondered what lies at the center of the Milky Way . Knowing this is crucial to understanding our universe and the lifespan of our solar system.
Therefore, we are going to dedicate this article to telling you what is at the center of the Milky Way and what its characteristics are.
What is in the center of the Milky Way
It wasn't until the 20th century that the location of the center of our galaxy was first estimated. In 1918, Harlow Shapley gave its possible location while studying the distribution of a globular cluster, which lies at the equatorial coordinates RA 17 h 45 m 40,04 s, Dec -29° 00′ 28,1″ (Julian Era J2000), or approximately 50.000 and approximately 15.000 parsecs from the Earth and the Sun. This was later revised, notably at the XIX Congress of the International Astronomical Union, which determined that the center of the Milky Way is 8.500 parsecs from the Sun, although this distance may be closer to 7.900 parsecs (±300), as indicated by later studies (because technology also allows for more precise observations). There is also an established UTC time zone, among other things.
We sometimes mention here that interstellar dust is one of the things that makes space observations difficult. This has left many people confused about the "mysterious" Tabby's Star, but with the advent of gamma-ray, infrared, and high-frequency X-ray observatories, and more, it's possible to understand it better despite the dust. Furthermore, these advances have been key to studying different parts of the Milky Way.
In 2002, it was these X-rays that revealed (or rather, detected) what lay at the center of the Milky Way, thanks to data sent back by a young Chandra telescope that seemed to confirm what had long been suspected: a supermassive black hole. In fact, the key to these rays, besides being able to penetrate this gaseous cloud, is the last trace of matter before it is swallowed by the black hole.
This massive black hole was subsequently adopted by further research and observatories, such as the European Southern Observatory (ESO, Chile), which allowed a team of German astronomers to track the movement of 28 stars orbiting the center of the Milky Way… especially around black holes four million times more massive than the sun, which lends further credence to the hypothesis that galaxies formed around them. Theories suggest that these black holes could influence the formation of other galactic structures. But as we mentioned at the beginning, just this week something changed. It turns out there isn't just one, but up to a dozen black holes at the center of the Milky Way, according to Reuters, based on the work of astrophysicist Chuck Haley and his team.
Chandra has also detected a cluster of smaller binary black holes orbiting Sagittarius A* in the center of our galaxy, estimating that there are up to 10.000 black holes in total around Sagittarius A*. Sagittarius A* is a very important source, the very compact and bright radius of the center of our galaxy, or the same, the supermassive black hole, which receives its name within the Sagittarius A (wider) structure.
What is the center of the Milky Way like?
As we saw when discussing current space observatories, the mechanics of this telescope can capture different wavelength spectra. In this case, thanks to infrared images, astronomers were able to study the star's motion in that location, helping them understand how the cluster formed, as well as its mass and structure. In 2018, Chandra and ESO enabled a 360-degree virtual tour of the Milky Way's center. A visualization allowed researchers to understand the presence of previously observed X-rays in a disk about 0,6 light-years outside Sagittarius A*, concluding that although it ended about a hundred years ago, it still continues to affect the surrounding areas.
A team of astronomers "painted" this potentially desolate place a few weeks ago. Chris Packham, professor of physics and astronomy at the University of Texas, and Pat Roche, professor of astrophysics at the University of Oxford, directed the high-resolution map of magnetic field lines drawn from Sagittarius A*.
To achieve this, they used data from the infrared cameras of the Gran Telescopio Canarias (on La Palma, Spain), since, as mentioned earlier, this radiation is able to penetrate the dust cloud between Earth and the galactic nucleus. In this case, they also benefited from the camera's equipment, which is capable of filtering polarized light in relation to magnetic fields, allowing them to trace these lines with a level of detail that has not been achieved until now. This is directly related to the study of the properties of galaxies and their interactions.
Results of studies on what is in the center of the Milky Way
The result: a kind of Van Gogh's starry night, but showing us stars that emit a lot of infrared radiation, entangled between these field lines , and the location of that supermassive black hole.
This is the sharpest infrared image ever obtained of the galactic center, and the first time magnetic field lines have been seen in detail at a distance of 25.000 light-years. As these things often happen, this is a window into learning more about the field and the nature of space phenomena.
The information they extracted when creating this map revolves around how the dust behaves with respect to magnetic fields and strong stellar winds, and that another (smaller) magnetic field that exists near the core would come into play. It plays an important role in the flow of gas and dust that surrounds super black holes.
The beauty of all this, beyond the photos or maps that can be created, is that, while answering the question, humanity is once again battling the obstacle to overcome it. When the visible spectrum isn't enough to observe certain regions, other lenses are devised to discover what surrounds us and gradually pinpoint the origin of it all. We hope you can learn more about what lies at the center of the Milky Way and its characteristics.
