But recently, the European Southern Observatory (ESO) endowed their Very Large Telescope array (VLT) with a new tool. Called GRAVITY, it combines light harvested by VLT’s four telescopes, yielding 15 times the resolving power and accuracy that just one of the telescopes could accomplish alone. Such resolution is equivalent to observing a tennis ball on the moon from Earth.This let astronomers make hour-by-hour measurements as the S2 star made its latest flyby of Sagittarius A*.They watched what happened as S2 approached the black hole, coming tantalizing close, cosmically speaking, at about 12 billion miles away. During this close encounter, S2 reached speeds of nearly 5,000 miles (8,000 kilometers) per second, which is equal to 2.7% the speed of light.The ESO team compared these new data with previously collected data on S2 to understand how its light was altered by dipping into the intense gravitational field. This is how they confirmed that light emitted from the star becomes less energetic – drained if you will – due the pull of the black hole and shifts to a lower frequency.“This is the second time that we have observed the close passage of S2 around the black hole in our galactic center. But this time, because of much improved instrumentation, we were able to observe the star with unprecedented resolution,” explains Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics. “We have been preparing intensely for this event over several years, as we wanted to make the most of this unique opportunity to observe general relativistic effects.”At the press conference Odele Staub from the Paris Observatory, explains, “Why is this important, why did we do this at all? Gravity is a fundamental property of the universe. Understanding gravity here on Earth, in the solar system, in the Milky Way, outside of the Milky Way – this is key to understanding our universe.“We looked at our galactic center and what we saw, is yes, it behaves like Einstein’s black hole. What we measured cannot be described by Newton anymore.”In the coming months, the researchers also plan to monitor how this encounter may have shifted S2’s trajectory, which will yield insights into the mass distribution of Sagittarius A*, the black hole that we love to admire from afar.This article originally appeared on Discovermagazine.com