Fastest Known Star in Milky Way Discovered Orbiting Black Hole 2026

The fastest known star in the Milky Way has been detected by astronomers, hurtling around the supermassive black hole at the galaxy's center. This remarkable discovery, published in the journal Nature, reveals a star named S301 that travels at an astonishing 25,000 kilometers per second—100,000 times faster than a commercial airplane. Its extreme orbit brings it closer to the black hole Sagittarius A* than any other known star, offering an unprecedented opportunity to study the fundamental properties of these cosmic giants.

Unprecedented Orbit Around Sagittarius A*

S301 completes a tight, highly eccentric orbit around Sagittarius A* in just 8.7 years, approaching the black hole at a distance only 12 times the Earth-Sun separation. This proximity is remarkable—closer than Saturn is to our Sun. According to Felix Mang, a PhD student at the Max Planck Institute for Extraterrestrial Physics (MPE) and lead author of the study, "What is special about this star is that it's orbiting Sagittarius A* on a very tight orbit, taking just 8.7 years to complete it, and is approaching the black hole at a mere 12 times the distance of Earth to the sun. That is unprecedented."

Testing Einstein's General Relativity

The star's extreme orbit provides a natural laboratory for testing Einstein's general theory of relativity. Black holes are predicted to spin, and a spinning black hole drags spacetime along with it, warping the orbits of surrounding stars. This effect, known as frame-dragging, is only measurable for objects orbiting fast-rotating black holes at close range. S301's highly eccentric and tight orbit makes it the perfect candidate to measure the spin of Sagittarius A* directly.

Dr. Stefan Gillessen, a senior scientist at MPE and co-author of the study, explains, "For the first time, we would actually be able to measure very directly the spin of a massive black hole, which would be a key test of Einstein's theory." Previously, scientists assumed that measuring the spin would require tracking multiple stars over several decades. Now, by tracing S301's orbit back to 2017 and observing its next closest approach in 2031, the team hopes to gather enough data to achieve this breakthrough.

Key Data on S301 and Sagittarius A*

Implications for Astrophysics

This discovery opens a new window into the extreme environment near a supermassive black hole. By measuring the spin of Sagittarius A*, scientists can better understand how black holes grow and evolve, and how they influence their host galaxies. The data from S301 could also reveal subtle deviations from Einstein's theory, potentially pointing to new physics.

Key Takeaways

• S301 is the fastest known star in the Milky Way, orbiting at 25,000 km/s.
• It completes an orbit around Sagittarius A* in just 8.7 years.
• Its close approach allows direct measurement of the black hole's spin.
• This test of general relativity could reshape our understanding of gravity.
• Observations in 2031 will provide crucial data for the spin measurement.

FAQ

This groundbreaking discovery not only sets a new record for stellar speed but also brings us closer to understanding the most mysterious objects in the universe. As we await the 2031 observations, the scientific community is buzzing with anticipation for what S301 will reveal about the nature of black holes and the fabric of spacetime itself.