Einstein's Theory Passes a Massive Test

Artist depiction of the three stars orbiting Sgr A* (Image: ESO/M Parsa/L. Calçada)
Artist depiction of the three stars orbiting Sgr A* (Image: ESO/M Parsa/L. Calçada)

The most basic physical laws you’ve learned—those drafted up by Isaac Newton in the 17th century—don’t work for everything. Once you try to applying them to really fast things moving nearly at the speed of light or things heavier than stars, they start to fall apart. That’s where Albert Einstein’s expanded theory of motion and gravity, the theory of general relativity, comes in.


General relativity works really well, and has made predictions scientists proved a hundred years later. The question then becomes: Can you break it?

A team of scientists used 20 years of data from several telescopes to watch how three stars orbited the center of our own Miky Way Galaxy, Sagittarius A*. They’ve created a general relativity theory test in a mass regime that isn’t well-tested today. The theory checks out, yet again... for now.

“Right now, this is basically a consistency test,” study author Andreas Eckart told Gizmodo. “We probed the data with what we expected from relativity,” and saw “very strong indications here that we got the expected answer.”

Scientists like Einstein draft up theories to explain something they don’t understand. But once the theory exists, it should make testable predictions. Scientists must then continue to test the theory several ways: by proving these predictions really exist, like the gravitational waves discovery announced in 2016, or by trying to break the theory by applying it to more extreme cases as the researchers are doing here.

The team gathered data from several papers as well as observations from Chile’s Very Large Telescope on three stars, called S2, S38, and S55/S0-102. These bodies orbit Sgr A*, the presumed supermassive black hole four million times the mass of our own Sun at the center of the Milky Way. The researchers were able to compare the stars’ orbits to the mathematical values Einstein’s laws predict. The team will publish their results in the Astrophysical Journal.

But this is far from a done deal. Despite two decades of data, the researchers only looked at three stars and saw a large uncertainty on their calculated value. There’s still plenty of room to potentially prove Einstein wrong. “To test whether or not there’s a violation you need to have a much much better signal to noise ratio,” said Eckart. More precise measurements can be done on these stars using other experiments to do much finer tests of relativity. “Whether that will lead to a modification, I cannot say.” The signal may be weak, but he hopes more data will improve the result.


But others think it’s an important step. “From my perspective, the exciting thing about this paper is that it improves tests of gravity in a regime that is not well-tested at the moment,” Tessa Baker, post doctoral researcher at the University of Oxford told Gizmodo. She pointed out that there is a lot of clutter and potential factors in the center of the galaxy that can cloud a measurement there, but “it seems like they’ve done a comprehensive and careful job of accounting for these.” She’d also like to see how modifications to general relativity would show up in their measurements.

But what Eckart’s team has ultimately done is set up an easy-to-replicate system with further data for scientists who want to repeat the test.


“All the data is published in tables,” said Eckhart.” Using the new paper, “you could take the data from the tables and run it again.”



Former Gizmodo physics writer and founder of Birdmodo, now a science communicator specializing in quantum computing and birds



Do you ever wonder how many other Einstein’s or parents of future Einstein’s we lost because of the Holocaust? Or the parents that never were because one or both of them died in the trenches of WWI, under the bombs over London, the fires of Dresden, the on the beaches of Normandy, in the jungles of Vietnam or in the global rape of Africa and its future?

How many female Einstein’s has society and knowledge been robbed of because of a medieval mindset that persists and empowers only a sliver of our population the knowledge and comfort to create, lead and thrive?

How many young, genius minds have been stunted because they just happened to be born in the ghetto and not the gated community?  

Humanity, it seems, finds incremental progress in spite of itself. But even with the incremental progress we do make, time and time again we slip back, losing countless scientists, engineers, writers and artists, either through racism and power struggles that keep others down, politicians who protect the few over the enrichment of the many, religions whose beliefs are rooted in those same rotten, patriarchic power centers and so obviously just another system to enslave the many while enriching the few.

I don’t know the answers, perhaps there aren’t any and this is our fate as a species. As no matter the ideological wellsprings that have risen up to break humanity from these cycles of power and privilege of the few, history shows that our innate human hunger for power over others always returns, like a weed, and corrupts those who ascend into positions of power in the place of those they overthrew.