How Conducting Galileo's Classic Experiment In Space Proved Einstein Right

A groundbreaking experiment proves a key tenet of Einstein's theory of gravity. 


An experiment designed by the legendary Italian astronomer Galileo Galilei (1564 - 1642) was recreated in space and proved another famous scientist right, confirming a part of Einstein’s theory of gravity with unprecedented precision. 

The original experiment allegedly involved Galileo dropping two balls from the Leaning Tower of Pisa. Doing that proved that they fell at the same rate, regardless of what they were made of. While it’s still debated if Galileo actually carried out such an experiment, scientists performed a similar one in an Earth-orbiting satellite.

Instead of balls, however, the researchers from the French-led MICROSCOPE satellite science team had two hollow cylinders free-falling inside a satellite for over 120 orbits or eight days worth of time. What they found is that accelerations exhibited by the cylinders matched to a two-trillionths of a percent. So pretty well. 

The results support the equivalence principle of Einstein’s general theory of relativity. It states that an object’s inertial mass, which determines the amount of force needed for acceleration, is equal to the gravitational mass - an indication of how the object is affected by the gravitational field. This idea proposes that things fall at the same rate in a vacuum (without air resistance), even if they are made of different stuff and have varying masses.

Here's more on how the equivalence principle works:

To conduct the experiment, the scientists put a hollow cylinder made of platinum alloy into another hollow cylinder made of titanium alloy. The satellite used electrical forces to keep the two aligned as the objects fell in orbit around Earth. A difference in the amounts of applied forces would have potentially indicated a violation of the equivalence principle. No such differences were observed between them, achieving 10 times the precision of previous tests.

The scientists hope to achieve precision that’s 100 times better than what others have been able to pull off. Why? Because even though the equivalence principle has held so far, there have been predictions that violations of the principle could be observed at some level that’s not been detected yet. Understanding if that’s true could hold the key to reconciling general relativity with quantum physics. 

You can read the study here, in Physical Review Letters.

LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Sponsored
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

What’s behind our appetite for self-destruction?

Is it "perverseness," the "death drive," or something else?

Photo by Brad Neathery on Unsplash
Mind & Brain

Each new year, people vow to put an end to self-destructive habits like smoking, overeating or overspending.

Keep reading Show less

Physicists puzzled by strange numbers that could explain reality

Eight-dimensional octonions may hold the clues to solve fundamental mysteries.

Surprising Science
  • Physicists discover complex numbers called octonions that work in 8 dimensions.
  • The numbers have been found linked to fundamental forces of reality.
  • Understanding octonions can lead to a new model of physics.
Keep reading Show less

Douglas Rushkoff – It’s not the technology’s fault

It's up to us humans to re-humanize our world. An economy that prioritizes growth and profits over humanity has led to digital platforms that "strip the topsoil" of human behavior, whole industries, and the planet, giving less and less back. And only we can save us.

Think Again Podcasts
  • It's an all-hands-on-deck moment in the arc of civilization.
  • Everyone has a choice: Do you want to try to earn enough money to insulate yourself from the world you're creating— or do you want to make the world a place you don't have to insulate yourself from?
Keep reading Show less