Einstein gets it right again: His 'elevator' thought experiment is proven correct
Physicists prove a core part of the theory of general relativity by using the whole Earth and the most precise clocks ever.
Albert Einstein was such a seminal figure in the modern scientific thought that a myriad studies have used his various theories and musings as jumping off points. Often, even Einstein’s suppositions are proven correct, many decades after he came up with them. Such is the case with a new study that confirms that Einstein’s famous “elevator” thought experiment came up with the right prediction. The results essentially proved the equivalence principle, one of the key concepts of Einstein’s theory of general relativity.
Einstein used “gedankenexperiments” or thought experiments to propose theories simply by thinking through them in his mind. In his “imaginary elevator” idea, Einstein conjectured that if you were stuck inside an elevator that is isolated from the outside world, you would not be able to tell whether an object in free fall inside it was being pulled down by Earth’s gravity or pulled up by the elevator accelerating rapidly. The objects inside the elevator would accelerate at the same rate.
And now, physicists from the National Institute of Standards and Technology (NIST) were able to prove this idea by comparing various kinds of remote atomic clocks - the world’s most accurate.
What the scientists actually did, as described in their paper in Nature Physics, is to imagine Earth as a freefalling elevator going through the Sun’s gravitational field. They wanted to prove the part of Einstein’s proposition that maintained that everything inside the elevator would feel the same accelerations, while their properties relative to each other would not change at all. This idea is called local position invariance (LPI).
The scientists compared “ticks” of a dozen atomic clocks around the planet, looking at 15 years of data, to show that there is almost no difference between them. The clocks were off from each other just by 0.00000022 plus or minus 0.00000025 - a very very small number, close to zero. This means that the hydrogen and cesium-based atomic clocks remained in synchronicity as they moved together in the falling elevator of Earth.
The NIST is building ever more precise atomic clocks that will bring the LPI even closer to zero, showing that it’s a fundamental property of the universe, as Einstein predicted.
Don't underestimate the power of play when it comes to problem-solving.
- As we get older, the work we consistently do builds "rivers of thinking." These give us a rich knowledge of a certain kind of area.
- The problem with this, however, is that as those patterns get deeper, we get locked into them. When this happens it becomes a challenge to think differently — to break from the past and generate new ideas.
- How do we get out of this rut? One way is to bring play and game mechanics into workshops. When we approach problem-solving from a perspective of fun, we lose our fear of failure, allowing us to think boldly and overcome built patterns.
Controversial map names CEOs of 100 companies producing 71 percent of the world's greenhouse gas emissions.
- Just 100 companies produce 71 percent of the world's greenhouse gases.
- This map lists their names and locations, and their CEOs.
- The climate crisis may be too complex for these 100 people to solve, but naming and shaming them is a good start.
The surprising results come from a new GLAAD survey.
- The survey found that 18- to 34-year-old non-LGBTQ Americans reported feeling less comfortable around LGBTQ people in a variety of hypothetical situations.
- The attitudes of older non-LGBTQ Americans have remained basically constant over the past few years.
- Overall, about 80 percent of Americans support equal rights for LGBTQ people.
SMARTER FASTER trademarks owned by The Big Think, Inc. All rights reserved.