Einstein, Kepler combine to discover Earth-like planet.

Scientists relied on Albert Einstein's relativity theory, in this case involving gravitational effect on light, to detect a planet orbiting a distant star.
Scientists relied on Albert Einstein’s relativity theory, in this case involving gravitational effect on light, to detect a planet orbiting a distant star.
( David A. Aguilar / Harvard-Smithsonian Center for Astrophysics)

These days, it’s not just finding an exoplanet. It’s how you find that Earth-like body.

Scientists using sophisticated telescopes and arrays can detect a planet revolving around a distant star by looking at radial velocity of the star (a faint wobble) or a “transit” of that planet across the star (a faint dimming).

But no one has ever found one via “induced relativistic beaming of light” from the host star.

Why would that be a big deal? It happens to be a method that relies on Albert Einstein’s general theory of relativity. And it also lets observers find planets without having to detect one of them “transiting” a star.


Here’s how it works. Researchers at Tel Aviv University and the Harvard-Smithsonian Center for Astrophysics used the Kepler Space Telescope to home in on three small effects, predicted by relativity, that occur simultaneously as a planet orbits a star.

The first effect is a “beaming” or brightening and dimming that happens as light is tugged back and forth by the gravity of the planet as it moves toward the observer – in this case, the Keppler Space Telescope - and then farther away.

The second is an effect of “gravitational tides” that cause a football-like exaggeration in the star’s shape when viewed from a certain angle. A third involves the starlight reflected by the planet.

“We are looking for very subtle effects. We needed high quality measurements of stellar brightnesses, accurate to a few parts per million,” said team member David Latham of the Harvard-Smithsonian center.


The method of detection had been predicted in 2003 by Avi Loeb, a Harvard University professor at Tel Aviv University, and professor Scott Gaudi, now at Ohio State University.

“This is the first time that this aspect of Einstein’s theory of relativity has been used to discover a planet”, says professor Mazeh, a participating scientist in the NASA Kepler mission. “We have been searching for this elusive effect for more than two years, and we finally found a planet!”

The findings have been published in the latest edition of Astrophysical Journal.

“Einstein’s planet,” formally known as Kepler-76b, is a very hot gaseous giant (3,600 degrees Fahrenheit), that is about 25% larger in diameter than Jupiter and has twice that planet’s mass. The type F star it orbits is about 2,000 light-years from Earth in the constellation Cygnus.


In case you were thinking of traveling there.