Albert Einstein's general theory of relativity predicts so much about the universe at large, including the existence of gravitational lenses or "Einstein rings." And yet his famous equations struggle ...

When the theory of relativity appeared in the early 1900s, it upended centuries of science and gave physicists a new understanding of space and time. Isaac Newton saw space and time as fixed, but in ...

If the universe were a soup, it would be more of a chunky minestrone than a silky-smooth tomato bisque. Sprinkled with matter that clumps together due to the insatiable pull of gravity, the universe ...

For decades, astronomers have used distant supernovae as cosmic lighthouses to test fundamental physics and to measure the universe. For Joseph Farah, a fifth-year graduate student at UC Santa Barbara ...

LAST month, I answered a reader question about space-time expansion. They wanted to know what space-time is expanding into, given that we scientists tend to analogise with a balloon that is being ...

For years, astronomers have wondered why real-life versions of Tatooine are so rare. With thousands of confirmed exoplanets and countless binary star systems in our galaxy, planets orbiting two suns ...

A huge amount of mysterious dark energy is necessary to explain cosmological phenomena, such as the accelerated expansion of the Universe, using Einstein's theory. But what if dark energy was just an ...

We've been through the first few episodes of our crash course on general relativity, and came out alive! But it's officially "time" for CURVED spacetime. Join Gabe on this week’s episode of PBS Space ...

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Gravity, the force that attracts objects toward each other, is currently framed by Albert Einstein's theory of general ...