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General Relativity
In general relativity, white holes are just as mathematically plausible as black holes. Black holes are real; what about white holes?
Many people out there, including scientists, claim to have discovered a series of game-changing revolutions. Here's why we don't buy it.
There might be a hard limit to our knowledge of the Universe.
The information we have in the Universe is finite and limited, but our curiosity and wonder is forever insatiable. And always will be.
Yes, dark energy is real. Yes, distant galaxies recede faster and faster as time goes on. But the expansion rate isn't accelerating at all.
As time goes on, dark energy makes distant galaxies recede from us ever faster in our expanding Universe. But nothing truly disappears.
All the things that surround and compose us didn't always exist. But describing their origin depends on what 'nothing' means.
The science fiction dream of a traversable wormhole is no closer to reality, despite a quantum computer's suggestive simulation.
Perhaps wormholes will no longer be relegated to the realm of science fiction.
We'll never be able to extract any information about what's inside a black hole's event horizon. Here's why a singularity is inevitable.
We confidently state that the Universe is known to be 13.8 billion years old, with an uncertainty of just 1%. Here's how we know.
The strongest tests of curved space are only possible around the lowest-mass black holes of all. Their small event horizons are the key.
The Universe is 13.8 billion years old, going back to the hot Big Bang. But was that truly the beginning, and is that truly its age?
The largest hazardous asteroid found in the last 8 years showcases a little-known class of planet-killers. And we're woefully unprepared.
In 1974, Stephen Hawking showed that even black holes don't live forever, but emit radiation and eventually evaporate. Here's how.
The Universe gravitates so that normal matter and General Relativity alone can't explain it. Here's why dark matter beats modified gravity.
Holograms preserve all of an object's 3D information, but on a 2D surface. Could the holographic Universe idea lead us to higher dimensions?
In the 20th century, many options abounded as to our cosmic origins. Today, only the Big Bang survives, thanks to this critical evidence.
The Big Bang is commonly misunderstood, warping our understanding about the Universe's size and shape.
The theory is accurate within at least one part in a quadrillion.
Einstein's relativity teaches us that time isn't absolute, but passes relatively for everyone. So how do telescopes see back through time?
Einstein's "happiest thought" led to General Relativity's formulation. Would a different profound insight have led us forever astray?
Our model of the Universe, dominated by dark matter and dark energy, explains almost everything we see. Almost. Here's what remains.
We only detected our very first gravitational wave in 2015. Over the next two decades, we'll have thousands more.
We live in a four-dimensional Universe, where matter and energy curve the fabric of spacetime. But time sure is different from space!
There's a speed limit to the Universe: the speed of light in a vacuum. Want to beat the speed of light? Try going through a medium!
At all distances, the Universe expands along our line-of-sight. But we can't measure side-to-side motions; could it be rotating as well?
The idea of gravitational redshift crossed Einstein's mind years before General Relativity was complete. Here's why it had to be there.
The Universe is expanding, and the Hubble constant tells us how fast. But how can it be a constant if the expansion is accelerating?