Quantum mechanics is our best theory of the fundamental nature of reality, but it's usually only distinguishable from familiar classical mechanics on the smallest scales. But it’s also possible that our entire galaxy is filled with a...

There are four fundamental forces - the strong and weak nuclear forces, electromagnetism, and gravity. Except maybe gravity is no more fundamental than the force of a stretched elastic band. Maybe gravity is just an entropic byproduct—an...

We know that the universe is getting bigger. And we know that the speed that the universe is getting bigger is also getting bigger. The standard assumption is that the acceleration rate is itself constant, which will surely result in...

There’s this idea that beauty is a powerful guide to truth in the mathematics of physical theory. String theory is certainly beautiful in the eyes of many physicists. Beautiful enough to pursue even if it’s wrong?
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The holographic principle emerged from many subtle clues – clues discovered over decades of theoretical exploration of the universe. Over the past several months on Space Time, we’ve seen those close clues, and we’ve built a the...

The great physicist Hermann Weyl once said: "My work always tried to unite the true with the beautiful, but when I had to choose one or the other, I usually chose the beautiful." But is this actually good advice for doing physics?

It’s been 120 years since Henry Cavendish measured the gravitational constant with a pair of lead balls suspended by a wire. The fundamental nature of gravity still eludes our best minds - but those secrets may be revealed by turning...

The holy grail of physics is to connect our understanding of the tiny scales of atoms and subatomic particles with that of the vast scales of planets, galaxies, and the entire universe. To connect quantum physics with Einstein’s general...

Reality has cracks in it. Universe-spanning filaments of ancient Big Bang energy, formed from topological defects in the quantum fields, aka cosmic strings. They have subatomic thickness but prodigious mass and they lash through space at...

Now that we have a primer on the aspects of the Big Bang Theory that we know definitely happened, let’s look further into what we don’t yet know, and how the theory could progress in the future. Since there is a discrepancy between...

We actually have a pretty good idea of what might have happened before the Big Bang. That is, as long as we define the Big Bang as the extremely hot, dense, rapidly expanding universe that is described by Einstein’s equations. That...

Black holes are very real, but are also a theoretical nightmare. It turns out that in order to make sense of their paradoxical nature, every black hole has to be thought of as a multitude of imaginary black holes, all connected by...

Black holes are a paradox. They are paradoxical because they simultaneously must exist but can’t, and so they break physics as we know it. Many physicists will tell you that the best way to fix broken physics is with string. String...

Some see string theory as the one great hope for a theory of everything - that it will unite quantum mechanics and gravity and so unify all of physics into one glorious theory.

TED curator Chris Anderson shares his obsession with questions that no one (yet) knows the answers to. A short intro leads into two questions: Why can't we see evidence of alien life? And how many universes are there?

Questions of good and evil, right and wrong are commonly thought unanswerable by science. But Sam Harris argues that science can -- and should -- be an authority on moral issues, shaping human values and setting out what constitutes a...

Physicist Brian Greene explains superstring theory, the idea that minscule strands of energy vibrating in 11 dimensions create every particle and force in the universe.

Black holes are the result of absolute gravitational collapse of a massive body: a point of hypothetical infinite density surrounded by an event horizon. At that horizon time is frozen and the fabric of space itself cascades inwards at...

Stephen Wolfram, creator of Mathematica, talks about his quest to make all knowledge computational -- able to be searched, processed and manipulated. His new search engine, Wolfram Alpha, has no lesser goal than to model and explain the...

TED curator Chris Anderson shares his obsession with questions that no one (yet) knows the answers to. A short intro leads into two questions: Why can't we see evidence of alien life? And how many universes are there?

Black Holes should have no entropy, but they in fact hold most of the entropy in the universe. Let's figure this out.

Is there more than one universe? In this visually rich, action-packed talk, Brian Greene shows how the unanswered questions of physics (starting with a big one: What caused the Big Bang?) have led to the theory that our own universe is...

On this Space Time Journal Club we look at how gravitational waves can be used to search for extra dimensions of space!

Knots are everywhere in our daily lives, but a new branch of mathematics is taking things to the next level.