What is Quintessence? Well we know that something is up with the way the universe is expanding - there’s some kind of anti-gravitational effect that’s causing the expansion to accelerate. We don’t know what it is - just that it competes...

A new white dwarf has been discovered (poetically named: ZTF J1901+1458) that’s doing some stuff that no white dwarf should ever be able to do. In fact, it has multiple properties that are so extreme that it almost certainly did NOT form...

By the time you've read this, a billion billion dark matter particles may have streamed through your body like ghosts. The particle or particles of the dark sector make up the vast majority of the mass of the universe - so to them, we're...

The Standard Model of particle physics is arguably the most successful theory in the history of physics. It predicts the results of experiments with a numerical precision unmatched by any other branch of science, and it does so almost...

That Einstein guy was a real bummer for our hopes of a star-hopping, science-fiction-y future. His whole “nothing travels faster than light” rule seems to ensure that exploration of even the local part of our galaxy will be an...

Hook up an old antenna to your TV and scan between channels. The static buzz you hear is mostly due to the ambient radio produced by our noisy pre-galactic civilization. But around one percent of that buzz is something very different –...

Where are you right now? Until you interact with another particle you could be any number of places within a wave of probabilities. This is only one way that quantum mechanics challenges our perception of reality. Matt dives into these...

Invisible to the naked eye, our night sky is scattered with the 100s of billions of galaxies the fill the known universe. Like the stars, these galaxies form constellations – hidden patterns that echo the reverberations of matter and...

The results are in - on this weeks episode of Spacetime we reveal the answer to our Asteroid Challenge, as well as our T-shirt winners! Check out who saved the world!

The Kepler telescope recently noticed a strange partial eclipse that some have speculated could be a Dyson Sphere. Are Dyson Sphere's possible? Are they practical? What other alternatives to futuristic energy capture do we have to choose...

Astronomers are the worst at naming things. Dark energy AND dark matter? Who can remember which is which. But perhaps one astronomer has just fixed it, with a theory that says perhaps actually they are they same stuff.

Our universe started with the big bang. But only for the right definition of “our universe”. And of “started” for that matter. In fact, probably the Big Bang is nothing like what you were taught.

A hundred years ago we discovered...

The foundations of quantum theory rests on its symmetries. For example, it should be impossible to distinguish our universe from one that is that is the perfect mirror opposite in charge, handedness, and the direction of time. But one by...

For some reason, animals keep evolving into things that look like crabs, independently, over and over again. What is it about the crab’s form that makes it so evolutionarily successful that non-crabs are apparently jealous of it?

We’ve been failing to detect dark matter for decades. Finally, the latest failure to detect dark matter may have actually proved its existence. One of these is true: either most of the matter in the universe is invisible and formed of...

Let’s talk about states of matter. You know your states of matter don’t you? We have solids, liquids and gasses, and plasmas, quark-gluon plasmas, nuclear matter, bose-einstein condensates, neutronium, time crystals, and sand. Come to...

The possibility that a black hole could actually impact Earth may seem straight out of science fiction, but the reality is that microscopic primordial black holes could actually hit Earth. If one did, it wouldn't just impact like an...

What shape is the event horizon of a black hole? Well, the answer to that question changes if our universe is hiding an extra dimension (or more). Black holes could come in an infinite number of shapes — including a precisely spinning...

From diabetes to Alzheimer's, there's a lot that we hope to be able to treat using stem cell therapies. But the stem cells we use tend to be hard to come by. But it turns out there's a new source of stem cells that has researchers...

We often use decibels, a measure of sound pressure, to describe how loud something is - but loudness is caused by how we perceive sounds, and the two often don't line up.

This video is about what happens if you try to pass a portal (like in the video game Portal or Portal 2) through itself - do you get a paradox? Infinite recursion? Impossibility? Contradiction? The end of the world? Collapse of the...

This video covers the General theory of Relativity, developed by Albert Einstein, from basic simple levels (it's gravity, curved space) through to the concepts of how curved spacetime is represented by psuedo-Riemannian manifolds with...

Have you ever wondered why 75% humidity in the summer feels sticky, but 75% humidity in the winter feels super dry? Turns out, the common definition of humidity is inconvenient and confusing. But there is a better way!

You’re probably aware that your blood can be A, B, AB or O, but it turns out that blood types can get a lot more complicated than that! *We made a mistake in the credits of this video: The writer of this episode was Alane Lim.