PBS
The Arrow of Time and How to Reverse It
Ever wish you could travel backward in time and do things differently? Good news: the laws of physics seem to say traveling backward in time is the same as traveling forwards. So why do we seem to be stuck in this inexorable flow towards...
PBS
The NEW SCIENCE of Moon Formation
Einstein once asked whether “the moon exists only when I look at it?". It was rhetorical objection to the idea that measurement in quantum mechanics causes reality to become real. But there was a time when the moon didn’t exist, and then...
PBS
Will Wormholes Allow Fast Interstellar Travel?
From Stargate to Interstellar, wormholes are our favorite method for traveling across fictional universes. But they are also a very serious field of study for some of our greatest minds over the last century. So what’s the holdup? When...
PBS
How Does Gravity Warp the Flow of Time?
There’s a deep connection between gravity and time - gravitational fields seem to slow the pace of time in what we call gravitational time dilation. And today we’ll explore the origin of this effect. And ultimately, we’ll use what we...
PBS
How We Know The Universe is Ancient
The universe is precisely 13.8 billion year old - or so our best scientific methods tell us. But how do you learn the age of the universe when there’s no trace left of its beginnings?
PBS
How The Penrose Singularity Theorem Predicts The End of Space Time
The Nobel prize in physics this year went to black holes. Generally speaking. Specifically, it was shared by the astronomers who revealed to us the Milky Way’s central black hole and by Roger Penrose, who proved that in general...
PBS
What Happens After the Universe Ends?
Conformal Cyclic Cosmology is a story of the origin and the end of our universe from great mathematical physicist Sir Roger Penrose. It’s goes like this: the infinitely far future, when the universe has expanded exponentially to to an...
PBS
Can Future Colliders Break the Standard Model?
In June, the consortium of Europe’s top particle physicists published their vision for the next several years of particle physics experiments in the EU. A big part of that is the Future Circular Collider, which, if it happens, will...
PBS
How Do Quantum States Manifest In The Classical World?
In quantum world things are routinely in multiple states at once - what we call a “superposition” of states. But in the classical world of large scales, things are either this or that. The famous thought experiment is Schrodinger’s cat -...
PBS
Are there Infinite Versions of You?
The cosmological equations that so beautifully describe our universe make an uncomfortable prediction: interpreting them in the most straightforward way, they tell us that the universe may be infinite. Or not; it could turn out that the...
PBS
Venus May Have Life!
If you rank the most habitable places in our solar system Venus lands pretty low, with surface temperatures hot enough to melt lead and sulphuric acid rain. And yet it may have just jumped to the front of the pack. In fact, we may have...
PBS
Was the Milky Way a Quasar?
The Milky Way galaxy is relatively calm by the destructive standards of the rest of the Universe, and compared to its own very violent past. But just recently we discovered that its violent past was much more recent than we thought - and...
PBS
Building Black Holes in a Lab
Black holes are about the worst subjects for direct study in the universe. But at this stage, it’s all we can do to convince ourselves of their existence. Actually studying the physics of real black holes is much, much harder. I mean, we...
PBS
Is Time Travel Impossible?
Time travel stories are cool because both the past and future are somehow more interesting that the present and because everyone wants a redo. But so far it appears we’re doomed to live consumed by regret in the eternal, boring present....
PBS
Does Antimatter Explain Why There's Something Rather Than Nothing?
The most precious substance in our universe is not gold, nor oil. It’s not even printer ink. It’s antimatter. But it’s worth every penny of it’s very high cost, because it may hold the answer to the question of why anything exists in our...
PBS
What’s On The Other Side Of A Black Hole?
Normal maps are useless inside black holes. At the event horizon - the ultimate point of no return as you approach a black hole - time and space themselves change their character. We need new coordinate systems to trace paths into the...
PBS
Will Constructor Theory REWRITE Physics?
The people behind the greatest leaps in physics - Einstein, Newton, Heisenberg, all had the uncanny ability to see the fundamentals - see the deepest, underlying facts about the world, and from simple statements about reality they built...
PBS
How Vacuum Decay Would Destroy The Universe
The universe is going to end. But of all the possible ends of the universe vacuum decay would have to be the most thorough - because it could totally rewrite the laws of physics. Today I hope to help you understand exactly how terrified...
PBS
Is the Proxima System Our Best Hope For Another Earth?
At just four light years away, Proxima Centauri is our closest solar neighbor. The recent discovery of the new exoplanet Proxima D, has reopened the discussion of whether the proxima system is our best chance at reaching another Earth....
PBS
How Many Universes Are There?
The universe is big, but it’s peanuts compared to the eternally inflating multiverse. But just how many universes are there? What are they like? And most importantly, what can they tell us about … aliens? Imagine it: the observable part...
PBS
Are there Undiscovered Elements Beyond The Periodic Table?
Adamantium, bolognium, dilithium. Element Zero, Kryptonite. Mythril, Netherite, Orichalcum, Unobtanium. We love the idea of fictional elements with miraculous properties that science has yet to discover. But is it really possible that...
PBS
Why the Muon g-2 Results Are So Exciting!
When a theory makes a prediction that disagrees with an experimental test, sometimes it means we should throw the theory away. But what if that theory has otherwise produced the most successful predictions in all of physics? Then, that...
PBS
Is 'Perpetual Motion' Possible with Superfluids?
The weird rules of quantum mechanics lead to all sorts of bizarre phenomena on tiny scales— particles teleporting through walls or being in multiple places at once or simultaneously existing and not. Shame all this magical behavior...
PBS
The Holographic Universe Explained
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...