PBS
Does Life Need a Multiverse to Exist?
Life exists in our universe. There we go - one hopefully uncontroversial statement. Therefore our universe is capable of producing and supporting life. How am I going? Two for two? Let’s try for three: therefore there are countless...
PBS
How We Know The Earth Is Ancient
In astronomy we talk about billions of years like it’s no big deal. But how can we be sure about timescales so far beyond the capacity for human intuition? Our discovery of what we now call deep time is very recent - as recent as our...
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
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
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
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
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
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
Is The Universe Finite?
Every time you walk out the door, light from the Big Bang strikes your face, enters your eyes. This is the cosmic microwave background radiation - the left-over heat-glow from the very early universe. We can’t see this microwave light...
PBS
How Does Gravity Affect Light?
We know that gravity exerts its pull on light, and we have an explanation for why. Actually, we have multiple explanations that all predict the same thing. And at first glance, these explanations seem to describe completely different...
PBS
Black Hole Harmonics
When physicists talk about black holes they’re usually referring to highly theoretical objects – static, unchanging black holes viewed from “infinitely” far away. This makes everything clean and simple enough to attempt the already...
PBS
Zeno's Paradox & The Quantum Zeno Effect
“A moving arrow is at rest.” This is obviously a nonsensical contradiction. But Zeno, a Greek philosopher famous for his metaphysical trolling, devised a paradox whose conclusion is just this. Here’s how it goes: if you look at an arrow...
PBS
How Do We Know What Stars Are Made Of?
Pin-pricks in the celestial sphere, through which shines the light of heaven? Or gods and heroes looking down from their constellations? Or lights kindled above middle earth by Varda Elbereth and brightened with the dew of the trees of...
PBS
How Quantum Entanglement Creates Entropy
Entropy is surely one of the most perplexing concepts in physics. It’s variously described as a measure of a system’s disorder - or as the amount of useful work that you can get from it - or as the information hidden by the system....
PBS
Gravitational Wave Background Discovered?
It was pretty impressive when LIGO detected gravitational waves from colliding black holes. Well we’ve just taken that to the next level with a galaxy-spanning gravitational wave detector that may have detected a foundational element of...
PBS
Why Is 1/137 One of the Greatest Unsolved Problems In Physics?
The Fine Structure Constant is one the strangest numbers in all of physics. It’s the job of physicists to worry about numbers, but there’s one number that physicists have stressed about more than any other. That number is 0.00729735256 -...
PBS
Does Gravity Require Extra Dimensions?
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...
PBS
How Decoherence Splits The Quantum Multiverse
Why is it that we can see these multiple histories play out on the quantum scale, and why do lose sight of them on our macroscopic scale? Many physicists believe that the answer lies in a process known as quantum decoherence.
PBS
What’s Your Brain’s Role in Creating Space & Time?
Physics is the business of figuring out the structure of the world. So are our brains. But sometimes physics comes to conclusions that are in direct conflict with concepts fundamental to our minds, such as the realness of space and time....
PBS
What Happens During a Quantum Jump?
Since the very beginning of quantum mechanics, a debate has raged about how to interpret its bizarre predictions. And at the heart and origin of that debate is the quantum jump or quantum leap - the seemingly miraculous and instantaneous...
PBS
How to Communicate Across the Quantum Multiverse
In the Many Worlds interpretation of quantum mechanics, the universal wavefunction is the reality, encompassing all possible histories and futures and all exist. But we are only sensitive to a slice of the wavefunction corresponding to...
PBS
How Luminiferous Aether Led to Relativity
As the 19th century came to a close, physicists were feeling pretty satisfied with the state of their science. The great edifice of physical theory seemed complete. A few minor experiments remained to verify everything. Little did those...
PBS
Is Earth's Magnetic Field Reversing?
Earth’s magnetic field protects us from deadly space radiation. What if it were drastically weakened, as a precursor to flipping upside down? I mean, it has before … many, many times.. Spaceship Earth has a literal deflector shield. A...