What We Don't Know

Neutron stars are one of the most extreme astronomical objects in the universe. They are so dense that a single teaspoon, if you were strong enough to collect it, would weigh 4 billion tons. They can spin as fast as 43,000 times per minute, and their magnetic field - for reference, Earth’s magnetic field is around 1 gauss - reaches a trillion gauss. The extreme conditions inside neutron stars suggest all kinds of unusual matter might make them up. From neutronium, to nuclear pasta, to so...

Very early in our school career, we learn about the states of matter. This table is hard wood - it's solid. This water flows, we can drink it - it’s a liquid. And the air around us, even though we cannot see it, is a gas. But these three states of matter are not the only three. In fact, wikipedia describes around 20 different states of matter. One of these is the Bose-Einstein condensate (BEC). In this state, a number of separate atoms or subatomic particles are cooled to near absolute z...

We often use the phrase ‘it’s the end of an era’ to signify some great change in our lives, like leaving school forever. But actual eras are far, far longer than our brains can comprehend, usually lasting several hundred million years, with dramatic, global ecological changes as their finale. Around 541 million years ago, there was such an ending. As the Neoproterozoic era came to a close, so did the Proterozoic eon, and nearly 3.5 billion years of bacterial rule. Suddenly the prokaryotic mat...

When particles escape from a black hole via Hawking radiation, they only contain information on the mass, spin and charge of the black hole’s original material. Other information, that is needed to reconstruct the black hole’s past, seems to be lost permanently. This breaks the fundamental principle of unitarity which says that total information must be conserved, creating a paradox. This episode, we’ll examine potential solutions to the paradox, with particular focus on AdS/CFT correspo...

Different areas of physics seem to be incompatible inside black holes. When combining general relativity, thermodynamics and quantum mechanics, you get a paradox, which suggests that our knowledge of these areas is flawed. A solution, whatever it may be, would irreversibly shake up our understanding of the physical world. It may rewrite fundamental laws. It may unveil a new theory of quantum gravity.In this episode I will unravel what ‘information’ means in physics and how it relates to unita...

What is consciousness? Who experiences it? Why? How?In this episode, I will first offer a definition of consciousness and consider the aspects that make it up. Then I’ll summarise some of the main questions we can ask about consciousness, drawing a distinction between the philosophical and neuroscientific sides to the problem. I will look over different scientific models of how the brain produces consciousness, as incomplete and flawed as they may be, before finishing with the practical conse...

What is dark matter? Why do we need it, and how can we find it? Dark matter is notorious for how it evades detection, and its presence is one of the biggest mysteries in cosmology. Yet we think it must exist. Not only that, but we think it must make up 80% of matter in the universe.This episode I will explore how physicists discovered dark matter, what we know so far, and the particles which attempt to solve its secrets. Then I’ll consider what dark matter fails to explain and the possible al...

This episode is about protein folding, specifically the protein folding problem that has pervaded biochemistry since 1960, when the first atomic-resolution protein structure was presented. First I will explain what proteins are, why they are important, what they are made of - proteins 101 - then begin unravelling the problem of how they fold. We will explore the motivations behind the problem and its greatest challenges. Finally we’ll consider the existing methods for determining protein stru...

In this episode I’ll discuss one of the most important problems in computing: the P versus NP problem. This is one of the seven Millennium Prize Problems, unsolved challenges in mathematics. The P vs NP problem concerns the field of computational complexity, a domain where theoretical computer science and maths regularly work together, and, in essence, it asks whether problems that have easily verifiable solutions also have reasonably fast ways to find these solutions. The answer to the ...

This episode is a bit different to the previous ones because neglected tropical diseases (NTDs) have treatments, so their biology is not beyond the horizon of science. However, in sharp contrast to how curable they are, 1.7 billion people still suffer their effects, and few of the general public elsewhere are aware of the terrible socioeconomic problem they present. In this episode I discuss what neglected tropical diseases are, how they devastate communities, and why they persist despit...

This episode I will explore quantum entanglement. Quantum entanglement is itself not unknown – many experiments have proven it a pillar of the quantum world – but it does herald interesting practical applications and theories in other aspects of physics. First I’ll give an introduction to quantum principles, then explain the basics of entanglement. I will talk about the Einstein-Podolsky-Rosen experiment and Bell’s inequality. There are many concepts to investigate: faster-than-light communic...

This episode I’ll be exploring one of the greatest mysteries in physics: the incompatibility of general relativity and quantum mechanics. Einstein asserted that gravity is actually the effect caused by space-time curvature. It is very inconvenient that this theory of the very big cannot work with our theory for the very small, the quantum theories that explain how particles behave at the subatomic level. At the heart of physics nowadays is a quest to create a new theory of quantum gravit...

Today I’m talking about the origin of the nucleus. All cells have organelles, which are like the organs of a cell, specialised subunits that carry out specific tasks. The nucleus is a particularly important organelle because it houses all the genetic information of the cell. Understanding how the nucleus came to be could unveil current mysteries surrounding the nucleus’ structure, function and why it sometimes goes wrong.https://whatwedontknow.buzzsprout.com/

Today we’re talking about the concept of silicon-based life. This is the idea that, instead of carbon being the only building block upon which life has flourished, somewhere in outer space there could be alien life using silicon in its molecular structure.https://whatwedontknow.buzzsprout.com/