The Science of Everything Podcast

Continuing from quantum electrodynamics part 1, here we explore the mathematical machinery used to compute interactions between particles, including propagators, Feynman diagrams, cross sections. We then walk through a simple example calculation to illustrate how these tools are applied. I conclude with an introduction to the problem of divergent loop integrals and how these can be resolved using renormalisation. Recommended pre-li...

A detailed look into the physics and mathematics of quantum electrodynamics, the theory of how light and matter interact. We discuss the generalisation of the Schrodinger equation to the Klein-Gordon and Dirac equations, and howw these describe the propogation of light and fermions respectively. We then consider the process of computing transition probabilities between quantum states, including the S matrix and perturbation theory,...

A survey of the Earth's history through the lens of the geologic timescale. We begin with a discussion of the terminology of geochronologic units and how they are specified using 'golden spikes'. We then review the development of Earth's atmosphere, geosphere, and biosphere through the Hadean, Archean, Proterozoic, and Phanerozoic eons. We cover many topics including the supercontinent cycle, the great oxidation event, the evolutio...

An introduction to the techniques used to study the history and ages of geological speciments. We begin with an overview of chronostratigraphy,  covering principles of relative dating, way up indicators, and biostratigraphy. We then discuss geochronology, including a review of early attempts to determine the age of the Earth, the principles and assumptions of radiometric dating, and the radioisotopes most commonly used for dating. ...

An introduction to the process of development, beginning with fertilisation and covering the stages of blastocyst formation, implantation into the uterus, gastrulation and its constituent cell movements, neurulation and the role of the notochord, and the beginnings of organogenesis. We also discuss the differences in gastrulation between protostomes and deuterostomes, along with the many specialised structures found in amniotes to ...

An overview of Magnetic Resonance Imaging (MRI), beginning from the basic physics of nuclear magnetic resonance, and covering the use of radiowaves to excite nuclear spin states, and the T1 and T2 modes of relaxation. We then explore how these phenomena are used to produce 3d images, including magnetic field gradients, frequency encoding, phase encoding, and Fourier transforms. We conclude with a discussion of functional imaging, i...

A review of the carbohydrate insulin model of obesity and the related proposal that low carbohydrate diets are superior to traditional low fat diets. I begin with a discussion of the theory behind the carbohydrate insulin model, and then assess its plausibility using relevant evidence from rodent studies, dietary studies, ahd controlled feeding experiments. I argue that the scientific evidence does not support the alleged benefits ...

An interview with Ariel Zeleznikow-Johnston, author of the book 'The Future Loves You: How and Why We Should Abolish Death'. We begin by discussing how best to define death, focusing on the idea of death as the permanent disruption of psychological identity, and how such identity is constituted by our personality, desires, and memories. We then consider the science of brain preservation, including the recently-developed technique o...

A review of the science between the metabolic syndrome, including discussion of obesity, diabetes, hypertension, and hyperlipidemia. We discuss the pathophysiology of how enlargement of adipocytes disrupts metabolic signalling pathways and leads to buildup of lipid intermediates. We then consider how these effects impair health, examining the causes of insulin resistance, atherosclerosis, and dysregulation of blood pressure. We con...

An introduction to human nutrition, in which we discuss the nutritional importance and role of carbohydrates, fats, proteins, vitamins, and minerals, before considering the effects of malnutrition, how it is measured, and its prevalence around the world. We conclude with an analysis of basal metabolic rate, reviewing evidence concerning its variability across persons and factors that affect it. Recommended pre-listening is Episode ...

An exploration into the exciting world of home appliances and devices. We begin with a journey through the kitchen, discussing the design and operating principles behind the refrigerator, rice cooker, convection oven, microwave, and dishwasher. We proceed to the laundry to examine how the washing machine, vacuum cleaner, clothes iron, and dryer work. Finally we take a bathroom break and consider how the flush toilet, sinks, and plu...

An introduction to the psychological study of personality, beginning with a definition of what is and is not personality and a brief history of the development of the field from Freud and Jung through the Myers-Briggs Indicator and the modern trait theories. I then discuss the Big Five personality traits, covering openness, conscientiousness, extraversion, agreeableness, and neuroticism, along with validation and criticisms of this...

An introduction to the processes by which cells control which genes are expressed. We begin with an overview of why genetic regulation is necessary and the key stages where such regulation occurs, including key concepts such as transcription factors and DNA binding domains. We then discuss prokaryotic gene regulation, focusing on the lac operon in E. coli. We then expand the discussion to cover the various mechanisms of eukaryotic ...

Here we survey of the causes and consequences of genetic mutation, including a discussion of mechanisms of endogenous and induced mutations, rates of mutation, types of single nucleotide mutations, and the phenotypic effects of mutation. We also discuss various mechanisms for detecting and repairing genetic mutations, including base excision repair, DNA mismatch repair, nucleotide excision repair, double strand break repair. We con...

An introduction to classical Mendelian genetics, in which we discuss Mendel's experiments with peas and the laws of heredity that he discovered, including inheritance of one allele from each parent, the law of dominance, and the law of independent segregation. We then consider more complex cases of genetic inheritance, including sex-linked traits, incomplete dominance, codominance, and epistasis. The episode concludes with a discus...

Continuing our series on General Relativity, we discuss the derivation of the Schwarzschild metric as a vacuum solution to Einstein's Field Equations, and analyse the physical meaning of this solution, including the properties of the singularity, event horizon, and effects of time dilation and length compression. We then consider how solutions like the Schwarzschild metric yield testable predictions such as gravitational lensing an...

Our climate change series concludes with a discussion of the various lines of evidence indicating that recent warming is the result of human-produced greenhouse gases, including greater warming at night, cooling of the stratosphere, and relative depletion of C14 in the atmosphere. We then consider the various expected impacts of climate change, including increased extreme weather events, acidification of the oceans, changes to crop...

An overview of climate models, beginning with a summary of the major types of models, and then a more detailed disussion of hte primitive equations and parameterised feedbacks that characterise the widely used Atmospheric General Circulation Models. We also discuss techniques for model validation and some evidence regarding the accuracy of various climate models. Recommended pre-listening is Episode 142: The Greenhouse Effect.

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A detailed discussion of the greenhouse effect and its impact on Earth's climate. We begin with a discussion of Earth’s energy budget, the various greenhouse gases and their interactions with longwave radiation, and a summary of major sources of greenhouse gas emisions. We then examine the mechanisms of the greenhouse effect in more detail using the idealised greenhouse model and radiative transfer models. We conclude with an analy...