Ask a Spaceman!

What does ‘time’ mean for light? What is the real lesson of the twin paradox? How can we all agree on the true age of the universe? Why is it all so technical? I discuss these questions and more in t…

How and when did we realize that atoms exist? How did we learn to understand their properties? How was Ernest Rutherford hogging all the science for himself? I discuss these questions and more in tod…

Where is the Oort Cloud and what is it made of? Why do we think some comets come from there? If the Oort Cloud exists, how did it form? I discuss these questions and more in today’s Ask a Spaceman!

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What makes time so hard to understand? Why is it so different from the spatial dimensions? Is time in any way connected to that most difficult of concepts, entropy? I discuss these questions and more…

How much energy is needed to blow up the sun? How is this connected to the idea of binding energy? Where is all the energy in the universe? I discuss these questions and more in today’s Ask a Spacema…

What do brown dwarfs teach us about stars? What do they teach us about planets? What keeps them warm, and how long do they live? And are they really brown? I discuss these questions and more in today…

What are the many sources of light in the universe? Why is a spectrum so important? What’s the difference between synchrotron and Cherenkov radiation? What’s the best word ever in physics? I discuss …

Today I'm reading a sample from my new book, Your Place in the Universe!

I'm also sharing details about how you can a) buy the book, b) contribute to my Patreon to get an autographed copy, c) get my …

What does the Drake Equation teach us about extraterrestrial civilizations? What does it NOT teach us? What complexities does it hide? Is it even science? I discuss these questions and more in today’…

What’s the connection between motion and magnetism? How can something like a black hole have a magnetic field? What’s the connection to quantum mechanics? How did Einstein use magnetism to develop sp…

Part 2! What was going in the very early universe? How does inflation provide the seeds of larger structures? How can we possibly test this? I discuss these questions and more in today’s Ask a Spacem…

Part 1! What are some weaknesses with the standard Big Bang model? What are the horizon and flatness problems? How does accelerated expansion solve these? I discuss these questions and more in today’…

What is the cosmological constant? How is the expansion of the universe related to quantum fields? How does a vacuum energy produce accelerated expansion? I discuss these questions and more in today’…

What is a quantum state? How can two particles share the same state? What is entanglement, and does it really allow for faster-than-light communication? I discuss these questions and more in today’s …

Were the dark ages really dark? What is a perturbation, and how did they grow in the early universe? When the first stars awoke, what happened? I discuss these questions and more in today’s Ask a Spa…

What does momentum have to do with rockets? Why are nozzles so dang important? What is a “potent mixture”, anyway? I discuss these questions and more in today’s Ask a Spaceman!

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What is the so-called “OMG Particle”? Where could it possibly come from, and how are magnetic fields involved? How can we detect these cosmic rays? I discuss these questions and more in today’s Ask a…

Part 3! How did Einstein develop General Relativity? What does it mean for different kinds of masses to be equivalent? How does gravity do what it does? Why is curvature so important in understanding…

Part 2! How did Einstein develop General Relativity? What does it mean for different kinds of masses to be equivalent? How does gravity do what it does? Why is curvature so important in understanding…

Part 1! How did Einstein develop General Relativity? What does it mean for different kinds of masses to be equivalent? How does gravity do what it does? Why is curvature so important in understanding…