Nothing lasts forever, even atoms. Heavier elements decay into lighter elements, releasing energy as radiation. But thanks to this radiation, astronomers can get a glimpse into what’s going on inside distant start. Let’s take a look at the whole process of radioactive decay, the different events that happen, and how humans use this fundamental force of nature for our own needs.

Just when you think you understand it, light will do some amazing things. Just look at the discovery of lasers, and their use in almost every technology you can think of: from cutting, to transmitting information to, yes, astronomy. And nature has figured out its own version of laser technology, called the maser, which has kept astronomers puzzled and excited for years.

Light can do some pretty strange stuff, like pass through objects and bounce off them; it can be broken up and recombined. In fact, everything we “see” is actually the end result of reflection and refraction of light. Time to understand how it all works.

Next time a kid asks you, why is the sky blue? Answer them: because of Rayleigh scattering. If they’re not happy with that answer, feel free to expand based on the knowledge we’re about to drop today, right into your brain.

Quantum theory is plenty strange, but one of the strangest discoveries is the realization that there’s a limit to how much you can measure at any one time. This was famously described by Werner Heisenberg, with his uncertainty principle: how you can never know both the position and motion of a particle at the same time.

Accuracy, precision and reproducibility. These are the foundations of science that make our progress possible. How do these play into a scientist’s daily activities? And just how precise can we get with our measurements?

You’ve probably all heard of Schrödinger’s Cat, that strange thought experiment designed by Erwin Schrödinger to show how the strange predictions of quantum theory could impact the real world. No cats will be harmed in the making of this episode, maybe.

Last week we talked about fusion, where atoms come together to form heavier elements. This week, everything comes apart as we talk about nuclear fission. How it occurs naturally in the Universe, and how it has been harnessed by science to produce power, and devastating weapons.

When the Universe formed after the Big Bang, all we had was hydrogen. But through the process of fusion, these hydrogen atoms were crushed into heavier and heavier elements. Fusion gives us warmth and light from the Sun, destruction with fusion bombs, and might be a source of inexpensive energy. We’ll also look into the controversy of cold fusion.

Now we’re going to answer a question that a 4-year old might ask – what is temperature? Why are things hot and why are they cold? How hot or cold can they get? And how is this all important for astronomy?

Everything in the Universe is spinning. In fact, without this rotation, life on Earth wouldn’t exist. We need the conservation of angular momentum to flatten out galaxies and solar systems, to make planets possible. Let’s find out about the physics involved with everything that spins, and finally figure out the difference between centripetal and centrifugal force.

One of the most amazing aspects of quantum mechanics is quantum entanglement. This is the strange behavior where particles can become entangled, so they’re somehow connected to one another – no matter the distance between them. Interact with one particle and the other reacts instantly; even if they’re separated by billions of light-years.

Last week we took a peek into the tiny world of quantum mechanics, and its unintuitive, but very accurate mathematical predictions. And although we all appreciate the physics lesson, you’re probably wondering what this all has to do with astronomy. Well, today we bring it all home and explain how quantum mechanics has given astronomers one of the most powerful tools they have to study the nature of the cosmos.

Quantum mechanics is the study of the very tiny; the nature of reality at the smallest scale. It’s a science that defies common sense, and delivers no helpful analogies. And yet it delivers the goods, making scientific predictions with incredible accuracy. Let’s look into the history of quantum theory, and then struggle to comprehend its connection to the Universe.