It’s still getting bigger - In episode 42, we learned that in 1923, Hubble found out that spiral nebula are actually spiral galaxies, changing our understanding of the size of our universe. In 1929, using spectral lines,

Frequency, wavelength, color and motion - What is the Doppler Effect, how does it work, and what does it tell us?

It takes two dead stars to make gold? - In episode 43, we talked about how our universe makes the chemical elements that our world and we are made of through processes like nuclear fusion, and exploding stars. That may not be enough.

What stars are made of - In order to find out what a star is made of, pass its light through a prism, and examine the resulting rainbow, or spectrum. - Here’s an article that includes an app that will let you play with the effect of different chemica...

Pop go the stars - For our universe to produce minds, we require many different chemical elements. Those elements were created by the stars. The lighter elements fuse together and provide the energy for stars to shine,

It’s bigger than we thought - In 1923 Edwin Hubble used a variable star to prove that the Andromeda Nebula was actually the Andromeda Galaxy. Before his measurements, it was widely believed that our galaxy, the Milky Way,

A bright approach - To measure distances to astronomical objects that are more than a few thousand lightyears away, astronomers use standard candles.

A matter of perspective - How do we know how far away the stars are? For relatively nearby stars, other than our own sun, we can use a trick of perspective called parallax. This gives rise to a unit of distanced called the parsec,

Size, distance, and the solar eclipse - From the earth’s surface, it can be difficult to tell how big or far away objects in the solar system are. From the earth’s surface, as illustrated by yesterday’s total solar eclipse,

Build a universe - In episode 35, I said that I don’t know how to make a big bang. Here’s the closest thing to that that I’ve found so far. - Build a Universe with the CMB Power Spectrum Analyzer