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Hey universe, let’s hear some noise! What would eventually be called the theory of the big bang was first described by Georges Lemaître in 1927. This early description included predictions later verified in 1929, but it wasn’t until 1964, when the cosmic background microwave radiation was accidentally detected, that the theory was taken seriously by …
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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, (see episode 44 and episode 46,) and building off of work previously done by Vesto Slipher, he discovered that …
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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. Elements like platinum gold and uranium might come from the collision of two …
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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 chemicals on a spectrum. Absorption/emission lines And here’s the …
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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, and to keep from collapsing under their own gravity. Heavier elements, anything heavier than iron, require the stars to …
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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, was the only island of stars in the universe. Boy, did we get it wrong! Have a look …
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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, roughly equivalent to 3.26 lightyears.
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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, the moon and sun are the same apparent size. Here’s a slightly cheesy YouTube video that describes …