Ep 45: It takes two dead stars to make gold?
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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 neutron stars, possibly the only way to have enough neutrons handy.
Here’s a video simulation of two neutron stars colliding to form a black hole.
Here’s an article on when such a collision was observed in this, our real world.
Ep 44: What stars are made of
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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.
And here’s the history, with names and dates, on how we figured out this particular trick.
Ep 43: Pop go the stars
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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 go pop—to explode into super novas which create the rest of the heavy elements.
Here’s a page on Nucleosynthesis, the process that created the chemical elements that make up our planet, and us.
Nucleosynthesis – The Physics Hypertextbook
There is some debate as to exactly when the first stars formed.
Here’s a page on an estimation of when the first stars formed based on data collected by NASA’s WMap satellite.
When did the first stars form in the universe?
Here’s a page with a different time, based on data collected by the European space agency’s Planck satellite.
Ep 42: It’s bigger than we thought
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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 at NASA’s page about when they pointed the telescope named after Edwin Hubble at the star he used to measure the distance to M31—Andromeda.
Ep 41: A bright approach
Ep 40: A matter of perspective
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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.
Ep 39: Size, distance, and the solar eclipse
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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 a method for measuring the actual size of our sun.
Let’s Measure the Diameter of the Sun!
And here’s an article on measuring the sun, that includes other sections describing ways and means of measuring within the solar system.
ep 38: Build a universe
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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.
Ep 37: The sound of the big bang
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The sound of the big bang
Today we take a closer look at the sound of the big bang © John g. Cramer – 2003, which he created from the data gathered by the WMAP satellite.
Here’s his original article on the subject.
Here are a bunch of versions of the sound of different lengths, and updated versions he created from the data gathered by the Planck mission in 2013.
You can also check out his home page, his Analog articles, and his science fiction novels—”Twister,” and “Einstein’s Bridge.”