Podcast: Play in new window | Download (Duration: 8:32 — 6.0MB) | Embed
When worlds literally collide It is theorized that our moon was formed when our planet was struck a glancing blow by an object roughly the size of Mars. The notion is known as the giant impact hypothesis. If such a large impact happened to our planet, what about the other planets. How common are giant …
Podcast: Play in new window | Download (Duration: 10:57 — 7.6MB) | Embed
Our big, beautiful moon According to the rare Earth hypothesis, see episode 59, a large moon is needed for the development of complex life. Our moon isn’t the biggest moon in our solar system; but the moons that are bigger are orbiting much larger planets. Our moon is the largest as a percentage of the …
Podcast: Play in new window | Download (Duration: 6:39 — 4.6MB) | Embed
Why do big ones orbit so strangely? Today, we consider all the large planets orbiting stars other than our sun, and their tendency to adopt eccentric orbits. The possible reasons include close encounters with other stars, interactions between the planets themselves, and different ways the large planets may have formed. Here’s an article on the …
Podcast: Play in new window | Download (Duration: 6:11 — 4.2MB) | Embed
Let’s keep it round According to the “rare earth” hypothesis, see episode 59, one of the requirements for the development of complex life is a stable, and nearly circular orbit. If the orbit is too eccentric, the planet would be cooked during one part of its year, and frozen most of the rest of the …
Podcast: Play in new window | Download (Duration: 8:21 — 5.8MB) | Embed
not quite a star, not quite a planet, not quite life After a somewhat disjointed primer on organic chemistry, we talk about how the radiation of a protostar, bathing the protoplanetary disk, See the previous episode, can create the early chemical building blocks of life. This has happened in laboratory experiments, and the chemicals have …
Podcast: Play in new window | Download (Duration: 8:13 — 5.5MB) | Embed
The bumpy road to becoming a star As a nebula collapses, there are forces which resist the collapse. Things like rotation, ionization and heat can overwhelm gravity and keep a given chunk of dust and gas from ever managing to start nuclear fusion and become a star. Those same forces, if the cloud manages to …
Podcast: Play in new window | Download (Duration: 9:39 — 6.7MB) | Embed
Oh where o where did our sun come from? In episode 59, we talked about the “rare Earth hypothesis.” According to that school of thought, when and where a star is born, and when and where it lives, matters. Our Sun apparently showed up after a very active epic of star formation. This may have …
Podcast: Play in new window | Download (Duration: 6:43 — 4.6MB) | Embed
How to make a mind—part2 What we need is our rare and wonderful Earth, and approximately 4.54 billion years. Of course, that begs the question. How did we end up with our Earth, and how important is it that a planet is like our Earth to create intelligent tool users? According to the “Rare Earth …
Podcast: Play in new window | Download (Duration: 7:37 — 5.2MB) | Embed
Can’t we just look at it? In episode 56 and episode 57, we looked at a couple of methods of detecting planets that are orbiting around stars other than our own sun. These methods involve a good deal of analysis and inference. Today, we learn about how astronomers can look directly at a planet around …
Podcast: Play in new window | Download (Duration: 7:20 — 5.0MB) | Embed
The hunt for planet tomato Unlike the method described in the previous episode, the transit method allows one to look at many stars at a time. When a planet crosses between us and the star it’s orbiting, the star’s light dims very slightly. If we can detect that dimming, we can detect said planet. Here’s …