Life is caught in a chicken-and-egg situation. For life to exist on a planet, the planet must of course have the right conditions for life. The planet must be habitable. But a planet’s habitability depends in large part on whether it already has life. It’s a lot easier for a planet with life to be habitable. So a planet needs life to be able to host life….
This post could also be titled: How blogging and social media help make science happen. Here is the story. Planet Nine was conjectured in late January 2016. In February 2016 I started to think about where Planet Nine may have come from. This led to 3 blog posts, each exploring a different origins story for…
Two days ago we built a planetary system with an Earth that has five Suns in the sky. It looks like this: Yesterday we explored the motions of the heavens on this 5-Sun Earth: how the Suns move across the sky and when night falls (not too often, it turns out). Today we are going…
In yesterday’s post we built a planetary system with an Earth that has five Suns in the sky. Here is what it looks like: Today we are going to pretend that we are inhabitants of this five-Sun Earth and look up at the sky. How do the Suns move across the sky? And, with all…
We Earthlings have just one Sun. Tatooine has two. Wouldn’t it be even cooler with three Suns in the sky? Or four or five or twenty? Several extra-solar planets have been found in triple- and even quadruple-star systems (for example, GJ 667C and PH1b). But none of these planets has more than two Suns because…
It is hard to know where things come from. If I drink a Belgian-style beer brewed in Colorado using hops from Washington state and I live in France, where did the beer actually come from? And what does that mean anyway? The cosmic situation is just as confusing. We know where the planets are right…
We are discussing the origins of Planet Nine. In part 1 we explored whether it could have been produced during an orbital instability in the early Solar System. In part 2 we showed that Planet Nine could have been captured from another star. Here we will explore another plausible idea that is a little less…
