The end of the Solar System

Earth will lose its oceans. Chaos may destabilize the rocky planets. The Sun will go red giant and swallow the inner planets. The outer planets’ orbits will widen as the Sun becomes a white dwarf. Passing stars will destabilize the planets’ orbits and, in about 100 billion years, finally strip away the last planet. … More The end of the Solar System


From planetesimals to planetary “embryos”

This is chapter 3 in the Solar System’s story. We’re chugging along, growing bigger and bigger things… Planetesimal accretion After mountain-sized (~100 km-scale) planetesimals form from concentrations of drifting pebbles, they continue to grow in two ways. The simplest growth route for planetesimals is simply to crash into other planetesimals; this is called planetesimal accretion. … More From planetesimals to planetary “embryos”

Cosmic fireworks!

Time for an astro-thought experiment. You belong to a super-advanced civilization with the ability to shape the cosmos as you wish. You can move around black holes, stars, planets, comets and moons (like the builders of the ultimate planetary systems). What would your civilization plan for big celebrations? What are their ‘fireworks’? What astronomical phenomena … More Cosmic fireworks!

Cohorts of stars orbiting black holes (with planets, moons, and eclipses!)

This post starts off with some world-building, jumps into eclipses and moons’ orbits, and finishes with a brand new Kalgash system that Isaac Asimov would be proud of (dropped into darkness every 2000 years!). More than one planet can share the same orbit around a star. This is not big news: the concept of Trojan … More Cohorts of stars orbiting black holes (with planets, moons, and eclipses!)