It’s time to revisit one of my favorite topics: co-orbital planetary systems, in which more than one planet share the same orbit around a star. (Side note: co-orbital systems can exist on different size scales — many stars can share an orbit around a black hole, or many moons share an orbit around a planet, … More Constellations of co-orbital planets
It’s time for an astronomy poem throw-down: me against Chat-GPT. It’s on like Donkey Kong! … More An astronomy poem battle against Chat-GPT
To celebrate the opening of Avatar 2, I made a series of slides to give a little more astrophysical context to Pandora. And, like the movies, it’s all about the visuals… … More Astrophysics of Pandora, the moon-world from Avatar
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
The list of factors needed for life to originate on Earth remains uncertain, although water was essential. Earth’s water was likely delivered by planetesimals scattered inward by Jupiter. Yet, ironically, Earth would probably be much wetter with no Jupiter. … More Water delivery and the origin of life on Earth
TL;DR: The planets’ orbital shapes, tilts and spins oscillate due to the gravity of the other planets — this has a strong effect on Earth’s climate. On billion-year timescales the terrestrial planets’ orbits are chaotic and cannot be predicted precisely. … More Billion-year evolution of the Solar System: climate forcing and orbital chaos
Asteroids and comets are the leftovers from the planets’ formation. They’re like the potato peels that end up on the floor instead of in the mashed potatoes. So, what have those leftovers been up to the past few billion years? … More Asteroids, comets, and dinosaur-killing impacts
TL;DR: The Moon is thought to have formed in Earth’s last giant impact with a planetary embryo about 100 million years after the start of planet formation. Highly-siderophile elements indicate that ~0.5% of Earth’s mass was accreted after that point. … More The Moon-forming impact and late accretion on the rocky planets
TL;DR: The giant planets underwent a dynamical instability that shook up the entire Solar System and likely ejected an extra ice giant. The instability happened early, perhaps triggered by the dispersal of the gaseous planet-forming disk. … More The giant planet instability (the “Nice model”)
This is chapter 6 in the Solar System’s story. This is an action-packed, epic chapter in which a lot of pieces of the puzzle are put together in different ways. (It’s my favorite part.) … More Formation of the rocky planets: choose your own adventure!
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