TL;DR: planetesimals are mountain-sized rocks (sometimes with ice) that grow from clumps of drifting dust (“pebbles”). The two types of meteorites come from planetesimals that formed in different parts of the Solar System and remained separate. … More From dust to planetesimals
The TL;DR version of this post: the Sun formed in a cluster of about 1000 stars. The Sun’s gas-dominated disk disappeared in a few million years, about the same timescale as the cluster’s dispersal. … More The Sun’s birth cluster and planet-forming disk
This blog series will discuss what we know (and don’t know) about the formation and evolution of our Solar System. … More The Solar System’s story
Here’s something brand new – we made a big splash!
A pile of free-floaters just dropped with a crash!
A hundred new rogue planets! Yup, we just found ‘em
They orbit among stars instead of around ‘em. … More A flock of free-floaters
If too many rocks hit a planet by chance
It breaks up the system’s whole resonant dance! … More Bombardment of 7 orbs
The time capsule must serve as a beacon. Any other civilization that detects it should immediately suspect that it is of artificial origin. And it needs to survive for countless billions of years. … More A cosmic time capsule
Just one stretched-out orbit takes up lots of space
Can’t add any planets, there just isn’t space
Now, circles are best. And trust me, I’ve tried
Eight or ten orbits fit nicely inside. … More We’re in the cosmic 1%
Where are those Trojans? Just where are they hiding?
Are they at the store, or maybe hang-gliding?
We think they exist — just what have we missed?
Well, every good story should end with a twist… … More The mystery of the missing planets
Some people like to call Jupiter and Saturn the “architects” of the Solar system, as though they had a clear plan for how our system should turn out. Not us. We think of the gas giants as bullies that pushed Earth around and made a lot of decisions for us. … More Behold Jupiter and Saturn, the bullies of our Solar System
This post is an adventure in world-building. I use N-body simulations to find orbital configurations of planetary systems that (I think) are completely new, pretty awesome and unexpected. It involves cohorts of co-orbital planets… … More Cohorts of co-orbital planets