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!)
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%
The Sun will puff up to gargantuan size
As big as Earth’s orbit. And fill up our skies
The red giant Sun will eat Venus alive
But Mercury’s first. It will not survive. … More Reading Earth’s Destiny in the “Blood Spatter” Around Other Stars
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
These poems were written for every age
There’s rhymes and astronomy on every page
There’s science galore, and plenty of jokes
It’s perfect for kids or for any old folks. … More Black Holes, Stars, Earth and Mars — my astronomy poem book!
Ceres is Queen of the belt. She’s the best-a.
Her husband is Pallas. Court jester is Vesta.
She makes up a third of the belt on her own
She’s cratered and icy and sits on her throne. … More Asteroids — the poem
Have you ever been lost in the desert?
Stumbling along the sand dunes, the Sun beating down on you, your mouth sticky and dry. All you can think about is water… … More Second chance planets 3: cosmic rain on dried-out worlds
Sometimes removing the outer atmosphere from a Neptune-like planet can reveal an ocean paradise! … More Second chance planets 2: Pre-terraformed, habitable evaporated cores of mini-Neptunes