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
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
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
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
To start things off, a limerick: My dear old friend ‘Oumuamua I asked her — What’s up? What is new-ah? “I’ve been thinking of That guy Borisov The interstellar number Two-ah!” Figuring out what’s up with a new population of astronomical objects is like going to a party without knowing the dress code. Here’s what’s … More How Borisov found Borisov (the second interstellar object)
Imagine this. You’re drinking your morning coffee. A small blob zooms at top speed through the kitchen, into the hall and out an open window. You only catch a quick fuzzy glimpse before it’s gone. What was that thing? What’s your first guess? A neighborhood cat? A squirrel? Maybe something more exotic like a raccoon … More ‘Oumuamua: was it aliens? (spoiler: no)