Dr James O'Donoghue 🪐
@interplanetary.bsky.social
Planetary scientist, astronomer and science communicator 🪐. Formerly at JAXA, NASA, Boston Uni, and the Uni of Leicester. Now Associate Professor at @UniofReading. Forbes 8 Billion Under 8 Billion. Website: odonoghuespace.github.io
Always wanted to show it like this. You can just about see the sine wave which marks the boundary between the hexagon and the rest of the planet, though it's very subtle.
October 22, 2025 at 10:20 PM
Always wanted to show it like this. You can just about see the sine wave which marks the boundary between the hexagon and the rest of the planet, though it's very subtle.
Let's unravel the mystery of Saturn's polar hexagon.
A jet stream speeds around the pole at 320 km/h (200 mph). That’s common among planets, but what's not is that it oscillates up and down *very* stably. Each low point of this sine wave becomes a corner of a hexagon, when projected onto a sphere:
A jet stream speeds around the pole at 320 km/h (200 mph). That’s common among planets, but what's not is that it oscillates up and down *very* stably. Each low point of this sine wave becomes a corner of a hexagon, when projected onto a sphere:
October 22, 2025 at 5:57 PM
Let's unravel the mystery of Saturn's polar hexagon.
A jet stream speeds around the pole at 320 km/h (200 mph). That’s common among planets, but what's not is that it oscillates up and down *very* stably. Each low point of this sine wave becomes a corner of a hexagon, when projected onto a sphere:
A jet stream speeds around the pole at 320 km/h (200 mph). That’s common among planets, but what's not is that it oscillates up and down *very* stably. Each low point of this sine wave becomes a corner of a hexagon, when projected onto a sphere:
Worst video ever, but go check out the lunar eclipse going on right now 🙂
September 7, 2025 at 7:17 PM
Worst video ever, but go check out the lunar eclipse going on right now 🙂
Ok, I did it just because, conveniently, Stellarium include some pretend sunspots. Here I start with an Alt Az (person standing upright kinda) mount, going from 10am-noon. You can see the spots rotate in the field. At the end I switch to Equatorial mount, and then you see it stop field-rotating.
March 29, 2025 at 11:36 PM
Ok, I did it just because, conveniently, Stellarium include some pretend sunspots. Here I start with an Alt Az (person standing upright kinda) mount, going from 10am-noon. You can see the spots rotate in the field. At the end I switch to Equatorial mount, and then you see it stop field-rotating.
It's Winter Solstice! Earth's 23.4° tilt and position in orbit mean the northern hemisphere gets the fewest daylight hours under the least intense sunlight of the year.
Today, Earth is on the left of the video below!
Today, Earth is on the left of the video below!
December 21, 2024 at 3:08 PM
It's Winter Solstice! Earth's 23.4° tilt and position in orbit mean the northern hemisphere gets the fewest daylight hours under the least intense sunlight of the year.
Today, Earth is on the left of the video below!
Today, Earth is on the left of the video below!
Yeah, I've got more older ones to share, but I'm excited to create more... this is a little model I have made over the last year, which allows me to show things like eclipses
November 29, 2024 at 9:56 AM
Yeah, I've got more older ones to share, but I'm excited to create more... this is a little model I have made over the last year, which allows me to show things like eclipses
Here's what might have happened to Uranus to make it rotate on its side: an impact by a planetary-scale body!
This is a simulation by Jacob Kegerris (Durham University)
This is a simulation by Jacob Kegerris (Durham University)
November 28, 2024 at 9:02 PM
Here's what might have happened to Uranus to make it rotate on its side: an impact by a planetary-scale body!
This is a simulation by Jacob Kegerris (Durham University)
This is a simulation by Jacob Kegerris (Durham University)
Alternatively, for dwarf planet Pluto lovers, here are the eight planets of our solar system, and some change 🔭
Added an additional dwarf planet, Ceres, which is in the asteroid belt, for symmetry... (there are many more still!)
Added an additional dwarf planet, Ceres, which is in the asteroid belt, for symmetry... (there are many more still!)
November 28, 2024 at 8:52 PM
Alternatively, for dwarf planet Pluto lovers, here are the eight planets of our solar system, and some change 🔭
Added an additional dwarf planet, Ceres, which is in the asteroid belt, for symmetry... (there are many more still!)
Added an additional dwarf planet, Ceres, which is in the asteroid belt, for symmetry... (there are many more still!)
The eight planets of our Solar System 🔭
November 28, 2024 at 8:46 PM
The eight planets of our Solar System 🔭
The planets orbit the Sun at different speeds, with the inner planets moving the fastest—they need to, to resist being pulled in by the Sun's gravity.
Here's a side-by-side comparison (race?) of their velocities!
Here's a side-by-side comparison (race?) of their velocities!
November 23, 2024 at 11:39 PM
The planets orbit the Sun at different speeds, with the inner planets moving the fastest—they need to, to resist being pulled in by the Sun's gravity.
Here's a side-by-side comparison (race?) of their velocities!
Here's a side-by-side comparison (race?) of their velocities!
The reasons why any illustration of the Solar System can only be partially accurate: this highlights the compromises an illustrator has to make to fit everything into view
November 23, 2024 at 5:10 PM
The reasons why any illustration of the Solar System can only be partially accurate: this highlights the compromises an illustrator has to make to fit everything into view