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 🙂
If you have eclipse glasses handy, check out the Sun today and you'll see a Sunspot without a telescope (if you've got modestly good vision). This is a quick pic with my phone, through eclipse glasses
May 3, 2025 at 1:21 PM
If you have eclipse glasses handy, check out the Sun today and you'll see a Sunspot without a telescope (if you've got modestly good vision). This is a quick pic with my phone, through eclipse glasses
A fast stream of solar wind slammed into Jupiter’s magnetosphere, triggering enhanced auroral activity, which amplified heating in the upper atmosphere.
That heat expanded the atmosphere around the planet in a thermal wave over 12 Earths long.
That heat expanded the atmosphere around the planet in a thermal wave over 12 Earths long.
April 3, 2025 at 1:22 PM
A fast stream of solar wind slammed into Jupiter’s magnetosphere, triggering enhanced auroral activity, which amplified heating in the upper atmosphere.
That heat expanded the atmosphere around the planet in a thermal wave over 12 Earths long.
That heat expanded the atmosphere around the planet in a thermal wave over 12 Earths long.
Jupiter’s magnetic field is huge, the biggest in the solar system, and its aurora is mostly controlled from within. Here it is to scale with the Moon, if we could *see* the magnetic field lines.
We found that external solar forcing plays a major role, despite this.
We found that external solar forcing plays a major role, despite this.
April 3, 2025 at 1:22 PM
Jupiter’s magnetic field is huge, the biggest in the solar system, and its aurora is mostly controlled from within. Here it is to scale with the Moon, if we could *see* the magnetic field lines.
We found that external solar forcing plays a major role, despite this.
We found that external solar forcing plays a major role, despite this.
🚨Our new paper is out now!
We caught Jupiter’s upper atmosphere reacting dramatically to a bursts of solar wind, which triggered a planet-wide wave of heat to flow from the auroras. This changes how we think about the Sun’s influence at the outer planets.
www.reading.ac.uk/news/2025/Re...
We caught Jupiter’s upper atmosphere reacting dramatically to a bursts of solar wind, which triggered a planet-wide wave of heat to flow from the auroras. This changes how we think about the Sun’s influence at the outer planets.
www.reading.ac.uk/news/2025/Re...
April 3, 2025 at 1:22 PM
🚨Our new paper is out now!
We caught Jupiter’s upper atmosphere reacting dramatically to a bursts of solar wind, which triggered a planet-wide wave of heat to flow from the auroras. This changes how we think about the Sun’s influence at the outer planets.
www.reading.ac.uk/news/2025/Re...
We caught Jupiter’s upper atmosphere reacting dramatically to a bursts of solar wind, which triggered a planet-wide wave of heat to flow from the auroras. This changes how we think about the Sun’s influence at the outer planets.
www.reading.ac.uk/news/2025/Re...
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.
Hans this is 'field rotation'. Chris's mount is 'Altitude Azimuth'. It's parallel to Earth's surface, like us when we stand up; watch a crescent Moon throughout the day, you'll see it rotate. 'Equatorial mounts' are tilted same as Earth's axis, so no rotation. Gif via calgary.rasc.ca/field_rotati...
March 29, 2025 at 11:23 PM
Hans this is 'field rotation'. Chris's mount is 'Altitude Azimuth'. It's parallel to Earth's surface, like us when we stand up; watch a crescent Moon throughout the day, you'll see it rotate. 'Equatorial mounts' are tilted same as Earth's axis, so no rotation. Gif via calgary.rasc.ca/field_rotati...
The Moon is going to block out a bit of the Sun this weekend! Also known as a partial solar eclipse, on 29th March! See the timing for your region at www.timeanddate.com/eclipse/sola...
Don't look at the Sun direct, use some eclipse glasses or make a pinhole camera: www.jpl.nasa.gov/edu/resource...
Don't look at the Sun direct, use some eclipse glasses or make a pinhole camera: www.jpl.nasa.gov/edu/resource...
March 27, 2025 at 11:18 PM
The Moon is going to block out a bit of the Sun this weekend! Also known as a partial solar eclipse, on 29th March! See the timing for your region at www.timeanddate.com/eclipse/sola...
Don't look at the Sun direct, use some eclipse glasses or make a pinhole camera: www.jpl.nasa.gov/edu/resource...
Don't look at the Sun direct, use some eclipse glasses or make a pinhole camera: www.jpl.nasa.gov/edu/resource...
Saturn's rings are now edge-on, as the planet is at equinox. This only occurs every ~15 years, but this time around, as Saturn is on the other side of the Solar System, the Sun is largely blocking our view. It'll still be nearly edge on for months though—a fun time to see an almost ringless Saturn!
March 23, 2025 at 6:43 PM
Saturn's rings are now edge-on, as the planet is at equinox. This only occurs every ~15 years, but this time around, as Saturn is on the other side of the Solar System, the Sun is largely blocking our view. It'll still be nearly edge on for months though—a fun time to see an almost ringless Saturn!
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!
It's a good time to see Jupiter next to the Moon this evening, in fact, even my Ring doorbell security camera can pick it up!
December 14, 2024 at 7:18 PM
It's a good time to see Jupiter next to the Moon this evening, in fact, even my Ring doorbell security camera can pick it up!
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 🔭
Back at it, image taken this minute! 🔭
November 27, 2024 at 6:26 AM
Back at it, image taken this minute! 🔭
The skies above Keck are clear (see live images: mkwc.ifa.hawaii.edu/current/cams...)
November 26, 2024 at 8:57 AM
The skies above Keck are clear (see live images: mkwc.ifa.hawaii.edu/current/cams...)
Bit busy, so just pretty pictures for now!
November 26, 2024 at 8:53 AM
Bit busy, so just pretty pictures for now!
We're now on Jupiter... here it is coming into view
November 26, 2024 at 8:23 AM
We're now on Jupiter... here it is coming into view
Live infrared image of SATURN from the 10-metre Keck telescope in Hawaii
We are observing the auroras of Saturn in the northern and southern hemispheres 🪐🔭
We are observing the auroras of Saturn in the northern and southern hemispheres 🪐🔭
November 26, 2024 at 7:37 AM
Live infrared image of SATURN from the 10-metre Keck telescope in Hawaii
We are observing the auroras of Saturn in the northern and southern hemispheres 🪐🔭
We are observing the auroras of Saturn in the northern and southern hemispheres 🪐🔭
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