Tony Dunn
@tony873004.bsky.social
Orbit simulations of planets, comets, asteroids and other interesting stuff. Amateur astronomer. BA: Physics & Astronomy, SFSU.
The ESCAPADE mission to Mars is about to launch. It will stay near Earth for about 1 year before using an Oberth maneuver to send it to Mars.
November 13, 2025 at 7:55 PM
The ESCAPADE mission to Mars is about to launch. It will stay near Earth for about 1 year before using an Oberth maneuver to send it to Mars.
The asteroid is now known as 2025 UC11. This animation shows where the observations were made. #astronomy
October 30, 2025 at 10:12 PM
The asteroid is now known as 2025 UC11. This animation shows where the observations were made. #astronomy
A quick trip through the thermosphere turns newly-discovered asteroid ST25J47 from an Apollo to an Aten. It is no bigger than a meter.
October 30, 2025 at 9:58 PM
A quick trip through the thermosphere turns newly-discovered asteroid ST25J47 from an Apollo to an Aten. It is no bigger than a meter.
After billions of years heading towards us, interstellar comet #3IATLAS is currently at its closest approach to the Sun right NOW. Perihelion. #astronomy #comet
October 29, 2025 at 4:46 AM
After billions of years heading towards us, interstellar comet #3IATLAS is currently at its closest approach to the Sun right NOW. Perihelion. #astronomy #comet
Another mini-moon? Maybe. Newly discovered 2025 US6 is officially listed as an asteroid.
Unlike our quasi-moon 2025 PN7, this one is actually bound to Earth, for now.
Its orbit is pure chaos. Enjoy it while it lasts. It’ll probably be demoted to space junk.
Unlike our quasi-moon 2025 PN7, this one is actually bound to Earth, for now.
Its orbit is pure chaos. Enjoy it while it lasts. It’ll probably be demoted to space junk.
October 26, 2025 at 7:24 PM
Another mini-moon? Maybe. Newly discovered 2025 US6 is officially listed as an asteroid.
Unlike our quasi-moon 2025 PN7, this one is actually bound to Earth, for now.
Its orbit is pure chaos. Enjoy it while it lasts. It’ll probably be demoted to space junk.
Unlike our quasi-moon 2025 PN7, this one is actually bound to Earth, for now.
Its orbit is pure chaos. Enjoy it while it lasts. It’ll probably be demoted to space junk.
Some YouTubes, even one by a famous astrophysicist, confuse mini-moons with quasi-moons.
Simple test:
🔴 Delete the Sun.
– Still orbiting Earth, even years later? Mini-moon (bound), like 2024 PT5.
– Gone forever? Quasi-moon, like 2025 PN7.
Simple test:
🔴 Delete the Sun.
– Still orbiting Earth, even years later? Mini-moon (bound), like 2024 PT5.
– Gone forever? Quasi-moon, like 2025 PN7.
October 24, 2025 at 6:55 PM
Some YouTubes, even one by a famous astrophysicist, confuse mini-moons with quasi-moons.
Simple test:
🔴 Delete the Sun.
– Still orbiting Earth, even years later? Mini-moon (bound), like 2024 PT5.
– Gone forever? Quasi-moon, like 2025 PN7.
Simple test:
🔴 Delete the Sun.
– Still orbiting Earth, even years later? Mini-moon (bound), like 2024 PT5.
– Gone forever? Quasi-moon, like 2025 PN7.
What was 'quasi-moon' 2025 PN7 doing before it entered its quasi state? It was tracing horseshoe orbits. Horseshoe orbits are called that because some people think they look like horseshoes.
October 24, 2025 at 1:11 AM
What was 'quasi-moon' 2025 PN7 doing before it entered its quasi state? It was tracing horseshoe orbits. Horseshoe orbits are called that because some people think they look like horseshoes.
Watch Earth’s newest quasi-moon in motion. 🌍🌀
The new paper “Meet Arjuna 2025 PN7” confirms #asteroid 2025 PN7 is trapped in a quasi-satellite orbit, looping around Earth (in a rotating frame) from the 1960s to the 2080s.
iopscience.iop.org/article/10.3...
The new paper “Meet Arjuna 2025 PN7” confirms #asteroid 2025 PN7 is trapped in a quasi-satellite orbit, looping around Earth (in a rotating frame) from the 1960s to the 2080s.
iopscience.iop.org/article/10.3...
October 21, 2025 at 7:13 PM
Watch Earth’s newest quasi-moon in motion. 🌍🌀
The new paper “Meet Arjuna 2025 PN7” confirms #asteroid 2025 PN7 is trapped in a quasi-satellite orbit, looping around Earth (in a rotating frame) from the 1960s to the 2080s.
iopscience.iop.org/article/10.3...
The new paper “Meet Arjuna 2025 PN7” confirms #asteroid 2025 PN7 is trapped in a quasi-satellite orbit, looping around Earth (in a rotating frame) from the 1960s to the 2080s.
iopscience.iop.org/article/10.3...
Simulation of the 2 asteroids against GAIA stars.
October 17, 2025 at 5:16 AM
Simulation of the 2 asteroids against GAIA stars.
What if Juno left Jupiter to get a closer look at interstellar comet 3I/ATLAS? With a couple of burns, Juno can get as close as 25 million km. Purely hypothetical, fun orbital mechanics! 🔭
Thanks @adamsspaceresearch.bsky.social for the research and trajectory data. @i4interstellar.bsky.social
Thanks @adamsspaceresearch.bsky.social for the research and trajectory data. @i4interstellar.bsky.social
October 11, 2025 at 1:39 AM
What if Juno left Jupiter to get a closer look at interstellar comet 3I/ATLAS? With a couple of burns, Juno can get as close as 25 million km. Purely hypothetical, fun orbital mechanics! 🔭
Thanks @adamsspaceresearch.bsky.social for the research and trajectory data. @i4interstellar.bsky.social
Thanks @adamsspaceresearch.bsky.social for the research and trajectory data. @i4interstellar.bsky.social
Nice find. Yes, your Mt. Lemmon Survey was first. Thanks for finding all these interesting rocks. It seems like there's been quite an uptick recently. Sep & Oct always produce a lot. It is the increase in night time hours, non-crowded Milky Way background unlike summer months or something else?
October 5, 2025 at 11:13 PM
Nice find. Yes, your Mt. Lemmon Survey was first. Thanks for finding all these interesting rocks. It seems like there's been quite an uptick recently. Sep & Oct always produce a lot. It is the increase in night time hours, non-crowded Milky Way background unlike summer months or something else?
After last week's asteroid buzzed over Antarctica, the North Pole gets its turn. Newly-discovered #asteroid 2025 TQ2 (2-4 meters wide) passed 3,000 miles above the Fortress of Solitude. #Astronomy
October 5, 2025 at 9:43 PM
After last week's asteroid buzzed over Antarctica, the North Pole gets its turn. Newly-discovered #asteroid 2025 TQ2 (2-4 meters wide) passed 3,000 miles above the Fortress of Solitude. #Astronomy
Interstellar #comet 3I/ATLAS is hidden on the far side of the Sun from Earth. But today it sweeps past Mars, where orbiting spacecraft have ringside seats. Let’s hope they look up. #astronomy #NASA
October 2, 2025 at 10:37 PM
Interstellar #comet 3I/ATLAS is hidden on the far side of the Sun from Earth. But today it sweeps past Mars, where orbiting spacecraft have ringside seats. Let’s hope they look up. #astronomy #NASA
If you were in Antarctica, here's the #asteroid's path across the twilight sky.
October 1, 2025 at 9:39 PM
If you were in Antarctica, here's the #asteroid's path across the twilight sky.
10 #asteroids passed closer than the Moon in a 5-day period from September 23-28. All were discovered this month. The largest up to 41 meters wide. #astronomy
September 30, 2025 at 9:48 PM
10 #asteroids passed closer than the Moon in a 5-day period from September 23-28. All were discovered this month. The largest up to 41 meters wide. #astronomy
October's comets. SWAN C/2025 R2, and Lemmon (C/2025 A6). Our interstellar visitor 3I/Atlas aka C/2025 N1, is unfortunately on the wrong side of the Sun for viewing, but I included it anyway because... well... it's interstellar. #Astronomy
September 27, 2025 at 4:53 AM
October's comets. SWAN C/2025 R2, and Lemmon (C/2025 A6). Our interstellar visitor 3I/Atlas aka C/2025 N1, is unfortunately on the wrong side of the Sun for viewing, but I included it anyway because... well... it's interstellar. #Astronomy
#Asteroid 2024 YR4 has a ~4 % chance of hitting the Moon on Dec 22 2032. A strike could spike micrometeoroid flux in low Earth orbit ~1000×, endangering satellites—so researchers even study nuclear disruption. arxiv.org/pdf/2509.12351
My sim: 2000 clones; 72 hit.
My sim: 2000 clones; 72 hit.
September 25, 2025 at 8:50 PM
#Asteroid 2024 YR4 has a ~4 % chance of hitting the Moon on Dec 22 2032. A strike could spike micrometeoroid flux in low Earth orbit ~1000×, endangering satellites—so researchers even study nuclear disruption. arxiv.org/pdf/2509.12351
My sim: 2000 clones; 72 hit.
My sim: 2000 clones; 72 hit.
In the last 6 days, 9 asteroids passed inside the Moon’s orbit. Estimated sizes: ~1–38 m. All were discovered this month, a reminder that countless small, faint NEOs slip by unnoticed until they make a close pass.
September 21, 2025 at 6:35 AM
In the last 6 days, 9 asteroids passed inside the Moon’s orbit. Estimated sizes: ~1–38 m. All were discovered this month, a reminder that countless small, faint NEOs slip by unnoticed until they make a close pass.