John Forbes
@redshiftless.bsky.social
Astronomer in Aotearoa/New Zealand at the University of Canterbury.
Pusher of pixels, pens, arrays, and computer keys.
www.johncforbes.com
Pusher of pixels, pens, arrays, and computer keys.
www.johncforbes.com
Pinned
John Forbes
@redshiftless.bsky.social
· Nov 25
The Galaxy is full of streams of interstellar objects!
Explainer thread below from @astrokiwi.bsky.social
🔭 🧪
Explainer thread below from @astrokiwi.bsky.social
🔭 🧪
A little 3I/ATLAS update building on @marshall-eubanks.bsky.social's nice RNAAS from last week. Given its non-grav acceleration and the rate at which it's losing mass, you can work out its size. The answer: a diameter around 1 km, very typical for comets. arxiv.org/abs/2512.18341 🔭 🧪
December 23, 2025 at 1:05 PM
A little 3I/ATLAS update building on @marshall-eubanks.bsky.social's nice RNAAS from last week. Given its non-grav acceleration and the rate at which it's losing mass, you can work out its size. The answer: a diameter around 1 km, very typical for comets. arxiv.org/abs/2512.18341 🔭 🧪
Bit of a queue to see the corpse flower at the Botanical Garden in Ōtautahi
December 19, 2025 at 10:25 PM
Bit of a queue to see the corpse flower at the Botanical Garden in Ōtautahi
Reposted by John Forbes
Ahead of 3I/ATLAS's closest approach to Earth (at nearly 2 au) tomorrow, here's our Elaine P. Snowden Fellow @astrohopkins.bsky.social on how we determined 3I's age 🇳🇿☄️🔭
Matthew Hopkins (Univ. of Oxford & Univ. of Canterbury) chats about his article on 3I/ATLAS and what it tells us about the interstellar object population — and what comes next. 🔭
📺 Watch now: www.youtube.com/watch?v=zz3e...
📺 Watch now: www.youtube.com/watch?v=zz3e...
AAS Journal Author Series: Matthew Hopkins on 2025ApJ...990L..30H
YouTube video by AAS
www.youtube.com
December 17, 2025 at 6:08 PM
Ahead of 3I/ATLAS's closest approach to Earth (at nearly 2 au) tomorrow, here's our Elaine P. Snowden Fellow @astrohopkins.bsky.social on how we determined 3I's age 🇳🇿☄️🔭
Reposted by John Forbes
A nice overview from our media folks of the theoretical and observational work our team has out so far on interstellar comet 3I/ATLAS ☄️
Kiwi team lead ‘out of this world’ study of new comet | UC
A Kiwi team is reaching for the stars with world-leading research into a new interstellar comet described as a ‘dusty snowball’.
www.canterbury.ac.nz
December 17, 2025 at 9:36 AM
A nice overview from our media folks of the theoretical and observational work our team has out so far on interstellar comet 3I/ATLAS ☄️
Reposted by John Forbes
Meanwhile, we have a new student-led theory paper out on interstellar objects: how the planets of their home systems change what speeds they fly out into the Galaxy.
Comments welcome!
Albrow et al., submitted
Comments welcome!
Albrow et al., submitted
The ejection velocities of interstellar objects signpost their progenitor system architectures
Interstellar objects (ISOs) ejected from planetary systems carry kinematic signatures of their formation environments. The properties of these velocity distributions govern the ISOs' propagation and d...
arxiv.org
December 9, 2025 at 10:12 AM
Meanwhile, we have a new student-led theory paper out on interstellar objects: how the planets of their home systems change what speeds they fly out into the Galaxy.
Comments welcome!
Albrow et al., submitted
Comments welcome!
Albrow et al., submitted
The 3 y.o.'s top 5 cutest current toddlerisms:
5. oak: "oaka"
4. saturn: "satur-in"
3. broccoli: "bruggoli"
2. instead: "umstead"
1. beetroot: "beetfruit"
5. oak: "oaka"
4. saturn: "satur-in"
3. broccoli: "bruggoli"
2. instead: "umstead"
1. beetroot: "beetfruit"
December 8, 2025 at 7:20 AM
The 3 y.o.'s top 5 cutest current toddlerisms:
5. oak: "oaka"
4. saturn: "satur-in"
3. broccoli: "bruggoli"
2. instead: "umstead"
1. beetroot: "beetfruit"
5. oak: "oaka"
4. saturn: "satur-in"
3. broccoli: "bruggoli"
2. instead: "umstead"
1. beetroot: "beetfruit"
Why does outlook assume I'm starting a new sentence (and hence autocapitalise the next word) every time I use a full stop? Surely I'm not the only one who uses abbreviations in emails!
November 30, 2025 at 10:53 AM
Why does outlook assume I'm starting a new sentence (and hence autocapitalise the next word) every time I use a full stop? Surely I'm not the only one who uses abbreviations in emails!
Ooh gross just discovered a bunch of youtube channels blaring about 3I/ATLAS using an AI-generated Brian Cox. The channel description says the videos are all AI, but the videos are clearly designed to make people think BC is actually saying these things..
November 17, 2025 at 4:05 AM
Ooh gross just discovered a bunch of youtube channels blaring about 3I/ATLAS using an AI-generated Brian Cox. The channel description says the videos are all AI, but the videos are clearly designed to make people think BC is actually saying these things..
Reposted by John Forbes
Ohio State astronomy is still waiting to see what happens with the federal funding landscape before deciding whether to proceed. With programs that are still TBD, I recommend waiting right now because *application fees do not get refunded if they decide to cancel after you have already paid*!!
So far the astronomy PhD programs that have cancelled admissions are Washington, Michigan State, and Case Western.
Sad to see the University of Washington Astronomy Department has suspended graduate admissions for the 2026-2027 Academic Year. astro.washington.edu/graduate-adm...
October 9, 2025 at 12:45 AM
Ohio State astronomy is still waiting to see what happens with the federal funding landscape before deciding whether to proceed. With programs that are still TBD, I recommend waiting right now because *application fees do not get refunded if they decide to cancel after you have already paid*!!
More hostility than I was expecting from a planter!
September 15, 2025 at 11:29 PM
More hostility than I was expecting from a planter!
Incredible stuff happening on wikipedia
August 27, 2025 at 1:39 PM
Incredible stuff happening on wikipedia
PSA to scientists: Google calculator appears to no longer do basic unit conversion correctly!
n.b. the correct answer here is 223.4 Myr, a factor of about 60 larger than Google's answer.
🔭 🧪
n.b. the correct answer here is 223.4 Myr, a factor of about 60 larger than Google's answer.
🔭 🧪
August 4, 2025 at 3:08 AM
PSA to scientists: Google calculator appears to no longer do basic unit conversion correctly!
n.b. the correct answer here is 223.4 Myr, a factor of about 60 larger than Google's answer.
🔭 🧪
n.b. the correct answer here is 223.4 Myr, a factor of about 60 larger than Google's answer.
🔭 🧪
Reposted by John Forbes
Crew-11 lifts off from Florida on their way to the International Space Station.
The heat signature from the launch could be seen from GOES-18.
The heat signature from the launch could be seen from GOES-18.
August 1, 2025 at 5:17 PM
Crew-11 lifts off from Florida on their way to the International Space Station.
The heat signature from the launch could be seen from GOES-18.
The heat signature from the launch could be seen from GOES-18.
Reposted by John Forbes
Cumulus clouds swirl along the Gulf Coast.
This mesmerizing view captured yesterday by GOES-19.
This mesmerizing view captured yesterday by GOES-19.
July 28, 2025 at 6:42 PM
Cumulus clouds swirl along the Gulf Coast.
This mesmerizing view captured yesterday by GOES-19.
This mesmerizing view captured yesterday by GOES-19.
Reposted by John Forbes
I wrote about Rubin again, this time about the telescope's capacity to find potentially dozens of interstellar objects.
It's going to be wild, as one astronomer put it, "like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it."
www.nationalgeographic.com/science/arti...
It's going to be wild, as one astronomer put it, "like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it."
www.nationalgeographic.com/science/arti...
Are interstellar objects proof of alien life? This could finally settle the debate.
The Vera Rubin telescope is poised to kick off an explosive era of discovery. "It's like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it. It's going to be fun."
www.nationalgeographic.com
July 24, 2025 at 6:00 PM
I wrote about Rubin again, this time about the telescope's capacity to find potentially dozens of interstellar objects.
It's going to be wild, as one astronomer put it, "like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it."
www.nationalgeographic.com/science/arti...
It's going to be wild, as one astronomer put it, "like old-fashioned astronomy: Find the thing, point telescopes at it, argue about it."
www.nationalgeographic.com/science/arti...
Reposted by John Forbes
It's paper day! The first science paper with data from @vrubinobs.bsky.social's survey camera, the mighty LSSTCam, is a VERY quick turnaround of Rubin's observations thus far of interstellar comet 3I/ATLAS. ☄️
Chandler et al., submitted 🔭
A 🧵
Chandler et al., submitted 🔭
A 🧵
NSF-DOE Vera C. Rubin Observatory Observations of Interstellar Comet 3I/ATLAS (C/2025 N1)
We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS), with the NSF-DOE Vera C. Rubin ...
arxiv.org
July 21, 2025 at 5:28 AM
It's paper day! The first science paper with data from @vrubinobs.bsky.social's survey camera, the mighty LSSTCam, is a VERY quick turnaround of Rubin's observations thus far of interstellar comet 3I/ATLAS. ☄️
Chandler et al., submitted 🔭
A 🧵
Chandler et al., submitted 🔭
A 🧵
I don't know about "the best," but my April Fool's rant is my personal contribution to this genre. arxiv.org/abs/2003.14327
July 16, 2025 at 1:22 AM
I don't know about "the best," but my April Fool's rant is my personal contribution to this genre. arxiv.org/abs/2003.14327
Reposted by John Forbes
It's paper day! We use our Ōtautahi-Oxford model of the Galaxy's interstellar object population to understand the origins of 3I/ATLAS, from only its velocity
@astrohopkins.bsky.social, Dorsey, @redshiftless.bsky.social, @astrokiwi.bsky.social, @chrislintott.bsky.social & Leicester, submitted
A 🧵🔭
@astrohopkins.bsky.social, Dorsey, @redshiftless.bsky.social, @astrokiwi.bsky.social, @chrislintott.bsky.social & Leicester, submitted
A 🧵🔭
From a Different Star: 3I/ATLAS in the context of the Ōtautahi-Oxford interstellar object population model
The discovery of the third interstellar object (ISO), 3I/ATLAS (`3I'), provides a rare chance to directly observe a small body from another Solar System. Studying its chemistry and dynamics will add t...
arxiv.org
July 9, 2025 at 3:29 AM
It's paper day! We use our Ōtautahi-Oxford model of the Galaxy's interstellar object population to understand the origins of 3I/ATLAS, from only its velocity
@astrohopkins.bsky.social, Dorsey, @redshiftless.bsky.social, @astrokiwi.bsky.social, @chrislintott.bsky.social & Leicester, submitted
A 🧵🔭
@astrohopkins.bsky.social, Dorsey, @redshiftless.bsky.social, @astrokiwi.bsky.social, @chrislintott.bsky.social & Leicester, submitted
A 🧵🔭
It's my favorite time of the year: new black-footed ferret kits born at the National Zoo and the return of ferretcam!
nationalzoo.si.edu/webcams/blac...
nationalzoo.si.edu/webcams/blac...
June 5, 2025 at 9:31 AM
It's my favorite time of the year: new black-footed ferret kits born at the National Zoo and the return of ferretcam!
nationalzoo.si.edu/webcams/blac...
nationalzoo.si.edu/webcams/blac...
Looks like a promising night for aurora chasing
June 1, 2025 at 4:56 AM
Looks like a promising night for aurora chasing
As far as I can tell this month is just 8 deadlines in a trenchcoat.
May 13, 2025 at 12:59 PM
As far as I can tell this month is just 8 deadlines in a trenchcoat.
Reposted by John Forbes
Reposted by John Forbes
Astronomers have found thousands of planets outside the solar system. All of them are, to my knowledge, garbage. Happy Earth Day to the only good one 🌍
April 22, 2025 at 12:44 PM
Astronomers have found thousands of planets outside the solar system. All of them are, to my knowledge, garbage. Happy Earth Day to the only good one 🌍
Reposted by John Forbes
𝗡𝗼, 𝗮 𝗯𝗶𝗼𝘀𝗶𝗴𝗻𝗮𝘁𝘂𝗿𝗲 𝘄𝗮𝘀 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗱𝗲𝘁𝗲𝗰𝘁𝗲𝗱 𝗶𝗻 𝗞𝟮-𝟭𝟴𝗯'𝘀 𝗮𝘁𝗺𝗼𝘀𝗽𝗵𝗲𝗿𝗲.
K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.
Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).
🔭🧪🪐 #exoplanet
K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.
Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).
🔭🧪🪐 #exoplanet
April 17, 2025 at 4:08 PM
𝗡𝗼, 𝗮 𝗯𝗶𝗼𝘀𝗶𝗴𝗻𝗮𝘁𝘂𝗿𝗲 𝘄𝗮𝘀 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗱𝗲𝘁𝗲𝗰𝘁𝗲𝗱 𝗶𝗻 𝗞𝟮-𝟭𝟴𝗯'𝘀 𝗮𝘁𝗺𝗼𝘀𝗽𝗵𝗲𝗿𝗲.
K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.
Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).
🔭🧪🪐 #exoplanet
K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.
Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).
🔭🧪🪐 #exoplanet