Greg Egan

Antimatter Trucker is finally a job title! But don’t worry, this isn’t going to be “The Wages of Fear, 2026”:

“The device on Cern’s truck will carry about 1,000 antimatter particles, weighing about a billionth of a trillionth of a gram. Should the containment fail, and the antimatter make contact with normal matter, the resulting pulse of energy would be so feeble, the load doesn’t even warrant a radioactive label.”

https://www.theguardian.com/science/2026/mar/14/please-drive-carefully-scientists-plan-to-transport-volatile-antimatter-for-first-time

“AI-powered writing tools are increasingly integrated into our e-mails and phones. Now a new study finds biased AI suggestions can sway users’ beliefs”

“We told people before, and after, to be careful, that the AI is going to be (or was) biased, and nothing helped,” Naaman said. “Their attitudes about the issues still shifted.”

https://www.scientificamerican.com/article/ai-autocomplete-doesnt-just-change-how-you-write-it-changes-how-you-think/

From gamma decay to photon rockets

Suppose an atomic nucleus with mass m₁ emits a gamma ray and ends up with mass m₂. How fast does the nucleus recoil?

In units where the speed of light is 1, the time and space components of the energy-momentum vectors are:

(𝑚₁, 0) for the initial nucleus
(γ, –γ) for the gamma ray
𝑚₂ (1, 𝑣)/√(1–𝑣²) for the recoiling nucleus

where γ, 𝑣 are unknowns.

Conservation of energy-momentum means:

(𝑚₁, 0) = (γ, –γ) + 𝑚₂ (1, 𝑣)/√(1–𝑣²)

This is solved by:

𝑣 = (𝑚₁² – 𝑚₂²) / (𝑚₁² + 𝑚₂²)
γ = (𝑚₁² – 𝑚₂²) / (2 𝑚₁)

We can also solve for the mass ratio:

𝑚₂/𝑚₁ = √[(1–𝑣)/(1+𝑣)]

But this result also gives us the “rocket equation” for an idealised relativistic rocket, that emits only photons as exhaust and works with perfect efficiency.

For example, it tells us that to accelerate such a rocket to half lightspeed, 𝑣=1/2, it will end up with a payload fraction of √[1/3].

“ChatGPT Health regularly misses the need for medical urgent care and frequently fails to detect suicidal ideation, a study of the AI platform has found, which experts worry could “feasibly lead to unnecessary harm and death”.”

“In 51.6% of cases where someone needed to go to the hospital immediately, the platform said stay home or book a routine medical appointment, a result Alex Ruani, a doctoral researcher in health misinformation mitigation with University College London, described as “unbelievably dangerous”.”

“The platform was also nearly 12 times more likely to downplay symptoms because the “patient” told it a “friend” in the scenario suggested it was nothing serious.”

https://www.theguardian.com/technology/2026/feb/26/chatgpt-health-fails-recognise-medical-emergencies

I know some people are keen on buying their eBooks from Bookshop dot org, so I’m happy to announce that almost* all my self-published DRM-free eBooks are now available there.

* Except for DICHRONAUTS, because the US rights are held by Night Shade so my own edition can only be sold outside North America.

This page lists all the eBooks:

https://www.gregegan.net/BIBLIOGRAPHY/Ebooks.html

“It Was Just An Accident” was powerful, tightly focused on its central quandary but still humanly messy.

Maybe “Death and the Maiden” was first to ask “What if you meet your torturer?” — but sadly the world has more than enough barbarity to justify another version of this story.

After listening to an entrepreneur, a philosopher and a psychologist burble confused inanities about “griefbots” for two consecutive nights on the radio [https://www.abc.net.au/listen/programs/the-radio-national-hour/grief-ai-end-death-bot/106338094 and https://www.abc.net.au/listen/programs/the-radio-national-hour/the-promise-and-pitfalls-of-ai-griefbots/106341670] my takeaway was this:

If someone you love needs to hear something from you, for fuck’s sake say it to them now, with your own voice and your own intention, lest some slimy techbro insert himself into their life after you’ve gone, and exploit their loss and pain. Also, tell your spouse/kids/whatever that no, you don’t want your face drawn in crayon on a clumsy digital sock puppet for all eternity.

I very much enjoyed “The Secret Agent”. It reminded me of “Once Upon A Time in Anatolia’’, in the sense it created of being immersed in a very specific time, place and culture, while the flash-forwards expanded the scope and gave everything an eerie poignancy.

Both of these Quanta articles describe fascinating mathematical developments — but they also come with encouraging human stories of the ultimate success of persistence over decades by individual mathematicians, fresh collaborations that reignite dormant ideas, and connections to work from long ago.

https://www.quantamagazine.org/long-sought-proof-tames-some-of-maths-unruliest-equations-20260206/

https://www.quantamagazine.org/two-twisty-shapes-resolve-a-centuries-old-topology-puzzle-20260120/

For x>0, define L(x)=log(x)/x.

L'(x) = (1-log(x))/x^2 has its sole zero at x=e.

So L(x) ≤ 1/e, with equality only at x=e.

This means:

e log(x) ≤ x
x^e ≤ e^x

for all x>0, with equality only at x=e.

For crying out loud, ABC news, never send a line graph to do a bar chart’s job. Link: https://www.abc.net.au/news/2026-01-21/midnight-oil-rob-hirst-pancreatic-cancer-death/106252876

Every Australian politician who has dragged their feet on emissions reductions is cordially invited to spend the upcoming 44°C day in Sydney’s western suburbs in a two-bedroom flat without air conditioning.

Google’s “AI overview”, pointlessly appended to their usual weather forecast for my suburb: “The weather in XXX is currently sunny with a temperature of about 17° C ... ” The forecast already states the current temperature, but no, it is not “currently sunny” as it’s 10:23 pm. The forecast by itself is perfectly understandable. It does not need a summary, an overview, an interpretation, a Reader’s Digest Condensed Version. FFS, Google, is this what you’re building new data centres and buying billions of dollars worth of GPUs to do?

In a future where the rich kids are being raised with a digital Cyrano beside them to sweet-talk their way into the best jobs, four friends train together for a battle to prove that other kinds of minds might still have the edge.

My new story “Understudies” in Clarkesworld.

Link: https://clarkesworldmagazine.com/egan_10_25/

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