Andrew Jaffe
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defjaf.bsky.social
Andrew Jaffe
@defjaf.bsky.social
Astrophysics, cosmology, Bayesian inference, parenthood, politics, rock ’n’ roll, & more. Professor at Imperial College. andrewjaffe.net He/him/his

The Random Universe—coming in November. https://yalebooks.yale.edu/book/9780300250503/the-random-universe/
November 25, 2025 at 9:38 PM
We want to make sourdough. Should I buy starter, or try to make my own?
November 25, 2025 at 4:54 AM
Thrilling to see The Random Universe in the real world.
November 24, 2025 at 8:32 AM
The Random Universe IRL!
Good to see @defjaf.bsky.social new book - the Random Universe - out in the wild. Heffers in Cambridge.
November 19, 2025 at 8:04 PM
Reposted by Andrew Jaffe
Come hear us talk about the first moments in the history of the Universe, part of Imperial Lates at Imperial College in South Kensington, London.
What happened in the first second of the universe?
Journey back nearly 14 billion years to the very first moments after the Big Bang.
www.imperial.ac.uk
November 19, 2025 at 4:52 PM
Come hear us talk about the first moments in the history of the Universe, part of Imperial Lates at Imperial College in South Kensington, London.
What happened in the first second of the universe?
Journey back nearly 14 billion years to the very first moments after the Big Bang.
www.imperial.ac.uk
November 19, 2025 at 4:52 PM
Grateful to the colleagues, friends, students, and others who showed up for The Random Universe launch last night, and to Imperial College and Yale University Press for sponsoring and enabling the event.
The Random Universe - Yale University Press London
An award-winning astrophysicist looks at how the understanding of uncertainty and randomness has led to breakthroughs in our knowledge of the cosmos   A...
yalebooks.co.uk
November 19, 2025 at 7:07 AM
First batch of winter buns.
November 17, 2025 at 9:10 PM
Listening to A History of Rock Music in 500 Songs on the Richmond origins of The Yardbirds while riding the 65 London bus through Richmond.
Episode 126: “For Your Love” by the Yardbirds
Episode 126 of A History of Rock Music in Five Hundred Songs looks at “For Your Love”, the Yardbirds, and the beginnings of heavy rock and the guitar hero.  Click the full post to read liner …
500songs.com
November 17, 2025 at 9:43 AM
The good news: The Random Universe is the “#1 New Release in Cosmology”. 

The bad news: a friend and cosmology colleague has found the first error in the book.
November 15, 2025 at 10:10 AM
Today in the NY Times: Lisa Lucas’ love letter to Leiden, one of the intellectual capitals of Europe.
November 12, 2025 at 10:43 AM
I talk about The Random Universe (the book, and the Universe itself) on [Sean Carroll's Mindscape. We cover epistemology, probability, quantum mechanics, cosmology and more. Sean and I were cosmology grad students at the same time, and it was a pleasure and an honour to spend time with him online.
335 | Andrew Jaffe on Models, Probability, and the Universe – Sean Carroll
www.preposterousuniverse.com
November 11, 2025 at 10:54 AM
The Random Universe is out! Buy it or borrow it, read it and review it!
November 11, 2025 at 8:57 AM
Reposted by Andrew Jaffe
in this week’s Mindscape, as @seanmcarroll.bsky.social talks with
@defjaf.bsky.social about “Models, Probability, and the Universe”, I learned that in Jaffe’s (and others’) model, the Hubble constant is 67.

kids today might be either thrilled or deflated by this value.

I myself would prefer 42.
November 10, 2025 at 2:02 PM
The Random Universe isn’t out until tomorrow (November 11), but the Kindle edition is on sale in both the US and in the UK. (And if you look very carefully, you’ll see that it has broken into the top 100 UK cosmology bestsellers…)
November 10, 2025 at 12:55 PM
Unboxing The Random Universe youtube.com/shorts/tvQJh...
Unboxing The Random Universe
YouTube video by Andrew Jaffe
youtube.com
November 5, 2025 at 6:23 PM
Reposted by Andrew Jaffe
What happens when science takes a backseat in government policy? A critical examination from @defjaf.bsky.social . 
The Trump Administration's Contempt for Science - Yale University Press
Andrew H. Jaffe— The biggest economy in the world has decided that science is not a priority, barely worth supporting. This is the arrogance of American leaders unable or unwilling... READ MORE
yalebooks.yale.edu
October 30, 2025 at 9:31 PM
The Random Universe isn’t due out until November 11, but not only can you pre-order your copy today, you can also download a free sample from the e-book. (Similar on Amazon UK and Apple Books — though it’s even better if you buy your hardcopy from an independent bookseller!)
October 27, 2025 at 4:17 PM
The clocks went back an hour here in London overnight—summertime is over. I suppose I’m happy for the extra time to rest (though in fact I didn’t sleep very well last night) but not looking forward to six months of early darkness.
October 26, 2025 at 6:44 AM
Apparently I am the subject of an unauthorised biopic.
October 20, 2025 at 11:23 AM
Lots of fun recording an episode of the Mindscape podcast with Sean Carroll. Should appear on November 10, just before the release of The Random Universe.
October 20, 2025 at 10:04 AM
I made a thing.
October 9, 2025 at 6:29 PM
Surprised that Taylor needs to promote her latest with an A4 poster at the Imperial College elevators (lifts).
October 3, 2025 at 5:29 PM