Gravity in Multiply Connected Space

September 6, 2021 7:13 PM

Author Greg Egan has a new book out, and wrote up an explainer behind the math: "A space that is connected (in the sense that there is always a path between any two points), but not simply connected, is known as a multiply connected space, because there are multiple, fundamentally different ways to get from A to B. ... The purpose of this page is to discuss the way that Newtonian gravity can be adapted to a multiply connected space like this."
posted by curious nu (26 comments total)

Until a young physicist is twenty-five, they still think, every so often, that under the right circumstances they could be the baddest motherfucker in mind-bending, ultra-hard sci-fi. If I got into Caltech for grad school and also the Clarion West writer's workshop. If I moved into a library and studied real hard for ten years. If I just dropped out and devoted my life to eating peyote and inventing theorems. Hiro used to feel that way, too, but then he read the work of Greg Egan. In a way, this is liberating. He no longer has to worry about trying to be the baddest motherfucker in mind-bending, ultra-hard sci-fi. The position is taken.
posted by tclark at 7:38 PM on September 6, 2021 [48 favorites]

I still favor the theory, which I think dates back to Usenet days, that Egan is the nom de plume of an AI buried under the University of Western Australia.
posted by tavella at 8:07 PM on September 6, 2021 [14 favorites]

I read The Clockwork Rocket and found it an interesting physics exercise in desperate need of a story. Despite this, I'm very glad that he's still at it, the mad lad.
posted by Mr.Encyclopedia at 8:10 PM on September 6, 2021 [7 favorites]

His short story collections are basically Ted Chiang before Ted Chiang.
posted by sixswitch at 8:22 PM on September 6, 2021 [9 favorites]

I read The Clockwork Rocket and found it an interesting physics exercise in desperate need of a story

Yeah, his physics / number theory stuff is by far the most successful part of his writing for me, so I prefer his short stories because they don't have enough time to do much of the other parts that he's less good at, i.e., plot and people.
posted by aubilenon at 8:53 PM on September 6, 2021 [3 favorites]

The position is taken.

If it's tickling your memory, that's a Snow Crash reference.
posted by ChurchHatesTucker at 9:06 PM on September 6, 2021 [2 favorites]

It might've been here that somebody described his work as "murder mysteries where physics is the culprit" and I think of them in that way. If the characterization is sometimes lacking, the mystery is still always on point.
posted by solarion at 9:54 PM on September 6, 2021 [2 favorites]

I have no comment on his generalized Newton gravity investigations, because I am not qualified in that kind of physics. But I can say this: The comparisons to Ted Chiang and Neal Stephenson are really not fair. Those two are more like fanfic and science name-dropping -- lots of vibe, but when you look closer, it doesn't fit together, it's more like magic. At least, that was my response. Obviously others see more in their work. But as a math major, some of Greg Egan's work touched on issues that I had stayed up thinking about deeply, and his writing shed new light on them. I have cited his science fiction in multiple hard-science papers, because it felt appropriate to credit sources.
posted by brambleboy at 10:31 PM on September 6, 2021 [10 favorites]

I quite liked both Yalda's political story in the Orthogonal books and the many characters on the long trip out and back. It slightly reminded me of the long trip out and back in the Chanur books, also a same-but-different novel about childrearing and autonomy.
posted by clew at 10:53 PM on September 6, 2021 [1 favorite]

I read Greg Egan books until I realized I wasn't smart enough to understand Greg Egan books.
posted by zardoz at 11:49 PM on September 6, 2021 [4 favorites]

Some of his more recent fiction has more physics than I can appreciate. I've liked a lot of his earlier fiction, but I don't know if I'm the only person who noticed how much of it is horror.
posted by Nancy Lebovitz at 1:59 AM on September 7, 2021 [2 favorites]

I loved Egan's first dozen or so books - they were some of my favorite science fiction ever. As I recall they featured characters with more than one dimension as well as introducing fascinating ideas. Schild's Ladder, Uncanny Valley, Oceanic, Permutation City - all were really enjoyable reads.

Since then, though, his books have progressively become more and more unreadable (at least to me). Anyway I'm glad to hear that he still has an audience.
posted by Umami Dearest at 2:17 AM on September 7, 2021 [5 favorites]

I think Egan was my first 'oh-- hard sci-fi is a thing!' was that quickly fell in love and devoured it all. Recently finished his Phoresis novella and it was such a delightfully alien perspective. Wish I could find more writers in that vein, nothing has quite scratched the same itch so completely.
posted by Static Vagabond at 3:16 AM on September 7, 2021 [2 favorites]

I re-read a bunch of Egan earlier this summer, not knowing this was on the way. I'll probably grab it.

My reread was the clockwork rocket series, incandescence, diaspora, and luminescence. The first three are--overall--hopeful novels in which seeking understanding leads to good outcomes. The last, short stories, are more dystopian and horror and it was really not what I was looking for at that moment.

None of them are good bedtime reading, they're better taken together with the companion physics textbook he always puts on his website.

In the novels there seems to be a short list of repeated elements: First, that there's physics to be discovered and the right people to discover and understand it; second, there is political opposition to a change in the status quo that vanishes once the reality of a threat is shown by the physicists; and third, an exploration of reproductive rights and self-determination in an alternate biology. Let's see whether the new novel has all these things.

My theory (*** NOT REALLY A THEORY, IT'S A JOKE ***) about who/what Greg Egan really is, is that it's a radio antenna pointed at a distant time-reversed star that from time to time receives novels and short stories which are then dutifully transmitted as well as published in ebook form. We are incredibly lucky that the system is being used only for works of fiction, and that overall they're not something everyone finds an uninventive plod.
posted by the antecedent of that pronoun at 5:37 AM on September 7, 2021 [1 favorite]

The thing about Egan's books is that while there's lot of science, or at least stuff that looks like science, and working out what the sciencey parts mean is part of the fun, you don't really need to work it out to enjoy them.

The first of his books that I read was Incandescence, and I found it impossible to follow the maths involved in the space bugs' gravity/inertia experiments, but the things going on around those experiments were so fascinating, and Egan's obvious lack of interest in the usual conventions of storytelling so intriguing, that I went out and bought Diaspora and several others as soon as I finished it. Or take Permutation City, which is partly about computation and makes more sense if you know some computer science, but is also about Charles Dickens, Yukio Mishima, Friedrich Nietzsche and the Death of God.

(Incandescence also has some really interesting subtext that you can start to tease out by asking: if saving the Ark was so important to the Aloof, why didn't they do it themselves?)

So anyway, The Book of All Skies is definitely on my list of lockdown reading.
posted by A Thousand Baited Hooks at 5:58 AM on September 7, 2021 [1 favorite]

Remember, a triangle is just a circle with all the curvature concentrated at the corners... I enjoyed most of Egan's early work (Diaspora is one of my favourite novels ever), but I also feel that he's become harder to read as time goes by - it'll be interesting to see if this follows the trend.
posted by memetoclast at 7:39 AM on September 7, 2021 [1 favorite]

I like allegory, and people aren't writing much of it these days. Egan's _Distress_ had three systems which were sustained by many parts supporting each other.

And his _Diaspora_ is the best sense of wonder sf novel I've read.
posted by Nancy Lebovitz at 7:42 AM on September 7, 2021 [2 favorites]

(Also, since you asked, the Ark-dwellers were the proto-Aloof, it's pretty clearly spelled out in the book; my issue is that the optics of their visual systems doesn't make sense, given the size they are and the wavelengths of light they perceive. A small thing, you might say, but he named the novel after it!)
posted by memetoclast at 7:44 AM on September 7, 2021

The comparisons to Ted Chiang and Neal Stephenson are really not fair. Those two are more like fanfic and science name-dropping -- lots of vibe, but when you look closer, it doesn't fit together, it's more like magic

You're right. It's not fair to compare Greg Egan (or anyone else, really) to Ted Chiang.

But that's not why.
posted by The Bellman at 8:31 AM on September 7, 2021 [10 favorites]

I picked this up last night, as soon as I found out about it, and finished reading it today. It's pretty good! A bit similar in concept and execution to his novella "Phoresis" from a couple years back (albeit with less weird biology and more weird physics) so if you liked that one, you'll probably like this too.

On a literary level, it's not bad, but definitely not one of Egan's greatest works ever. Like a lot of his more recent output, it really seems to struggle to reach a satisfying endpoint, and I'm a little apprehensive about the fact that it seems to have been totally self-published.

If he can keep putting out novels of this caliber for $3 a pop, I'm happy to keep buying them, but my gut tells me that bypassing the traditional editorial process is doing his work a disservice.
posted by teraflop at 9:17 AM on September 7, 2021

Love his work. I'm so glad there is hard scifi of this caliber out there.
posted by garbhoch at 10:07 AM on September 7, 2021

I think Egan has gotten a little bored with conventional story-telling, but I'll be patient with him, because his story-telling chops are amazing.

Diaspora and Permutation City are good novels by any account.

But many of his short stories are among the best to be written by anyone in SF in the last quarter century -- full of narrative craft ... dare I say Ted Chiang full?
posted by MattD at 11:10 AM on September 7, 2021

In Incandescence, the characters muse at the end of the novel about the nature of the Aloof, and the idea that the Aloof are the cousins of the Arc Dwellers is a good one, but the closest the book gets to saying it is Rakesh to Zey (an ark dweller) about the aloof at the end: "I don't know anything about them for certain...I think they might be sleepwalking, like your team-mates".

We aren't shown or told much more about the Aloof than what Rakesh and Parantham see or speculate about among themselves, so if Rakesh won't jump to this conclusion about who the Aloof are, I'm not sure why I should. That said, I'm willing to entertain the idea.

Ah, well, there is an element that Rakesh didn't know that we as readers do, but I didn't make the connection until reading this just now namely that maybe the system that the arc dwellers speculate about creating at the end of the Roi narrative thread: "The Hub is a dangerous place...If [others] come this way we should send them back, the way you guide a hatchling away from danger: just pick them up and turn them around".

OK, now I believe (some of) the Ark Dwellers became the Aloof.
posted by the antecedent of that pronoun at 12:47 PM on September 7, 2021 [1 favorite]

Thanks, Bellman. You made me check my comment, and -- this is embarrassing -- I confused Ted Chiang with Liu Cixin, the author of "The Three Body Problem", which wasn't my cup of tea. I actually haven't read Ted Chiang, although he is on my must-read list, and I look forward to it. There go all my sci fi creds.

This thread has also put a bunch more Egan on my must-read list.
posted by brambleboy at 3:08 PM on September 7, 2021 [1 favorite]

Only Egan would write a portal fantasy -- complete with circling around and round a mound -- and accompany it with this textbook.
posted by joeyh at 4:17 PM on September 7, 2021

the antecendant of that pronoun: see this - Egan clearly meant for readers to connect those dots.
posted by memetoclast at 7:26 AM on October 4, 2021