Anders Sandberg, a researcher in futurism and transhumanism, writes about Dyson spheres, megastructures, the far future of the universe, and the Fermi paradox.
HN commenters link his Dyson Sphere FAQ and transhumanism pages as enjoyable reading, and discuss the physics of large-scale structures and the long-run cooling universe.
I could be wrong (my physics background isn't that strong either) but I think Dyson's "time without end" paper http://www.aleph.se/Trans/Global/Omega/dyson.txt shows that eventually the universe will cool down enough to make all keys brute-force-attackable despite Bremermann's limit.
Given a finite amount of attacker computation you're willing to defend against, you can get a real advantage from key stretching (though not from mere salting). If you want a password strength of 256 bits, you can memorize a password of 226 bits and require work equivalent to 2³⁰ key-hashing operations to derive the actual encryption key or crypted password. This is normally called a KDF; reasonable ones are scrypt, bcrypt, and Argon2, in ascending order of goodness.
If you make the work factor unreasonably large, you won't be able to use the password in practice, because you have to do that work every time you use it. For example, if you try to memorize 170 bits of password and use a 2¹⁷⁰ work factor in your KDF to reach the 340-bit security level, recommended here, you have to do 2¹⁷⁰ work on your laptop every time you log in. Assuming a trillion operations per second (a safe upper bound for current laptops) each login will take about 47 nonillion years, about a sextillion times longer than the history of the universe so far and about 50 times longer than the expected lifetime of the last galaxies (see https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future). It may be inconvenient to…
I wouldn't put it that way. The problem is that a ton of the stuff impinging on us is not knowledge. It's propaganda, fluff, stupid memes, click bait, and systems with interfaces designed to be addictive and to act like Skinner boxes.
What I really see happening is a "part 2" repeat of the spam apocalypse that hit e-mail, Usenet, and other federated systems on the early Internet. In the late 1990s spam destroyed most of these systems. E-mail was so valuable it had to be saved, but saving it has mostly involved delegating it to a small oligopoly of vertically integrated e-mail providers with the resources to fight spam. Usenet and other less well known federated systems were destroyed.
I think we are now seeing a similar kind of spam assault against the open web, social media, and the news. The latter with the whole "fake news" phenomenon really resembles a Sybil attack. In recent years I've seen an avalanche of totally fake news sites that look like legitimate newspapers popped up (apparently from templates) and used to spam social media with a whole slew of unfounded allegations and other assorted bullshit. The role they've had in the election has gained a lot of press but it's in no way limited to that or even to politics. A lot of it seems to be shilling for quack medical products and other traditional mainstays of... spam!
I've started calling this whole phenomenon "spam 2.0." I'd define spam 2.0 as the semi-automated bulk creation of fake news outlets, fake social…
> This is just silly
Given an HN reader took the trouble to email me their thanks for my comment, I respectfully disagree. To do this, they had find my email address by following some of my other comments, linking to a website, following through to github... The email they wrote was articulate. They put in real effort to say "thanks".
> "he" is a gender neutral pronoun when referring to a person of unspecified gender (as in other languages).
In some dictionaries, yes. A possible counter-argument to this is that the tradition of that usage comes from cultures with significant inbuilt misogyny.
> "They" is plural.
Sometimes.
- https://en.oxforddictionaries.com/definition/they
- http://www.merriam-webster.com/words-at-play/singular-nonbinary-they
> "Ve" is not a word.
I can read it, write it, say it and find other like usages in numerous places. To me, that reflects most of the necessary facets of "a word".
- https://genderneutralpronoun.wordpress.com
- http://vevemvir.tumblr.com
- http://www.aleph.se/Trans/Cultural/Art/eganrev.html
- http://www.dictionary.com/browse/etymology
- http://www.wikihow.com/Create-a-Made-Up-Word
> "S/he" is awkward and unnecessary
Agreed. I dislike this form. A similar option is to alternate use of "he" and "she". This form is common, and probably the simplest. I wish I'd suggested it.
> we can argue that it is misandrous because you're capitalizing the "S" and prioritizing "She" over "he"
That was you, not me.
Reminds me of the Space Odyssey series: http://www.aleph.se/Trans/Cultural/Art/2001.html
"In these, they roamed among the stars. They no longer built spaceships, they were spaceships.
But the age of Machine-entities swiftly passed. In their ceaseless experimenting, they had learned to store knowledge in the structure of space itself, and to preserve their thoughts for eternity in frozen lattices of light. They could become creatures of radiation, free at last from the tyranny of matter.
Into pure energy, therefore, they presently tranformed themselves; and on a thousand worlds, the empty shells they had discarded twitched for a while in a mindless dance of death, then crumbled into rust.
Now they were lords of the galaxy, and beyond the reach of time. They could rove at will among the stars, and sink like a subtle mist through the very interstices of space. But despite their godlike powers, they had not wholly forgotten their origin, in the warm slime of a vanished sea."
Edit: A big brain fart, ignore the retracted part below. Colonizing the universe is of course impossible in 100My, barring FTL. What the paper I referred to [1] says is that colonizing the Milky Way may take less than that, and if you can do that, spreading to the rest of the observable universe is fairly easy, very relatively speaking.
<retracted> According to some calculations, it should in principle be possible to colonize the entire observable universe in less than a hundred million years. It's much too fast for the expansion to affect except marginally.</retracted>
The relative jump in difficulty from interstellar to intergalactic is much smaller than from interplanetary to interstellar.
Anyway, as others said, mere intragalactic (and intra-Local Group) travel is not affected by expansion in any way whatsoever.
[1] https://www.sciencedirect.com/science/article/abs/pii/S0094576513001148, PDF at https://www.aleph.se/papers/Spamming%20the%20universe.pdf
> a Matrioshka Brain would put out such a small amount of radiation, it'd be invisible for all sensor technology
A huge object emitting infrared radiation would be quite detectable.
At the level of energy output from our Sun, a Dyson sphere with a diameter of the Earth's orbit, would actually have a surface temperature of 395K or 122C. It would put out lots of infrared radiation, and would be very detectable against the cosmic background which has a radiation temperature of 2.7K.
Some SETI programs have looked for these, and already in 1984 we had the technology to observe, and as it turns out, to rule out any of these (Dyson spheres around stars with energy output comparable to our Sun) existing within the nearest 300 light years.
https://www.aleph.se/Nada/dysonFAQ.html#HEAT
https://www.aleph.se/Nada/dysonFAQ.html#OBS
http://www.projectrho.com/public_html/rocket/weirdastronomy.php#id--Object_X