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Comment Re: No Dragon 2 Soft Landing Yet (Score 2) 140

Venus is the only target that makes sense. Much easier in the long run than Mars or Luna, but the initial stake is high, as you have to get a fairly sizeable dirigible there to start things off. Once you do, though: proper gravity, proper pressure, reasonable temps, plenty of atmospheric rad shielding, plenty of oxygen, trace elements there for the scavenging so you don't need a "perfect" sealed colony that would never work. It's a great idea, really.

Comment Re: Rockets are too expensive (Score 2) 140

Half the energy to obit at GEO comes from lateral acceleration. A space elevator would be a giant pendulum. And not a nice freshman-physics harmonic oscillator, but a nasty chaotic system with multiple modes of vibration. The energy stored in the system would increase with every payload until it destroyed itself, because there's no way to shed that unwanted energy - minimal friction, trivial air resistance, and so on.

Comment Re:Too good to be true. (Score 2) 181

Not in the sense of a mirror, but yes, it does, nondirectionally. More importanty, it tends to radiate at frequencies not absorbed by the material.

Look, "reflection" is a specific concept, OK? It's a different thing than absorption and emission. They are two different effects, which is why we use different words to describe them. There is some refraction by clouds, and I'm sure some trivial percentage is refracted multiple times to end up headed back towards the surface, but that's about it.

Why does the distinction matter? Actual reflection of IR nearly blocks radiative cooling (at some point the reflective surface, not being perfect, heats up and starts radiating). This is why a really good thermos needs a reflective layer in addition to a vacuum gap. If IR were being reflected close to the emitter, which it's not, changing the frequency to one not reflected would make a huge difference.

Absorption is very different. Sure, the atmosphere absorbs IR and becomes warmer as a result, but it's not like that happens meaningfully within a few yards of the ground! Changing the frequency of your thermal radiation a bit will not make a meaningful difference in cooling. OTOH, covering something sitting in the sun with a reflective surface makes a significant difference.

Comment Re:No (Score 1) 116

Technology is extremely brittle.

And yet it has never gone backwards.

If the power grid were down for two weeks, society would devolve into barbarian survival fighting.

In some of the cities, perhaps. People will riot over anything. But there are a lot of "preppers" out there who would take 2 weeks just to stop patting themselves on the back. Power would be restored and the military would restore order.

large a population wanting too much energy, generating too much pollution for the balloon to keep inflating forever

Pollution in the US has fallen dramatically in my lifetime. The same will eventually happen in China and India as they become fully industrialized; heck, there's already some movement in China.

. It is now beyond obvious that individual greed will prevent humans from doing anything about this because it is not profitable to a few individuals

Human nature hasn't changed ever, but here we are, with centuries of amazing scientific and technological advancement.

Comment Re:Too good to be true. (Score 3, Informative) 181

Outer space is at ~3K/-270C: having that as your cold sink *day and night* is really quite significant.

Radiative cooling doesn't work that way: all that matters is your temperature. You don't radiate more into a cold area than a hot (a hot area sends more thermal radiation to warm you up, but that's orthogonal). It would be different if the atmosphere reflected IR, but that's not the case.

Comment Re:Using SHA-1 in this day and age is just lazy (Score 1) 187

It's arguably a major Bug in Git if the Git software keeps track of an object Solely by Hash, and lazily assumes that the Hash uniquely identifies a specific version of the file,

A hash of 128 bits or more is a more reliable unique ID than anything custom you could code up. Safe vs malicious attackers is different, and as others have pointed out, sign your commits. But as just a way to get a reliably unique ID for a document (or set thereof)? It's a very solid approach.

Comment Re:Sounds too simple to be true (Score 1) 982

While more people find Trump credible than the old-school media, it still less than half the people who find him credible. The destruction of credibility of the old-school media was self-inflicted - Trump merely comments on the obvious fact. Have you never been directly involved in something that was reported by a journalist?

Comment Re:Using SHA-1 in this day and age is just lazy (Score 1) 187

You think hashes are unique. You're insane.

A 128-bit hash (from a common library or hardware implementation) is more likely to be unique than any code you write in the attempt to create a unique ID. Why? Because the risk of an accidental 128-bit hash collision within a pool of, say 1 billion items, is lower than the risk of a bug in your code.

If you doubt it, ask yourself this: what's the occurrence of bugs, per million lines of code, in high quality software? I bet there's a better than 1:1 million chance of a bug in any code you write to generate a unique ID. But even if you're the greatest coder ever, in all of time and space, I bet the risk of a bug is higher than 1:1 trillion.

Comment Re:Using SHA-1 in this day and age is just lazy (Score 5, Insightful) 187

Time for Torvalds to drop the attitude and fix this

As far as I can tell, this is a non-cryptographic use of hashing. I've used MD5 in plenty of places just to get a fast (hardware-accelerated) unique ID for a chunk of data, or as a checksum. No security purpose at all.

Comment Re:That will die down (Score 2) 982

Well-played, sir.

OP said:

when it has clearly devolved into one of the worst, most openly racist and least interesting communities on the internet

So he's clearly new here. We get far fewer GNAA posts here today than the early days. The political stories that don't belong here are, in fact, clickbait to broaden the appeal of /. beyond "news for nerds", since "news for nerds" is what's makes it the least interesting community for more people out there.

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