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Comment: Re:Hmm (Score 1) 81

by Rei (#48623175) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

That's not all that different from how he got started with Tesla. He had no intention of starting a car company (he already had SpaceX), he just wanted AC Propulsion to build him a copy of their t-zero - but they had no interest, even for a small fortune. But then they pointed him to this guy named Martin Eberhard who had this wild idea to commercialize the t-zero's tech base on a Lotus Elise body and was looking for funding... and thus Tesla was born.

Comment: Re:Pretty sad (Score 1) 152

by Rei (#48619997) Attached to: Dr. Dobb's 38-Year Run Comes To an End

g++ supports it with __restrict__. And if you're writing high performance code but not having support for the features of modern compilers, you're an idiot. In appropriate situations, the performance difference for using restrict or not is huge. Array-heavy tasks like image processing often get a 2-fold or more benefit with using restrict. There's very few places in the coding word where a single keyword can raise your performance that much.

Comment: Re:As with all space missions: (Score 1) 185

by Rei (#48619855) Attached to: NASA Study Proposes Airships, Cloud Cities For Venus Exploration

I'll begin by stating that I I don't support such a mission, as I prefer robotic exploration. But this proposal isn't as extreme as it may sound - it's probably a heck of a lot easier than landing on a planet and taking off. It's only 640 m/s from earth escape to Venus (3/5ths that of Mars). Transit time is less and launch windows a lot more frequent. Venus offers very easy aerocapture. You don't have to deal with the randomness of the surface - your "landing" is a lot more forgiving. Your habitat is probably simpler, not having to deal with a surface (although there's a few potential complications that need to be studied, such as storms, and I don know the radiation level at the desired altitude). Keeping it aloft is easy - even normal earth air is a lifting gas on Venus. Solar energy arriving at Venus is double that of Earth. Nearly earth's gravity eliminates a lot of the uncertanties about skeletal and muscular wasting.

One of the neat things is that a person could potentially step outside without any sort of special suit, just an oxygen mask. It's a "maybe", though, as there's a few complicating factors. It's 37C (100F) at the same sort of heights that it's about 600mb; for US analogies, it's Phoenix temperatures at Mount Whitney air pressures (lower or higher for both, depending on your exact altitude - you can choose). So it's not a perfect match - but probably tolerable. But there's two potential complicating gases: SO2/sulfuric acid and carbon monoxide. Breathing them is right out, but even long-term (hours at a time) skin exposure might be problematic at the given concentrations; it's not certain whether at these altitudes they'd be prohibitive. They would however make eye protection a must at the very least, the eyes are more sensitive to both CO and SO2 than the skin.

Manned or not, the main advantage of a Venus blimp would be the lower altitude it would provide to scientific equipment versus satellites. So you'll get a lot more information on the atmosphere, which could help answer questions about Venus's evolution (and how other worlds in other systems might be). You'll get higher resolution radar imaging of the surface. You simplify to some extent sample return missions from the surface, as each sample collection doesn't have to be a self contained return mission. Etc.

One thing on Venus I'd love to see studied more is the super-reflective radar surfaces. It's now believed to be due to a "galena snow", snow made of shiny, electrically conductive lead sulfide. I'd really love to know more about the surface minerology of Venus in general.

Comment: Re:Hmm (Score 1) 81

by Rei (#48616615) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

I'm not talking about ideals, or tourism, or saving the world, or finding anything "up there", or anything of that nature (did you even read what I wrote?). I'm talking about the sheer awesomeness of, at your whim, shooting up a 1500 tonne rocket into orbit then landing it on an automated oceanic platform. It's like playing Kerbal with a real-life 70-meter tall rocket. Why don't more billionaires do stuff like that if only just for the fun of it?

But clearly you have an axe to grind against something for some reason, so I'll let you get back to that wheel.

Comment: Hmm (Score 4, Interesting) 81

by Rei (#48616227) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

Why don't more billionaires do stuff like this?

I'm not saying do it "for the benefit of humanity", or even "for a profit". Just simply.... if you have billions of dollars, and you want to spend it on something, what can you possibly spend it on that wins in a sheer awesomeness category as "shooting a gigantic rocket up into orbit and then landing it on a robot boat in the middle of the ocean"? That's like a freaking video game, played with 1500 tonnes of aluminum and highly combustible fuel.

Comment: Re:Pretty sad (Score 1) 152

by Rei (#48615965) Attached to: Dr. Dobb's 38-Year Run Comes To an End

Back in the day, Dr. Dobbs was giving the world invaluable stuff like Mode X. Your average programmer had to be a lot more connected with the hardware, and working with the hardware was somewhat of a black art. Nowadays there's still some black art stuff out there for getting good performance (even a lot of simple, important stuff is inexplicably obscure... I bet you that 90% of C/C++ programmers don't even know what the restrict keyword does, for example), and you still see the occasional inner loop of some high performance code use assembly, but that's not the general case.

Comment: Re:Anti-Aging is a Fraud Magnet (Score 4, Informative) 165

by Rei (#48615927) Attached to: Researchers Accidentally Discover How To Turn Off Skin Aging Gene

Usually most aging-preventing discoveries cause cancer. For example, the p21 knockout mice that gained almost salamander-like regeneration also gained a high tumor rate. Usually processes in your body involving the stopping of growth and areas dying off are things that help prevent cancer from forming or growing.

Comment: Cautious? (Score 1) 81

by Rei (#48615899) Attached to: Spacecraft Spots Probable Waves On Titan's Seas

Scientists involved in the discoveries have been cautious, saying that the features could also be floating debris or bubbles

Um, wouldn't those things be even more awesome? Trust me, I won't be disappointed if there's geological activity causing bubbling from under the seas (heat plus organics!), or if there's floating objects (cryopumice / super fluffy snow? organics foams? something else? what the heck floats on methane, after all?)

Comment: Re:Is Titan slowly drying off? (Score 1) 81

by Rei (#48615873) Attached to: Spacecraft Spots Probable Waves On Titan's Seas

Probably not, but the hydrocarbon cycle on Titan is still very poorly understood. I really look forward to the next Titan mission, but unfortunately everyone's obsessed with Europa so the next launch window is almost certainly going to be missed and it'll be decades before a new spacecraft gets there. The presence of seas and the low gravity plus a dense atmosphere leaves one with a plethora of great exploration options (all nuclear powered, of course, there's essentially no sunlight): hydrogen blimp (it's noncombustible on Titan) (with or without propulsion), hot air or hot hydrogen blimp (it takes surprisingly little heat there to get lift), hybrid blimp / lifting body aircraft, helicopter, fixed wing aircraft, tilt wing aircraft, boat, hybrid aircraft / boat (with any other aircraft design), etc.

My favorite design (although probably the most expensive) would be a tilt wing aircraft with floating landing gear for either surface or sea landings. You get the high speed travel and freedom of motion of a fixed wing aircraft so you can cover the whole planet, but you can land anywhere, do science for a day or so while you recharge your flight batteries (so you don't need a huge RTG or reactor), then take off again for the next location. The view from the air (whether optical or radar) of the previous day's hop would be used by the ground team to figure out where to have it go for the next day.

Comment: Re:yeah right (Score 4, Interesting) 81

by Rei (#48615833) Attached to: Spacecraft Spots Probable Waves On Titan's Seas

They worded it poorly, as the seas are methane, which is not oil - on earth it's the prime component of natural gas, so the better term would simply be "hydrocarbons". That said, hydrocarbons do not need life to form - just hydrogen, carbon, and a shortage of any oxidizers that could break them down into the lower energy states of H2O and CO2. Even longer chain hydrocarbons can form naturally - on Titan, that happens in the upper atmosphere by photochemical reactions.

It's important not to overgeneralize Earth to other celestial bodies. For example, you can even have bodies with oxygen atmospheres without life. We see this (to a tiny extent) on Europa, which has an extremely thin oxygen atmosphere from photolysis of water ice. It's quite possible that in other systems there could be an environment that produces a denser O2 atmosphere through a similar process - or through other processes, both known or not yet conceived of.

The universe is a weird place. Think about what a tidally locked rocky planet orbiting close to its parent star would experience. I read about one planet whose night side temperature was expected to be earthlike but with a hot side temperature of thousands of degrees. So think about it for a second, what's going to happen? The hot side is going to constantly boil off, potentially even to plasma, be circulated around to the cold side, and then rain down rock. Rockstorms. Depending on the properties of the rock, the rate of boil-off, the rate of redistribution, and the properties of the atmosphere, it could be anywhere from dust to large chunks, and anything from volcanic-like ash to pele's hair (rock wool) to breccias to gemstones. Lightning would be tremendous, like in some volcanic eruptions. Given the amount of energy at hand, winds in storms could get up to ridiculous intensities. The redistribution of mass is going to cause a continual planetary slump from the cold side to the hot side, so one would expect frequent, super-intense earthquakes and frequent volcanic eruptions. You might get some intense magnetic effects via an exceptionally strong dynamo effect, plus the star's magnetic field itself would be orders of magnitude stronger. Aurora could be intense enough to light the sky on the cold side and power photosynthesis. Aurora could be intense enough to light the sky and power photosynthesis on the cold side. Liquid water would be stable in certain places (if it managed not to be all blown off over geological timescales, that is, the planet would have to be large), but would be thrashed about to biblical extends by the other aforementioned processes. If the magnetic fields are strong enough, flowing saltwater may even be visibly dragged by Lorentz forces and build up charges when constrained. The dissociation of the rock on the hot side would free up oxygen into the atmosphere, which would not be all immediately consumed on the cold side (some oxidation reactions are slow). And on and on. So it's potentially possible to have livable, breathable planet with a soil made from regular rains of rock wool and gemstones, lit by aurorae and in a constantly undergoing one catastrophe after the next.

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