scott_sanford: (Daria proofreads)
An interesting science demonstration on youtube; these fellows have a laser and a very fast camera...


Watching this, I realize I am not used to considering lightspeed delays over distances of a few centimeters.
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According to this article human energy use over time plots very close to linearly on a logarithmic scale (~10x per century), back to 1650. Extrapolating, we become a Kardashev Type I in only 400 years - much less than I'd guess, but not impossible with SPS arrays. Past that we hit Type II only a thousand years later, and that seems rather soon for a full Dyson Swarm.

While many functions that look logarithmic eventually go sigmoid, it's unclear where the inflection point is - except that we haven't gotten there yet, and it may be quite a ways out. Much like Moore's Law; we know it tops out somewhere... I'll take a stand that it will inflect well before reaching Type II, and that we definitely won't reach Type III on schedule; if nothing else this would require massive FTL travel, which looks unlikely.

The article also points out that if we're using this amount of energy on Earth, the waste heat is going to become first a nuisance and then a damn problem, as the planet cannot radiate that much energy into space without active assistance. (I expect the author will get some flames because only atmospheric CO2 levels are supposed to be mentioned in this context.) It's not clear how much heat we could lose by, for example, a low-orbit radiator disk and orbital towers - but even trying wouldn't be cheap.

PS: Because I know my readers are the kind of people to be curious, humanity currently uses about 22 terawatts per year, about 0.16% of Earth's total energy budget, putting us around 0.72 on Carl Sagan's revised Kardashev scale.
scott_sanford: (Default)
According to this article, CERN has measured a neutrino beam at a whisker above lightspeed. However, this is the media, which does not have a good track record for accuracy, particularly when the implications are large. As pointed out in the comments, a 0.00246% measurement error may be all that is needed to explain this, although no such error has been found yet. Stay tuned.

PS: Also reported on Livejournal by seawasp and James Nicoll.
scott_sanford: (Default)
I'm posting this so I will not lose the link to this article about cities and economics, which is not only intellectually interesting but useful to anyone doing world building for fiction or RPG purposes.

PS: For the, oh, two people who read me but not James Nicoll, see here for his take on it.
scott_sanford: (Default)
Okay, so a friend finds a link to this article, talking about a particular kind of basin found in Egypt, ancient limestone basins clearly manufactured for a specific purpose. Okay, reasonable enough. But the author seems to think these are made of artificial limestone, for levitating...something. And so we get stuff like this:

The high-resonance form of hydrogen is called protium, being the lightest hydrogen isotope, known for its powerful rejuvenative effects, in stark contrast to the cellular aging induced by heavy water. The levitation of water by solar-driven infrasound resonance allows separation of lighter protium water molecules from the heavier isotopes of deuterium and tritium (above).

Wait, what? Rejuvination? Infrasound? Levitation of water? Solar power? (And deuteurium and tritium are only 0.015% of all hydrogen anyway.) I didn't even include the stuff about pizoelectricity. Frankly, I'm lost. I'm pretty sure the author is trying to say something, and he's got a better command of English than the Time Cube guy, but I don't follow the argument and I'm going to quietly sneak out of the room while nobody is looking.

It has some pretty pictures of ruins, though.
scott_sanford: (Default)
Wait, that's everyone I know. I got pointed to The Secret Life of Cats, a National Geographic documentary viewable online to anyone willing to put up with the site's slightly quirky video player.

The film examines the predatory behaviour of cats rather more than their other 'secrets' but there's only so much cat life you can cover in an hour. The piles of small dead things are impressive, but it doesn't address how many Mighty Hunters are in the cat population compared to the well known Ambulatory Pillow and Feline Drama Queen types.

It's not to be confused with this study which involved putting tracking systems onto cats, but that report makes a fun read - and the fate of the Stephens Island wren is a memorable factoid.

Orion!

Jun. 28th, 2011 01:28 am
scott_sanford: (Default)
I know this will be of interest to some of my readers. Back in 1959 the Orion project was still getting funding (sanity had not yet set in) and some actual flight tests were done. This short video clip shows an unmanned 105kg test vehicle taking off propelled by 1kg C4 charges.

(Related only by reader interest, it seems that Los Alamos has a large wildfire.)
scott_sanford: (Default)
I mentioned the web comic Nukees the other day. I am aware that not everyone reads this, but I enjoy it.

scott_sanford: (Default)
According to this article the structure of the outer heliosphere is more complex than anyone suspected. (You know, before we shot the Voyager probes into it.) There doesn't seem to be any horrifying doom implied by large frothy magnetic field bubbles a hundred AU from home, but no doubt some author will do something with them.
scott_sanford: (Default)
Back in my first post on this subject I said I hoped to try this again the next day, and I have been asked to write up what happened on the second day of sign holding. Okay.

More after the cut! )
scott_sanford: (Default)
I post this knowing that it may not be read by anyone who cares about mad science or cats. *grin*

A recent study of radio tracked cats reveals interesting things about their habits. For example, individual territories vary widely, with feral cats covering much more area than domestic felines. Also, cats spend more time laying around than you might think.

You can read an article or catch a quick Scientific American podcast about it.
scott_sanford: (Default)
In my city shabbily dressed people can often be seen standing at street corners holding carboard signs, apparently as an alternative to panhandling from pedestrians. For a long time my friends and I have wondered how practical this really is. So I finally ran the experiment.

Read more... )
scott_sanford: (Default)
This article has much to say about how humans weigh evidence vs. beliefs, and the pitfalls of telling people what they don't want to hear.

The comments fell to ad hominim attacks surprisingly quickly.
scott_sanford: (Default)
The exoplanet WASP-18b is gifted with a few quirks, like 3800F daytime temperatures and an 22.5 hour year, but they pale beside the fact that it's de-orbiting and will soon hit the Roche limit and break up, after which the bits will fall into the sun. One thing about astronomy, there's always someplace that makes even the less favored parts of Earth look good.
scott_sanford: (Default)
So I'm wasting time on the net as usual when I run across an anecdote from Operation Plumbob, a nuke testing program back in the 1950s.

It seems that their point criticality tests led to some interesting learning experiences. Follow along: Pascal-A was supposed to check that a single faulty detonator could not actually set off the whole bomb (an implosion type design counts on having a bunch of carefully timed detonators to, well, implode). So the test unit is lowered down a 147 meter shaft and set off, which is when they discover that someone's slipped a decimal point somewhere - the yield is about 55 tons, or 50,000 times what they expected. Oops.

Witness Robert Campbell said, "Biggest damn Roman candle you ever saw! It was beautiful. Big blue glow in the sky..."

Right. After this little learning experience, they redesigned things a bit for the next test.

Pascal-B was a near duplicate of Pascal-A, but after the fireworks display last time, the scientists decided to put a cap on the hole. (The military has a very good understanding of "tube with explosives at one end.") Starting with a piece of four inch thick armor plate, a one-ton steel cap for the hole was made and lowered into place for the test.

Like the first time, this test was predicted to yield about as much force as 1-2lbs worth of TNT. Like the first time, this wasn't particularly accurate. Pascal-B went off at around 1/3 kiloton, or 600,000 times what it should have. Oops, again.

The surface high-speed camera caught exactly one frame of that one-ton steel plate as it left the ground, headed upwards at what was later estimated as six times Earth escape velocity, never to be seen again. A flying manhole cover moving face-on through the air is a spectacularly un-aerodynamic shape, and the best guess is that it vaporized long before it left the atmosphere.

While the cap was very, very gone it was not forgotten; this incident was brought up later in connection with the Project Orion concept. There's probably a moral in there somewhere.
scott_sanford: (Default)
Among [livejournal.com profile] james_nicoll's verbose postage was a link to a space warfare essay, Battle of the Spherical War Cows: Purple vs. Green. Well! How can you pass up a title like that?

But from there we link to the Atomic Rockets site, with...even more essays! I am doomed! DOOOOMED!
scott_sanford: (Default)
For a friend (she knows who she is): a trip to HAARP! Read more... )
scott_sanford: (Default)
I see that Neal Stephenson has things to say on Slate, the gist of which is (a) rockets are expensive and (b) changing the game is hard. Naturally he says this in more detail than I do, and I was tickled to see him mention Jordin Kare.
scott_sanford: (Default)
Apparently this is an actual object.

Read more... )
scott_sanford: (Default)
The world's oldest pot stash has been discovered. Technically speaking (as I understand these things) it is not really a stash, as the cannabis was among the valuables buried with someone rather than being hidden away for later use - but I'm a layman in that field. More interestingly, the plant had apparently been bred for THC potency, suggesting the species has been domesticated longer than we knew.

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