Near the earth-sun Lagrange point one. It changes course for no apperant reason. I geuss that is the beauty of Lagrange points.
It's partly that, but mostly just the fact that the picture is in a rotating reference frame. Anything in Earth's gravity well will more or less be dominated by Earth's gravity and have elliptical-looking orbits, but anything outside will follow strange-looking paths instead of the ellipses we expect.
The big hint for this is that the object is deflected down (on the picture) when travelling left to right, but deflected up when travelling right to left, while in both cases travelling above the lagrange point (so neither being consistently attracted nor deflected).
Did anyone really want a word processor to be able to produce html?
Yes, because it's one of the few portable, widely-supported document formats that exists. It's my first choice for telling people what to re-save as when someone sends a Word document to my *nix account (postscript saves are much larger).
I don't know about "surprising", but the following demos are certainly crowd-pleasers:
Turning sugar into a carbon sponge.
To do this, put some sugar in a beaker under a fume hood and use tongs to pour a bit of concentrated sulphuric acid on it from a second beaker. The acid catalyzes water extraction from the sugar (which is exothermic), giving you a big mass of carbon puffed up with steam. This sponge is much larger than the original sugar sample (demo looks coolest if this greatly overflows the beaker; you get a column of carbon coming out of it). Handle the acid with great respect, as it'll eat through anything organic or metallic. Phosphoric acid probably works for this too, though I haven't seen it done.
Shrinking a balloon in liquid nitrogen.
Inflate a balloon, tie a string to it, and then lower it into a dewar of liquid nitrogen. As the balloon approaches the nitrogen, the air nearest it cools and becomes a lot more compact (remember gas laws). What you end up with is something that looks like a deflated balloon, with either very cold air or (if you dunked it) liquid oxygen and nitrogen in it. Leave it on a counter, and it may re-inflate (try not to freeze all of the rubber if you want it to do this).
Shattering things with liquid nitrogen.
Dip just about anything containing water into liquid nitrogen, and it turns into a rock. Do this with something fragile, like a flower, and you get a flower that shatters as if it was made of glass when you tap it on a desk. This is very impressive. I've heard of someone dunking a banana and shattering it with a hammer, but you'd have to leave it in for quite a while to make sure it's good and cold. When I tried similar things, the ice deformed instead of shattering.
Removing a balloon "cateract".
This one only works if you have a high-powered laser handy. I suppose in a pinch a sufficiently powerful ordinary light source would do too. Stick a coloured balloon inside a transparent one, inflate the inner balloon half way, tie it off, and then inflate the outer balloon fully. You end up with a coloured balloon inside a transparent one. Shine a laser or other very bright, localized light through the balloons and the coloured balloon will have a hole melted in it and pop, leaving the transparent balloon intact. This was a fun demo put on by the local science centre. I suppose you could use a fresnel lens to focus sunlight down, but a) that's cheating and b) that works by a different method (the hot spot is only at the focal point).
Shattering glass with a feedback squeal.
Do do this demo, mount a speaker and a microphone next to a target. For best results, use a directional mic and the mic/target line at right angles to the speaker/target line (i.e. pick up sound from the target, not the speaker). Place an object prone to vibration (like a wine glass or other drinking glass) in the target zone, turn on your amp, and tap the glass's rim. It will shatter very shortly.
Making standing waves.
Get a glass or plastic tube, fill it a third full of water, seal the ends in a way that's waterproof, and lay it on its side. Put a speaker at one end, and hook up a signal generator to an amp to feed the speaker. Feed it with a sine wave and vary the range from about 1-10 kHz. When the frequency matches one of the resonant frequencies of the air channel in the tube, water "walls" will form at the antinodes due to the pressure vibration at the nodes exerts on the surface of the water. I suppose if you turned the power up sufficiently you could get the same thing happening in a tilted or even vertical tube, but this would get quite loud and possibly dangerous (if you hit a resonant frequency of part of your support frame, vibration could damage a tube made of glass).
Making mad scientist potions with liquid nitrogen or dry ice.
Fill beakers or glasses with coloured water (or kool-aid), and then either drop in a pellet of dry ice or pour on a couple of teaspoons of liquid nitrogen. Both will sit on a vapour cushion on top of the water for quite a while, and the cold will make dense fog on top of the water. Instant mist-boiling potion. If you decide to drink this, use dry ice instead of liquid nitrogen, and blow out when you sip so the pellet drifts away from you. Better yet, don't drink from it at all. Frostbite isn't fun.
Melting through cans with thermite.
This is a fun and safe demo, but needs to be done in a fume hood due to fumes and sparks. Set up a retort stand holding two or three small cans. Cut the tops off of the cans, and fill them half full of sand. Line up the cans over each other, and put a patio stone or similar large flat slab of stone or concrete under the retort. Put a large can filled with sand on top of the stone, under the bottommost can. Over the topmost can put a ring stand with a piece of steel mesh you don't mind losing. Put a piece of paper or tissue on top of this, and put a small pile of thermite powder on the paper. Put on a leather gauntlet, and use a firework sparkler to touch off the thermite (ignition temperature is higher than an ordinary flame provides, a burner flame may detonate the pile, and a sparkler is safer than a powder trail of something easier to ignite). Optionally, put a small amount of something more sensitive on top of the thermite and light that with a burning wooden splint, but a sparkler is both simpler and safer.
NOTE: Do this with the fume hood down most of the way, and for safest results put a blast shield in front of the retort stand. There will be many, many sparks thrown by this demo.
The thermite will burn very brightly yellow-white, and will throw sparks everywhere and give off vapours (probably either water from the paper, or boiling iron oxide that wasn't consumed; I haven't checked). The thermite will burn the paper almost instantly, dumping white-hot molten iron through the rapidly disintegrating screen, through the sand in each can, through the bottom of each can, and down to the large can of sand at the bottom of the retort stand. It may eat through the bottom of this, but at worst will just slightly etch the stone (the stone won't react catastrophically with molten iron, and has enough heat capacity that you certainly won't melt through it and is thick enough that it won't crack through from heat shock).
This demo is quite safe, with proper precautions, and very impressive.
Lastly, things not to do. This is not an exhaustive list:
Don't dip your hand in lead.
If done right, this can be safe, as water boiling off your hand forms a vapour cushion briefly. This is easy to screw up, and has drastic consequences if anything goes wrong. Don't do it.
Don't put liquid nitrogen or dry ice in your mouth.
This can also be done safely if done right, for the same reason - the dry ice or liquid nitrogen boils, forming an insulating vapour cushion. Briefly. If you hold it too long, or are just unlucky, you get a very painful and inconvenient case of frostbite, or worse. Don't do this.
I've heard of people drinking small amounts of liquid nitrogen. This is beyond stupid.
Don't do anything involving pryrotechnics, shattering objects, molten metal or other hot liquids, liquid nitrogen or other cryogenic liquids, or strong acids or bases without a blast shield between the demo and your audience.
Protective gear is a must too, but even without it, a spark or a splash will only hurt _you_. Hurting your audience must be avoided at all costs.
(or, for the extreme crowd, demonstrating the Leidenfrost effect by sticking one's hand into a vat of molten lead [PDF]).
Ah yes, this would be the one where the paper says, "Never, ever do this.". [If you use too much water, you get a steam explosion that sends molten lead everywhere.]
You might be able to do a safer variant by dipping apples or bananas or what-have-you, though, with a blast shield between the crucible and the audience, though (and a leather apron and gauntlets and visor, unless you *like* liquid metal scars).
No, subliminal messages don't work, but you could still print messages on the screen (invisible to the naked eye) using this system, and then only people trying to pirate the movie with a camcorder would be treated to the messages
This would actually be pretty easy to do. Just shine a bright near-IR light onto the screen, and any camcorder without an IR filter will be washed out. Ditto with soft UV, though fluoresence will be a problem.
Aleternatively you could project with "white" light made from colours that muck with the colour balance of camera detectors. What looks white to you would look ugly on camera (or to someone with partial colour blindness, though).
Alternatively, you could sell sunglasses that let you read the subliminal messages (they'd have digital camcorders built in with displays on the inside of the glasses,) AND let you see that hilarry rosen is really an alien.
If you're using the colour-balance approach, ordinary coloured filters should let you see the patterns your fake white light is making. IR and UV are a bit harder to catch cheaply (UV could be seen cheaply by focusing an image on a slide painted with fluorescent material, but near-IR is harder).
The part that confuses me is that, since code would need to be recompiled to make use of this, you might as well just compile for x86-64 and make use of a larger flat register space. While the idea is interesting, there doesn't seem to be any advantage to using it (and a few disadvantages, pointed out by other posters).
The guy does not realize that what he proposed is not at all simple to implement in silico.
This two additional mapping register would complicate the pipeline hazard detection in an exponential way.
It shouldn't. You'd just have to flag any modification of the map register as a hazard, and move the rest of the hazard detection after the mapping stage. It mostly just adds latency, not complexity.
You do not understand how computer really works. If you have more registers, more instructions for manipulating those registers and finally more cache.. you don't need high bus speeds. Processor won't need to get much of data from memory anyway, because it will have 99% of what it needs already in registers & internal cache.
Unfortunately this is not true. The working set of most programs is either small enough to already fit in the caches of most processors, or large enough that you can throw as much cache as you want at it without making a dent.
Regarding registers, the only thing that registers affect is L1 accesses. Think of the register file as being a level-zero cache. Having a larger GP register file does not change the working set of the program; it only reduces the number of stalls waiting for L1 data. The load on the system memory bus will be the same.
In summary, if the memory bus is a bottleneck with current processors, it'll be a bottleneck for this proposed processor too.
You know, the claims that some music CD user owner will want to make a legit rip/copy of some CD he bought is plausible. But how many game owners make backup copies of his game CDs ?
I do.
I've had two music CDs die of scratches. I don't want my game CDs to suffer a similar fate with no recourse.
I'm in the process of backing up my music CDs as well.
The main conditions for humans to thrive aught to be size (and thus gravity), temperature, and atmosphere.
Sure, being on a moon around a bigger planet would make for funny (i.e., not like on Earth) day cycles, tides, eclipses, seasons and so on. But those are secondary considerations.
The problem is that a moon of a gas giant isn't likely to have a friendly climate. Because it'll be tidally locked to the gas giant, days will be the equivalent of several Earth weeks long at *best*, and at worst will last for half the orbital period of the gas giant (if the plane of the moon's orbit is perpendicular to the ecliptic). In both cases, you get one side of the moon becoming very hot, and one side very cold, and hellishly powerful winds whipping around the planet trying to equalize the temperatures.
When the orbit of the moon passes behind the gas giant, you'll also get a night that lasts anywhere from Earth days on up, which will drop the moon's temperature enough to be problematic. Imagine your city being plunged into antarctic temperatures on a monthly basis. Not fun.
In summary, while a gas giant's moon would be an interesting place, it wouldn't necessarily be very friendly to human habitation.
Where would you prefer to live, on Mars on on Endor (given that Endor has say no seasonal variations, a 100 hour day cycle, and a spectacular eclipse twice a year).
Mars, for the reasons listed above. Give Mars a thick atmosphere by breaking down rocks, and you get an Earth-like climate. Dump a significant amount of CO2 in it, and you get enough of a greenhouse effect to make the temperature livable. Even as-is, it's a lot less hostile to life than Earth's moon.
But I think it's sort of pointless to look for earth-ish planets. I know that we're looking for existing life or possible places to live, but isn't it very possible there is some sort of life that lives in a drastically different environment than we do? There could very well be some crazy lifeform that lives on gas giants.
While it's _possible_ that life exists in other environments, environments with liquid water are likely to be the most _favourable_ to life because several physical and chemical properties of water make it absurdly friendly to complex chemistry and to hosting stable environments. See the last article on extra-solar planets for a more in-depth discussion.
Gas giants have water, but not in liquid form, and have convection currents carrying any material in the atmosphere up and down through layers with vastly different temperature and pressure extremes. Any life that survives in this environment would have to be very, very robust.
Not only that, but all of the plaets outside our solar system are many light-years away. It takes way too long to get to them.
Even without faster-than-light travel, it can be done in one or two human lifetimes, if the expense is ever considered worthwhile. Sailcraft driven by stationary laser arrays are probably the cheapest method (antimatter is extremely expensive to produce, and you can re-use your laser array). Even if we don't bother sending colonists or even probes, the demonstrated existance of earth-like planets outside the solar system will spur public interest in all things space-related, which is worthwhile.
I think time would be much better spent on figuring out how to live in unfavorable places, or change their climate to be favorable to our life.
These goals are not mutually exclusive. Research on these other topics is already going on. Why not do both?
The cost of the current family of planet searches is very, very low compared to space missions, as it's being done with ground-based equipment. Even the planned planet-finding space telescopes will be useful for many other types of research, and will be cheaper than any kind of manned mission.
In summary, I find no fault with the search for earth-like planets.
Y'know, maybe I'm biased, but having such a unique "grand prize" makes me think that losing would be devastating, in a way other "survivor"-esque shows aren't. If you're optimistic you think *maybe* this isn't "once in a lifetime", if we manage to make space travel a little less unique, but still.
I'd argue that that's part of the price of playing. If anybody goes into this program without *expecting* that they're not going to be picked, I have little sympathy for them (ditto people who put winning the lottery into their budget).
Yes, this is a very nifty toy. Yes, it deserves to be posted to slashdot.
But can you, the submitter, not scrape together the two brain cells required to post a summary in your own words? Or space the two seconds to type, "From the site:" and put quotes around your text?
It's getting to the point where two thirds of the articles posted have summary text directly copied from the site being linked to. This went from "minor irritant" to "annoyance" a while back.
Another problem with those paper cell phones.
on
Discarded Cell Phones
·
· Score: 3, Funny
Every year or so we run a story on paper, disposable cell phones but even these would generate a fair amount of waste.
Not to mention the dangerous buildup of bogonium that would result in the disposal sites.
Weren't the prototype phones always found to be disguised Nokia hardware? Hasn't the company producing these paper phones been denounced as a fraud every time this story comes up?
What we need is something that is trustworthy, anonymous (private from the prying eyes of 3rd parties), indenpendent of a government monetary authority or any centralized authority, easy to send and transfer electronicly, and with general predictability and liquidity in value.
The only thing that gives any form of money value is endorsement by some large entity. The pieces of paper in your wallet are called "notes" for a reason - they're statements by the government to the effect that the bearer of the note has control of a certain amount of capital. Once upon a time this actually correlated with a certain amount of gold (e.g. for the US) or silver (e.g. for England), but even without the correlation, the principle remains. The reason paper money has value is that the government says it has value.
Similarly, the reason a cheque or money order has value is that your bank says it has value.
Take away the backing authority, and you lose the value of any e-cash you'd implement. Whether it's the government or a bank or a company like PayPal or Ebay, you need _someone_.
I'd personally prefer it be the government, but I'm one of those communist Canadians;).
While I was going to make some insightful comments about continual growth of electric cars lately, this 'product' is just plain laughable.
[...]
And seriously, whats with the 8 wheel design?
That was my first thought too, but on closer inspection, this looks less like a car and more like a small bus with a nicer-than-usual interior. Under that category (luxury chartered bus), it could easily work.
For light you are talking wavelengths in the 400nm range - which is a frequency of c/400nm=749 terrahertz. I don't know of anything which samples in quite that range (that would be HIGH!!!). Also, you need to record time in the trillionth of a second range (picoseconds). That probably isn't all that easy either (I don't know much about atomic clocks, but I think that is feasible, though you have to sync the time recording to the data recording, which isn't easy).
At two samples per cycle, you need better than femtosecond (10^-15 second) resolution.
Atomic clocks are stable to one part in 10^14+, but that doesn't mean we can measure time in femtoseconds. Just that drift between two clocks will be less than ten femtoseconds per second.
You can make a strong circumstantial case for direct waveform sampling of visible light being outright impossible with machines built from normal matter, as the relaxation time of most electron state transitions is longer than the required sampling rate, meaning that there would be no way for any possible device to switch fast enough Various forms of exotic matter have faster state transitions, but making measurements from the surface of a white dwarf or a neutron star is difficult:).
OTOH, I can believe direct sampling of far-infrared, which would at least give many orders of magnitude better resolution than radio telescopes, with baselines longer than are practical for optical interferometers.
that we still can't see planets becuase most planets don't have radio stations on them:)
Jupiter does. Some amatures can even detect Jupiter's radio emmissions from home-built radio scopes
Any planet with a magnetosphere should produce substantial radio emissions from both trapped particles in their equivalent of the van Allen belts, and from diverted solar wind crashing down near the poles (the aurorae come from _somewhere_:)).
In practice, this means anything Earth-sized or larger (i.e. something with a molten nickel-iron core, or [for gas giants] with a metallic hydrogen ocean). In principle, ice moons with mantles of saltwater deep beneath the surface might have magnetospheres too, but in practice they won't have much, as you need a powerful heat source to drive the dynamo.
I have read that Jupiter broadcasts more radio noise than the Sun, but don't quote me on this.
I'd have to look that up. It sounds more like a mangling of another quote (that Jupiter emits more energy than it receives from the sun), but the Jupiter/Io flux tube does emit a lot of crud.
It's just that switchback currents in solar flares do too:).
"Duck, this is Doc. Sushi's moved back to 9. See you then." (10 seconds, tops) vs. "Sushi at 9"
You can't really tout losing all context as being an advantage. If we were supposed to eat at 8, my message is clear while your message leaves my friend wondering if I mistyped or if they're going to be waiting for an hour.
So change it to "Sushi now 9", and you have all of the original context (the fact that you will see him then is obvious, and sender is indicated by the message header).
My point is that the amount of information being conveyed by the original statement is very low, and so doesn't *need* a very long typed message.
Checking/leaving voicemail is not a busy wait; I can be walking down the street and do it.
In my own daily routine, checking/leaving voicemail _is_ usually a busywait, for a number of schedule and circumstance-related reasons. If you have enough walking time or what-have-you for it yourself, more power to you. However, I doubt I'm unique.
Re. driving, I do not consider text messaging or voice mailing while driving a good idea.
Now if everyone was taking mass transit, yes pervasive SMS would beat trying to talk over other people on an already noisy bus/train.
Last time I checked, there are plenty of mass-transit commuters on this side of the ocean, too.
I'm not arguing that _everyone_ should use SMS over voice mail. Just that for a large fraction of the population it seems to make sense, so I'm puzzled by statements alleging the opposite.
Same thing goes with pictures; it's just not in the culture.
At no point did my argument touch pictures; they're a non-issue for this discussion (I agree that they're useless for most purposes).
"Duck, this is Doc. Sushi's moved back to 9. See you then." (10 seconds, tops)
vs.
3#88222550777788777744 4440280... (I spent a minute on just this part)
You're trying to type something as verbose as what you'd say. Try something like:
"Sushi at 9"
You're also leaving out waiting through four rings and a "hi, I'm not in" to leave the message, which alone is likely enough for me to type the above. Then waiting through "welcome to FooPhone's automated voice messaging system", "You have Qux new messages", etc. to retrieve the reply.
I find leaving and retrieving voicemail far more cumbersome and time-consuming. YMMV.
While I don't doubt the value a radio telescope might have for planetary research, I'm willing to bet you're thinking about something akin to being able to see the individual cells on Pathfinder's solar-array on the surface of Mars from a telescope mounted here on Earth.
Anyone know the _optical_ resolution for maximum "zoom" on Hubble...?
A really good telescope will usually be limited by diffraction effects (the fact that the telescope is of finite size causes light being focused to blur out a bit as it passes through the telescope aperture).
A back of the envelope calculation suggests that the diffraction-limited resolution of the Hubble (at 2.5m) for 500 nm light is about 0.2 microradians (letting it resolve features ten million kilometres wide at Alpha Centauri, five light-years away [give or take], or letting you read a typewritten letter at 5 km).
A radio telescope typically operates on wavelengths on the order of a tenth of a metre (as a gross approximation; it's really an order of magnitude in either direction from there, if I understand correctly). The largest radio telescope dish on the planet is about 300m wide, giving a diffraction-limited resolution of about 0.3 milliradians, or about three times sharper than the unaided human eye is at optical wavelengths (the equivalent of reading a typewritten letter at about 10 feet).
An interferometric radio telescope with an aperture the size of the planet would have a resolution of about 10 nanoradians, letting it resolve features about 0.5 million kilometres wide at Alpha Centauri [slightly smaller than our sun] (the equivalent of reading a typewritten letter at a distance of 100 km, or the title on a paperback book from low Earth orbit).
If we had a radio telescope with an atomic clock on the moon (about 400,000 km away), we could resolve objects the size of Jupiter in the Alpha Centauri system. If we had a space-based radio telescopes in the Earth-Sun L4 or L5 points (each 150 million km from Earth), we could resolve individual cities on an Earth-like planet.
This is cheap enough to do that we're probably going to put radio telescopes there within the next couple of decades. Any planet with a magnetosphere within 50-200 light years would be detectable, and we'd have detailed maps of magnetic effects on the surfaces of every star within a thousand light-years.
It seems to me this "feature", just like text messaging, is being pushed by a culture that just doesn't understand Americans. Just because SMS is all the rage in Norway and the Japan has the highest per capita camera ownership doesn't mean some asshole American like myself simply doesn't want to have just a phone to, you know, fucking talk to people.
SMS is great for the same reason email is great - it's asynchronus. I *could* leave a voicemail message asking a friend when/if we're meeting for dinner, but text messaging is far simpler. Most of the time, we're either working or in some other setting where the phone is turned off, so you can't "just talk to people" very easily.
Yes, it is true that a CISC design will run faster with smaller/faster transistors, but a typical CISC design isn't very adaptable to make use of the much larger number of transistors that become available (assuming that the die size stays similar).
RISC doesn't magically allow more transitors to be used either, but it does tend to enable using multiple execution units and larger branch history/prediction tables tend to help performance as the pipeline is grown to more, faster stages.
Branch prediction and history tables should be independent of instruction set architecture. I agree that a RISCian instruction set makes it easier to find operations that can be performed in parallel, though. [ObDisclaimer that everything's a RISC nowadays, no matter what its user-visible instruction set. [ObDisclaimerDisclaimer: Except for DSPs and other VLIW chips]]
However, most of the die area for a modern chip isn't spent on functional units, if I understand correctly. It's spent on bigger on-die caches, bigger prediction tables, bigger TLBs, and so forth. We've actually been running out of ways to get performance gains from larger transistor counts (n-way issue gets ugly for large n, and working sets give you diminishing returns for making most other structures larger).
Either way, to truely take advantage of a significantly smaller geometry process (for performance instead of cost), the CPU needs to be redesigned to make use of a LOT more transistors as well as their faster speed.
Which is why CMP's suddenly in vogue among manufacturers.
Slashdot Mirror
Near the earth-sun Lagrange point one. It changes course for no apperant reason. I geuss that is the beauty of Lagrange points.
It's partly that, but mostly just the fact that the picture is in a rotating reference frame. Anything in Earth's gravity well will more or less be dominated by Earth's gravity and have elliptical-looking orbits, but anything outside will follow strange-looking paths instead of the ellipses we expect.
The big hint for this is that the object is deflected down (on the picture) when travelling left to right, but deflected up when travelling right to left, while in both cases travelling above the lagrange point (so neither being consistently attracted nor deflected).
Did anyone really want a word processor to be able to produce html?
Yes, because it's one of the few portable, widely-supported document formats that exists. It's my first choice for telling people what to re-save as when someone sends a Word document to my *nix account (postscript saves are much larger).
I would just like to point out that magnesium ribbon is useful for igniting thermite.
The magnesium ribbons I've seen tended to be difficult to light and to go out, but it may be that they were just old or otherwise unsuitable.
To do this, put some sugar in a beaker under a fume hood and use tongs to pour a bit of concentrated sulphuric acid on it from a second beaker. The acid catalyzes water extraction from the sugar (which is exothermic), giving you a big mass of carbon puffed up with steam. This sponge is much larger than the original sugar sample (demo looks coolest if this greatly overflows the beaker; you get a column of carbon coming out of it).
Handle the acid with great respect, as it'll eat through anything organic or metallic. Phosphoric acid probably works for this too, though I haven't seen it done.
Inflate a balloon, tie a string to it, and then lower it into a dewar of liquid nitrogen. As the balloon approaches the nitrogen, the air nearest it cools and becomes a lot more compact (remember gas laws). What you end up with is something that looks like a deflated balloon, with either very cold air or (if you dunked it) liquid oxygen and nitrogen in it. Leave it on a counter, and it may re-inflate (try not to freeze all of the rubber if you want it to do this).
Dip just about anything containing water into liquid nitrogen, and it turns into a rock. Do this with something fragile, like a flower, and you get a flower that shatters as if it was made of glass when you tap it on a desk. This is very impressive.
I've heard of someone dunking a banana and shattering it with a hammer, but you'd have to leave it in for quite a while to make sure it's good and cold. When I tried similar things, the ice deformed instead of shattering.
This one only works if you have a high-powered laser handy. I suppose in a pinch a sufficiently powerful ordinary light source would do too. Stick a coloured balloon inside a transparent one, inflate the inner balloon half way, tie it off, and then inflate the outer balloon fully. You end up with a coloured balloon inside a transparent one. Shine a laser or other very bright, localized light through the balloons and the coloured balloon will have a hole melted in it and pop, leaving the transparent balloon intact.
This was a fun demo put on by the local science centre. I suppose you could use a fresnel lens to focus sunlight down, but a) that's cheating and b) that works by a different method (the hot spot is only at the focal point).
Do do this demo, mount a speaker and a microphone next to a target. For best results, use a directional mic and the mic/target line at right angles to the speaker/target line (i.e. pick up sound from the target, not the speaker). Place an object prone to vibration (like a wine glass or other drinking glass) in the target zone, turn on your amp, and tap the glass's rim. It will shatter very shortly.
Get a glass or plastic tube, fill it a third full of water, seal the ends in a way that's waterproof, and lay it on its side. Put a speaker at one end, and hook up a signal generator to an amp to feed the speaker. Feed it with a sine wave and vary the range from about 1-10 kHz. When the frequency matches one of the resonant frequencies of the air channel in the tube, water "walls" will form at the antinodes due to the pressure vibration at the nodes exerts on the surface of the water.
I suppose if you turned the power up sufficiently you could get the same thing happening in a tilted or even vertical tube, but this would get quite loud and possibly dangerous (if you hit a resonant frequency of part of your support frame, vibration could damage a tube made of glass).
Fill beakers or glasses with coloured water (or kool-aid), and then either drop in a pellet of dry ice or pour on a couple of teaspoons of liquid nitrogen. Both will sit on a vapour cushion on top of the water for quite a while, and the cold will make dense fog on top of the water. Instant mist-boiling potion.
If you decide to drink this, use dry ice instead of liquid nitrogen, and blow out when you sip so the pellet drifts away from you. Better yet, don't drink from it at all. Frostbite isn't fun.
This is a fun and safe demo, but needs to be done in a fume hood due to fumes and sparks. Set up a retort stand holding two or three small cans. Cut the tops off of the cans, and fill them half full of sand. Line up the cans over each other, and put a patio stone or similar large flat slab of stone or concrete under the retort. Put a large can filled with sand on top of the stone, under the bottommost can. Over the topmost can put a ring stand with a piece of steel mesh you don't mind losing. Put a piece of paper or tissue on top of this, and put a small pile of thermite powder on the paper. Put on a leather gauntlet, and use a firework sparkler to touch off the thermite (ignition temperature is higher than an ordinary flame provides, a burner flame may detonate the pile, and a sparkler is safer than a powder trail of something easier to ignite). Optionally, put a small amount of something more sensitive on top of the thermite and light that with a burning wooden splint, but a sparkler is both simpler and safer.
NOTE: Do this with the fume hood down most of the way, and for safest results put a blast shield in front of the retort stand. There will be many, many sparks thrown by this demo.
The thermite will burn very brightly yellow-white, and will throw sparks everywhere and give off vapours (probably either water from the paper, or boiling iron oxide that wasn't consumed; I haven't checked). The thermite will burn the paper almost instantly, dumping white-hot molten iron through the rapidly disintegrating screen, through the sand in each can, through the bottom of each can, and down to the large can of sand at the bottom of the retort stand. It may eat through the bottom of this, but at worst will just slightly etch the stone (the stone won't react catastrophically with molten iron, and has enough heat capacity that you certainly won't melt through it and is thick enough that it won't crack through from heat shock).
This demo is quite safe, with proper precautions, and very impressive.
Lastly, things not to do. This is not an exhaustive list:
If done right, this can be safe, as water boiling off your hand forms a vapour cushion briefly. This is easy to screw up, and has drastic consequences if anything goes wrong. Don't do it.
This can also be done safely if done right, for the same reason - the dry ice or liquid nitrogen boils, forming an insulating vapour cushion. Briefly. If you hold it too long, or are just unlucky, you get a very painful and inconvenient case of frostbite, or worse. Don't do this.
I've heard of people drinking small amounts of liquid nitrogen. This is beyond stupid.
Protective gear is a must too, but even without it, a spark or a splash will only hurt _you_. Hurting your audience must be avoided at all costs.
Have fun.
(or, for the extreme crowd, demonstrating the Leidenfrost effect by sticking one's hand into a vat of molten lead [PDF]).
Ah yes, this would be the one where the paper says, "Never, ever do this.". [If you use too much water, you get a steam explosion that sends molten lead everywhere.]
You might be able to do a safer variant by dipping apples or bananas or what-have-you, though, with a blast shield between the crucible and the audience, though (and a leather apron and gauntlets and visor, unless you *like* liquid metal scars).
No, subliminal messages don't work, but you could still print messages on the screen (invisible to the naked eye) using this system, and then only people trying to pirate the movie with a camcorder would be treated to the messages
This would actually be pretty easy to do. Just shine a bright near-IR light onto the screen, and any camcorder without an IR filter will be washed out. Ditto with soft UV, though fluoresence will be a problem.
Aleternatively you could project with "white" light made from colours that muck with the colour balance of camera detectors. What looks white to you would look ugly on camera (or to someone with partial colour blindness, though).
Alternatively, you could sell sunglasses that let you read the subliminal messages (they'd have digital camcorders built in with displays on the inside of the glasses,) AND let you see that hilarry rosen is really an alien.
If you're using the colour-balance approach, ordinary coloured filters should let you see the patterns your fake white light is making. IR and UV are a bit harder to catch cheaply (UV could be seen cheaply by focusing an image on a slide painted with fluorescent material, but near-IR is harder).
The part that confuses me is that, since code would need to be recompiled to make use of this, you might as well just compile for x86-64 and make use of a larger flat register space. While the idea is interesting, there doesn't seem to be any advantage to using it (and a few disadvantages, pointed out by other posters).
The guy does not realize that what he proposed is not at all simple to implement in silico.
This two additional mapping register would complicate the pipeline hazard detection in an exponential way.
It shouldn't. You'd just have to flag any modification of the map register as a hazard, and move the rest of the hazard detection after the mapping stage. It mostly just adds latency, not complexity.
You do not understand how computer really works. If you have more registers, more instructions for manipulating those registers and finally more cache.. you don't need high bus speeds. Processor won't need to get much of data from memory anyway, because it will have 99% of what it needs already in registers & internal cache.
Unfortunately this is not true. The working set of most programs is either small enough to already fit in the caches of most processors, or large enough that you can throw as much cache as you want at it without making a dent.
Regarding registers, the only thing that registers affect is L1 accesses. Think of the register file as being a level-zero cache. Having a larger GP register file does not change the working set of the program; it only reduces the number of stalls waiting for L1 data. The load on the system memory bus will be the same.
In summary, if the memory bus is a bottleneck with current processors, it'll be a bottleneck for this proposed processor too.
You know, the claims that some music CD user owner will want to make a legit rip/copy of some CD he bought is plausible. But how many game owners make backup copies of his game CDs ?
I do.
I've had two music CDs die of scratches. I don't want my game CDs to suffer a similar fate with no recourse.
I'm in the process of backing up my music CDs as well.
Yes, I *do* buy my music and games.
The main conditions for humans to thrive aught to be size (and thus gravity), temperature, and atmosphere.
Sure, being on a moon around a bigger planet would make for funny (i.e., not like on Earth) day cycles, tides, eclipses, seasons and so on. But those are secondary considerations.
The problem is that a moon of a gas giant isn't likely to have a friendly climate. Because it'll be tidally locked to the gas giant, days will be the equivalent of several Earth weeks long at *best*, and at worst will last for half the orbital period of the gas giant (if the plane of the moon's orbit is perpendicular to the ecliptic). In both cases, you get one side of the moon becoming very hot, and one side very cold, and hellishly powerful winds whipping around the planet trying to equalize the temperatures.
When the orbit of the moon passes behind the gas giant, you'll also get a night that lasts anywhere from Earth days on up, which will drop the moon's temperature enough to be problematic. Imagine your city being plunged into antarctic temperatures on a monthly basis. Not fun.
In summary, while a gas giant's moon would be an interesting place, it wouldn't necessarily be very friendly to human habitation.
Where would you prefer to live, on Mars on on Endor (given that Endor has say no seasonal variations, a 100 hour day cycle, and a spectacular eclipse twice a year).
Mars, for the reasons listed above. Give Mars a thick atmosphere by breaking down rocks, and you get an Earth-like climate. Dump a significant amount of CO2 in it, and you get enough of a greenhouse effect to make the temperature livable. Even as-is, it's a lot less hostile to life than Earth's moon.
But I think it's sort of pointless to look for earth-ish planets. I know that we're looking for existing life or possible places to live, but isn't it very possible there is some sort of life that lives in a drastically different environment than we do? There could very well be some crazy lifeform that lives on gas giants.
While it's _possible_ that life exists in other environments, environments with liquid water are likely to be the most _favourable_ to life because several physical and chemical properties of water make it absurdly friendly to complex chemistry and to hosting stable environments. See the last article on extra-solar planets for a more in-depth discussion.
Gas giants have water, but not in liquid form, and have convection currents carrying any material in the atmosphere up and down through layers with vastly different temperature and pressure extremes. Any life that survives in this environment would have to be very, very robust.
Not only that, but all of the plaets outside our solar system are many light-years away. It takes way too long to get to them.
Even without faster-than-light travel, it can be done in one or two human lifetimes, if the expense is ever considered worthwhile. Sailcraft driven by stationary laser arrays are probably the cheapest method (antimatter is extremely expensive to produce, and you can re-use your laser array). Even if we don't bother sending colonists or even probes, the demonstrated existance of earth-like planets outside the solar system will spur public interest in all things space-related, which is worthwhile.
I think time would be much better spent on figuring out how to live in unfavorable places, or change their climate to be favorable to our life.
These goals are not mutually exclusive. Research on these other topics is already going on. Why not do both?
The cost of the current family of planet searches is very, very low compared to space missions, as it's being done with ground-based equipment. Even the planned planet-finding space telescopes will be useful for many other types of research, and will be cheaper than any kind of manned mission.
In summary, I find no fault with the search for earth-like planets.
Y'know, maybe I'm biased, but having such a unique "grand prize" makes me think that losing would be devastating, in a way other "survivor"-esque shows aren't. If you're optimistic you think *maybe* this isn't "once in a lifetime", if we manage to make space travel a little less unique, but still.
I'd argue that that's part of the price of playing. If anybody goes into this program without *expecting* that they're not going to be picked, I have little sympathy for them (ditto people who put winning the lottery into their budget).
Really, aside from the cardinal sin of not quoting the source, the submissions heavily ladened with quotes are often the better.
Which is why quoting the source was one of the two options I noted in my original post.
Posting the article text as one's own is, IMO, Very Wrong. Especially given that adding attribution takes next to no effort.
Ok, I've reached my plagarism threshold.
Yes, this is a very nifty toy. Yes, it deserves to be posted to slashdot.
But can you, the submitter, not scrape together the two brain cells required to post a summary in your own words? Or space the two seconds to type, "From the site:" and put quotes around your text?
It's getting to the point where two thirds of the articles posted have summary text directly copied from the site being linked to. This went from "minor irritant" to "annoyance" a while back.
Every year or so we run a story on paper, disposable cell phones but even these would generate a fair amount of waste.
Not to mention the dangerous buildup of bogonium that would result in the disposal sites.
Weren't the prototype phones always found to be disguised Nokia hardware? Hasn't the company producing these paper phones been denounced as a fraud every time this story comes up?
What we need is something that is trustworthy, anonymous (private from the prying eyes of 3rd parties), indenpendent of a government monetary authority or any centralized authority, easy to send and transfer electronicly, and with general predictability and liquidity in value.
;).
The only thing that gives any form of money value is endorsement by some large entity. The pieces of paper in your wallet are called "notes" for a reason - they're statements by the government to the effect that the bearer of the note has control of a certain amount of capital. Once upon a time this actually correlated with a certain amount of gold (e.g. for the US) or silver (e.g. for England), but even without the correlation, the principle remains. The reason paper money has value is that the government says it has value.
Similarly, the reason a cheque or money order has value is that your bank says it has value.
Take away the backing authority, and you lose the value of any e-cash you'd implement. Whether it's the government or a bank or a company like PayPal or Ebay, you need _someone_.
I'd personally prefer it be the government, but I'm one of those communist Canadians
While I was going to make some insightful comments about continual growth of electric cars lately, this 'product' is just plain laughable.
[...]
And seriously, whats with the 8 wheel design?
That was my first thought too, but on closer inspection, this looks less like a car and more like a small bus with a nicer-than-usual interior. Under that category (luxury chartered bus), it could easily work.
For light you are talking wavelengths in the 400nm range - which is a frequency of c/400nm=749 terrahertz. I don't know of anything which samples in quite that range (that would be HIGH!!!). Also, you need to record time in the trillionth of a second range (picoseconds). That probably isn't all that easy either (I don't know much about atomic clocks, but I think that is feasible, though you have to sync the time recording to the data recording, which isn't easy).
:).
At two samples per cycle, you need better than femtosecond (10^-15 second) resolution.
Atomic clocks are stable to one part in 10^14+, but that doesn't mean we can measure time in femtoseconds. Just that drift between two clocks will be less than ten femtoseconds per second.
You can make a strong circumstantial case for direct waveform sampling of visible light being outright impossible with machines built from normal matter, as the relaxation time of most electron state transitions is longer than the required sampling rate, meaning that there would be no way for any possible device to switch fast enough Various forms of exotic matter have faster state transitions, but making measurements from the surface of a white dwarf or a neutron star is difficult
OTOH, I can believe direct sampling of far-infrared, which would at least give many orders of magnitude better resolution than radio telescopes, with baselines longer than are practical for optical interferometers.
that we still can't see planets becuase most planets don't have radio stations on them :)
:)).
:).
Jupiter does. Some amatures can even detect Jupiter's radio emmissions from home-built radio scopes
Any planet with a magnetosphere should produce substantial radio emissions from both trapped particles in their equivalent of the van Allen belts, and from diverted solar wind crashing down near the poles (the aurorae come from _somewhere_
In practice, this means anything Earth-sized or larger (i.e. something with a molten nickel-iron core, or [for gas giants] with a metallic hydrogen ocean). In principle, ice moons with mantles of saltwater deep beneath the surface might have magnetospheres too, but in practice they won't have much, as you need a powerful heat source to drive the dynamo.
I have read that Jupiter broadcasts more radio noise than the Sun, but don't quote me on this.
I'd have to look that up. It sounds more like a mangling of another quote (that Jupiter emits more energy than it receives from the sun), but the Jupiter/Io flux tube does emit a lot of crud.
It's just that switchback currents in solar flares do too
"Duck, this is Doc. Sushi's moved back to 9. See you then." (10 seconds, tops)
vs.
"Sushi at 9"
You can't really tout losing all context as being an advantage. If we were supposed to eat at 8, my message is clear while your message leaves my friend wondering if I mistyped or if they're going to be waiting for an hour.
So change it to "Sushi now 9", and you have all of the original context (the fact that you will see him then is obvious, and sender is indicated by the message header).
My point is that the amount of information being conveyed by the original statement is very low, and so doesn't *need* a very long typed message.
Checking/leaving voicemail is not a busy wait; I can be walking down the street and do it.
In my own daily routine, checking/leaving voicemail _is_ usually a busywait, for a number of schedule and circumstance-related reasons. If you have enough walking time or what-have-you for it yourself, more power to you. However, I doubt I'm unique.
Re. driving, I do not consider text messaging or voice mailing while driving a good idea.
Now if everyone was taking mass transit, yes pervasive SMS would beat trying to talk over other people on an already noisy bus/train.
Last time I checked, there are plenty of mass-transit commuters on this side of the ocean, too.
I'm not arguing that _everyone_ should use SMS over voice mail. Just that for a large fraction of the population it seems to make sense, so I'm puzzled by statements alleging the opposite.
Same thing goes with pictures; it's just not in the culture.
At no point did my argument touch pictures; they're a non-issue for this discussion (I agree that they're useless for most purposes).
Come again? Try:
"Duck, this is Doc. Sushi's moved back to 9. See you then." (10 seconds, tops)
vs.
3#88222550777788777744 4440280... (I spent a minute on just this part)
You're trying to type something as verbose as what you'd say. Try something like:
"Sushi at 9"
You're also leaving out waiting through four rings and a "hi, I'm not in" to leave the message, which alone is likely enough for me to type the above. Then waiting through "welcome to FooPhone's automated voice messaging system", "You have Qux new messages", etc. to retrieve the reply.
I find leaving and retrieving voicemail far more cumbersome and time-consuming. YMMV.
While I don't doubt the value a radio telescope might have for planetary research, I'm willing to bet you're thinking about something akin to being able to see the individual cells on Pathfinder's solar-array on the surface of Mars from a telescope mounted here on Earth.
Anyone know the _optical_ resolution for maximum "zoom" on Hubble...?
A really good telescope will usually be limited by diffraction effects (the fact that the telescope is of finite size causes light being focused to blur out a bit as it passes through the telescope aperture).
A back of the envelope calculation suggests that the diffraction-limited resolution of the Hubble (at 2.5m) for 500 nm light is about 0.2 microradians (letting it resolve features ten million kilometres wide at Alpha Centauri, five light-years away [give or take], or letting you read a typewritten letter at 5 km).
A radio telescope typically operates on wavelengths on the order of a tenth of a metre (as a gross approximation; it's really an order of magnitude in either direction from there, if I understand correctly). The largest radio telescope dish on the planet is about 300m wide, giving a diffraction-limited resolution of about 0.3 milliradians, or about three times sharper than the unaided human eye is at optical wavelengths (the equivalent of reading a typewritten letter at about 10 feet).
An interferometric radio telescope with an aperture the size of the planet would have a resolution of about 10 nanoradians, letting it resolve features about 0.5 million kilometres wide at Alpha Centauri [slightly smaller than our sun] (the equivalent of reading a typewritten letter at a distance of 100 km, or the title on a paperback book from low Earth orbit).
If we had a radio telescope with an atomic clock on the moon (about 400,000 km away), we could resolve objects the size of Jupiter in the Alpha Centauri system. If we had a space-based radio telescopes in the Earth-Sun L4 or L5 points (each 150 million km from Earth), we could resolve individual cities on an Earth-like planet.
This is cheap enough to do that we're probably going to put radio telescopes there within the next couple of decades. Any planet with a magnetosphere within 50-200 light years would be detectable, and we'd have detailed maps of magnetic effects on the surfaces of every star within a thousand light-years.
It seems to me this "feature", just like text messaging, is being pushed by a culture that just doesn't understand Americans. Just because SMS is all the rage in Norway and the Japan has the highest per capita camera ownership doesn't mean some asshole American like myself simply doesn't want to have just a phone to, you know, fucking talk to people.
SMS is great for the same reason email is great - it's asynchronus. I *could* leave a voicemail message asking a friend when/if we're meeting for dinner, but text messaging is far simpler. Most of the time, we're either working or in some other setting where the phone is turned off, so you can't "just talk to people" very easily.
Yes, it is true that a CISC design will run faster with smaller/faster transistors, but a typical CISC design isn't very adaptable to make use of the much larger number of transistors that become available (assuming that the die size stays similar).
RISC doesn't magically allow more transitors to be used either, but it does tend to enable using multiple execution units and larger branch history/prediction tables tend to help performance as the pipeline is grown to more, faster stages.
Branch prediction and history tables should be independent of instruction set architecture. I agree that a RISCian instruction set makes it easier to find operations that can be performed in parallel, though. [ObDisclaimer that everything's a RISC nowadays, no matter what its user-visible instruction set. [ObDisclaimerDisclaimer: Except for DSPs and other VLIW chips]]
However, most of the die area for a modern chip isn't spent on functional units, if I understand correctly. It's spent on bigger on-die caches, bigger prediction tables, bigger TLBs, and so forth. We've actually been running out of ways to get performance gains from larger transistor counts (n-way issue gets ugly for large n, and working sets give you diminishing returns for making most other structures larger).
Either way, to truely take advantage of a significantly smaller geometry process (for performance instead of cost), the CPU needs to be redesigned to make use of a LOT more transistors as well as their faster speed.
Which is why CMP's suddenly in vogue among manufacturers.