Wikipedia:Reference desk/Archives/Miscellaneous/2009 March 1

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March 1

What is direct wire USB control?

What is the meaning of USB DIRECT CONTROL available in in car audio systems now-a-days? —Preceding unsigned comment added by Akshun1991 (talk • contribs) 11:06, 1 March 2009 (UTC)

USB Direct Control appears to describe the ability to connect an iPod via a USB cable and use the stereo's controls to select music on the iPod. In other words, the iPod isn't just treated as a line in source; you can "control" the iPod from the head unit without using the iPod's controls. – 74  13:00, 1 March 2009 (UTC)

Pink

What is the lightest shade of pink? List of colors baffles me. Queenie ^Talk 16:36, 1 March 2009 (UTC)

Someone may correct me, but I don't think there's an authority for that. The colours above are simply accepted; they may be Pantone. But by my reckoning, surely R:256, G:255, B:255 (Hex close to this) is the lightest shade of pink (essentially the whitest red). - Jarry1250 ^{(t, c)} 16:48, 1 March 2009 (UTC)

The lightest shade with a name might be found from Pantone. Jarry1250 didn't quite get the numbers right: the lightest shade of pink you can display using an 8 bit per component computer graphics card is #FFFEFE (that's R:255, G:254, B:254)...but it's SO similar to pure white that you'd find it hard to tell:

PINK (#FF8080)

WHITE (#FFFFFF)

The lightest possible pink (#FFFEFE)

PINK (#FFEEEE) per User:Jarry1250

However, that's limited only by 8bits-per-color computer graphics cards. Some fancy setups can do 10 bits or more per component. There are laser projectors that can do 16 bits per component. Those permit VASTLY more subtle colors - and pinks that are so amazingly subtly different from pure white that it would take extremely subtle instruments to tell the difference.

In the end, it's down to the ability of our eyes to distinguish it - and that's a question that varies between individuals, it varies depending on the ambient light levels and a bunch of other parameters. So there really isn't a single "correct" answer. SteveBaker (talk) 17:05, 1 March 2009 (UTC)

Yep, my error (I was typing off the top of my head, always a mistake), but actually if you look at the three boxes, then back, to the first one etc, it's very hard to tell (as you say). - Jarry1250 ^{(t, c)} 17:38, 1 March 2009 (UTC)

Thanks. I've decided to use white, as it actually looks pinkish when compared to the blue-tinted Wikipedia backdrop. Thanks once again, Queenie ^Talk 17:43, 1 March 2009 (UTC)

Good plan - although the complementary color of blue is yellow - not pink - so your white box ought to be looking yellowish...but the Wikipedia logo and backdrop is grey - not blue. SteveBaker (talk) 04:07, 2 March 2009 (UTC)

On my screen the white box looks more light pink than the lightest pink. Btw, the complementary colours are a primary and the other two primary colours combined, so for blue it's actually orange; purple's complementary is yellow. Julia Rossi (talk) 22:03, 2 March 2009 (UTC)

The complementary colour of a primary colour is a secondary colour. In the RGB system, the complement of blue is red+green=yellow. "Purple" isn't a primary or secondary colour, you probably mean magenta, which is red+blue, so its complement is green. Orange isn't a secondary colour, either, it contains more red than green. --Tango (talk) 13:43, 3 March 2009 (UTC)

Julia Rossi's system works for subtractive colors or the "pigment color" system. Tango's system works for additive colors or the "light color" system. Sometimes, you both can be right! --Jayron32.talk.contribs 13:49, 3 March 2009 (UTC)

Yes, I just realised that and came back to clarify. The OP is talking about computer screens, though, which are additive. So Julia is right, but about the wrong thing. I'm right about the right thing, so I win! :) --Tango (talk) 13:55, 3 March 2009 (UTC)

The lightest shade of pink is not that difficult to calculate if you listen to "A Whiter Shade of Pale" while wearing rose-tinted glasses. BrainyBabe (talk) 18:16, 3 March 2009 (UTC)

Thank you Jayron32. I was in colour pencil mode. Ok Tango, you win, you trag' you, ;) Julia (damn that logout) 4 March 2009 (UTC)

SETI failure

Since the Search for Extra-Terrestrial Intelligence has failed so far, it seems probable that it will continue to fail. What are the consequences of this failure for science and for theology. Phil_burnstein (talk) 18:44, 1 March 2009 (UTC)

I don't know that it seems probably it will continue to fail. It's a big sky and you need to be looking in just the right direction at just the right time - it could well be that we just haven't gotten lucky yet. Even if it continues to fail for the next 100 years, it doesn't mean much for science or theology - just because there is no intelligent life out there sending signals we can detect doesn't mean there isn't any intelligent life out there, they could just have better things to do with their time and energy than send out random signals. We aren't currently sending out any signals that we could detect if they had come from another star, so there is no reason to assume other civilisations will be. Things may improve as our search of extrasolar planets continues - if we find some planets that look habitable by life as we know it then we can carefully listen to them (and maybe even beam signals to them) and might stand a chance of hearing something. Listening pretty much at random (there is some science to where they point the receivers, but it's mostly guesswork) is never going to give a very high chance of success unless there is an enormous number of civilisations out there. --Tango (talk) 19:00, 1 March 2009 (UTC)

The odds that SETI will ever detect anything is basically almost zero (we are looking for the tiniest needles in the biggest of haystacks, and needles that may have not even been put in a place where we could find them, have long since passed us by, or will not be around for the tiny window of time, on a universe-wide scale, that we are actively looking for them). This does not reflect, though, on whether there are extra-terrestrial intelligences out there—it just reflects on our limited means of detecting them. Personally I think there is very limited scientific justification for something like SETI, but that fact has no implications on science or theology in general. --98.217.14.211 (talk) 19:22, 1 March 2009 (UTC)

There are lots of things which have not worked as yet, but that does not mean we abandon them. There were some rather long odds on other events which turned out to be quite real; people a century ago thought heavier-than-air flight was technologically impossible, and yet here we are today. SETI operates on a shoe-string budget, with meager resources, and it has a LOT of space to cover (well, ALL of it). I don't think its lack of data yet means much of anything. What fraction of known space has it analyzed? When that gets to 100%, then we can pronounce failure. --Jayron32.talk.contribs 19:26, 1 March 2009 (UTC)

Actually, we wouldn't even be able to declare failure then, because new civilizations might have sprung up in areas of space searched early on. Thanks, Genius101^Guestbook 19:37, 1 March 2009 (UTC)

And you have to study each bit of sky at a wide range of wavelengths. And then there are stars that have currently been ruled out as very unlikely to harbour life, but ought to be checked at some point just in case. And then there are other galaxies that it might be worth having a look at (although it would require a very powerful civilisation to signal over such a distance). --Tango (talk) 20:27, 1 March 2009 (UTC)

Let me make an analogy. SETI, to me, is like making a giant bucket for your backyard—at some expense—in order to catch a meteorite in it. Would this be a reasonable endeavor? Operation Catch a Meteorite has so far been a failure... but that doesn't mean it won't succeed in the future, does it? Sorry, I don't buy it. I think the SETI money could be spent better elsewhere (for scientific research, even), and I think things like Seti@Home are a total waste of processing power that could otherwise be used for most practical projects (like protein folding). If we lived in a world where there were infinite resources, then sure. But we don't.

The problem with SETI is that if you reframe it around activities that are not done by licensed scientists it sounds stupid. You might as well bring up perpetual motion machines as your example along with heavier-than-air—just because none of the plans have worked yet, and we have no reason to think they might work under our current understanding, doesn't mean we should give up on financing research into them, does it? Or maybe it does. --98.217.14.211 (talk) 01:29, 2 March 2009 (UTC)

We have positive reasons for not searching for perpetual motion machines, since they violate of the law of conservation of energy. We have no such positive reason w.r.t. SETI, so a comparison of SETI and PM is flawed in conception. Sorry. --Tagishsimon (talk) 01:36, 2 March 2009 (UTC)

But you don't need to build a big bucket to catch meteorites, you just need to wait for one to fall and then go and get it. You do need to build big radio telescopes and point them at distant stars if you want to find ETI. --Tango (talk) 12:13, 2 March 2009 (UTC)

Absolutely none. Lack of news is not news. Jimmy Hoffa was not found either, with equally profound results. Clarityfiend (talk) 20:28, 1 March 2009 (UTC)

Well, except with Hoffa, you can make conclusions based on his lack of being found—even if they aren't specific ones. You can say, for example, that if someone killed him—as seems almost surely to be the case—they did a pretty good job of getting rid of him. You can also say that the ability of the FBI to find him is somewhat diminished. All of this is because you know there actually was a Hoffa to begin with. You can't make any conclusions on the lack of SETI success—there's no way to distinguish the many possible reasons for that (there are no aliens; aliens can't communicate with us; they tried to and we didn't miss it; we're looking in the wrong place; we're looking in the wrong way; etc.). Which in my opinion is not encouraging. --98.217.14.211 (talk) 01:34, 2 March 2009 (UTC)

The thing to bear in mind is this: If you took the most powerful radio transmitter than mankind has ever made - placed it in orbit around the nearest star to ours - then the most powerful radio telescope that humans have ever made would not be able to detect it. We have a LONG way to go. SteveBaker (talk) 03:56, 2 March 2009 (UTC)

I said that already... Your strategy of being the last to reply to questions does have its drawbacks! ;) --Tango (talk) 12:13, 2 March 2009 (UTC)

Er, I don't think that's quite true. This proposal notes that – using 1979 technology and a reasonable observing program – we could quite comfortably detect a signal from an Aricebo Observatory-type radio telescope using our own Aricebo at distances exceeding 1000 light years. I expect that in the intervening three decades, both our detectors and our data crunching capabilities have improved substantially.

...Which is not to say that the problem is easy to solve — that assumes that the aliens have deliberately pointed their transmitter at us, and that we happen to watching at the moment that they did. The situation is much worse if we are relying on leakage of things like television signals; there we probably can't pull in stuff from anything but the few nearest stars, though I'd check that with someone who knows a lot more about the topic than I. TenOfAllTrades(talk) 15:05, 2 March 2009 (UTC)

Yes and no. That's only true because using the Arecibo telescope as a transmitter would produce a very narrow beam of radio waves - you'd pretty much have to aim it at a particular star and push all the energy down that narrow beam. For omnidirectional broadcasting (such as - say - a TV station might produce), we have no hope...as I indicated. Assuming this is 'first contact', either we have to be able to pick up an omnidirectional broadcast from some unsuspecting alien - or he/she/it is going to have to pick up an omnidirectional broadcast from us. Once that initial detection is made - we could chat happily (but S-L-O-W-L-Y) via some kind of narrow-beam link. But if their (omnidirectional) transmitters are only as powerful as the best we can manage - or if their radio telescopes are no better than our best - then we're all going to be blissfully unaware of each other no matter how close we happen to be.

Update

Update In the past forty eight years, SETI has searched millions of radio channels over the entire sky, and has found no sign of any ETI life. Therefore, at least some of its original assumptions has been proven false. We know, for example, that ETI civilizations are not as prevalent as was once thought. This implies that either climates that support ETI life aren not very common, or ETI civilizations tend to self-destruct.
The SETI Institute itself has abandoned the search, but SETI@Home is still going strong.
Getting back to my question, Assuming that SETI has found that the probability of finding ETI life approaches zero, what are the implications? Phil_burnstein (talk) 19:08, 2 March 2009 (UTC)

Your premise completely ignores the question why an ETI would bother blasting radio information into space. Does the fact that an ETS fails to send such radio waves render them unintelligent? Are we sending such radio waves? – 74  19:15, 2 March 2009 (UTC)

Yes we are, and have been for over a hundred years. Think television. -mattbuck (Talk) 19:55, 2 March 2009 (UTC)

Oh, we're transmitting locally all right, but as multiple people have pointed out above, our transmitters are barely up to the task of interstellar transmission, assuming anyone would even bother to set one up for such a purpose (which, I might add, was the point of my question). Do you know of any current projects attempting to beam radio waves into space in hopes of an ETI contact? – 74  21:26, 2 March 2009 (UTC)

We are, but some have suggested (one recent example) that Earth's radio output may be decreasing in favor of terrestrial transmission. It's not unreasonable to surmise that ETI wouldn't blast radio information. — Lomn 20:51, 2 March 2009 (UTC)

It's certainly true that as our technology improves, our radio receivers get more sensitive and so there is no need to transmit with so much power. Hence the net output of our planet isn't increasing as much as you might hope. Worse still, we're adopting complex multiplexed digital signalling and employing 'spread spectrum' techniques. These make our signals look more and more like white noise (which is what a perfectly designed signalling system would sound like)...which makes it less and less likely that the aliens would realise we're sending intelligent signals at all. It's not like we're sending a bunch of prime numbers in morse code! But the key here is to note the difference between an omnidirectional broadcast and a narrow-beam broadcast. If we tried to send a signal out (using our most powerful transmitter) in a tiny, narrow beam, aimed specifically at one particular star - then we could put out enough energy for the aliens to detect. However, our radio, TV, cellphone, etc traffic is spread all over the sky. Consider a 1 arc-second-wide narrow beam - it's something like 360x60x60x180x60x60x2 = 1,700,000,000,000...1.7 trillion times more powerful than an omnidirectional beam because all of the energy is focussed down that narrow 'slot'. But the trouble is that with a 1 arc-second beam - you could only talk to one reasonably close star at a time. Whilst we've been putting out omnidirectional signals for a long time - we've only tried sending such a narrow (and hence appropriately powerful) beam a few times. There has been no effort to try narrow-casting signals at nearby stars on a regular basis. Doing it for just a few seconds per star isn't really enough for the aliens to get a 'fix' on us - and it's not enough for use to transmit a useful amount of information. We would need a fairly major engineering program to set up enough narrow-field/high-power transmitters to transmit for long periods to all of the nearby stars. SteveBaker (talk) 19:16, 3 March 2009 (UTC)

Who assumed SETI would find what it was looking for in the first 48 years? Plenty of people may have hoped they would, but did anyone involved actually assume it? You've ignored the possibility of ETI that isn't blasting out powerful radio signals. If the SETI institute aren't looking any more, what numbers are the SETI@home people crunching? --Tango (talk) 23:24, 2 March 2009 (UTC)

It doesn't appear that the SETI Institute was ever related to the SETI@HOME project. Rmhermen (talk) 04:29, 3 March 2009 (UTC)

It seems you're right. SETI@home is run by the Space Sciences Laboratory, which doesn't seem to be connected with the SETI Institute. However, as far as I can tell, the SETI Institute is still active. --Tango (talk) 13:35, 3 March 2009 (UTC)

You might be interested in the Fermi paradox article. --JGGardiner (talk) 23:23, 2 March 2009 (UTC)

Thank you all. The Fermi paradox article combined with the articles on SETI, the Allen Telescope Array, and the ideas expressed here have answered my questions. Phil_burnstein (talk) 03:16, 3 March 2009 (UTC)