Well, yeah; we're listening to the vibrations in the radio's speaker. The radio waves transmit the information that tells the speaker how to vibrate. Or more specifically, their reception in the antenna creates electrical potentials that are transmitted through the radio's wires to its speaker magnets, causing them to vibrate, causing the speakers to create compression waves in the air which travel to our ears, causing our eardrums to vibrate and create electrical potentials in our auditory nerves, which our brains interpret as sound. And of course the radio waves themselves are translated by the microphone and transmitter from the original acoustic vibrations. (Unless you're listening to static, or to signals from a radio telescope. That's the closest you can get to "hearing" actual radio waves.) At least, that's how analog radio works. I'd assume digital radio transmits binary info that a computer chip inside the receiver converts into the electrical signals that vibrate the speaker magnets. And of course in TV or video, the signals, whether sent over the air or through a cable, are converted into electrical signals that trigger the electron gun to stimulate the phosphors in a certain pattern, or that turn on the LCDs in a certain pattern, or whatever.
I once read a wonderful electrical engineering book that set out to correct a serious problem in engineering education by explaining radio from the ground up, both intuitively and with a bit of algebra. The problem the professor was addressing was that the EE curriculum was set up back when most of the incoming freshman majoring in the field already knew all about radio, and in most cases had been building AM radios and Ham radios for years before they got to college (much like the way many computer science freshman now show up with seriously advanced programming skills). So naturally the curriculum was set up to take students with a good basic understanding of radio and electronics (it was a big hobby back then) and move them from the high-school algebra level of electronics (complete with oscillators, amplifiers, and tuned circuits) to the calculus and physics level. So when I hit college the freshman introductory circuits course started out on day one with solving big linear equations for circuits that included multiple ideal current sources. But many of the students no longer understood any of the basics, so I had to explain to my dorm neighbor (majoring in EE) that no, you can't just run down to Radio Shack and buy an ideal current source for .39 cents. It's not something like a battery or a resistor. By the time he graduated he could do omega i all day long, and knew Maxwell's equation and his fields and waves, but probably couldn't build a crystal radio or a stable oscillator to save his life. Later I was working with an EE with a master's degree and one day he asked me what the base of a bi-polar transistor is for. He know there was a base, and emitter, and a collector, but he'd forgotten what the base is supposed to do. He said that his professor only covered it really quickly in one lecture. But then on his first engineering job they'd looked over his impressive resume and said "Wow. You're way overqualified for this. We just need to do some relay logic." He replied, "What's a relay?" Sometimes I liken it to starting freshman in an oncology course without making sure they've had organic chemistry, biology, and anatomy first.
Oh please, what a bunch of hogwash. It's just the same old argument from climate change deniers, trying to cast the majority of scientists as a bunch of craven, greedy hucksters who only care about acquiring grant money, and who don't care about the scientific method, etc etc. I just find this stuff so insulting. Scientists are not perfect, and sometimes bad research gets through, but there's hardly some giant conspiracy or "agenda" driving everything they do.
You just made his point. post-Cosmos science can only support the accepted consensus, and can't ever be allowed to challenge it. Any scientist who does is accused of not being a "true scientist" (Last week's news was the poster child for the no-true Scotsman fallacy, with an IPCC lead author and the head of the Indiana department of environmental quality dismissed as "non-scientists" because they failed to voice support for the reining orthodoxy). Just supporting the IPCC position on global warming can get one branded as a "denier", because the science has diverged from the alarmist dogma (No scientific evidence for increased or more severe weather, etc). Real science doesn't always confirm your preconceived beliefs and conceits, it often challenges them. Sometimes new results rip a big hole in your comfortable worldview. It's supposed to do that. These days any subject with any political or social component is virtually off limits, such as fracking, global warming, anything touching on gender and race that says people aren't exactly equal and interchangeable cogs, that human evolution didn't suddenly stop as soon as we elected the first village chieftan, or that culture or religion is actually socially important (has real effects) at any level in the modern world. In portraying science as a battle of good versus evil, knowledge over superstition, those who believe they're scientific are often left believing that any scientist who disagrees with their comfortable notions must be a superstitious bigot, a paid shill, or a closet cleric. They have become the antithesis of a scientist, and the behavior is showing up more and more frequently, with politicians rushing to declare that "the debate is over!" In science, accepted ideas are always subject to being overturned in light of new experiments and theories. That's what makes it science.
This. I thought it was fascinating. I didn't know some of these things; it was the first episode that I didn't feel was dumbed down for the masses. It actually taught me something new and did it very well.
What a waste of energy somebody spent in typing up that nonsense. When has Cosmos (whether Sagan or Tyson) ever not said this?
Well sure, you're "technically" correct, but you missed my point. What I was actually referring to is the process by which that information is transmitted via radio. The transmitter itself is broadcasting at a certain frequency on the electromagnetic spectrum, say between 87 and 108 MHz. You pick one of those frequencies, and generate an electromagnetic wave at that frequency. That frequency is then "modulated", meaning instead of a nice sinusoidal waveform, you actually have a jagged-edge waveform that resembles a sine wave, using superposition. (AM radio does the same thing, however it is modulating the amplitude and not the frequency). The receiver (your radio) then takes that jagged-edge waveform, and subtracts the original sinusoidal waveform from it, leaving you with only the energy levels of the audio portion. This is what is translated to vibrations in the speaker. There's some cool advanced stuff in there, such as how you're able to get stereo from an FM signal (the transmitter sends two signals at the same frequency but sends them orthogonally, meaning one is sent at a phase shift 90 degrees away. One phase is left channel, the other phase is right channel). So, the reason I bring all this up is that radio waves are simply electromagnetic waves just like visible light. Take a look at your remote control: it has an infrared light emitter on the end of it. When you press a button, the emitter sends a signal that we can't see because our eyes can't detect infrared. But if you look at it through a cell phone camera, you can actually see the flashes. If we wanted to, we could send audio through a modulated light wave (say for example, a laser), but you run into issues such as the wavelength being extremely short, whereas radio waves have much longer wavelengths and can go through walls and stuff like that. Not to mention laser lights are extremely focused and radio can radiate in all directions.
I enjoy the new one. It's the first show since when Sorkin was still with The West Wing that I've made a point "I HAVE TO WATCH THIS NOW". But, I agree. Sagan was just something else. "...the momentary masters of a fraction of a dot." Beat that with a stick.
There's nothing wrong with challenging the consensus. And from everything I've seen and read in the past, most of the alternative explanations and ideas put forth by the minority (whether about evolution, climate change, or whatever) HAVE been considered before by other scientists.... and then ultimately rejected because they were not adequate or did not meet all the necessary criteria. With explanations that most of the time sound perfectly reasonable, I think. And even then, no one is saying the majority opinion is absolutely and completely correct, for all time. All it is, is a consensus. From a majority of scientists who are mostly just out in the field doing research, and who probably couldn't care less about politics or agendas, or whatever some scientific body decides to do with people.
Again, you make his point as well as any medieval monk who stuck his finger in his ears anytime someone questioned the consensus on the celestial spheres. This is quite a change from the post-Sputnik era when overturning widely accepted truths in light of new findings was lauded. The result has been science beset by a combination of feel-good babble and apocalyptic prophecies of doom, both based on very sloppy methods, noble-cause corruption, selective reporting (only "positive" results get published), leading to a elevated non-repeatability of findings, especially in social sciences, health, and the environment. As examples, NASA Goddard recently released a report claiming that unless we all adopt socialism now, Western civilization will collapse in two decades due to environmental pressure, using a model called Human and Nature Dynamics (HANDY). A statistics professor at Cornell shredded the paper because they took a predator prey equation and just arbitrarily assigned its variables to human social classes, probably based on a bizarre dream about Kermit the Frog and Miss Piggy. You can't take a validated equation like F=ma and use it in a paper where F is Frenchmen, m is mothers, and a is a**holes. NASA of course quickly distanced themselves from the paper, but a scientific journal actually published it. Another example is the recent Neukom paper on multi-proxy temperature reconstructions, where they used a statistical test to sift through hundreds and hundreds of potential temperature proxies to select those that met a matching criterion against the instrumental temperature record, without establishing scientifically why any of their proxies would relate to temperature, or how. That done, they showed that the average of the massive data set was pretty much flatline prior to the modern temperature record. Mathematically, that's to be expected because what they did was select from a large number of essentially random curves to pick those that showed an uptick at one end that matched the uptick they had. They could've selected Wall Street stocks or randomly generated numbers that had the same curve toward the end and it would've been just as well. When you average such a data set, everywhere outside where your selection criterion was applied will tend to cancel out (being random), and you get a flat line. That's incredibly sloppy work, and as Richard Feynman said, one of the most important things in science is to make sure you're not fooling yourself with a clever technique that you don't really understand, just because it's giving you the result you're looking for. Then there's the problem of skipping really important steps in validating measures, such as tree rings. A whole lot of proxy temperature reconstructions relied on tree rings (instead of something scientifically shown to be a good temperature proxy, like delta-O18 or other isotopes) without anyone in the "tree sciences" showing that tree rings are in any way a good proxy for temperatures. Indeed, they're a horrible proxy for a variety of reasons that tree folks know all about. For one, trees don't just respond to temperatures, they respond to a wide range of inputs and conditions, and there's no way to tell which condition was the limiting growth factor. For another, trees respond more to annual and multi-year changes in conditions more than the conditions themselves. If it's been very wet for many years the trees won't have developed really big, elaborate root systems because they didn't need them. When conditions become drier the trees will devote years of growth to their root systems instead of their trunks and crowns, but once the root systems are built up they'll return to their previously high growth rates because they've adapted to the changed environment. Trees have to constantly tune things like their root/crown ratio to re-optimize, so the growth rings are responding to annual and multi-year changes in temperature more than the temperature itself. This is also why you can't go to a lumberyard and identify how far south a particular board is from by its tree ring width. Another nagging issue is that the older trees that are still standing (and thus still available for sampling) are still around because they grew very slowly in their youth. So when you use them, you'll see little tiny tree rings in the far past and assume temperatures were much lower back then, instead of the obvious conclusion that the fast-growing trees from that era grew to full size and died long ago. Once pointed out, scientists realized there isn't a good mathematical way around this age related selection bias. Yet if you dare mention any of this quality science, you're branded as anti-science, even though the science really doesn't support the use of tree rings as accurate temperature proxies. Indeed, the whole "hide the decline" fiasco was caused because the tree-ring data wildly diverged from the late-20th century temperature records, itself a glaring indicator that tree rings aren't a good proxy for temperatures. And the whole past temperature reconstruction debate is itself a meaningless distraction, because the climate swings back and forth all the time, almost completely unrelated to mans' historic development of the scientific method. We've been advancing through all those ups and downs of climate, and where we happened to pop up on the curve (with our new mental tools) is essentially random. We could just as well have been at the peak of a climate cycle or the trough, and that position would be completely irrelevant to the question of climate sensitivity. But it is vitally important for those who need to believe that we'd been living in the Garden of Eden and are now about to be cast into the pits of Hell, and disputing such a truth is tantamount to questioning the divinity of Jesus.
You're using religious imagery and American-centric material to preach to a Canadian atheist who would far rather have correct science than the crap that our governments are trying to tell us is real.
That's why I'm using the religious imagery, so atheists can better note if they're falling for the same storyline delivered by priests in different robes. Let me try a simple questionaire: Does your belief system include an impending apocalypse due to mankind's sins, and are you required to repent and change your ways? Can you buy indulgences, carbon offsets, and the like? Are you preparing for the day that millions of animals and plants are driven to extinction by global warming, even though the IPCC AR5 report notes that the current number of climate caused extinctions stands at zero? Is your belief system kind of nutty, like holding that there's one perfect number representing an ideal temperature, and that any slight deviation from this number spells doom and catastrophe for all mankind, despite the fact that it really doesn't matter what this number is in any particular location, since individual locations vary by almost two order's of magnitude more than the apocalyptic shift? (The number line is large, but all numbers are equal as long as none of them ever change.) Do you lie awake at night worrying that Canada might one day become as warm as North Dakota, and that human life there will therefore cease to exist? Have you ever wondered why you're vacationing in the apocalyptic hell of Florida's intensely hot climate instead of hunting seals in Nunavut, but then thought that if the Earth were two degrees warmer, both flamingos and harp seals would go extinct because science?
No one denies that the climate swings back and forth. But to pretend that CO2 levels haven't risen dramatically in the last 100 years, at a faster rate than ever before recorded (and coinciding with when we started pumping so much of into the atmosphere), just seems silly. And there's a lot more evidence to rely on for that that just some tree rings. Sure some of the gloom and doom is probably a bit overblown, and the Earth will likely recover no matter what we do to it, but in the meantime we do still have to live here.
Atheist, remember? Science is not a "belief system." I've lived long enough in this region and seen enough to know that conditions are not the same now as they were when I was a small child 45 years ago (I'm 50). I have no reason to doubt the integrity of the journalists of the Canadian Broadcasting Corporation (CBC) when they show footage of polar bears, and report how some of these bears - mostly cubs - have been discovered to have drowned because there isn't enough pack ice, and they die because they can't swim far enough. As for "repenting" - it's called becoming more aware of the wasteful and environmentally harmful things humans do out of carelessness or greed or apathy, and deciding to stop adding to the problem. This is the only planet we have, and it's to our benefit to keep it livable. Corporations believe they can do that. I'm a human, not a corporation. Link, please. And do NOT tell me to "google it". You're the one making the claim, so it's up to you to provide the proof so I can check it out for myself. My "belief system" has no bearing on this issue. The rest of your post seems vaguely-worded. Please rephrase. I'm unfamiliar with the general climate of North Dakota. I have never been to Florida, and don't expect I ever will. I have also never been to Nunavut, and don't expect I ever will. I have never hunted seals, and don't condone anyone doing so unless the alternative would be to starve to death.
Living here would be a lot easier if the planet warms up dramatically, because just about all the people and species cluster along the equator and tropics so they don't freeze. In the tropics you can get by fine with just flip-flops and a T-shirt, as opposed to a parka, snow boots, an SUV, a home insulated to Swedish standards, and a whole lot of fuel oil. When we re-enter a glaciation period, and we will, we'll all have to move down there anyway as our northern cities get buried under a mile of ice. It will happen despite our emissions because the Earth has previously slipped into ice ages with CO2 levels ten to fifteen times higher than now. Of course, any suggestion that warmer temperatures, longer growing seasons, and increased food production is a good thing is considered heresy, so nobody is allowed to state the obvious. We also don't know if CO2 has risen any faster than in the past, because none of the CO2 proxies record high-frequency variations. In the ice cores the firn is very sloppy at locking in CO2, and resolutions finer than about century can't be achieved. We do know that CO2 levels follow temperature, and recent work indicates that CO2 follows temperature with a 90-degree phase lag. Regarding Sagan, he's the one who popularized climate scare stories, with his nuclear winter (later falsified), his prediction of climate catastrophe from the burning oil wells during the Gulf War (didn't remotely happen), and his "runaway greenhouse effect", which as it turns out seems to be the result of not correctly setting the boundary conditions on the differential equation for IR emissions through a planetary atmosphere. The Milne equations he and everyone else still uses make the assumption of an infinite optical thickness, since the equation was originally for light trying to escape from deep within a star. If the boundary conditions are corrected the result is dramatically different, showing that a runaway greenhouse effect isn't actually possible through a finite transparent atmosphere, and that the atmosphere will tend to maintain a constant IR optical depth by reducing water vapor content as CO2 goes up, quite the opposite of the trend predicted by global warming theory. Measurements have confirmed that water vapor isn't behaving at all according to accepted global warming theory, and is behaving more like it would in an atmosphere of finite optical depth. Of course the scientist who pointed this out was pressured to resign from NASA, since they get a whole lot of money for satellites to study global warming.
Well, you'll be happy to know that there are about five times more polar bears now than when you were born, back when conditions were allegedly ideal for polar bears. As it turns out, the dying polar bear paper (published in 2006) has just been retracted. Their tagging methods and data handling didn't account for the fact that some of their bears had wandered into the tagging area, got tagged, and wandered back home again. Those were listed as "dead", and the conclusion that polar bears should be listed as endangered. Another paper that led people to think that polar bears were in trouble turns out of have been completely misrepresented. As it turns out (yet again), polar bear populations in some areas are very dependent on seal populations, and seals don't survive well if there's multi-year pack ice, because it's too hard to keep their breathing holes open. If polar bear numbers continue to increase, Canada might have to go back to hunting them to keep the population under control. Sin! You're talking about sin! Good to see you've repented. Even as an individual, Al Gore will sell you some offsets. You'll sleep better. I don't need offsets because I'm the person who saved half the African rain forests by convincing the Nigerians to use e-mail instead of mass mailings to notify people throughout the world of millions of dollars in Nigerian government funds that need to be moved to Western bank accounts. You can thank me later, once the planet is healed. From Der Spiegel The second part of the IPCC's new assessment report is due to be presented next Monday in Yokohama, Japan. On the one hand, a classified draft of the report notes that a further "increased extinction risk for a substantial number of species during and beyond the 21st century" is to be expected. On the other hand, the IPCC admits that there is no evidence climate change has led to even a single species becoming extinct thus far. Interestingly, the predictions of tens of millions of extinctions were made based on a fascinatingly flawed model. When you go into some new area of the tropical rain forest, for example, and search an area of X hectares, you can expect to discover Y new species (a new beetle, maybe a frog). So then they reasoned backwards and said that if you destroyed those X hectares by farming it, those undiscovered species would go extinct. From there they estimated how many new farms were going in, and from that how many species must be going extinct. The flaw is best illustrated this way. Say that every time you visit a new bars or pub, you meet two people whose family name you've not encountered before, perhaps a McDiddlary and a MacCrackleheim. By their reasoning, if that bar burned down then the entire McDiddlary and MacCrackleheim families would cease to exist. That nonsense went unnoticed in ecological circles for decades. That's a good thing! Just imagine it as a tropical paradise. Odd fact. During the Eemian period Canada had palm trees.
The dark lines in the spectrum were what surprised me. I had never thought about it, I had never heard about the reasons behind the dark lines in the spectrum. I didn't know such reasons existed! This was another excellent episode.