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Monday, 5th November, 2012, 12:37 AM #151
Hydra (Lvl 25)
No, Columbus did not set out to prove the Earth was not flat. As Russell said, "no educated person in the history of Western Civilization from the third century B.C. onward believed that the earth was flat" and other historians say "there was scarcely a Christian scholar of the Middle Ages who did not acknowledge [Earth's] sphericity and even know its approximate circumference".
Then again, this thread has revealed far more bizarre viewpoints than that to me.
Last edited by Morrus; Monday, 5th November, 2012 at 12:43 AM.
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Monday, 5th November, 2012, 12:51 AM #152
Grandfather of Assassins (Lvl 19)
Some of Colombus' opponents were of the opinion that according to their calculations the trip to Asia would be far too long for his crew to survive it without starving to death. I think that might have been where the whole 'fall off the face of the Earth' thing started from. The interesting thing is that they weren't wrong. If the Americas hadn't been there the trip really would have been too long.
Monday, 5th November, 2012, 01:45 AM #153
Hydra (Lvl 25)
Originally Posted by Wikipedia
Monday, 5th November, 2012, 01:49 AM #154
The Great Druid (Lvl 17)
We are also tought (in public hs in 1996 anyway) that the civil war was fought becuse aberham lincon wanted to free the slaves, in collage I learned of the social economics that may also play into it
In 2002 a friend was told by a chemistry teacher in hs that there are only 3 stages of mattter, and another friends older brother went to the school (he is a chemical engener) that she was just plain wrong.
In my older sister's HS she was told aids was an african deases that started in monkies, 4 years later my teacher laughed at the idea that it was from a monky, but it was from africa ???
Even today with a 1st grade nephew we teach basic but wrong things.then correct them 4-5 years later but still misslead until collage gives you all the information.
I'm with D&D...Any Edition
Monday, 5th November, 2012, 03:11 AM #155
Time Agent (Lvl 24)
Part of the reason for some of the jaw-dropping oddities in American education is that schools in the USA are controlled at the state level- IOW, almost no nationwide standards exist. Each state gets to choose how and what its students learn about math, history, science, etc. It is as if there were not objective standards!
in addition, the process of choosing books has become politicized. I live in Texas, and there are so many students in our system, that other states often use our approved books list, and you may have seen articles about the shenanigans that goes on here.
One of the ones approved by Texas a few years ago talked about how we won the Korean War by dropping the Atomic Bomb.
But Texas isn't alone- I'm an army brat, and I got to go to public schools in many states. I once had a school book that talked about how we may someday land a man on the Moon (this was in the mid-1970s).
Thank God I'm a "reader" whose grandparents & Mom were ALL educators (from K to grad school), whose Dad is a MD- no way my education was going to be compromised by the idiocy of others.
Monday, 5th November, 2012, 03:59 AM #156
Hydra (Lvl 25)
Monday, 5th November, 2012, 04:28 AM #157
The Great Druid (Lvl 17)
Current theory is that HIV had its origins in non-human primates in west-central Africa.
Now going back to 92-93 my sister was tought that, and 96-97 I was tought that was prajadice propaganda. NEW ENGLAND middle school and grade schools are horrable with it, and High schools were only a little better, I graduated in 1998 from high school and still to this day find things like this columbus thing.
I'm with D&D...Any Edition
Monday, 5th November, 2012, 06:31 AM #158
Defender (Lvl 8)
Wowsers, get busy for a couple of days and watch the thread explode! I'm a bit tired and in the middle of some work, but I want to address a couple of points quickly.
OK, as Umbran says, the usual Doppler effect is not something that "happens" to the photon but is due to the relative motion of the photon's source and receiver. At low relative speeds, you can think that the receiver moves past the peaks of the light wave (photon) more quickly/slowly if the receiver is moving toward/away from the source. At these low speeds, the relative change in the light's wavelength = v/c, the relative speed over the speed of light (assuming head-on motion). This picture isn't quite right at relativistic speeds (a significant fraction of the speed of light), but it is a reasonable picture if you also throw in some words about "relativistic time dilation" (the equation changes a lot, though). A proper explanation would traditionally come after a couple of years of university physics, but I could try to give you something better in a few days (when I'm less busy) if someone wanted to start a different thread. I'm happy to do physics Q&A when I'm not swamped at work. Anyway, Nellisir also, I think, gave something similar to this explanation but may have been mixing in some of what I'm about to say next.
All that said, the normal Doppler effect is not quite what happens in the cosmological expansion of the universe, at least not in Einstein's general relativity, although you can think about it that way when you talk about light moving from galaxy to galaxy. However, it's more useful (and generalizes better mathematically) to think that the galaxies are really not moving with respect to some grid you've laid down in space (at least not due to the expansion of the universe). Instead, it's the space inside the grid lines that's getting bigger. In this way of thinking, the photon/light wave itself really does get stretched out as space grows between successive peaks of the wave. In my work, I find this to be the clearest way of thinking about it, especially in the very early universe, which is just a big plasma without galaxies (or much other structure), so it's very hard to think about objects moving apart unless you go down to the single particle level. On the other hand, it's very easy to think about the overall plasma being at rest and just diluting as the universe expands --- and the photons redshift as it does so.
Monday, 5th November, 2012, 07:17 AM #159
Defender (Lvl 8)
The other thing I wanted to talk about (hope I'm coherent now, 'cause I'm way past bedtime) is KarinsDad's discussion with Morrus and others. I don't want to get into the whole thing about open-mindedness other than to make one point: I am a physicist by profession and know a lot of other physicists. With very few exceptions, we try to be open-minded in the sense of weighing every new idea. We might make quick judgements sometimes, we might disagree with each other's opinions, and sometimes we (either individually or as a community consensus) are wrong, but we have well-thought out reasons for those decisions nearly all the time. And, frankly, those reasons have to do with the data at hand.
But I do want to say a bit more about dark matter and alternatives, since that came up and it's an area of my research. Dark matter was first discovered about 80 years ago, like KarinsDad mentioned, but most scientists didn't pay much attention at the time because there wasn't enough data to demand it --- the observations could have been fluky in some way. So the first big "demand" for dark matter was the discovery that galaxies rotate faster than they ought to if (1) gravity works the way Newton and Einstein said and (2) there's just normal matter. But it works if you add a invisible, nearly pressureless form of matter that interacts via gravity with about 5 times as much total mass as normal matter. That's the how we define "dark matter." You can also describe galaxy rotation well if you change gravity. This is the idea of MOdified Newtonian Dynamics (MOND) and similar theories (I'll lump them together). However, you can also look at galaxies moving in clusters of galaxies. They also move faster than they "should" based on normal gravity and just normal matter. If you add 5 times as much dark matter, you get a prediction consistent with observation. If you use MOND, you also have to add some kind of invisible, nearly pressureless matter usually identified by MOND enthusiasts as neutrinos (from the Standard Model of particle physics). So MOND doesn't work perfectly on its own. Next, you can look at the cosmic microwave background light (CMB), which is the oldest light that's possible to see (any older, and the universe was opaque). It looks very uniform, but there are tiny variations in its temperature over the sky. Based on dark matter, people made detailed predictions for the patterns of the CMB years in advance of their measurement. These predictions match the measurements very well. For MOND to make these predictions, you need a relativistic version, and there are 2 problems: (1) it's not clear that the relativistic version of MOND is a self-consistent theory of physics as it looks pretty ugly and (2) there's controversy -- meaning conflicting calculations -- about whether it can predict (postdict now, maybe) the pattern of the CMB.
So, dark matter makes good predictions, MOND, not so much. Nonetheless, MOND is an intriguing option, so there are physicists still working on it, getting grants, etc. As long as there is a way it might fit the data, people will talk and think about it. But I hope I've explained why dark matter is the prevalent idea. It just works with the data, and it has the added bonus of being something that makes sense in terms of particle physics (I haven't gotten into that). I also hope you can see that it's not like what KarinsDad has said about Neptune's winds; it's not that we think we know what's going on and make a prediction in the absence of data (though that is supposed to be one part of the scientific method). There really is a lot of data consistent with and predicted by the dark matter hypothesis.
Monday, 5th November, 2012, 01:51 PM #160
Spellbinder (Lvl 16)
What you just proved is that many people do not read what is actually written, but put their own spin on it.
The first sign of a broken rule is when someone suggests that the way to stop it is by readying an action.