I hear admirals LOVE it when when they have to rescue naval ships at sea because their gizmos broke. It's quite likely that the captain and some officers would have indeed been screwed. It's also more than possible that a ship without the ability to navigate will encounter a reef or shoal before someone comes to rescue it.
You are incorrect. The sextant is over 300 years old and is just the most recent incarnation of the celestial sighting device. Various staff-type devices have been associated with ancient Greek and Egyptian ships and there are navigation instructions using the stars for direction finding in the Odyssey.
The ability to easily determine your longitude is only about 250 years old, but latitude determination using polaris or meridian transits dates back to at least the ninth century when arab sailors used the kamal. Knowing your latitude is enourmously valuable: you simply sailed along your desired line of latitude until you made landfall.
My friend had one of the ones that had GPS problems. It was pretty entertaining. Failing that, phones today seem to be pretty eerily accurate most (but not all) of the time.
Given a bit of reasonable hardware, I don't think it would be that hard. Provided the camera is sensitive enough to see stars, you could code something up on an iphone that works in mostly clear skies pretty quickly, and cloudy ones with a bit more work. A bit of user intervention to mark the horizon and maybe the sun or a few stars would make it even easier. I've looked into writing something like that to do auto locating and alignment on robotic telescopes. Most of the commercial ones that do it currently get their location from GPS.
But the point of teaching celestial navigation is that you can navigate without using gadgets that require batteries.
It's certainly handy to take a course with a good teacher, but if you'd like a challenge the first PDF shows you how to build a sextant out of things you'd find at home, and the second will teach you how to use it to navigate. The third one has the daily pages and sight reduction tables.
I'm a sailing instructor, trained in celestial navigation. I've heard stories of people in midocean who've had their GPS (and their backup) flake out, and had to use celestial navigation to make landfall. If nothing else, I get a lot of satisfaction from being able to navigate anywhere in the world using a book and simple tools. Even the sextant and compass can be made from scratch if necessary.
Using a compass well enough to navigate long distances isn't trivial at all. You have to know how to plot rhumb lines, perform dead reckoning, and deal with the fact that in much of the world compasses don't actually point north.
I have an ordinary handheld Garmin GPS that works just fine in an airliner at 30,000 ft and 900 km/h. I've had an iphone up to about 8000 feet on a hang glider, and it worked just fine too. Cruise missiles typically fly quite low and are generally subsonic.
It's also kind of a ridiculous restriction because any determined enemy is going to have no problem building their own GPS receivers for their cruise missiles.
You can model it's current behaviour, but if you poke it too hard you'll disturb it and the rules will change.
Economic models often work reasonably well so long as the conditions remain the same. When you can't help yourself and you found a company that trades tens of billions with the hope of making OMG MORE BILLIONS, you disturb the system. Same as if you hook a generator up to that pendulum, or catch all the fish.
If you're dumb enough to vote for someone on the take, you'll get someone on the take. Rich donors don't wield any political power at all unless the people choose to hand it to them.
To start with, they're multiple choice. I wouldn't be surprised to find that members of a culture that values snap judgements and conformity do better on multiple choice than cultures that value deep understanding or independence.
Not that it matters. The people who do well in particular programs are likely to be ones who do well on the entrance tests, if the tests reflect what the people who designed the program think is important.
IQ is correlated with all sorts of things. Your own link says that kids raised in poor families who tested borderline mentally disabled were up to near normal IQ a few years after being adopted by high income families.
Academic success, which is more relevant to the present story than IQ, is also correlated with all sorts of things. Some of it IS genetic, but the major predictor is socioeconomic status of the family.
It's extremely difficult to test for "potential." It's hard to even define it. Even if you could, are you sure you want to? Would you rather put a kid who has lots of "potential" in a gifted program who won't end up benefitting much from it because of outside school issues, or a kid who has a bit less "potential" but will ultimately achieve more?
Academic achievement in school (and success later in life) is overwhelmingly predicted by socioeconomic status of the home. The fact that richer (likely whiter) kids are overrepresented in a gifted program in a poor neighbourhood isn't evidence of unfair discrimination. The problem is likely that the non-whites in the area are disproportionately poor.
2) shop class, including some automobile repair, was a required course in my high school. Also home ec. Both have come in handy, although I am not a professional mechanic or seamstress.
3) computers, including some coding, was also a required course when I was in high school, twenty some years ago.
Lunars aren't that hard. I've done them from a sailboat. They're a bit more finicky than straight elevation observations, but not that much. Determining latitude with a sextant ALSO requires finicky observations, error prone table lookups and/or a bunch of calculations. And you can only do it at dawn, dusk or noon (NOT at night), unless you have one of those newfangled lighted bubble levels (good luck using one of those at sea) and not in bad weather.
The big reason clocks won out over lunars is that Harrison's clocks were more accurate.
An easier way to use the moon is by measuring it's position relative to the stars. Then you don't have to wait for a particular phase. In fact, that's the method that was in competition with Harrison.
I live in the "Canadian woods." There are people here. American Midwest? Been there. People. Australian Outback and Sahara, ditto. I haven't been to Siberia or the Antarctic, but I know people who have, and guess what? Permanent inhabitants. These places were all colonized centuries ago, except for Antarctica, which was more recent.
Will we have Mars colonies? Probably, someday. Someone will have to think of a good reason to go there first. Moon colonies are more interesting right now. If we set up a water, fuel and mining infrastructure, a permanent moon base might plausibly be able to do interesting things, from building and running giant far side telescopes to vacuum industry. If we can get it paid for as support for a Mars PR stunt? Great!
You know, you probably should read your own link. Mars Direct involves several launches. At least one to get the ascent vehicle to Mars, then almost certainly multiple launches to build the crewed transfer vehicle and hab module. A lunar refuelling station would also make Mars Direct style trips cheaper.
If you want a one off publicity stunt trip to Mars, a pure Mars Direct scheme is probably the best way to go. If you want to do repeated trips (to Mars or elsewhere) and also build some useful space infrastructure while you're at it, a lunar fuel mining operation has a lot of advantages.
Slashdot Mirror
I hear admirals LOVE it when when they have to rescue naval ships at sea because their gizmos broke. It's quite likely that the captain and some officers would have indeed been screwed. It's also more than possible that a ship without the ability to navigate will encounter a reef or shoal before someone comes to rescue it.
A millenium anyway: https://en.wikipedia.org/wiki/.... Probably a few more before that without the use of formal instruments.
You are incorrect. The sextant is over 300 years old and is just the most recent incarnation of the celestial sighting device. Various staff-type devices have been associated with ancient Greek and Egyptian ships and there are navigation instructions using the stars for direction finding in the Odyssey.
The ability to easily determine your longitude is only about 250 years old, but latitude determination using polaris or meridian transits dates back to at least the ninth century when arab sailors used the kamal. Knowing your latitude is enourmously valuable: you simply sailed along your desired line of latitude until you made landfall.
Samsung Galaxy?
My friend had one of the ones that had GPS problems. It was pretty entertaining. Failing that, phones today seem to be pretty eerily accurate most (but not all) of the time.
Given a bit of reasonable hardware, I don't think it would be that hard. Provided the camera is sensitive enough to see stars, you could code something up on an iphone that works in mostly clear skies pretty quickly, and cloudy ones with a bit more work. A bit of user intervention to mark the horizon and maybe the sun or a few stars would make it even easier. I've looked into writing something like that to do auto locating and alignment on robotic telescopes. Most of the commercial ones that do it currently get their location from GPS.
But the point of teaching celestial navigation is that you can navigate without using gadgets that require batteries.
Here you go:
http://solarscience.msfc.nasa....
http://www.dacust.com/navigati...
http://www.thenauticalalmanac....
It's certainly handy to take a course with a good teacher, but if you'd like a challenge the first PDF shows you how to build a sextant out of things you'd find at home, and the second will teach you how to use it to navigate. The third one has the daily pages and sight reduction tables.
I'm a sailing instructor, trained in celestial navigation. I've heard stories of people in midocean who've had their GPS (and their backup) flake out, and had to use celestial navigation to make landfall. If nothing else, I get a lot of satisfaction from being able to navigate anywhere in the world using a book and simple tools. Even the sextant and compass can be made from scratch if necessary.
Using a compass well enough to navigate long distances isn't trivial at all. You have to know how to plot rhumb lines, perform dead reckoning, and deal with the fact that in much of the world compasses don't actually point north.
Sailing instructor's words of wisdom: you're an idiot if you go to sea without GPS. You're an idiot if you go to sea with ONLY GPS.
I was under the impression most militaries still taught the use of pointy sticks, primarily in the form of bayonets and knives.
I have an ordinary handheld Garmin GPS that works just fine in an airliner at 30,000 ft and 900 km/h. I've had an iphone up to about 8000 feet on a hang glider, and it worked just fine too. Cruise missiles typically fly quite low and are generally subsonic.
It's also kind of a ridiculous restriction because any determined enemy is going to have no problem building their own GPS receivers for their cruise missiles.
Someone who's too young to remember the fdiv bug.
Best comment of the story.
You can model it's current behaviour, but if you poke it too hard you'll disturb it and the rules will change.
Economic models often work reasonably well so long as the conditions remain the same. When you can't help yourself and you found a company that trades tens of billions with the hope of making OMG MORE BILLIONS, you disturb the system. Same as if you hook a generator up to that pendulum, or catch all the fish.
If you're dumb enough to vote for someone on the take, you'll get someone on the take. Rich donors don't wield any political power at all unless the people choose to hand it to them.
To start with, they're multiple choice. I wouldn't be surprised to find that members of a culture that values snap judgements and conformity do better on multiple choice than cultures that value deep understanding or independence.
Not that it matters. The people who do well in particular programs are likely to be ones who do well on the entrance tests, if the tests reflect what the people who designed the program think is important.
Technically, concertos. Each one is a concerto.
Do you want them played on the original violin, or can I use a real instrument?
IQ is correlated with all sorts of things. Your own link says that kids raised in poor families who tested borderline mentally disabled were up to near normal IQ a few years after being adopted by high income families.
Academic success, which is more relevant to the present story than IQ, is also correlated with all sorts of things. Some of it IS genetic, but the major predictor is socioeconomic status of the family.
It's extremely difficult to test for "potential." It's hard to even define it. Even if you could, are you sure you want to? Would you rather put a kid who has lots of "potential" in a gifted program who won't end up benefitting much from it because of outside school issues, or a kid who has a bit less "potential" but will ultimately achieve more?
Academic achievement in school (and success later in life) is overwhelmingly predicted by socioeconomic status of the home. The fact that richer (likely whiter) kids are overrepresented in a gifted program in a poor neighbourhood isn't evidence of unfair discrimination. The problem is likely that the non-whites in the area are disproportionately poor.
1) computer science does not equal coding
2) shop class, including some automobile repair, was a required course in my high school. Also home ec. Both have come in handy, although I am not a professional mechanic or seamstress.
3) computers, including some coding, was also a required course when I was in high school, twenty some years ago.
Lunars aren't that hard. I've done them from a sailboat. They're a bit more finicky than straight elevation observations, but not that much. Determining latitude with a sextant ALSO requires finicky observations, error prone table lookups and/or a bunch of calculations. And you can only do it at dawn, dusk or noon (NOT at night), unless you have one of those newfangled lighted bubble levels (good luck using one of those at sea) and not in bad weather.
The big reason clocks won out over lunars is that Harrison's clocks were more accurate.
An easier way to use the moon is by measuring it's position relative to the stars. Then you don't have to wait for a particular phase. In fact, that's the method that was in competition with Harrison.
I wonder how the rest of the world regards the west' fascination with celebrities.
In the general assembly:
"Who is that man speaking?"
"He sings in a popular musical group."
"Okay, but what does he know about communications? Is he an engineer? A scientist?"
"No, he just sings."
"Then why are we listening to him?"
I live in the "Canadian woods." There are people here. American Midwest? Been there. People. Australian Outback and Sahara, ditto. I haven't been to Siberia or the Antarctic, but I know people who have, and guess what? Permanent inhabitants. These places were all colonized centuries ago, except for Antarctica, which was more recent.
Will we have Mars colonies? Probably, someday. Someone will have to think of a good reason to go there first. Moon colonies are more interesting right now. If we set up a water, fuel and mining infrastructure, a permanent moon base might plausibly be able to do interesting things, from building and running giant far side telescopes to vacuum industry. If we can get it paid for as support for a Mars PR stunt? Great!
You know, you probably should read your own link. Mars Direct involves several launches. At least one to get the ascent vehicle to Mars, then almost certainly multiple launches to build the crewed transfer vehicle and hab module. A lunar refuelling station would also make Mars Direct style trips cheaper.
If you want a one off publicity stunt trip to Mars, a pure Mars Direct scheme is probably the best way to go. If you want to do repeated trips (to Mars or elsewhere) and also build some useful space infrastructure while you're at it, a lunar fuel mining operation has a lot of advantages.