It takes months of watching the path of an asteroid in space to be able to pinpoint its orbit, and then time to do the calculations to identify the risk. So several months is about as swift as it gets.
And more to the point, did you actually RTFA? Because the researchers DON'T use the word maturity; the Dartmouth Public Affairs office uses the word maturity. The researchers conclude that significant anatomical changes occur in the brain long after an age that's generally -- and legally -- accepted as "adulthood." This is an important conclusion, because it tells us something about how encountering new and more challenging circumstances has a significant and measurable effect on brain development. That's especially important knowledge, because it has implications for how we go about teaching young adults, whether its college instruction or training young soldiers or whatever.
The conclusions of the study -- and their potential benefits in practical circumstances -- hold regardless of any arbitrary definition of maturity.
Mod parent up! To suggest that, because calculating the values of trigonometric functions is non-trivial when done by hand, we shouldn't teach them anymore is incredibly foolish. Yes, trig functions can be used in triangles, and yes, this new -- and equally complicated approach -- can as well. But much of more advanced mathematics requires the use of trig functions. Fourier series and transforms, rotations, polar & spherical coordinates, complex analysis, signal processing, just to name a few, all require a fairly deep understanding of trig functions.
I've been teaching physics to college students for many years, and I can say from experience that our incoming students are badly prepared enough already without robbing them of exposure to trig functions too.
I'm thinking about going to graduate school, and not having a traditional library would rule out a school immediately...
I should hope so! In my field -- a branch of physics full of tech savvy people, so I assume this is true in most any field -- none of the seminal papers and texts of the field are available electronically. Toss out those books and you've tossed out any chance of doing any meaningful scholarly research.
I completely agree, there's no substitute for books when it comes to reading anything longer than a few paragraphs. But this is almost never a problem for today's undergrads: a majority of the students I teach won't bother to do any reading assignment that's longer than about 3 pages. So what would they want with a "book" or "library"?
Not that I'm surprised to discover this, but who would have thought it possible to copy -- almost exactly -- a beautifully designed piece of hardware and have it look like crap. Whatever its flaws, the Mac Mini is practically a work of art; this looks like, well, what it is: a cheap and unattractive knockoff.
Put a lit candle under an inverted PYREX beaker (you have to kind of prop it up so the candle doesn't use up all the oxygen). Put this right in the middle of the microwave without the rotating plate. Turn it on and you'll see some strange fireworks, then suddenly a big blob of glowing material will rise to the top of the beaker.
This material is plasma (and the blob is called a plasmoid). The ionized particles in the plasma get trapped by the magnetic fields generated by the microwave and lifted to the top of the beaker. Some fussing is generally necessary to get this to work, and you can't let the microwave run for too long once the plasmoid forms or you'll probably damage it. But it's pretty cool. Extra cool if you take out the lightbulb so you can really see what's happening.
If you have trouble getting it to work, turn to google. I'm sure other people out there have done this.
My graduate fellowship (in physics) requires me to spend two days a week working with the science classes at a local high school, and I can say from experience that gimmicky pedagogical tricks like those mentioned in the article aren't the way to get kids (except maybe very young children) interested in science. The stuff just comes off as incredibly lame, and physicists end up looking like bigger geeks than they already are.
The way to engage kids is simply to show them the physics at work. I've got kids making plasma in a microwave, measuring the temperature of the sun with a cup of water, studying paper airplane trajectories, making stereo speakers. Physics is interesting and it's ubiquitous, so there's always something kind of cool that the kids can relate to. The secret is to let them see what's happening, get their hands dirty, and most importantly, let them ask the questions.
Find interesting (but safe) project, put them in charge, and they're hooked.
And isn't the target market for this computer people who already own a Windows machine and would like to switch over? If you already own monitor, keyboard, etc., maybe $500 isn't all that much to make a switch you've been contemplating but didn't want to spend $1500 to do.
Two days ago you could still buy any old low-end box for about $400. So these brilliant fellows were probably thinking the same thing they are today: "Let's make a crapload of money off of old people who don't know anything about computers."
Maybe someone can convince me otherwise, but I can't imagine who they think they're going to con into buying this...
Wavelet compression however is used in jpeg2000 which is a bit better than jpeg but even that isn't supported by any digital cameras.
I've been working with wavelets (eg.) in several contexts for many years now. Saying wavelet compression does 'a bit' better than jpeg is an enormous understatement. Especially in applications where you need serious compression ratios, wavelets are vastly better than the traditional jpeg compression algorithm.
But it sounds like this has more to do with improving transfer times for images that already exist in jpeg than developing a new standard for compression. But if some digital cameras started supporting jpeg2000, it'd be a boon: you could fit many more images in memory without a perceptiable decrease in quality OR could fit the same number at much higher quality.
> But they're talking now about outlawing lasers to the general public?
A scientific colleague of mine told me a story from when he was in grad school that went something like this. For some reason, some general legislative stupidity, the state of Wisconsin considered passing a law banning all devices that emitted electromagnetic radiation. Before the law passed, my colleague's advisor, a physics professor of some repute, was asked to testify at a hearing about the law.
He said to the legislators on the panel, "I'm about to remove from my pocket a device that emits a great deal of electromagnetic radiation, switch it on, and point it at you." The panel was, of course, terrified. He then took out a flashlight. Needless to say, the law didn't pass.
I suspect this laser business will be somewhat similar. Could a laser conceivably be a public danger? Yes. So could hammers, matches, fertilizer, etc. I seriously doubt there's going to be a laser ban.
It seems to me that what we have is a cost-benefit question. There are both political and logistical problems with storing nuclear waste, but the actual immediate danged to the environment posed by nuclear power (on a global scale, at any rate) is small. Radioactive material could, I suppose, contaminate some localized region so severely that it became uninhabitable, but that's no different than a huge number of landfill/toxic waste disposal sites right now.
Power by fossil fuel does not produce waste that's nearly as hazardous and difficult to store in the long term, but it poses a clear global environmental threat right now.
It seems like these are really the only two viable solutions available to us with current technology. So you ask, which is worse? My gut says probably coal, but there's a case either way.
For the Greens, I think the question is one of idealism versus realism. Ideally, yes, we'd switch to 100% renewable energy. Realistically, though, we need a solution that addresses our big problems NOW. It seems like they're a bunch of well-intentioned people in need of a more pragmatic position.
I think Cobb's purpose is to find some all-inclusive way to describe people who are not white. 'Colored people' is simply an outdated way of describing black people, and it's considered offensive by many, since it was generally used in a derogatory way in the days of Jim Crow. To me, 'non-white' carries some connotation of exclusivity, where 'people of color' is artful and inclusive.
But maybe someone else can suggest a better alternative...
It is HIGHLY short sighted and extremely selfish to NOT continue pushing further into space.
This may be true, but it's just as short-sighted to rush into space before we're prepared to do it, and at a time when the benefits will be outweighed by the costs. Just as you wouldn't try to teach a one-year-old who can't walk how to ride a bicycle, there's no point in throwing $500 billion into a Mars mission that won't serve any particular purpose outside of PR.
Let me provide one example of why we should wait to go to Mars that's particularly close to me as a member of the space physics community. In order to fund this Mars initiative, they've pulled a big chunk of NASA funding from the solar-terrestrial science and diverted it to spaceflight. But this funding is really important, since understanding the mechanisms that drive solar flares, coronal mass ejections, the solar wind, and the earth's magnetosphere is absolutely critical to protecting any hardware we have in space, and a lot of earth-based technology too. The more we depend on these things, the more important good space-weather forecasts and damage prevention protocols will become. Cut this funding now, rush a Mars expedition, and your explorers -- unprotected once they leave the magnetosphere -- could end up stranded or dead when some massive solar storm hits. This could happen to any probe of course, but losing a $500 million unmanned probe won't hurt nearly as much as losing a $100 billion dollar craft with seven crewmembers aboard.
If you think public sentiment is against space exploration now, just wait until people die in space and a big chunk of their tax dollars has been flushed.
Of course we need to go into space eventually. But we shouldn't do it prematurely, just because it's cool. Wait 50 or 75 years, until propulsion is cheap and efficient, space-weather forecasting is a near-exact science, and the the expedition can be mounted cheaply, quickly, and safely; and can do some kind of really useful science or pave the way for permanent colonization.
If we're going to Mars, we should wait and get it right on the first try. Like the previous poster said: It is all about seeing the BIG picture, instead of 50 years, just start thinking 100 years, thinking beyond our own lifetimes and start thinking about making multi-generation advancements.
>So isn't the thickness of the atmosphere more or less proportional to the planet's mass?
A number of factors, including mass, determine the thickness of a planet's atmosphere. Others include composition and temperature, along with a whole host of more subtle effects.
Mars, in fact, could (and did, at one point) have an atmosphere as thick as the Earth's. Mars' atmosphere was literally blasted away by meteor impacts early in the solar system's history. Mass was definitely the main factor here: because of Earth's larger mass, its escape velocity is higher than Mars'. So the Earth was able to pull back significant amounts of atmosphere afer an impact, whereas impacts on Mars simply blew the atmosphere off into space.
But I don't think there's any reason, now that impacts are considerably more infrequent, that Mars couldn't retain a more dense atmosphere.
Slashdot Mirror
It takes months of watching the path of an asteroid in space to be able to pinpoint its orbit, and then time to do the calculations to identify the risk. So several months is about as swift as it gets.
How exactly is this worthless?
And more to the point, did you actually RTFA? Because the researchers DON'T use the word maturity; the Dartmouth Public Affairs office uses the word maturity. The researchers conclude that significant anatomical changes occur in the brain long after an age that's generally -- and legally -- accepted as "adulthood." This is an important conclusion, because it tells us something about how encountering new and more challenging circumstances has a significant and measurable effect on brain development. That's especially important knowledge, because it has implications for how we go about teaching young adults, whether its college instruction or training young soldiers or whatever.
The conclusions of the study -- and their potential benefits in practical circumstances -- hold regardless of any arbitrary definition of maturity.
Mod parent up! To suggest that, because calculating the values of trigonometric functions is non-trivial when done by hand, we shouldn't teach them anymore is incredibly foolish. Yes, trig functions can be used in triangles, and yes, this new -- and equally complicated approach -- can as well. But much of more advanced mathematics requires the use of trig functions. Fourier series and transforms, rotations, polar & spherical coordinates, complex analysis, signal processing, just to name a few, all require a fairly deep understanding of trig functions.
I've been teaching physics to college students for many years, and I can say from experience that our incoming students are badly prepared enough already without robbing them of exposure to trig functions too.
I'm thinking about going to graduate school, and not having a traditional library would rule out a school immediately...
I should hope so! In my field -- a branch of physics full of tech savvy people, so I assume this is true in most any field -- none of the seminal papers and texts of the field are available electronically. Toss out those books and you've tossed out any chance of doing any meaningful scholarly research.
I completely agree, there's no substitute for books when it comes to reading anything longer than a few paragraphs. But this is almost never a problem for today's undergrads: a majority of the students I teach won't bother to do any reading assignment that's longer than about 3 pages. So what would they want with a "book" or "library"?
When you write, remember to include five copies plus an original.
(For some reason, they require that "if sent by mail, an original and five copies of any comment should be addressed to...")
Not that I'm surprised to discover this, but who would have thought it possible to copy -- almost exactly -- a beautifully designed piece of hardware and have it look like crap. Whatever its flaws, the Mac Mini is practically a work of art; this looks like, well, what it is: a cheap and unattractive knockoff.
Put a lit candle under an inverted PYREX beaker (you have to kind of prop it up so the candle doesn't use up all the oxygen). Put this right in the middle of the microwave without the rotating plate. Turn it on and you'll see some strange fireworks, then suddenly a big blob of glowing material will rise to the top of the beaker.
This material is plasma (and the blob is called a plasmoid). The ionized particles in the plasma get trapped by the magnetic fields generated by the microwave and lifted to the top of the beaker. Some fussing is generally necessary to get this to work, and you can't let the microwave run for too long once the plasmoid forms or you'll probably damage it. But it's pretty cool. Extra cool if you take out the lightbulb so you can really see what's happening.
If you have trouble getting it to work, turn to google. I'm sure other people out there have done this.
My graduate fellowship (in physics) requires me to spend two days a week working with the science classes at a local high school, and I can say from experience that gimmicky pedagogical tricks like those mentioned in the article aren't the way to get kids (except maybe very young children) interested in science. The stuff just comes off as incredibly lame, and physicists end up looking like bigger geeks than they already are.
The way to engage kids is simply to show them the physics at work. I've got kids making plasma in a microwave, measuring the temperature of the sun with a cup of water, studying paper airplane trajectories, making stereo speakers. Physics is interesting and it's ubiquitous, so there's always something kind of cool that the kids can relate to. The secret is to let them see what's happening, get their hands dirty, and most importantly, let them ask the questions.
Find interesting (but safe) project, put them in charge, and they're hooked.
And isn't the target market for this computer people who already own a Windows machine and would like to switch over? If you already own monitor, keyboard, etc., maybe $500 isn't all that much to make a switch you've been contemplating but didn't want to spend $1500 to do.
Two days ago you could still buy any old low-end box for about $400. So these brilliant fellows were probably thinking the same thing they are today: "Let's make a crapload of money off of old people who don't know anything about computers."
Maybe someone can convince me otherwise, but I can't imagine who they think they're going to con into buying this...
For $500 and $8.33 a month, you could get a Mac mini and do the same thing, with less viruses and spyware.
And you can burn CDs and install whatever software you want. I can't imagine how this could possibly become a profitable endeavor.
Wavelet compression however is used in jpeg2000 which is a bit better than jpeg but even that isn't supported by any digital cameras.
I've been working with wavelets (eg.) in several contexts for many years now. Saying wavelet compression does 'a bit' better than jpeg is an enormous understatement. Especially in applications where you need serious compression ratios, wavelets are vastly better than the traditional jpeg compression algorithm.
Want proof? See for yourself.
But it sounds like this has more to do with improving transfer times for images that already exist in jpeg than developing a new standard for compression. But if some digital cameras started supporting jpeg2000, it'd be a boon: you could fit many more images in memory without a perceptiable decrease in quality OR could fit the same number at much higher quality.
> But they're talking now about outlawing lasers to the general public?
A scientific colleague of mine told me a story from when he was in grad school that went something like this. For some reason, some general legislative stupidity, the state of Wisconsin considered passing a law banning all devices that emitted electromagnetic radiation. Before the law passed, my colleague's advisor, a physics professor of some repute, was asked to testify at a hearing about the law.
He said to the legislators on the panel, "I'm about to remove from my pocket a device that emits a great deal of electromagnetic radiation, switch it on, and point it at you." The panel was, of course, terrified. He then took out a flashlight. Needless to say, the law didn't pass.
I suspect this laser business will be somewhat similar. Could a laser conceivably be a public danger? Yes. So could hammers, matches, fertilizer, etc. I seriously doubt there's going to be a laser ban.
It seems to me that what we have is a cost-benefit question. There are both political and logistical problems with storing nuclear waste, but the actual immediate danged to the environment posed by nuclear power (on a global scale, at any rate) is small. Radioactive material could, I suppose, contaminate some localized region so severely that it became uninhabitable, but that's no different than a huge number of landfill/toxic waste disposal sites right now.
Power by fossil fuel does not produce waste that's nearly as hazardous and difficult to store in the long term, but it poses a clear global environmental threat right now.
It seems like these are really the only two viable solutions available to us with current technology. So you ask, which is worse? My gut says probably coal, but there's a case either way.
For the Greens, I think the question is one of idealism versus realism. Ideally, yes, we'd switch to 100% renewable energy. Realistically, though, we need a solution that addresses our big problems NOW. It seems like they're a bunch of well-intentioned people in need of a more pragmatic position.
"How is that better than 'colored people'?"
I think Cobb's purpose is to find some all-inclusive way to describe people who are not white. 'Colored people' is simply an outdated way of describing black people, and it's considered offensive by many, since it was generally used in a derogatory way in the days of Jim Crow. To me, 'non-white' carries some connotation of exclusivity, where 'people of color' is artful and inclusive.
But maybe someone else can suggest a better alternative...
It is HIGHLY short sighted and extremely selfish to NOT continue pushing further into space.
This may be true, but it's just as short-sighted to rush into space before we're prepared to do it, and at a time when the benefits will be outweighed by the costs. Just as you wouldn't try to teach a one-year-old who can't walk how to ride a bicycle, there's no point in throwing $500 billion into a Mars mission that won't serve any particular purpose outside of PR.
Let me provide one example of why we should wait to go to Mars that's particularly close to me as a member of the space physics community. In order to fund this Mars initiative, they've pulled a big chunk of NASA funding from the solar-terrestrial science and diverted it to spaceflight. But this funding is really important, since understanding the mechanisms that drive solar flares, coronal mass ejections, the solar wind, and the earth's magnetosphere is absolutely critical to protecting any hardware we have in space, and a lot of earth-based technology too. The more we depend on these things, the more important good space-weather forecasts and damage prevention protocols will become. Cut this funding now, rush a Mars expedition, and your explorers -- unprotected once they leave the magnetosphere -- could end up stranded or dead when some massive solar storm hits. This could happen to any probe of course, but losing a $500 million unmanned probe won't hurt nearly as much as losing a $100 billion dollar craft with seven crewmembers aboard.
If you think public sentiment is against space exploration now, just wait until people die in space and a big chunk of their tax dollars has been flushed.
Of course we need to go into space eventually. But we shouldn't do it prematurely, just because it's cool. Wait 50 or 75 years, until propulsion is cheap and efficient, space-weather forecasting is a near-exact science, and the the expedition can be mounted cheaply, quickly, and safely; and can do some kind of really useful science or pave the way for permanent colonization.
If we're going to Mars, we should wait and get it right on the first try. Like the previous poster said:
It is all about seeing the BIG picture, instead of 50 years, just start thinking 100 years, thinking beyond our own lifetimes and start thinking about making multi-generation advancements.
Its orbit never crosses earth's orbit; it can never pass between earth and the sun. So it will never transit (eclipse) the sun.
>So isn't the thickness of the atmosphere more or less proportional to the planet's mass?
A number of factors, including mass, determine the thickness of a planet's atmosphere. Others include composition and temperature, along with a whole host of more subtle effects.
Mars, in fact, could (and did, at one point) have an atmosphere as thick as the Earth's. Mars' atmosphere was literally blasted away by meteor impacts early in the solar system's history. Mass was definitely the main factor here: because of Earth's larger mass, its escape velocity is higher than Mars'. So the Earth was able to pull back significant amounts of atmosphere afer an impact, whereas impacts on Mars simply blew the atmosphere off into space.
But I don't think there's any reason, now that impacts are considerably more infrequent, that Mars couldn't retain a more dense atmosphere.