I'm the resident "computer guy" in the optics laboratory of the local astronomical observatory...
First of all, most people here is technically-minded. That means, if they need a simple program, they can often program it on their own. No one is scared by the command line, etc. The astronomers still have lots of Sun workstations still around, but in our department we basically only have PCs.
There are three categories of software: hardware interface, data analysis and complete systems (in our case, that would be a telescope).
For the hardware interface, you use whatever is available at the moment. Most experiments are one-off jobs that will last from a few days to a few months tops. Usually the hardware has an SDK with a C interface and, possibly, a Labview module. What I usually do is to wrap the C interface to the higher-level languages we use in the lab (see below)
Data analysis is done in Matlab and IDL (IDL is quite popular in astronomical and medical environments). IDL's syntax is horrible, but it's a powerful data and visualization package. Most people here are proficient in at least one of those two languages, and if I write the appropriate wrapper, they can use the lab devices on their own. Windows and linux share about 50% each of the computers, and all window machines, including laptops, have putty, winscp and possibly X servers installed and regularly used.
At the telescope, everything is custom-built from the ground up, because you want to know what it's doing down to the last bit. The lower level part is in usually in C, then you may have user interfaces written in Qt or whatever, databases keeping the records, modules in Python or perl or something else etc. Things are developed by teams rather than individuals, so there is lots of documentation to write and APIs to specify. Windows is usually banned from this environment, and *everything* is done in Linux.
It would probably be easier to have two water tanks(lakes) at different heights and pump the water using solar/wind energy to the high one when possible. Then have it steadily go through a generator like current dams have now when energy is needed throughout the day or night.
That's called Pumped storage and is commonly used at hydroelectric facilities.
In an era where we can communicate around the world with unprecedented ease and speed, shouldn't we be flying LESS?
I'm not thinking about social/pleasure travel, but business travel (which accounts for a large percentage of all flyers). If you work in IT, there are very few tasks you can't accomplish over the WWW, and it seems that most of one's travel obligation has more to do with proving to management that you actually exist. "Face time" is a crutch for managers who don't get it.
Oh sure, we do fly less - in percentage terms, not in absolute terms. At my workplace it seems there is some kind of telephone- or video-conference with the other side of the world something like every other day, for various projects. A videoconference is much cheaper and convenient than an actual meeting.
But, we are now used to a much higher degree of interaction with our foreign partners. So, if ten years ago it was two meeting and two flights a year, today it's ten meetings, of which 2/3 are by videocon - and three or four by plane. Only 1/3 of the meetings involve flying, but the number of flights has gone up anyway.
Serious question: is the light that can be collected a few hundred meters away better or even different from the light that can be collected close to each other? In other words, is a group of small mirrors with the same surface area as a single large mirror inherently better?
There are two main factors determining the power of a telescope mirror.
1) Collecting area. A bigger mirror will collect more light and allow you to see fainter objects. A group of small mirrors will have a collecting area more or less equivalent to a single mirror with the same total area. 2) Resolving power, that is, the ability of detecting very small details. For diffractive optics reasons, this is proportional to the diameter of the mirror. If you have a group of telescopes, it is instead proportional to the distance between them, and if you can space them say 100 meters apart it's potentially *much* better. Such a system is called an interferometer
Combining light in interferometric mode from two or more telescopes is difficult. For example, you have to know the exact distance between them within a small fraction of the wavelength you are observing. For optical or infrared observation, that means a small fraction of a micron. On the LBT, it is easier than usual because the two mirror are mounted on the same supporting structure. Radio interferometers are common because they work with millimeter and centimeter wavelengths, and beam combining is relatively easy.
Another problem is that an interferometer will "see" an image only along a single direction - it will detect changes in illumination (corresponding to the features in the image: borders, points, etc.) only if they are perpendicular to the line connecting the two mirrors. If you want a more or less complete image, you have to rotate the telescope with respect to the sky, or use many telescopes so that you have many different directions to play with.
If it wasn't for dynamic physic, he would be certainly completely forgotten.
Apart from some minor things like pointing a telescope to the sky for the first time, and demonstrating that celestial bodies were not really "celestial" after all. And the first demonstration that a system where everything revolves around the Earth is really infeasible (see "Galilean moons"). And... you get the idea.
To put it another way, I don't believe in God in order to explain anything. I believe in God because I think all the evidence points that being true.
Well, this is another way of saying that you believe in God in order to explain all the evidence, and that if there was no evidence, you wouldn't believe in God. And the GP's point was that this evidence is getting smaller all the time.
I apologize if that's not correct. But it's important to know why you believe in something. Faith does not require evidence, scientific explanations do.
And don't go on about wind and solar - even maxed out they barely make a dent.
The available solar energy on Earth more than 5,000 times the total amount of energy used by all mankind. It's a pretty big dent. Oh, and wind energy is "only" 200 times.
As old as the house is, it has slightly unnerving properties:
Move to some European major city, and ask for an apartment in the city center. Houses built around 1900 will be the newest you'll be able to find. They would be the worst too... Basically anyone living in the center of an Italian city is living in an apartment whose walls were built around 1500. Of course, they were made of stone those times, and half a meter thick, that means good thermal insulation and no unnerving properties. Usually, interiors have been renovated:-)
Now if these 200,000 galaxies are all in a particular region of the universe, THAT would be explosive news, but, unless I completely misread the article, this isn't the case.
It is the case. They were specially selected to be close to us (redshift < 0.20). I suspect these 200,000 galaxies are a fairly significant fraction of all the galaxies near us. Of course, they are close to us because more distant galaxies would be too difficult to investigate, but this doesn't change the fact that they are all in the same particular region of the universe.
The modern theory of evolution rests on natural selection. Given that natural selection relies on the death of untold billions of beings, usually by hunger or eaten alive by some animal, such a God would be extremely sadistic.
Your idea of looking for non-natural patterns is interesting but note that it would very much limit search results to life so intelligent that like ourselves we would consider it above natural.
Non-natural patters wouldn't be some grid-shaped city. The basic non-natural pattern you can get is chemical non-equilibrium: if let alone, all the Earth oxygen would combine with some rocks and disappear. The presence of oxygen in the Earth atmosphere is a condition far from chemical equilibrium, and inequivocable proof that *something* keeps throwing the chemical balance out.
I keep hearing that solar panels are coming down. I don't see it. Five years ago I priced out an 11,000 watt system. Estimates put it at around $75,000. Last month I repriced a similar system with a different vendor using the latest panels. Estimate was $83,000.
...and applying an inflation factor of 5% per year...
Applying your inflation estimate, the original $75,000 are now worth $95,721, so the price is indeed lower. Not much, actually (-10% over five years).
Why stop at thousands of years? if the deity likes to plant false evidence, how about creating the Earth three years ago, and planting false memories in your head? Or three hours ago. Or three seconds. Anyone supporting creationism must support this argument too.
No. There is absolutely no difference between free fall in a gravitational field and absence of a gravitational field. This is the famous Equivalence Principle of General Relativitiy. This link gives more detail: http://galileo.phys.virginia.edu/classes/252/gener al_relativity.html [virginia.edu]
So there exists no difference at all between free fall and zero gravity. As for your second point, no experiment can distinguish between the two cases. So no observation can differentiate between the two.
This is incorrect. For a point-like object, it's true that you can't distinguish between the two. But for an extended body, if the intensity of the gravitational field varies with the position, different parts of the body will try to follow different "free falls" trajectories and this will result in very real forces inside the body - so called tidal forces. BTW, to have any kind of measurable difference you need either a gravitational field with a very steep gradient, for example very near to a black hole center, or a very big object like the Earth.
Under Wiki's license shouldn't everything, including edits, be available to anyone?
No, wikipedia's license doesn't force wikipedia to redistribute your content. If wikipedia decides to redistribute it, then it must follows the license's rules.
Slashdot Mirror
I'm the resident "computer guy" in the optics laboratory of the local astronomical observatory...
First of all, most people here is technically-minded. That means, if they need a simple program, they can often program it on their own. No one is scared by the command line, etc. The astronomers still have lots of Sun workstations still around, but in our department we basically only have PCs.
There are three categories of software: hardware interface, data analysis and complete systems (in our case, that would be a telescope).
For the hardware interface, you use whatever is available at the moment. Most experiments are one-off jobs that will last from a few days to a few months tops. Usually the hardware has an SDK with a C interface and, possibly, a Labview module. What I usually do is to wrap the C interface to the higher-level languages we use in the lab (see below)
Data analysis is done in Matlab and IDL (IDL is quite popular in astronomical and medical environments). IDL's syntax is horrible, but it's a powerful data and visualization package. Most people here are proficient in at least one of those two languages, and if I write the appropriate wrapper, they can use the lab devices on their own. Windows and linux share about 50% each of the computers, and all window machines, including laptops, have putty, winscp and possibly X servers installed and regularly used.
At the telescope, everything is custom-built from the ground up, because you want to know what it's doing down to the last bit. The lower level part is in usually in C, then you may have user interfaces written in Qt or whatever, databases keeping the records, modules in Python or perl or something else etc. Things are developed by teams rather than individuals, so there is lots of documentation to write and APIs to specify. Windows is usually banned from this environment, and *everything* is done in Linux.
It would probably be easier to have two water tanks(lakes) at different heights and pump the water using solar/wind energy to the high one when possible. Then have it steadily go through a generator like current dams have now when energy is needed throughout the day or night.
That's called Pumped storage and is commonly used at hydroelectric facilities.
In an era where we can communicate around the world with unprecedented ease and speed, shouldn't we be flying LESS?
I'm not thinking about social/pleasure travel, but business travel (which accounts for a large percentage of all flyers). If you work in IT, there are very few tasks you can't accomplish over the WWW, and it seems that most of one's travel obligation has more to do with proving to management that you actually exist. "Face time" is a crutch for managers who don't get it.
Oh sure, we do fly less - in percentage terms, not in absolute terms. At my workplace it seems there is some kind of telephone- or video-conference with the other side of the world something like every other day, for various projects. A videoconference is much cheaper and convenient than an actual meeting.
But, we are now used to a much higher degree of interaction with our foreign partners. So, if ten years ago it was two meeting and two flights a year, today it's ten meetings, of which 2/3 are by videocon - and three or four by plane. Only 1/3 of the meetings involve flying, but the number of flights has gone up anyway.
Serious question: is the light that can be collected a few hundred meters away better or even different from the light that can be collected close to each other? In other words, is a group of small mirrors with the same surface area as a single large mirror inherently better?
There are two main factors determining the power of a telescope mirror.
1) Collecting area. A bigger mirror will collect more light and allow you to see fainter objects. A group of small mirrors will have a collecting area more or less equivalent to a single mirror with the same total area.
2) Resolving power, that is, the ability of detecting very small details. For diffractive optics reasons, this is proportional to the diameter of the mirror. If you have a group of telescopes, it is instead proportional to the distance between them, and if you can space them say 100 meters apart it's potentially *much* better. Such a system is called an interferometer
Combining light in interferometric mode from two or more telescopes is difficult. For example, you have to know the exact distance between them within a small fraction of the wavelength you are observing. For optical or infrared observation, that means a small fraction of a micron. On the LBT, it is easier than usual because the two mirror are mounted on the same supporting structure. Radio interferometers are common because they work with millimeter and centimeter wavelengths, and beam combining is relatively easy.
Another problem is that an interferometer will "see" an image only along a single direction - it will detect changes in illumination (corresponding to the features in the image: borders, points, etc.) only if they are perpendicular to the line connecting the two mirrors. If you want a more or less complete image, you have to rotate the telescope with respect to the sky, or use many telescopes so that you have many different directions to play with.
Hope this helps.
If it wasn't for dynamic physic, he would be certainly completely forgotten.
Apart from some minor things like pointing a telescope to the sky for the first time, and demonstrating that celestial bodies were not really "celestial" after all. And the first demonstration that a system where everything revolves around the Earth is really infeasible (see "Galilean moons"). And... you get the idea.
To put it another way, I don't believe in God in order to explain anything. I believe in God because I think all the evidence points that being true.
Well, this is another way of saying that you believe in God in order to explain all the evidence, and that if there was no evidence, you wouldn't believe in God. And the GP's point was that this evidence is getting smaller all the time.
I apologize if that's not correct. But it's important to know why you believe in something. Faith does not require evidence, scientific explanations do.
And don't go on about wind and solar - even maxed out they barely make a dent.
The available solar energy on Earth more than 5,000 times the total amount of energy used by all mankind. It's a pretty big dent. Oh, and wind energy is "only" 200 times.
but in the end they're still asking us to use our money to fund their research
It's not "their". Results are published in peer-review journals (see here). Benefits go to all mankind.
So thanks to this one person paying the legal fees, other people can just do a 'same thing, gimme the cash' type deal?
He didn't have to pay the legal fees, he got those refunded too. This is normal in Italy, which has a loser pay legal system.
that operates out of a house built around 1900.
:-)
As old as the house is, it has slightly unnerving properties:
Move to some European major city, and ask for an apartment in the city center. Houses built around 1900 will be the newest you'll be able to find. They would be the worst too... Basically anyone living in the center of an Italian city is living in an apartment whose walls were built around 1500. Of course, they were made of stone those times, and half a meter thick, that means good thermal insulation and no unnerving properties. Usually, interiors have been renovated
This is the clearest explanation I've seen of "space-like". Thanks.
Explorers looked for northwest passage from 1400s to 1900
And didn't found it.
in 1906 Roald Amunsen navigated the passage in an ice-fortified ship
Funny that it took him two years (mostly spent with his ship blocked by ice) and several dogsleds. That's not my idea of "passage".
Now if these 200,000 galaxies are all in a particular region of the universe, THAT would be explosive news, but, unless I completely misread the article, this isn't the case.
It is the case. They were specially selected to be close to us (redshift < 0.20). I suspect these 200,000 galaxies are a fairly significant fraction of all the galaxies near us.
Of course, they are close to us because more distant galaxies would be too difficult to investigate, but this doesn't change the fact that they are all in the same particular region of the universe.
Wikia is the for-profit arm of Wikimedia. A large amount of Wikia profits help cover Wikimedia costs,
Nope. Wikia is a separate entity from the Wikimedia Foundation. And all Wikimedia cash comes from donations, not from Wikia's accounts.
The modern theory of evolution rests on natural selection. Given that natural selection relies on the death of untold billions of beings, usually by hunger or eaten alive by some animal, such a God would be extremely sadistic.
Your idea of looking for non-natural patterns is interesting but note that it would very much limit search results to life so intelligent that like ourselves we would consider it above natural.
Non-natural patters wouldn't be some grid-shaped city. The basic non-natural pattern you can get is chemical non-equilibrium: if let alone, all the Earth oxygen would combine with some rocks and disappear. The presence of oxygen in the Earth atmosphere is a condition far from chemical equilibrium, and inequivocable proof that *something* keeps throwing the chemical balance out.
I've often wished I could wake up one morning and discover that around 70%-75% of the global population had simply disappeared during the night.
Chances are that you wouldn't wake up.
I keep hearing that solar panels are coming down. I don't see it. Five years ago I priced out an 11,000 watt system. Estimates put it at around $75,000. Last month I repriced a similar system with a different vendor using the latest panels. Estimate was $83,000.
...and applying an inflation factor of 5% per year ...
Applying your inflation estimate, the original $75,000 are now worth $95,721, so the price is indeed lower. Not much, actually (-10% over five years).
even though europe and it's ridiculous farm subsidies, at the expense of african development, comes to mind
Both the US and Europe heavily subside their farmers. The US value is around $17000 per farmer, and the amount European farmers receive is similar.
Your counter-argument does not answer my question. Your counter-argument is simply flamebait and should be modded as such.
It's not a counter-argument. It's your argument, slightly rephrased. If you don't like it there's nothing I can do.
Why stop at thousands of years? if the deity likes to plant false evidence, how about creating the Earth three years ago, and planting false memories in your head? Or three hours ago. Or three seconds. Anyone supporting creationism must support this argument too.
[..] It takes about 9.8 Watts to move one kilogram one meter in one second. [...] 27.4 kW * 12.5 hours = 343 kW-h.
Congratulations! You just calculated how much energy you need to lift the car to an altitude of 250 km (!)
No. There is absolutely no difference between free fall in a gravitational field and absence of a gravitational field. This is the famous Equivalence Principle of General Relativitiy. This link gives more detail: http://galileo.phys.virginia.edu/classes/252/gener al_relativity.html [virginia.edu]
So there exists no difference at all between free fall and zero gravity. As for your second point, no experiment can distinguish between the two cases. So no observation can differentiate between the two.
This is incorrect. For a point-like object, it's true that you can't distinguish between the two. But for an extended body, if the intensity of the gravitational field varies with the position, different parts of the body will try to follow different "free falls" trajectories and this will result in very real forces inside the body - so called
tidal forces. BTW, to have any kind of measurable difference you need either a gravitational field with a very steep gradient, for example very near to a black hole center, or a very big object like the Earth.
Under Wiki's license shouldn't everything, including edits, be available to anyone?
No, wikipedia's license doesn't force wikipedia to redistribute your content. If wikipedia decides to redistribute it, then it must follows the license's rules.
The galaxy is 30,000 light years across.
The grandparent post was right. It's 100,000 light years across.