Getting Hubble healthy again and deliver a new set of glasses would be a major technical achievement. Some of the challenges will be the remote docking of spacecraft and all the complicated swapping of hardware. Remember however that Hubble was originally built for human maintenance and that Dextre was built to replace modules at the ISS. It was designed from the beginning for the ISS, but came as an afterthought at Hubble. This will lead to enormous costs that only came available after public outcry. I would think that the same 1B$ could also have been spent on 1 or 2 smaller telescopes. They would probably be smaller than Hubble, but this might be compensated by new technology that wasn't available when Hubble was built 20 years ago. Expendable telescopes are an order of magnitude cheaper than maintainable ones.
Artist impression of the mission is here, anybody know if there are some videos?
I did try this some time ago as a friday afternoon experiment at work (I'm in optics). What you basically do is take some black and white image, take the 2D-fourier and add some random phase noise. This gives you an image that looks just like white noise. Print this with a laser printer on a transparency and hold it in front of an expanded laser beam. Et voila, there's your original image back. There's one caveat: This is essentially a black and white 'amplitude' hologram which contains no phase information like a real hologram. The result is that you always get a ghost image that is point symmetric with the original.
For more details have a look at this thread, it refers to a paper that explains the math.
Machine number one will go to Livermore, probably for doing some nuclear stuf. Number two will go to the Netherlands for the Lofar project. This is a 300 kilometer diameter radio telescope that observes at low frequencies (up to 250 MHz). It constists of thousands of small antennas spread across half the country. Their signals will be interferometrically combined to form the images (compare e.g. to the VLA). Blue Gene will be used to combine all the signals in real time, I believe the total bandwidth from the antennas is some terabyte/sec.
I said a healthy system has BETWEEN 5 and 10 parties (roughly). At least that is my experience with the Netherlands, where I come from. Your numbers for India add up to 20. I might be biased, but I think our political system and of most of the surrounding countries is reasonably stable. We typically have 9 parties in parlement, of which only 4 or 5 have more than 10% of the seats. For as long as I know coalitions consisted of 2 or 3 parties, so that is manageble.
5. ELECTION/VOTING REFORM: To the candidates, you talk a lot about the importance of promoting democracy in other countries. However, I have never heard you take on the issue of election reform in our own country. The current presidential system seems to have several shortcomings, including two-party duopoly and the ability to win the Election without winning the popular vote. This hardly seems democratic. What are your positions on instant-runoff voting and proportional representation?
with both Bush & Kerry giving no real answers. I think this question touches on an issue that causes a lot of the problems of American politics. The present system is effectively a two party system. This gives you only one choice between left and right wing. One party has power until it screws up and then the other takes over. Support for both parties will always stay in the 45-55% range.
I think a healthy system should have place for somewhere between 5 and 10 parties, ranging from greens, labour, religion based, conservative, liberals, etc. You will probably require a coalition to rule the country, but that is the whole idea of democracy: to make compromises between the various wishes from society.
We used to have a system like that in the Netherlands, where you would have to pay a certain amount of money (~50 Euro??) per year if you owned a TV set. This was in a country where probably 95 percent of the people has a TV. The system involved TV ads that reminded you to pay and an army of inspectors to check if those who didn't pay were not secretly watching.
Occasionally politicians do have common sense, so they got rid of the system a few years ago. Now it's just payed by taxes, regardless if you are watching or not. This was a big win: no more bureaucracy, no more paranoia for the inspectors (we never payed in my student house) and the state saved around 20MEuro instantly on salaries.
Apparently you can build the largest (100 meter) steerable radio telescope for 75M$. Arecibo is not steerable and is build in a valley, so it will probably cost less than that. Add in a few dozen smaller dishes all over the world, probably costing less than 30M$ each for a small one. Add some bandwith costs, supercomputers and other fancy equipment. Grand total for all hardware worldwide won't be much more than 1B dollar, or about 1 or 2 shuttle launches without the cost of a hubble.
However, that does not mean that you could ditch Hubble and its colleagues: Hubble observes at visible wavelenths (~500 nm), radio telescopes operate at wavelengths of some centimeters. This lets you observe totally different physical properties of stars. The two techniques are thus complementary, for good science you need both.
It is also important to understand why you need big telescopes spread all over the world to obtain roughly the same resolution as hubble's two meter dish: resolution scales with (wavelength/diameter). To obtain a better (smaller) resolution, you need a smaller wavelength or a larger diameter dish. Instead of building one really large disk, you can also build several smaller and place them far apart.
No, there are certain hard limits imposed by physics that you can't break with some fancy image processing. Sure, you might reduce some of the noise, and you might gain a factor of 2, but that's it. Why do you think they build 10 meter diameter telescopes (100 meter in the works: OWL) if they could achieve the same with a 1 meter diameter and some processing.
The CIA will have better pictures than those available on Terraserver but there are limits to the resolution. Due to the fact that light has a finite wavelength, there are certain limits in resolution you can get depending on the size of your telescope. This phenomenon is known as the diffraction limit. A very rough calculation would say that Resolution=wavelength*Distance/Telescope_diameter. This gives 5 cm with a 2 meter telescope from 200 km at visible wavelengths. So take of your tinfoil hats
I don't know if those are gravitational waves you are seeing (They are building big machines to observe those, if you're the first to see one you got yourself a Nobel prize). The lines running oblique trough the image are obviously the rings of Saturn. The waves you are probably referring to run exactly horizontal. I therefore suspect it is an image artifact, caused by something in the CCD or because the image was recorded line for line. This might be a raw image, which still has to go through image processing to get the 'waves' out with some previous calibration. If it were something to do with the rings themselves than i would expect it to be either parallel or perpendicular to the rings, and not exactly parallel to the frame.
Compared to the seemingly crappy 0.000005 Megapixel cams they put on those things now..
FYI: all the cameras on board the rovers have 1024x1024 pixels, so i think you could call that exactly one megapixel. Even better, they put 10 of those on each rover: 2 front and 2 back looking fisheyes, 1 microscope, one descend imager, 2 medium resolution navigation cams and two high resolution panorama cams. Using the last one, they stich together something like 50 to 100 images together to get a full panorama. Check the panoramas at the rover site if your short on megapixels. Take notice how well they are able to remove the seams between the images.
Seems like a prime opportunity for a nuclear powered rover!
I believe that's exactly the thing they want to do with the Mars Science Laboratory, to be launched around 2009. Some time ago I saw a presentation on Laser Induced Spectroscopy, which they want to include in that mission. Essentially what they want to do is to put a high power pulsed laser with a small telescope on top of the rover mast. Its light can be focused to a tiny spot some tens of meters away. You pick up the light that is caused by the heated/burnt/evaporated rock and analyse it with an optical spectrum analyser. In this way you can remotely analyse a rock in a few minutes, which costs them a whole day right now with the robotic arm.
I recently saw the 'fusion roadshow' by our national plasma research institute. Although it was actually targetted at highschools it was great fun to watch with a whole audience of physicists. Their predictions were however a little bit negative: almost all of the fossil fuels will be used up in the next century when we achieve a maximum population of around 10 billion. Renewable energy sources such as wind power and hydraulics will be used more, but they will never be able to supply more than 25% of total demand. Their obvious answer was to invest in nuclear fusion now, all the other types cannot be scaled up enough.
Apparently the current best fusion reactor, JET, is close to break even point (energy in versus energy out). The future project ITER, to be built in France/Japan/Spain (depending on politics), will be the first to actually be a net energy producer. This will still only be a research plant. Production type plants are expected around 100 years from now, mightbe just in time to save us when the oil dries up.
We are talking interferometry here: you have to compare the phase of the lightwaves from the different telescopes. Taking an image only gives information about the intensity of the waves, which is in proportion to the square of the amplitude of the waves. The phase information is lost. Also remember that visible light has a frequency of +- 10^14 Hz, so there is no easy way of comparing that to a clock. Do a first year physics course on (optical) wave mechanics to see the difference.
You are probably thinking about a radio telescope. In that case you can measure the phase of the incoming waves relative to an atom clock. Do the same at a distant location (after synchronising the clocks first) and you can combine the signals with a computer. Remember that atom clocks also have a finite accuracy, so you cannot increase the distances indefinitely.
With an optical telescope, which we are discussing here, you can't compare the phase of the light to some clock (yet). Therefore the only way to do interferometry is by sending the light physically (with some mirrors or a fiber) to a common combination point. This limits any practical solutions at the moment to a few hundred meters.
I am somewhat involved with the European version of these missions (the Darwin mission, to be launched around 2014), so I might clear some things up.
Goal: to detect earth-like planets around other starts. Extra-solar planets detected thus far are usually 'hot Jupiters': big planets that orbit the star in a few days. These are relatively easy to detect. Detecting an earth-like planet (which have not been found yet) is far more difficult. It is usually compared to detecting the light of a firefly (reflection of the planet) flying very close to a lighthouse (the star). Measurements need to be done in the far infrared because there the ratio between the planet and the starlight is the highest (but still only 1:10^6 !!). With some luck they might find traces of ozone and CO2 in the spectrum that might be an indication for life.
Methods: -Coronography: Simply put it is just a conventional big (~10 meter) telescope with a shadow mask that blocks the light of the star. The light of the planet should get past the mask on the detector.
-Interferometry: Somewhat similar to the techniques used in radio astronomy. The resolution of a telescope improves by increasing its size. The trick is to combine several small telescopes. The resolution should then be comparable to the resolution of one big telescope that is as wide as the separation between the small ones. With radio interferometry you can do the 'beam combination' by computer. In optics however you have to physically combine the beams of the different telescopes. This requires flying satellites in formation with stabilities on the order of nanometers!! Current schemes are limited to several hundred meters. There are also some attemps to do this on earth.
There is quite a lot of politics going on between NASA and ESA at the moment about how they should cooperate. First ideas where to do an interferometry mission together, but now NASA has decided to go for coronography and postpone interferometry to 2020. ESA is sticking to interferometry.
"The big question is, if we can get down, can we get back out?" Wallace said.
If you look at the driving plan thus far and at the surroundings, you see that endurance crater is pretty much the only big interesting feature in the area. Also, given the finite life of the rovers (extended design life is 180 days?) there must come an end some time. The rovers seem to operate perfectly right now, but i believe that the thermal cycling of the batteries is a definite show-stopper in a couple of months. Considering this, i think it is a fair gamble to drive into the crater with the risk of never coming out. If you do you might get some very interesting data on all the deep soil layers. By the time you would get out you are almost dead anyhow.
I recently had the pleasure of attending a talk by a guy that worked on the focal plane of GAIA, a spacecraft to be launched by ESA around 2010. It is not designed for imaging, but for very accurately determining the position of stars (astrometry).
Their specs for the focal plane of the telescopes: size of around 0.6*0.8 meter, 180 CCD chips packed together for a total of 1.2 Gigapixels! I believe handling the thermal power alone (~100 Watt), without moving the location of the pixels a bit already was a typical case of rocket science.
If I was John Carmack and was serious about winning the X-prize, I would be very worried about Rutan & his SS1. True, Rutan only got 14Km, but that is the whole point of a test campaign: you get to your goal in small steps. And how heigh did Carmack got by now?
Don't understand me wrong: I don't have anything against Carmack and I think it's great what he is doing. From a betting perspective, however, who would you put your money on: a game developer with lot of creativity and spare time, or a company led by a famous aircraft designer who is in the business for more than 20 years?
I guess you where sleeping your way through the optics lectures: These lenses could definitely work. If you look at the picture you see that there are two fluids: brown one on top and a blue one on the bottom. If you remember Snell's law (ray bends towards the normal in the denser medium), you can conclude from the picture that the 'brown' fluid has a higher refractive index than the 'blue' fluid. The left picture thus resembles a hollow/concave/negative lens and the right picture resembles a convex/positive lens. Of these the positive (on the right) can be used to form a real image (one you can capture on a CCD or a retina), whereas the negative only forms a virtual image.
A colleague of mine did his internship at the group that invented these and my boss still works part-time at Philips.
... I have been attacked on Slashdot as a flag waving, right wing, conservative neonazi, capitalist pig, America right or wrong type and a politically correct, commie pinko, marxist cant spouting anticapitalist lacky. ..
for the same bloody post,...
I suggest that you can, as a good scientist, provide us with a reference of that claim for peer review and for our reading pleasure?
We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.
Bummer that firefox.com, firefox.org and firefox.net are already taken! Furthermore, Google already knows 76700 instances of firefox. Should we expect yet another name by version.9??
The logo is nice though. Can't wait to give it a try.
Slashdot Mirror
Getting Hubble healthy again and deliver a new set of glasses would be a major technical achievement. Some of the challenges will be the remote docking of spacecraft and all the complicated swapping of hardware. Remember however that Hubble was originally built for human maintenance and that Dextre was built to replace modules at the ISS. It was designed from the beginning for the ISS, but came as an afterthought at Hubble. This will lead to enormous costs that only came available after public outcry. I would think that the same 1B$ could also have been spent on 1 or 2 smaller telescopes. They would probably be smaller than Hubble, but this might be compensated by new technology that wasn't available when Hubble was built 20 years ago. Expendable telescopes are an order of magnitude cheaper than maintainable ones.
Artist impression of the mission is here, anybody know if there are some videos?
I did try this some time ago as a friday afternoon experiment at work (I'm in optics). What you basically do is take some black and white image, take the 2D-fourier and add some random phase noise. This gives you an image that looks just like white noise. Print this with a laser printer on a transparency and hold it in front of an expanded laser beam. Et voila, there's your original image back. There's one caveat: This is essentially a black and white 'amplitude' hologram which contains no phase information like a real hologram. The result is that you always get a ghost image that is point symmetric with the original.
For more details have a look at this thread, it refers to a paper that explains the math.
Machine number one will go to Livermore, probably for doing some nuclear stuf. Number two will go to the Netherlands for the Lofar project. This is a 300 kilometer diameter radio telescope that observes at low frequencies (up to 250 MHz). It constists of thousands of small antennas spread across half the country. Their signals will be interferometrically combined to form the images (compare e.g. to the VLA). Blue Gene will be used to combine all the signals in real time, I believe the total bandwidth from the antennas is some terabyte/sec.
I said a healthy system has BETWEEN 5 and 10 parties (roughly). At least that is my experience with the Netherlands, where I come from. Your numbers for India add up to 20. I might be biased, but I think our political system and of most of the surrounding countries is reasonably stable. We typically have 9 parties in parlement, of which only 4 or 5 have more than 10% of the seats. For as long as I know coalitions consisted of 2 or 3 parties, so that is manageble.
with both Bush & Kerry giving no real answers. I think this question touches on an issue that causes a lot of the problems of American politics. The present system is effectively a two party system. This gives you only one choice between left and right wing. One party has power until it screws up and then the other takes over. Support for both parties will always stay in the 45-55% range.
I think a healthy system should have place for somewhere between 5 and 10 parties, ranging from greens, labour, religion based, conservative, liberals, etc. You will probably require a coalition to rule the country, but that is the whole idea of democracy: to make compromises between the various wishes from society.
We used to have a system like that in the Netherlands, where you would have to pay a certain amount of money (~50 Euro??) per year if you owned a TV set. This was in a country where probably 95 percent of the people has a TV. The system involved TV ads that reminded you to pay and an army of inspectors to check if those who didn't pay were not secretly watching.
Occasionally politicians do have common sense, so they got rid of the system a few years ago. Now it's just payed by taxes, regardless if you are watching or not. This was a big win: no more bureaucracy, no more paranoia for the inspectors (we never payed in my student house) and the state saved around 20MEuro instantly on salaries.
Apparently you can build the largest (100 meter) steerable radio telescope for 75M$. Arecibo is not steerable and is build in a valley, so it will probably cost less than that. Add in a few dozen smaller dishes all over the world, probably costing less than 30M$ each for a small one. Add some bandwith costs, supercomputers and other fancy equipment. Grand total for all hardware worldwide won't be much more than 1B dollar, or about 1 or 2 shuttle launches without the cost of a hubble.
However, that does not mean that you could ditch Hubble and its colleagues: Hubble observes at visible wavelenths (~500 nm), radio telescopes operate at wavelengths of some centimeters. This lets you observe totally different physical properties of stars. The two techniques are thus complementary, for good science you need both.
It is also important to understand why you need big telescopes spread all over the world to obtain roughly the same resolution as hubble's two meter dish: resolution scales with (wavelength/diameter). To obtain a better (smaller) resolution, you need a smaller wavelength or a larger diameter dish. Instead of building one really large disk, you can also build several smaller and place them far apart.
No, there are certain hard limits imposed by physics that you can't break with some fancy image processing. Sure, you might reduce some of the noise, and you might gain a factor of 2, but that's it. Why do you think they build 10 meter diameter telescopes (100 meter in the works: OWL) if they could achieve the same with a 1 meter diameter and some processing.
The CIA will have better pictures than those available on Terraserver but there are limits to the resolution. Due to the fact that light has a finite wavelength, there are certain limits in resolution you can get depending on the size of your telescope. This phenomenon is known as the diffraction limit. A very rough calculation would say that Resolution=wavelength*Distance/Telescope_diameter. This gives 5 cm with a 2 meter telescope from 200 km at visible wavelengths. So take of your tinfoil hats
As a physicist who works daily with (only moderate power) lasers, i might share our old and well known survival trick:
DON'T LOOK INTO LASER WITH REMAINING EYE!
... i still have to ask a guy named Donald working for Disney and a guy named Dubya working at the whitehouse, if they ever received any mail for me.
I don't know if those are gravitational waves you are seeing (They are building big machines to observe those, if you're the first to see one you got yourself a Nobel prize). The lines running oblique trough the image are obviously the rings of Saturn. The waves you are probably referring to run exactly horizontal. I therefore suspect it is an image artifact, caused by something in the CCD or because the image was recorded line for line. This might be a raw image, which still has to go through image processing to get the 'waves' out with some previous calibration. If it were something to do with the rings themselves than i would expect it to be either parallel or perpendicular to the rings, and not exactly parallel to the frame.
I recently saw the 'fusion roadshow' by our national plasma research institute. Although it was actually targetted at highschools it was great fun to watch with a whole audience of physicists. Their predictions were however a little bit negative: almost all of the fossil fuels will be used up in the next century when we achieve a maximum population of around 10 billion. Renewable energy sources such as wind power and hydraulics will be used more, but they will never be able to supply more than 25% of total demand. Their obvious answer was to invest in nuclear fusion now, all the other types cannot be scaled up enough.
Apparently the current best fusion reactor, JET, is close to break even point (energy in versus energy out). The future project ITER, to be built in France/Japan/Spain (depending on politics), will be the first to actually be a net energy producer. This will still only be a research plant. Production type plants are expected around 100 years from now, mightbe just in time to save us when the oil dries up.
We are talking interferometry here: you have to compare the phase of the lightwaves from the different telescopes. Taking an image only gives information about the intensity of the waves, which is in proportion to the square of the amplitude of the waves. The phase information is lost. Also remember that visible light has a frequency of +- 10^14 Hz, so there is no easy way of comparing that to a clock. Do a first year physics course on (optical) wave mechanics to see the difference.
With an optical telescope, which we are discussing here, you can't compare the phase of the light to some clock (yet). Therefore the only way to do interferometry is by sending the light physically (with some mirrors or a fiber) to a common combination point. This limits any practical solutions at the moment to a few hundred meters.
I am somewhat involved with the European version of these missions (the Darwin mission, to be launched around 2014), so I might clear some things up.
Goal: to detect earth-like planets around other starts. Extra-solar planets detected thus far are usually 'hot Jupiters': big planets that orbit the star in a few days. These are relatively easy to detect. Detecting an earth-like planet (which have not been found yet) is far more difficult. It is usually compared to detecting the light of a firefly (reflection of the planet) flying very close to a lighthouse (the star). Measurements need to be done in the far infrared because there the ratio between the planet and the starlight is the highest (but still only 1:10^6 !!). With some luck they might find traces of ozone and CO2 in the spectrum that might be an indication for life.
Methods:
-Coronography: Simply put it is just a conventional big (~10 meter) telescope with a shadow mask that blocks the light of the star. The light of the planet should get past the mask on the detector.
-Interferometry: Somewhat similar to the techniques used in radio astronomy. The resolution of a telescope improves by increasing its size. The trick is to combine several small telescopes. The resolution should then be comparable to the resolution of one big telescope that is as wide as the separation between the small ones. With radio interferometry you can do the 'beam combination' by computer. In optics however you have to physically combine the beams of the different telescopes. This requires flying satellites in formation with stabilities on the order of nanometers!! Current schemes are limited to several hundred meters. There are also some attemps to do this on earth.
There is quite a lot of politics going on between NASA and ESA at the moment about how they should cooperate. First ideas where to do an interferometry mission together, but now NASA has decided to go for coronography and postpone interferometry to 2020. ESA is sticking to interferometry.
If you look at the driving plan thus far and at the surroundings, you see that endurance crater is pretty much the only big interesting feature in the area. Also, given the finite life of the rovers (extended design life is 180 days?) there must come an end some time. The rovers seem to operate perfectly right now, but i believe that the thermal cycling of the batteries is a definite show-stopper in a couple of months. Considering this, i think it is a fair gamble to drive into the crater with the risk of never coming out. If you do you might get some very interesting data on all the deep soil layers. By the time you would get out you are almost dead anyhow.
I recently had the pleasure of attending a talk by a guy that worked on the focal plane of GAIA, a spacecraft to be launched by ESA around 2010. It is not designed for imaging, but for very accurately determining the position of stars (astrometry).
Their specs for the focal plane of the telescopes: size of around 0.6*0.8 meter, 180 CCD chips packed together for a total of 1.2 Gigapixels! I believe handling the thermal power alone (~100 Watt), without moving the location of the pixels a bit already was a typical case of rocket science.
Don't understand me wrong: I don't have anything against Carmack and I think it's great what he is doing. From a betting perspective, however, who would you put your money on: a game developer with lot of creativity and spare time, or a company led by a famous aircraft designer who is in the business for more than 20 years?
I guess you where sleeping your way through the optics lectures: These lenses could definitely work. If you look at the picture
you see that there are two fluids: brown one on top and a blue one on the bottom. If you remember Snell's law (ray bends towards the normal in the denser medium), you can conclude from the picture that the 'brown' fluid has a higher refractive index than the 'blue' fluid. The left picture thus resembles a hollow/concave/negative lens and the right picture resembles a convex/positive lens. Of these the positive (on the right) can be used to form a real image (one you can capture on a CCD or a retina), whereas the negative only forms a virtual image.
A colleague of mine did his internship at the group that invented these and my boss still works part-time at Philips.
I suggest that you can, as a good scientist, provide us with a reference of that claim for peer review and for our reading pleasure?
The logo is nice though. Can't wait to give it a try.