There is also no way to prove that god doesn't exist.
Most people believe the above two statements.
If you believe that god exists then you are religious (despite the fact that it can't be proved)
If you believe that god doesn't exist then you are an atheist (despite the fact that it can't be proved)
If you are not sure whether or not god exists (because it can't be proved either way) then you are an agnostic.
Most people actually agree that they are agnostic when they actually think about it.
I count myself as an agnostic who thinks it is very unlikely that god exists. Close to being an atheist sure, but there is still the possibility that there is a greater being out there. A very small possibility in my view but I can't discount it. That makes me an agnostic.
Check the video. That very much isn't a tightly focused beam. It is a line laser and not a point laser and as such the beam diverges by what looks like +/-30 degrees or so. The laser eye safety test is based on a 7mm pupil diameter so at 1m the beam strength entering the eye would be 0.007 of the total assuming an even light spread. It isn't going to be an even light spread so 0.01 is a better figure.
FYI, no laser is perfect and a typical 100mW laser pointer will be eye safe at a distance of 100m or more due to beam spread.
The green line lasers used here http://www.youtube.com/watch?v=WOU563OvpUY look like they are in the 1mW to 5mW range type devices. These are eye safe under all conditions as it isn't possible to get all that light focused onto the back of you eye even if you hold it within a few mm of your eyeball. At 1m distance, the power entering your eye will be approx 1/100 of this so there is absolutely zero chance of eye damage from this sort of thing.
Dazzle on the other hand is far more of an issue. It is quite possible that a reflected beam could distract or dazzle a driver for a few seconds. Not something you want to happen.
Technically the batteries have the same mass while on Earth as they do while orbiting it. The weight in orbit is zero. (which is the point the above are making)
Only true if the HST + shuttle were stationary and balanced on a very tall table rather than being in orbit. As they are actually in free fall, effective gravity is zero and hence the weight is zero too.
(Yes I do understand that gravity is acting on the HST + shuttle to keep it in orbit but there is no force required to support them which is the definition of weight)
We see spherical objects as spherical because of the shadows and light reflected from it causing different intensities of light reaching our eyes from it.
The sun is different, it has no shadows or light landing on it. It is the light source. If you assume that the sun is a black body of a constant temperature across its surface, the light reaching us from anywhere on its surface is constant which would make it appear to be a completely flat disc. This effect is due to two cos(theta) terms cancelling each other out if you want to do the maths and would be true no matter what the shape that the sun (or any perfect black body) actually was. If for example, the sun was a cube, we would just see the silhouette of the cube as a flat surface and none of the sides.
Now, in reality, the sun isn't a perfect black body of constant temperature and is both less dense and cooler at the edges than at the centre. This makes the edges darker and makes it look more like a spherical object. The post below on limb darkening gives the details.
"When we made the decision, the odds were 1-in-473 that we would have a problem on the shuttle for which a rescue shuttle was the solution," Griffin said. "Now, there are a lot of problems you can have on the shuttle, right? There are a lot of ways you can die on the shuttle, which is what gives you the overall shuttle PRA (probabilistic risk assessment) of about 1-in-75 or so. So you're roughly five-and-a-half, six times likelier to die on the shuttle for some reason that the backup shuttle can't save you from than you are to die from one the backup shuttle can save you from.... From a statistical point of view, it makes no real sense to have a backup shuttle.
"However, here's the flip side.... Those numbers cannot be explained to politicians or the general public. And should we have a failure with those 1-in-473 or whatever odds it was, should we have a failure that the rescue shuttle could have saved you from and we had not done it, the consequence to NASA would have been incalculable. We would appear to have been cavalier with human life, we would appear to have not taken every possible precaution, we would appear to have been coldly calculating the odds and rolling the dice with people's lives. And the appearance of behaving that way, in my judgment, was unacceptable. I could not risk that for NASA."
While the overall risk of impact damage is about three times higher for a Hubble mission than a flight to the International Space Station, it is not as bad as flight planners initially feared.
"We know we're accepting a little higher risk for this flight," Steve Stich, manager of the orbiter project office at the Johnson Space Center, said in an interview. "That's why we've tracked it very carefully."
Even factoring in debris from a satellite collision in February between a defunct Russian Cosmos satellite and an Iridium telephone relay station, the mean odds of a catastrophic impact during the Hubble mission are on the order of 1-in-229, which is well below the 1-in-200 threshold that requires an executive-level decision by NASA's leadership.
A preliminary analysis put the odds at 1-in-185, but the numbers improved after recent radar observations and consideration of the shuttle's orientation in space during the Hubble mission. The planned orientation, or attitude timeline, reduces the crew's exposure to impacts that could damage critical areas of the ship's heat shield, the coolant loops in the shuttle's cargo bay door radiators and cockpit windows.
Daveime, no I'm not an expert but I do understand the laws of physics and have read up on this. Some of what you say is correct, but a lot isn't.
A small amount of fuel could be used to get the shuttle to visit the ISS. Unfortunately, this would be in a very elliptical orbit so they would only be able to (very) briefly wave through the window as they flew past each other at a very large differential speed before ploughing into the Earth in an unfortunately bright fireball.
To get to the same altitude as the ISS (keeping the orbit circular) requires dropping by 210km and speeding up by 200m/s. Not in itself a great requirement on fuel. The problem is that the orbit inclinations are so different (HST is 28.5 degrees, ISS is 51.6 degrees). To make this change requires something like a 3000m/s speed change sideways (this calc is only order of magnitude accurate). This requires a lot of fuel.
As others have stated, the current design of the shuttle has some major faults. Not being on the top of the rocket being one of them. This is not news and has been known for a long time and yes it has been taken into account in the next design (which isn't a shuttle at all).
The latter. The photos and laser scans made of the chips have been made with an inspection boom which is now carried on the shuttle to make these inspections post Columbia.
Normally (again post Columbia) the shuttle does a back flip when arriving at the ISS so that dinks can be photographed by the ISS. On this trip, this obviously isn't possible.
Oh and past shuttle flights have had far far worse damage than this which is minor.
The ISS is below hubble so to get to it you need to drop in height. As there is no friction in space, this change takes just as much fuel to lose potential energy as it does to gain it so it doesn't make much difference. The shuttle would also have to increase in speed a bit (from 7500m/s to 7700m/s) so energy would be required for this too. However, these two requirements are insignificant compared to the change in orbit inclination required. HSS is 28.5 degrees, ISS is 51.6 degrees. That will take a lot of fuel.
Nasa experts have looked into all of these issues and potential solutions.
A mere couple of hundred miles is not a problem (you do know how fast the shuttle flies don't you?) Orbital mechanics is the problem. The fuel required for the shuttle to change orbits would weigh too much for it to get off the ground in the first place.
The risks have been very carefully considered, with the mission ruled out of safety grounds for a long time. Yes, they are pushing the risks on this mission but having a back up shuttle on the pad ready to lift off in three days (you do know about this don't you?) mitigates some of the risks. That together with other changes they have made have kept the risks of a catastrophic failure below the limit set for every mission.
"And Scooter, also I've got some good news about the tile damage that we saw on the starboard chine area earlier today," astronaut Alan Poindexter radioed from mission control shortly after 8 p.m.
"Oh, I'm looking forward to that. Go ahead," replied shuttle commander Scott "Scooter" Altman.
"It turns out that a focussed inspection of that area on the starboard chine is not going to be required," Poindexter reported.
"All right, you've got some happy EVA campers on that," Altman said.
When encapsulated within a system so that it is not possible for the beam to escape under normal usage then the whole system can be given a class 1 rating and a class 1 label. The laser itself is a class 3B and would have to have this rating if removed from the player. Current Blu-ray recorders are 250mW but are considered safe as they are encapsulated.
Nope. The key ring laser pointers are 1mW to 5mW so this thing is 2000 to 10000 times the average power. A 10W laser is very good at setting fire to things but won't drill a hole through your still twitching body.
22.6 Kg x 1m x 9.8 m/s^2 / 4 hours = 0.015W if conversion is 100% efficient (which it won't be)
The red led on the front of your modem requires around this amount so the glow will be feable. To get the equivalent of a filament 40W bulb requires around 10W so the system is only around a factor of 1000 out.
Slashdot Mirror
Totally agree with you. Science has shown us that there is no easy answer to this question.
There is no way to prove that god exists.
There is also no way to prove that god doesn't exist.
Most people believe the above two statements.
If you believe that god exists then you are religious (despite the fact that it can't be proved)
If you believe that god doesn't exist then you are an atheist (despite the fact that it can't be proved)
If you are not sure whether or not god exists (because it can't be proved either way) then you are an agnostic.
Most people actually agree that they are agnostic when they actually think about it.
I count myself as an agnostic who thinks it is very unlikely that god exists. Close to being an atheist sure, but there is still the possibility that there is a greater being out there. A very small possibility in my view but I can't discount it. That makes me an agnostic.
http://www.thinkbroadband.com/news/4002-talktalk-follow-suit-on-phorm.html
I hope nobody owns Phorm shares...
Check the video. That very much isn't a tightly focused beam. It is a line laser and not a point laser and as such the beam diverges by what looks like +/-30 degrees or so. The laser eye safety test is based on a 7mm pupil diameter so at 1m the beam strength entering the eye would be 0.007 of the total assuming an even light spread. It isn't going to be an even light spread so 0.01 is a better figure.
FYI, no laser is perfect and a typical 100mW laser pointer will be eye safe at a distance of 100m or more due to beam spread.
The green line lasers used here http://www.youtube.com/watch?v=WOU563OvpUY look like they are in the 1mW to 5mW range type devices. These are eye safe under all conditions as it isn't possible to get all that light focused onto the back of you eye even if you hold it within a few mm of your eyeball. At 1m distance, the power entering your eye will be approx 1/100 of this so there is absolutely zero chance of eye damage from this sort of thing.
Dazzle on the other hand is far more of an issue. It is quite possible that a reflected beam could distract or dazzle a driver for a few seconds. Not something you want to happen.
Technically the batteries have the same mass while on Earth as they do while orbiting it. The weight in orbit is zero. (which is the point the above are making)
See here: http://en.wikipedia.org/wiki/Mass_versus_weight
Only true if the HST + shuttle were stationary and balanced on a very tall table rather than being in orbit. As they are actually in free fall, effective gravity is zero and hence the weight is zero too.
(Yes I do understand that gravity is acting on the HST + shuttle to keep it in orbit but there is no force required to support them which is the definition of weight)
Sensible question but a non obvious answer.
We see spherical objects as spherical because of the shadows and light reflected from it causing different intensities of light reaching our eyes from it.
The sun is different, it has no shadows or light landing on it. It is the light source. If you assume that the sun is a black body of a constant temperature across its surface, the light reaching us from anywhere on its surface is constant which would make it appear to be a completely flat disc. This effect is due to two cos(theta) terms cancelling each other out if you want to do the maths and would be true no matter what the shape that the sun (or any perfect black body) actually was. If for example, the sun was a cube, we would just see the silhouette of the cube as a flat surface and none of the sides.
Now, in reality, the sun isn't a perfect black body of constant temperature and is both less dense and cooler at the edges than at the centre. This makes the edges darker and makes it look more like a spherical object. The post below on limb darkening gives the details.
Ooh-eck!
"dropping" means reducing velocity, which requires fuel.
Actually, "dropping" (210km in this case) means increasing velocity (by 200m/s). Not obvious but true.
http://spaceflightnow.com/shuttle/sts125/090508sts400/
"When we made the decision, the odds were 1-in-473 that we would have a problem on the shuttle for which a rescue shuttle was the solution," Griffin said. "Now, there are a lot of problems you can have on the shuttle, right? There are a lot of ways you can die on the shuttle, which is what gives you the overall shuttle PRA (probabilistic risk assessment) of about 1-in-75 or so. So you're roughly five-and-a-half, six times likelier to die on the shuttle for some reason that the backup shuttle can't save you from than you are to die from one the backup shuttle can save you from. ... From a statistical point of view, it makes no real sense to have a backup shuttle.
"However, here's the flip side. ... Those numbers cannot be explained to politicians or the general public. And should we have a failure with those 1-in-473 or whatever odds it was, should we have a failure that the rescue shuttle could have saved you from and we had not done it, the consequence to NASA would have been incalculable. We would appear to have been cavalier with human life, we would appear to have not taken every possible precaution, we would appear to have been coldly calculating the odds and rolling the dice with people's lives. And the appearance of behaving that way, in my judgment, was unacceptable. I could not risk that for NASA."
While the overall risk of impact damage is about three times higher for a Hubble mission than a flight to the International Space Station, it is not as bad as flight planners initially feared.
"We know we're accepting a little higher risk for this flight," Steve Stich, manager of the orbiter project office at the Johnson Space Center, said in an interview. "That's why we've tracked it very carefully."
Even factoring in debris from a satellite collision in February between a defunct Russian Cosmos satellite and an Iridium telephone relay station, the mean odds of a catastrophic impact during the Hubble mission are on the order of 1-in-229, which is well below the 1-in-200 threshold that requires an executive-level decision by NASA's leadership.
A preliminary analysis put the odds at 1-in-185, but the numbers improved after recent radar observations and consideration of the shuttle's orientation in space during the Hubble mission. The planned orientation, or attitude timeline, reduces the crew's exposure to impacts that could damage critical areas of the ship's heat shield, the coolant loops in the shuttle's cargo bay door radiators and cockpit windows.
Thanks for that, Mr $0.02, that made me smile :-)
Daveime, no I'm not an expert but I do understand the laws of physics and have read up on this. Some of what you say is correct, but a lot isn't.
A small amount of fuel could be used to get the shuttle to visit the ISS. Unfortunately, this would be in a very elliptical orbit so they would only be able to (very) briefly wave through the window as they flew past each other at a very large differential speed before ploughing into the Earth in an unfortunately bright fireball.
To get to the same altitude as the ISS (keeping the orbit circular) requires dropping by 210km and speeding up by 200m/s. Not in itself a great requirement on fuel. The problem is that the orbit inclinations are so different (HST is 28.5 degrees, ISS is 51.6 degrees). To make this change requires something like a 3000m/s speed change sideways (this calc is only order of magnitude accurate). This requires a lot of fuel.
As others have stated, the current design of the shuttle has some major faults. Not being on the top of the rocket being one of them. This is not news and has been known for a long time and yes it has been taken into account in the next design (which isn't a shuttle at all).
The latter. The photos and laser scans made of the chips have been made with an inspection boom which is now carried on the shuttle to make these inspections post Columbia.
Normally (again post Columbia) the shuttle does a back flip when arriving at the ISS so that dinks can be photographed by the ISS. On this trip, this obviously isn't possible.
Oh and past shuttle flights have had far far worse damage than this which is minor.
Not quite right.
The ISS is below hubble so to get to it you need to drop in height. As there is no friction in space, this change takes just as much fuel to lose potential energy as it does to gain it so it doesn't make much difference. The shuttle would also have to increase in speed a bit (from 7500m/s to 7700m/s) so energy would be required for this too. However, these two requirements are insignificant compared to the change in orbit inclination required. HSS is 28.5 degrees, ISS is 51.6 degrees. That will take a lot of fuel.
So what makes you such an expert?
Nasa experts have looked into all of these issues and potential solutions.
A mere couple of hundred miles is not a problem (you do know how fast the shuttle flies don't you?) Orbital mechanics is the problem. The fuel required for the shuttle to change orbits would weigh too much for it to get off the ground in the first place.
The risks have been very carefully considered, with the mission ruled out of safety grounds for a long time. Yes, they are pushing the risks on this mission but having a back up shuttle on the pad ready to lift off in three days (you do know about this don't you?) mitigates some of the risks. That together with other changes they have made have kept the risks of a catastrophic failure below the limit set for every mission.
More info here: http://spaceflightnow.com/shuttle/sts125/090512fd2/index5.html
"And Scooter, also I've got some good news about the tile damage that we saw on the starboard chine area earlier today," astronaut Alan Poindexter radioed from mission control shortly after 8 p.m.
"Oh, I'm looking forward to that. Go ahead," replied shuttle commander Scott "Scooter" Altman.
"It turns out that a focussed inspection of that area on the starboard chine is not going to be required," Poindexter reported.
"All right, you've got some happy EVA campers on that," Altman said.
Did it work?
YouTube video
Most people are missing the point of this. It isn't a sensible solution, it is a FUN solution. I would love to have a go.
I would love to know why it was kept quiet for so long.
"The breakthrough was made in 2005. Only now are researchers confident enough about their work to discuss the details publicly."
So what were they not confident about? Hot temperatures - check. No drill bit left - check. Rock fused to end of drill - check.
When encapsulated within a system so that it is not possible for the beam to escape under normal usage then the whole system can be given a class 1 rating and a class 1 label. The laser itself is a class 3B and would have to have this rating if removed from the player. Current Blu-ray recorders are 250mW but are considered safe as they are encapsulated.
Nope. The key ring laser pointers are 1mW to 5mW so this thing is 2000 to 10000 times the average power. A 10W laser is very good at setting fire to things but won't drill a hole through your still twitching body.
Crocodile's Immune System Kills HIV - story from 2005
Try again with that. You are only a factor of 1000 out in your calculations. Remember google is your friend when trying to work these things out:
http://www.google.co.uk/search?hl=en&q=22700+grams+*+9.8+m%2Fs%5E2+*+1.5+m+in+watt+hours
10W are the energy efficient bulbs (factor of 4 better than filament). The best LEDs might be able to bring this down to 5W if you lucky.
22.6 Kg x 1m x 9.8 m/s^2 / 4 hours = 0.015W if conversion is 100% efficient (which it won't be)
The red led on the front of your modem requires around this amount so the glow will be feable. To get the equivalent of a filament 40W bulb requires around 10W so the system is only around a factor of 1000 out.