First, sending alerts to people who do not need to take immediate specific action will cause many to turn off alerts entirely. I was woken by one of the large scale Amber alerts - about a child kidnapped 300 MILES from my house. So I've turned off all the alerts that I can.
Secondly, there is no specific action for people to take when police are in distress. I can't imagine that the police want a bunch of armed citizens with no situational awareness converging on the site of some emergency. Seems like that will make almost any situation worse.
Finally, while I believe that most police do a good service to the community, I do not seem them as being unusually noble or risk-taking. Firemen, pilots, and roofers and many others are also exposed to danger while serving the community. Why not an "asphalt alert" when a roofer falls and is injured?
Conferences have a similar problem. Most labs require attendees to present something. So if you want to go to a conference you need to put together something to show - even if you know it isn't very interesting.
Its a classic problem of using the wrong metric of success.
Objects sent to Mars need to be COMPLETELY sterilized to avoid the chance of contaminating Mars with earth bacteria and possibly hiding any signs of independent development of life. I hope he doesn't actually do this stunt.
In any case, even with a high chance of failure, payload to mars could be used for scientific or engineering experiments. Maybe an experimental atmosphere -> fuel processor, or maybe even a hail Mary at a sample return mission.
The article said that it didn't decrease the use of BitTorrent, but it didn't say whether the amount of material decreased.
Another poster also had a good point that streaming has a very limited selection. That probably doesn't include the recent popular titles that are most likely to be pirated.
I'm happy to pay for streaming content, but much content is either not available at all on streaming, or only included with a subscription, rather than a pay-per-use basis.
For automobiles, hybrid engines make sense. The batteries can store energy from deceleration and downhill and release it when needed. They can also buffer the large changes in power required for normal driving, allowing the engine to operate at its maximum efficiency power - and allow the use of engines optimized for single power operation. This outweighs the small extra drag from the battery weight.
Airplanes are different. They already store energy as potential and kinetic energy: the energy spent in climbing is largely recovered in descent, the energy of accelerating is recovered in decelerating. Aircraft engines spend most of their time operating at near maximum-efficiency power already. OTOH, battery weight directly adds to induced drag and reduces efficiency. Aircraft do sometimes use drag devices, and running a fan as a generator would reduce that loss, but it is usually only for a small fraction of the flight.
I don't see how a hybrid engine in an aircraft helps. I must be missing something.
I could see adding small electric traction motors for ground operations to reduce engine idle fuel consumption and pollution. Presumably so far the weight of batteries and motors is too much to make this a net efficiency win - but I could imagine it being useful in some cases.
Almost correct. The temperatures are not actually hotter than a chemical rocket, but you can use pure hydrogen as fuel. Since hydrogen molecules are lighter than typcal exhaust gasses (water, CO2 etc), at the same temperature they are moving faster. That means you need less mass for the same velocity change in the rocket, or you can go faster on the same fuel.
The best chemical fuels are around 4500 M/s exhaust velocity. Storable chemicals are more like 3000 M/s. Nuclear thermal rockets get to around 10,000M/s So in principal you can go 2X as fast with the same fuel to mass ratio.
There are lots of caveats. The reactor is heavy. The radiation shielding is heavy - these both mean that you need a very large spacecraft before you have a net win in performance.
You probably don't want to turn one of these on before you are in orbit due to the potential problems with an accident (and the thrust to weight is pretty small anyway).
An additional problem is that its difficult to store hydrogen for long periods of time - you would need a complex and heavy refrigeration system. Or you can just use the nuclear rocket for leaving earth, and conventional storable chemicals for arrival.
Its a reasonable idea but with a lot of engineering tradeoffs that need to be considered. Its.... rocket science.
This is very interesting from a theoretical / experimental point of view. Its an analog of nuclear fusion but done with quarks. That is fun and interesting and well worth a nature paper. It is NOT however in any way a possible source of energy. The quarks in normal matter are already in their lowest energy state. The lambda_c particles they are fusing have a half life of a fraction of a picosecond - not something you might find lying around. Making lambdas would take far more energy than comes out of the "fusion".
So its an interesting example of a large binding energy between charmed quarks, but since you have to create the input particles out of energy, its not a path to net energy production. The abstract of the paper says as much.
I've also seen the old US reusable spaceplane models - you can still find some in the Smithsonian and other museums. We also had dynosaur, and the various lifting body craft. Sill we never built a real one. (unless you count the partially-reusuable shuttle).
They are also not making a big deal about it in their internal museums - at lest nothing in the space section of the Shanghai technology museum a couple of years back.
I'm not doubting that the Chinese are working on it - just the 2020 date. Still, I'd like to be surprised.
Nothing fundamentally wrong with a fully re-usable space plane but the 2020 launch date would imply that they are very far along. If so, I'm surprised no design information has leaked out. They should already be testing full scale gliding models etc.
I hope its real and they have just been keeping it hush hush: the more human capability there is to do space, the happier I am. I'll believe it though when I see some pictures of actual hardware .
I should be more clear. I will "consider" evidence from secret sources, however I will weigh that information as unverified unless I have sufficient details on how it was collected. With a low weight, that information will not significantly contribute to my estimation as to whether or not the defendant's probability of guilt exceeds my standards for "reasonable doubt".
I view evidence from secret sources as having similar weight to hearsay. I base this on the widespread evidence that electronic systems can be hacked, and so without additional information I have no reason to believe that the data from the stingray device is valid. I would explain this argument to other jurors.
I don't see how someone can receive a fair trial if the the mechanism used to collect evidence is secret. The prosecution can only claim to have phone records, there is no way for the defense to question their accuracy, or whether the evidence could be spoofed.
The only reason to keep the operation of stingrays secret is of there is some way to spoof them. In that case how can you be sure that there aren't already spoofing systems in the wild?
I wonder if this fix is now available because there is some other backdoor available to government agencies. Besides, how will a typical consumer know that this has actually been disabled?
There is no root source of trust, so security is impossible for anyone who is not themselves an expert.
The most serious dangers from AI come from the inability to predict or control it. I'm not concerned someone is going to create an AI to wipe out humanity, I'm concerned about side effects from complex optimization algorithms that are doing exactly what we ask them to do.
Using an AI to adjust tax policies to reduce hunger might not reduce it in the way people desire.
It may also be the sort of thing you put out to keep people from being unreasonably afraid.
I work at an accelerator lab where we have dangerous radiation levels when the accelerator is on, but quite low levels when it is off. I was talking with some emergency response guys and they said "I'm not walking past all those radiation signs". These are the same guys who will walk into burning refineries to save people. The problem is that they had not been given accurate information on the relative risks of radiation and other risks.
10rem is not "safe" in that the general public should not be exposed to that level of radiation. It is also not so dangerous that people should take higher risks to avoid being exposed to that level of radiation.
The issue is giving people accurate information so that they can balance risks.
I'm a career scientist and I often use wikipedia to get some basic information on a topics where I'm not already familiar. its quite useful to have real technical information in the articles rather than just an basic introduction.
Many articles do have basic introductions - but sometimes that isn't all that practical. Expecting a simple layman's introduction to electro-weak interactions may be too optimistic. There are probably a few people who could explain it that way, but most experts would not be able to do so.
As another poster said, anyone is free to add non-technical introductions to articles.
They are looking for worlds that could see us using our current technology. Its an interesting study, but 100 years ago we would have tried (and failed) with a very different technique (direct telescopic examination). 100 years from now we may be using a completely different technology (solar system sized interferometers?, Some new trick to drastically reduce stray light in an image? X-ray telescopes? I have no idea) )
We know nothing about alien technology (if it even exists). It may have followed similar paths to ours, but it might be wildly different.
Not as silly as it sounds. When the SLAC LCLS laser first operated the thing that convinced us we had roughly the power we thought was that it burned a hole in a metal foil. Actually finding something to serve as an X-ray beam stopper is not so easy at these powers.
Slashdot Mirror
First, sending alerts to people who do not need to take immediate specific action will cause many to turn off alerts entirely. I was woken by one of the large scale Amber alerts - about a child kidnapped 300 MILES from my house. So I've turned off all the alerts that I can.
Secondly, there is no specific action for people to take when police are in distress. I can't imagine that the police want a bunch of armed citizens with no situational awareness converging on the site of some emergency. Seems like that will make almost any situation worse.
Finally, while I believe that most police do a good service to the community, I do not seem them as being unusually noble or risk-taking. Firemen, pilots, and roofers and many others are also exposed to danger while serving the community. Why not an "asphalt alert" when a roofer falls and is injured?
Conferences have a similar problem. Most labs require attendees to present something. So if you want to go to a conference you need to put together something to show - even if you know it isn't very interesting.
Its a classic problem of using the wrong metric of success.
Objects sent to Mars need to be COMPLETELY sterilized to avoid the chance of contaminating Mars with earth bacteria and possibly hiding any signs of independent development of life. I hope he doesn't actually do this stunt.
In any case, even with a high chance of failure, payload to mars could be used for scientific or engineering experiments. Maybe an experimental atmosphere -> fuel processor, or maybe even a hail Mary at a sample return mission.
The article said that it didn't decrease the use of BitTorrent, but it didn't say whether the amount of material decreased.
Another poster also had a good point that streaming has a very limited selection. That probably doesn't include the recent popular titles that are most likely to be pirated.
I'm happy to pay for streaming content, but much content is either not available at all on streaming, or only included with a subscription, rather than a pay-per-use basis.
For automobiles, hybrid engines make sense. The batteries can store energy from deceleration and downhill and release it when needed. They can also buffer the large changes in power required for normal driving, allowing the engine to operate at its maximum efficiency power - and allow the use of engines optimized for single power operation. This outweighs the small extra drag from the battery weight.
Airplanes are different. They already store energy as potential and kinetic energy: the energy spent in climbing is largely recovered in descent, the energy of accelerating is recovered in decelerating. Aircraft engines spend most of their time operating at near maximum-efficiency power already. OTOH, battery weight directly adds to induced drag and reduces efficiency. Aircraft do sometimes use drag devices, and running a fan as a generator would reduce that loss, but it is usually only for a small fraction of the flight.
I don't see how a hybrid engine in an aircraft helps. I must be missing something.
I could see adding small electric traction motors for ground operations to reduce engine idle fuel consumption and pollution. Presumably so far the weight of batteries and motors is too much to make this a net efficiency win - but I could imagine it being useful in some cases.
This can be tested statistically. Iâ(TM)m not going to guess the answer.
Space is big. Really big. You may think its a long way to the chemist, but that's nothing to space.....Douglas Adams
Almost correct. The temperatures are not actually hotter than a chemical rocket, but you can use pure hydrogen as fuel. Since hydrogen molecules are lighter than typcal exhaust gasses (water, CO2 etc), at the same temperature they are moving faster. That means you need less mass for the same velocity change in the rocket, or you can go faster on the same fuel.
The best chemical fuels are around 4500 M/s exhaust velocity. Storable chemicals are more like 3000 M/s. Nuclear thermal rockets get to around 10,000M/s So in principal you can go 2X as fast with the same fuel to mass ratio.
There are lots of caveats. The reactor is heavy. The radiation shielding is heavy - these both mean that you need a very large spacecraft before you have a net win in performance.
You probably don't want to turn one of these on before you are in orbit due to the potential problems with an accident (and the thrust to weight is pretty small anyway).
An additional problem is that its difficult to store hydrogen for long periods of time - you would need a complex and heavy refrigeration system. Or you can just use the nuclear rocket for leaving earth, and conventional storable chemicals for arrival.
Its a reasonable idea but with a lot of engineering tradeoffs that need to be considered. Its .... rocket science.
Look how well that has worked out......
If it sounds like the intro to a horror movie / game, maybe you should think twice about proceeding....
This is very interesting from a theoretical / experimental point of view. Its an analog of nuclear fusion but done with quarks. That is fun and interesting and well worth a nature paper. It is NOT however in any way a possible source of energy. The quarks in normal matter are already in their lowest energy state. The lambda_c particles they are fusing have a half life of a fraction of a picosecond - not something you might find lying around. Making lambdas would take far more energy than comes out of the "fusion".
So its an interesting example of a large binding energy between charmed quarks, but since you have to create the input particles out of energy, its not a path to net energy production. The abstract of the paper says as much.
The Chinese certainly aren't stealing space technology from us these days......
Thank you for the links.
I've also seen the old US reusable spaceplane models - you can still find some in the Smithsonian and other museums. We also had dynosaur, and the various lifting body craft. Sill we never built a real one. (unless you count the partially-reusuable shuttle).
They are also not making a big deal about it in their internal museums - at lest nothing in the space section of the Shanghai technology museum a couple of years back.
I'm not doubting that the Chinese are working on it - just the 2020 date. Still, I'd like to be surprised.
Nothing fundamentally wrong with a fully re-usable space plane but the 2020 launch date would imply that they are very far along. If so, I'm surprised no design information has leaked out. They should already be testing full scale gliding models etc.
I hope its real and they have just been keeping it hush hush: the more human capability there is to do space, the happier I am. I'll believe it though when I see some pictures of actual hardware .
I should be more clear. I will "consider" evidence from secret sources, however I will weigh that information as unverified unless I have sufficient details on how it was collected. With a low weight, that information will not significantly contribute to my estimation as to whether or not the defendant's probability of guilt exceeds my standards for "reasonable doubt".
I view evidence from secret sources as having similar weight to hearsay. I base this on the widespread evidence that electronic systems can be hacked, and so without additional information I have no reason to believe that the data from the stingray device is valid. I would explain this argument to other jurors.
I've never sat a trial either - an I really don't try to get out. My honest answers seem to be quite sufficient .
I don't see how someone can receive a fair trial if the the mechanism used to collect evidence is secret. The prosecution can only claim to have phone records, there is no way for the defense to question their accuracy, or whether the evidence could be spoofed.
The only reason to keep the operation of stingrays secret is of there is some way to spoof them. In that case how can you be sure that there aren't already spoofing systems in the wild?
As a Juror I would ignore any "secret" evidence.
I wonder if this fix is now available because there is some other backdoor available to government agencies. Besides, how will a typical consumer know that this has actually been disabled?
There is no root source of trust, so security is impossible for anyone who is not themselves an expert.
The most serious dangers from AI come from the inability to predict or control it. I'm not concerned someone is going to create an AI to wipe out humanity, I'm concerned about side effects from complex optimization algorithms that are doing exactly what we ask them to do.
Using an AI to adjust tax policies to reduce hunger might not reduce it in the way people desire.
It may also be the sort of thing you put out to keep people from being unreasonably afraid.
I work at an accelerator lab where we have dangerous radiation levels when the accelerator is on, but quite low levels when it is off. I was talking with some emergency response guys and they said "I'm not walking past all those radiation signs". These are the same guys who will walk into burning refineries to save people. The problem is that they had not been given accurate information on the relative risks of radiation and other risks.
10rem is not "safe" in that the general public should not be exposed to that level of radiation. It is also not so dangerous that people should take higher risks to avoid being exposed to that level of radiation.
The issue is giving people accurate information so that they can balance risks.
I'm a career scientist and I often use wikipedia to get some basic information on a topics where I'm not already familiar. its quite useful to have real technical information in the articles rather than just an basic introduction.
Many articles do have basic introductions - but sometimes that isn't all that practical. Expecting a simple layman's introduction to electro-weak interactions may be too optimistic. There are probably a few people who could explain it that way, but most experts would not be able to do so.
As another poster said, anyone is free to add non-technical introductions to articles.
They are looking for worlds that could see us using our current technology. Its an interesting study, but 100 years ago we would have tried (and failed) with a very different technique (direct telescopic examination). 100 years from now we may be using a completely different technology (solar system sized interferometers?, Some new trick to drastically reduce stray light in an image? X-ray telescopes? I have no idea) )
We know nothing about alien technology (if it even exists). It may have followed similar paths to ours, but it might be wildly different.
Not as silly as it sounds. When the SLAC LCLS laser first operated the thing that convinced us we had roughly the power we thought was that it burned a hole in a metal foil. Actually finding something to serve as an X-ray beam stopper is not so easy at these powers.
Yes, that is why a high rate is helpful, you can do lots of repeated measurements to build up a time response measurement.
The X-ray pulse is so short that you get an image before the sample flies apart