What's the time dilation factor of a 3 billion solar mass black hole traveling at 2.7% the speed of light? For a spacecraft at that speed it wouldn't be much, but a massive black hole has its own time- and space-warping effects. Are there any actual physicists here who'd care to speculate?
In a similar vein, the science journalist Peter Hadfield (aka Potholer54) has a hilarious quote about this: "I know a lot of editors at the Mail, and the nugget of science they understand is so small it could be drowned in their lunchtime gins & tonics."
The quote is from Hadfield's excellent video debunking myths about climate change. (This video is just one of a series on the subject, which is very much worth the time.)
An all-corn diet has virtually no protein... The body will eventually rebel against such a diet, and force a change in nutrient availability. I was born and raised in Iowa, so I love the taste of corn, but even I know that a man cannot live on corn alone... nor a rat.
Not to mention that coal contains trace amounts of Thorium and Uranium, which escape to the atmosphere in the exhaust. Ironically, a coal-fired power plant would not pass inspection as a nuclear plant because it emits far more radioactive pollution than would ever be allowed from a nuke plant. (But the way US law is written, coal plants don't have to be tested for radiation.)
I'm in the process of building my own tDCS device right now. I bought the components last Saturday and built the circuit on Sunday; on Monday I built the electrodes and on Tuesday I started using it (still on the breadboard). The circuit is pretty simple, just a voltage regulator and a few pots and resistors (there are many ways to do it, this approach just happens to use a voltage regulator). There is no way a 9V battery running through this circuit could generate the hundreds of milliamperes necessary to kill, or the dozens necessary to cause harm. When resistors fail, they tend to result in an open circuit -- zero current.
My circuit currently uses two potentiometers to ramp up the current to the desired level. Even with both of them wide open, the current is only 2.4mA, which is well within the safe range. (The recommended standard is to operate between 0.5mA and 2.0mA, but an order of magnitude above that is when you start to approach hazardous levels.) And of course, I run the it through a multimeter, so I always know the output of the circuit -- before, during, and after I put on the electrodes.
I first heard about tDCS in an episode of RadioLab last summer, which gives a pretty good intro to the topic. I finally got around to actually doing it last weekend.
Thus far, my experience has been entirely positive. The only glitch was yesterday when an "intermittency" developed in my electrode cable, which resulted in some phosphene flashes (due to an alligator clip + stranded wire). So I skipped my tDCS session today, and instead used the time to build the "finished" electrode cable, with soldered joints. That problem will not recur.
On the positive side, it seems to be having the desired effect. I became interested in tDCS because I have a "condition" which results in a lot of "unwanted thoughts" -- and I have noticed a remarkable decline in the frequency of these episodes.
You can naysay all you want from your armchair, but I'm actually doing this, and it works.
For more info on safety issues check out the/r/tDCS sub-reddit's FAQ.
Hm... my impression was that the Japanese had only invested a couple-hundred million in this area, primarily in IThEMS. AFAIK no entity on earth has ever put "tens of billions" on this. If you have info indicating otherwise, please cite.
As for the Chinese, it appears I got a few details wrong. They have spent $300M thus far, with plans to maintain this level of funding for the next few decades. You'll find a decent description of their program here. (But one thing I do know, which is not mentioned in the article: the project is led by a guy named Jiang Mianheng, who happens to be the son of Jiang Zemin, the former president. So I would guess their funding is pretty secure.)
Anyway, thanks for prompting me to look into it and get my facts straight.
China also has a billion-dollar program to develop a Liquid Fluoride Thorium Reactor (LFTR). It is the best-funded such program in the world, with (last I heard) 500 PhD engineers and scientists. Their goal is to have LFTRs in production by the early 2020s.
Presumably they're talking about something like this: Using renewable energy to synthesize liquid fuels for storage and transport. They can either work in conjunction with carbon capture or simply harvest CO2 from the air. I've heard of several ways to do it, but thus far it's mostly still in the lab. I haven't seen any "grid-scale" deployment. Apparently the Chinese intend to be first.
Yes, it has always been the customer's option, but it's not free. Moving rockets around costs money. A trifling amount, perhaps, compared to the overall launch cost, but a non-zero sum nonetheless.
I'd bet that from now on SpaceX will have a Hi-Def camera mounted on every lightning tower, recording 24/7, whenever there is a rocket on the pad. Also, if possible, they might add a few more sensors to the upper stage if they can spare enough telemetry channels for the data.
I suspect they'll also voluntarily eat the cost of running the static-fire tests before integrating the payload for the next year or so, just to avoid higher insurance fees for their customers. (How long before they start offering vertical integration as a 'menu option' service?)
(I of course am a lot more interested in hearing the results of their AMOS-6 investigation right now than about their ITS plans... as are I think most people)
I for one am more interested in hearing about the Mars architecture. AMOS-6 is just another anomaly that will eventually get resolved. Yes, of course I'm interested in finding out what happened, but the Falcon platform has already proven to be pretty reliable, especially considering it's undergone several major revisions in less than 30 flights. But the Mars architecture is going to be inspiring in a way that recalls the glory days of Apollo.
It's certainly possible, but... cui bono? Blue Origin? Boeing?
I don't think 2.5km is far enough to get past the exclusion zone, but a good sniper could probably sneak within range. Of course, you'd need an incendiary round to be sure of a kill shot, but I would think a bullet would leave some sort of tell-tale signature in the wreckage that would survive the explosion. (OTOH, if you could find a way to do the job without leaving such a signature, that could really mind-fuck SpaceX engineers for years to come.)
Let the games begin! I for one welcome a worthy competitor to Musk. The more billionaires we have focusing their attention and resources on real-world problems (rather than squeezing a few more basis points out of their high-frequency trading algorithms) the better off we'll all be. Even Bill Gates -- however buggy his software and however ill-gotten his gains -- appears to be using his economic power for "good" these days.
Meanwhile, what has Jamie Dimon done for you lately? (cough!)2008
Constitutionality?... Ok, let's assume we can do all this in the "cutting" room... bring in our "desirable" traits while also rendering the offspring infertile. We're not talking about a lab mouse here, it's a sentient human being...
Yes, there are circumstances wherein a fetus may be viable but not fertile, but to do this deliberately? That strikes me as unnecessarily cruel.
I don't deny that it may happen someday, but I would be comfortable with keeping this beyond the "prohibition" line, and thus relegate it to the black market. But now we're back to square one again. How do you simultaneously prevent the deliberate creation of circus freaks while also allowing reasonable prophylactic measures and enhancements for people who just want a healthy child?
It's an interesting question; where should we draw the line? Obviously, if your embryo/fetus is destined for cystic fibrosis, we would all cheer for a genetic intervention. But if you just think it would be cool if you kid would glow in the dark, it may be quite reasonable for the rest of us to resist allowing those "imported" genes into our collective gene pool.
I think a key concept to consider in all genetic modifications is the difference between vertical gene transfer and horizontal gene transfer. The former is manipulation of genes within the same family tree, whereas the latter involves importation of exogenous genes from other species.
If you ask me where I would draw the line, in terms of legislation, this is it: endogenous (vertical) vs. exogenous (horizontal) gene transfer. Do whatever you want within the human genome, but don't import any genes from any other genome.
We may enact some legislation to "prevent" this sort of thing, but it's going to happen anyway, because there will be a demand for it.
Prohibition simply doesn't work, whether it's prohibition of drugs, prostitution, alcohol... or genetic manipulation. One way or another we're going there. Perhaps this is a chance to "get it right" for a change, and educate the public about this emerging technology, rather than the usual FUD tactics.
True enough. But by the same token, if you're paying $60M to launch your $120M satellite, you might want to pay the extra $500k* to protect your asset.
* Note: I have no idea what the extra cost would be. But at minimum it would have to pay for hauling the booster stack back to the hangar after the static fire, to 'integrate' the payload, and then hauling the now-loaded rocket back to the launch pad again.
Perhaps, in response to this, SpaceX will figure out some sort of gantry system to allow vertical integration right on the launch pad. That way, they could avoid this situation entirely.
I would bet that SpaceX probably does carry some kind of insurance for this sort of thing, though 'how much' is a different question. In any case, I would also bet that whatever they've been paying for that insurance, the price just went up.
More info here: YouTube user Scott Manley has a 9-min video with frame-by-frame analysis. Well worth the time.
One thing I learned was that, although the satellite was insured, technically the insurance doesn't "kick in" until the rocket is actually launched, so in this case, they probably won't pay out. (This would explain the lawsuit mentioned in my post above.)
However, I've read elsewhere that they could have done this test without the payload on board, but that would cost extra. It is up to the customer to decide if they want to pay extra to protect their asset. It will be interesting to see how this all works out.
In a more recent story, SpaceX is being sued by Spacecom (owner of the AMOS-6 satellite that was lost). I have a hard time believing they could win such a suit, but that depends on what caused the "anomaly".
As for the Ars Technica op-ed, urging SpaceX to "focus" on NASA's priorities, I suspect that Elon will still reveal his plans for the MCT at the upcoming Int'l Astronautical Conference, but he will also spend a fair amount of time explaining what they've learned from this mishap. And I think he will probably take some of the advice from Ars... perhaps announcing that MCT will be put on the "back burner" for a while, so that they can get Crew Dragon and Falcon Heavy flying ASAP.
Yeah, I watched that video when it came out a few weeks ago. I've been subscribed to Thunderf00t's Youtube channel for several years already. If I'm not mistaken, this is his second rant on the same topic. And he brings up a lot of very salient points.
But I keep coming back to the same conclusion: There are hundreds of expert engineers with (cumulatively) centuries of experience among them who all agree that this is not only possible but doable. And then there's Phil Mason, a lone voice in the wilderness, saying it will never work.
Pardon me if I side with the optimists on this one.
It would seem that Elon and his team disagree with you. OTOH, it would seem that the folks at Hyperloop One disagree with Elon, since they are using mag-lev instead.
I reckon that's the whole point of setting up test tracks like this, to figure out what the best methodology would be. They'll have some races, eat some hot dogs, and collect a shit-load of data along the way. I think Elon is well aware that this technology is still in gestation, it's not quite ready for prime time yet, whatever H1 or HTT may say. Sponsoring a competition like this is a great way to advance the field with minimal cost.
As I understand it, the original white paper was more of a suggestion than a specification. For example, Elon suggested that air-cushion levitation would be the best method, but also acknowledged that magnetic levitation was a viable option. One of the hyperloop companies currently in development (the one that had a live test a couple of months ago) is using magnetic levitation in their design.
I agree that this particular competition is aimed more at students, but so what? It's a cool idea that gets people interested and motivated. I don't see a down-side here.
Meanwhile H1 and HTT are working on real-life implementations, and seem to be getting enough funding to meet their milestones. I'm looking forward to watching their progress.
Finally, because somebody has to say it: I for one welcome our new hyperloop overlords.
Slashdot Mirror
What's the time dilation factor of a 3 billion solar mass black hole traveling at 2.7% the speed of light? For a spacecraft at that speed it wouldn't be much, but a massive black hole has its own time- and space-warping effects. Are there any actual physicists here who'd care to speculate?
In a similar vein, the science journalist Peter Hadfield (aka Potholer54) has a hilarious quote about this: "I know a lot of editors at the Mail, and the nugget of science they understand is so small it could be drowned in their lunchtime gins & tonics."
The quote is from Hadfield's excellent video debunking myths about climate change. (This video is just one of a series on the subject, which is very much worth the time.)
An all-corn diet has virtually no protein... The body will eventually rebel against such a diet, and force a change in nutrient availability. I was born and raised in Iowa, so I love the taste of corn, but even I know that a man cannot live on corn alone... nor a rat.
Not to mention that coal contains trace amounts of Thorium and Uranium, which escape to the atmosphere in the exhaust. Ironically, a coal-fired power plant would not pass inspection as a nuclear plant because it emits far more radioactive pollution than would ever be allowed from a nuke plant. (But the way US law is written, coal plants don't have to be tested for radiation.)
I'm in the process of building my own tDCS device right now. I bought the components last Saturday and built the circuit on Sunday; on Monday I built the electrodes and on Tuesday I started using it (still on the breadboard). The circuit is pretty simple, just a voltage regulator and a few pots and resistors (there are many ways to do it, this approach just happens to use a voltage regulator). There is no way a 9V battery running through this circuit could generate the hundreds of milliamperes necessary to kill, or the dozens necessary to cause harm. When resistors fail, they tend to result in an open circuit -- zero current.
My circuit currently uses two potentiometers to ramp up the current to the desired level. Even with both of them wide open, the current is only 2.4mA, which is well within the safe range. (The recommended standard is to operate between 0.5mA and 2.0mA, but an order of magnitude above that is when you start to approach hazardous levels.) And of course, I run the it through a multimeter, so I always know the output of the circuit -- before, during, and after I put on the electrodes.
I first heard about tDCS in an episode of RadioLab last summer, which gives a pretty good intro to the topic. I finally got around to actually doing it last weekend.
Thus far, my experience has been entirely positive. The only glitch was yesterday when an "intermittency" developed in my electrode cable, which resulted in some phosphene flashes (due to an alligator clip + stranded wire). So I skipped my tDCS session today, and instead used the time to build the "finished" electrode cable, with soldered joints. That problem will not recur.
On the positive side, it seems to be having the desired effect. I became interested in tDCS because I have a "condition" which results in a lot of "unwanted thoughts" -- and I have noticed a remarkable decline in the frequency of these episodes.
You can naysay all you want from your armchair, but I'm actually doing this, and it works.
For more info on safety issues check out the /r/tDCS sub-reddit's FAQ.
Hm... my impression was that the Japanese had only invested a couple-hundred million in this area, primarily in IThEMS. AFAIK no entity on earth has ever put "tens of billions" on this. If you have info indicating otherwise, please cite.
As for the Chinese, it appears I got a few details wrong. They have spent $300M thus far, with plans to maintain this level of funding for the next few decades. You'll find a decent description of their program here. (But one thing I do know, which is not mentioned in the article: the project is led by a guy named Jiang Mianheng, who happens to be the son of Jiang Zemin, the former president. So I would guess their funding is pretty secure.)
Anyway, thanks for prompting me to look into it and get my facts straight.
China also has a billion-dollar program to develop a Liquid Fluoride Thorium Reactor (LFTR). It is the best-funded such program in the world, with (last I heard) 500 PhD engineers and scientists. Their goal is to have LFTRs in production by the early 2020s.
Presumably they're talking about something like this: Using renewable energy to synthesize liquid fuels for storage and transport. They can either work in conjunction with carbon capture or simply harvest CO2 from the air. I've heard of several ways to do it, but thus far it's mostly still in the lab. I haven't seen any "grid-scale" deployment. Apparently the Chinese intend to be first.
Yes, it has always been the customer's option, but it's not free. Moving rockets around costs money. A trifling amount, perhaps, compared to the overall launch cost, but a non-zero sum nonetheless.
I'd bet that from now on SpaceX will have a Hi-Def camera mounted on every lightning tower, recording 24/7, whenever there is a rocket on the pad. Also, if possible, they might add a few more sensors to the upper stage if they can spare enough telemetry channels for the data.
I suspect they'll also voluntarily eat the cost of running the static-fire tests before integrating the payload for the next year or so, just to avoid higher insurance fees for their customers. (How long before they start offering vertical integration as a 'menu option' service?)
(I of course am a lot more interested in hearing the results of their AMOS-6 investigation right now than about their ITS plans... as are I think most people)
I for one am more interested in hearing about the Mars architecture. AMOS-6 is just another anomaly that will eventually get resolved. Yes, of course I'm interested in finding out what happened, but the Falcon platform has already proven to be pretty reliable, especially considering it's undergone several major revisions in less than 30 flights. But the Mars architecture is going to be inspiring in a way that recalls the glory days of Apollo.
It's certainly possible, but... cui bono? Blue Origin? Boeing?
I don't think 2.5km is far enough to get past the exclusion zone, but a good sniper could probably sneak within range. Of course, you'd need an incendiary round to be sure of a kill shot, but I would think a bullet would leave some sort of tell-tale signature in the wreckage that would survive the explosion. (OTOH, if you could find a way to do the job without leaving such a signature, that could really mind-fuck SpaceX engineers for years to come.)
Let the games begin! I for one welcome a worthy competitor to Musk. The more billionaires we have focusing their attention and resources on real-world problems (rather than squeezing a few more basis points out of their high-frequency trading algorithms) the better off we'll all be. Even Bill Gates -- however buggy his software and however ill-gotten his gains -- appears to be using his economic power for "good" these days.
Meanwhile, what has Jamie Dimon done for you lately? (cough!)2008
Obviously just a typo... they clearly meant "Otto Pilot".
Constitutionality? ... Ok, let's assume we can do all this in the "cutting" room... bring in our "desirable" traits while also rendering the offspring infertile. We're not talking about a lab mouse here, it's a sentient human being...
Yes, there are circumstances wherein a fetus may be viable but not fertile, but to do this deliberately? That strikes me as unnecessarily cruel.
I don't deny that it may happen someday, but I would be comfortable with keeping this beyond the "prohibition" line, and thus relegate it to the black market. But now we're back to square one again. How do you simultaneously prevent the deliberate creation of circus freaks while also allowing reasonable prophylactic measures and enhancements for people who just want a healthy child?
It's an interesting question; where should we draw the line? Obviously, if your embryo/fetus is destined for cystic fibrosis, we would all cheer for a genetic intervention. But if you just think it would be cool if you kid would glow in the dark, it may be quite reasonable for the rest of us to resist allowing those "imported" genes into our collective gene pool.
I think a key concept to consider in all genetic modifications is the difference between vertical gene transfer and horizontal gene transfer. The former is manipulation of genes within the same family tree, whereas the latter involves importation of exogenous genes from other species.
If you ask me where I would draw the line, in terms of legislation, this is it: endogenous (vertical) vs. exogenous (horizontal) gene transfer. Do whatever you want within the human genome, but don't import any genes from any other genome.
No wait... I meant "Gattaca! Gattaca!"
We may enact some legislation to "prevent" this sort of thing, but it's going to happen anyway, because there will be a demand for it.
Prohibition simply doesn't work, whether it's prohibition of drugs, prostitution, alcohol... or genetic manipulation. One way or another we're going there. Perhaps this is a chance to "get it right" for a change, and educate the public about this emerging technology, rather than the usual FUD tactics.
Thanks for pointing that out. I hadn't caught that distinction the first time.
True enough. But by the same token, if you're paying $60M to launch your $120M satellite, you might want to pay the extra $500k* to protect your asset.
* Note: I have no idea what the extra cost would be. But at minimum it would have to pay for hauling the booster stack back to the hangar after the static fire, to 'integrate' the payload, and then hauling the now-loaded rocket back to the launch pad again.
Perhaps, in response to this, SpaceX will figure out some sort of gantry system to allow vertical integration right on the launch pad. That way, they could avoid this situation entirely.
I would bet that SpaceX probably does carry some kind of insurance for this sort of thing, though 'how much' is a different question. In any case, I would also bet that whatever they've been paying for that insurance, the price just went up.
More info here: YouTube user Scott Manley has a 9-min video with frame-by-frame analysis. Well worth the time.
One thing I learned was that, although the satellite was insured, technically the insurance doesn't "kick in" until the rocket is actually launched, so in this case, they probably won't pay out. (This would explain the lawsuit mentioned in my post above.)
However, I've read elsewhere that they could have done this test without the payload on board, but that would cost extra. It is up to the customer to decide if they want to pay extra to protect their asset. It will be interesting to see how this all works out.
In a more recent story, SpaceX is being sued by Spacecom (owner of the AMOS-6 satellite that was lost). I have a hard time believing they could win such a suit, but that depends on what caused the "anomaly".
As for the Ars Technica op-ed, urging SpaceX to "focus" on NASA's priorities, I suspect that Elon will still reveal his plans for the MCT at the upcoming Int'l Astronautical Conference, but he will also spend a fair amount of time explaining what they've learned from this mishap. And I think he will probably take some of the advice from Ars... perhaps announcing that MCT will be put on the "back burner" for a while, so that they can get Crew Dragon and Falcon Heavy flying ASAP.
Yeah, I watched that video when it came out a few weeks ago. I've been subscribed to Thunderf00t's Youtube channel for several years already. If I'm not mistaken, this is his second rant on the same topic. And he brings up a lot of very salient points.
But I keep coming back to the same conclusion: There are hundreds of expert engineers with (cumulatively) centuries of experience among them who all agree that this is not only possible but doable. And then there's Phil Mason, a lone voice in the wilderness, saying it will never work.
Pardon me if I side with the optimists on this one.
It would seem that Elon and his team disagree with you. OTOH, it would seem that the folks at Hyperloop One disagree with Elon, since they are using mag-lev instead.
I reckon that's the whole point of setting up test tracks like this, to figure out what the best methodology would be. They'll have some races, eat some hot dogs, and collect a shit-load of data along the way. I think Elon is well aware that this technology is still in gestation, it's not quite ready for prime time yet, whatever H1 or HTT may say. Sponsoring a competition like this is a great way to advance the field with minimal cost.
As I understand it, the original white paper was more of a suggestion than a specification. For example, Elon suggested that air-cushion levitation would be the best method, but also acknowledged that magnetic levitation was a viable option. One of the hyperloop companies currently in development (the one that had a live test a couple of months ago) is using magnetic levitation in their design.
I agree that this particular competition is aimed more at students, but so what? It's a cool idea that gets people interested and motivated. I don't see a down-side here.
Meanwhile H1 and HTT are working on real-life implementations, and seem to be getting enough funding to meet their milestones. I'm looking forward to watching their progress.
Finally, because somebody has to say it: I for one welcome our new hyperloop overlords.