Some time ago, I made my personal short list of 'hobbies which are utterly insanely dangerous'. That list is (in no particular order) base jumping and cave diving. And note that 'utterly insanely dangerous' assumes the practitioner has had lots of practice before trying the really dangerous stuff.
Presumably bids would come labelled with the time slice they are intended to act in. Anything which comes late would be ignored, not applied to the next time slice (unless the bid's labels say this should happen.)
And if the results of trades come back 1 second after the close off? Now all trades take a minimum of 1 second to resolve. How much advantage is there in the high speed trader having 1.001 second resolution of trades compared to the low speed trader's 1.5 to 6 second resolution?
Also, what information is the high speed trader trading off? If it is the results of previous trades (which I expect would normally be the case) then everyone has 5 seconds (or 4 seconds, if you delay release of trade results) in which to absorb and react to these. The high speed trader's advantage is gone.
Also, the clock tick need not be 5 seconds, it could be 30 seconds or 60 seconds or 5 minutes. What are the odds the high speed trader will get value-changing knowledge that just happens to come along in the last few milliseconds before the clock tick? If the new knowledge comes at any other time in the clock cycle, then all market participants can react equally, and the high speed trader has no advantage.
The economic point of share markets is to allow companies to raise capital for long term investments. If doing stuff on millisecond or microsecond timescales is profitable, then that profit is doing nothing productive and can only be leeching value from actual productive economic activity. The investors who really matter economically are those who buy and sell over timescales of months or years, who will not be hurt in the slightest by trades being on a 30 second clock tick. (I really don't know what the time quantum should be - probably somewhere between 1 second and 1 hour.)
"... as a treatment for rare forms of epilepsy that primarily afflict children."
So what happens with time? 1 They grow out of the epilepsy 2 It change to a different form in adults 3 It kill most sufferers before adulthood 4 The statement is wrong, it should say onset is in children
Lennox-Gastaut syndrome No support for 1 or 2, refutes 3 (mortality rate on order of 5% over 10 years).
Diamond is so spectacular because of its high refractive index. If you want a fake diamond, cubic zirconia or silicon carbide are the favoured ways to go. Refractive indices: diamond 2.42; cubic zirconia 2.15; silicon carbide 2.65; fused silica glass 1.46.
Audio attack? This has supposedly been happening for months (in Cuba). The very first thing any competent investigator would do is put microphones on the 'targets', to confirm the hypothesis of audio attack, to start understanding where and how the attacks are taking place, and to have evidence to present to the world that the attacks are real. I've seen no claims of there being such evidence. (I'm not perfect, so if I've missed something in the news, I'm happy to be corrected.)
On the other hand, the mass hysteria hypothesis explains the known facts very well - except that we have to also assume US State Department incompetence, given that they expelled diplomats over this.
Fair point. Neil Gemmell is a specialist in mitochondrial DNA. (I'm not, but I've co-authored with him.) So I expect they'll pick out any DNA which look like they are mitochondrial by using highly conserved mitochondrial genes, and then see how that mitochondria compares to known species. If all the mitochondria they find is closely related to known fish, snails, birds etc. then this is evidence against Nessie. If they find something unlike anything known but looks like it had a common ancestor with birds or crocodiles 250 million years ago, this would be evidence for Nessie.
The general method is called metagenomics. You sequence everything, then compare the sequences to genbank, likely using the BLAST program. Any sequences which are very similar to a known sequence from genbank you conclude come from the same or similar organism to the one the genbank sequence came from. If you find a sequence which is quite close but not an exact match to lots of genbank mitochondrial sequences, that is when you might jump up and down and shout "Nessie!". (You might also get lucky with Nessie nuclear DNA.)
This explanation is simplified, partly to keep it short, and partly because I haven't done any metagenomics myself so I only know a simplified version of it.
You need to apply enough force to generate enough acceleration to attain orbital velocity before you fall back into the atmosphere. Typically this means you need several km/s delta v in a few minutes. 5000m/s in 500 s requires 10 m s^-2 acceleration, or (close enough) 1g.
Unlike the EM drive, ion drives actually do work, but you can't use them to get into orbit because of this reason. They produce wonderful delta v, but lousy acceleration.
My understanding is that the 'thrust' comes from radiation pressure in a truncated cone cavity, and the false result comes about by accounting for radiation pressure on the ends of the cone but ignoring it on the conical sides. If you include the conical sides in your calculation, you find zero thrust.
However, it isn't actually necessary to point out the exact error. If you give me a list of numbers to add up, and all the numbers in the list is even, and I tell you I've calculated the total, and the total is an odd number, you know I've messed up. It isn't necessary to go over my calculations with a fine tooth comb to identify exactly where I went wrong. This case is the same - input physics conserves momentum, calculated result does not, calculations must be in error.
Yes, it can be, and that system is called an electrodynamic tether, and it doesn't make use of the microwave cavity which is at the heart of the EM drive (which, according to this latest experiment, wasn't doing anything in the first place.)
Once you've taken an EM drive and removed the useless cavity and microwave emitter, what you are left with is an electrodynamic tether which may indeed be useful, but doesn't owe anything to the EM drive.
The EM drive, if it works, violates conservation of momentum, which can easily be used to also violate conservation of energy. (/. commenters on previous EM drive stories have gone into this at some length.)
The EM drive was originally designed using standard physics (I think electromagnetism and possibly special relativity) and the inventor's calculations showed it would produce thrust. They did not realize that as the input physics conserved momentum but their calculation result violated it, this guaranteed their calculation was in error.
The chances of this result being real were always really tiny. I'm happy there is now a good explanation for the anomalous experimental results.
A folding wing option was offered when the 777 was first being developed. No airline wanted to pay for it, so it never happened.
Here is a discussion on why that was, and how the new 777x folding wing differs from the old rejected folding wing plan. The new folding wing section is much smaller and lighter than the old proposal. The old plan required flight controls on the folding section, which the new plan does not.
I question your claim that airlines primarily get pilots from the military. A great many come through private pilot training followed by working for regional airlines. I expect that ex-military pilots would be a minority, although a sizeable one. Feel free to try to find an authoritative source to prove me wrong.
Even of the military pilots, a minority of them will have dealt with folding wings.
But I do agree that ensuring wings are unfolded should not be a big deal. It would be simple to implement either a warning or override to prevent more than taxiing thrust to be used when wings are folded.
Almost everywhere in the world has danger of natural disaster, but we tend to become accustomed to the threats where we live, and alarmed by threats that we do not face, in other places.
Having said that, living close to Kilauea is probably more dangerous than most places, but Kilauea is high threat to property, comparatively low threat to life, as volcanos generally give you enough warning to be somewhere else (at least with modern technology they do.)
Over 23 million people live in Taiwan, with close to the highest earthquake risk in the world, and typhoon risk on top of that.
A much better (i.e. much bigger) example is Mt Tambora, 1815, and also in Indonesia (like Krakatoa.)
However the Hawaiian volcanos are the wrong type make a Krakatoa sized bang. If Hawaii wants to create a epic disaster, it would do it by an under sea landslide triggering a tsunami.
SpaceX have adopted a policy that any pre-block 5 booster will fly at most twice, and so have not been landing pre-loved boosters (called "flight proven" in SpaceX's spin.) All these boosters which would make wonderful museum pieces are being discarded into the ocean.
However, there are a few flown boosters which have not been lost. The first booster to successfully land is on display outside SpaceX's headquarters. The two side boosters from the Falcon Heavy launch were previously flown and have been recovered. I think the first booster to fly a second time was recovered, as this was before the don't-recover-used-boosters policy came into effect.
Am I correct on all these? Are there any other recovered twice-flown boosters? Does anyone know what SpaceX intends to do with them? Can I hope to see any of them in a museum one day?
I am not one of the privileged few who was on ARPANET in 1978: I was at high school and in the wrong country.
I was, however, present for a somewhat later milestone in spam history: the green card lottery spam. On 12 April 2994, a pair of exceptionally unscrupulous lawyers spammed every newsgroup on Usenet with ads for (utterly unnecessary and very expensive) assistance in entering a lottery for USA green card (permanent residence.) This generated a great deal of internet hatred.
SpaceX has big capital intensive plans of its own, and may not be available to bail out Tesla. Not only is SpaceX building the BFR, but they're also planning to build and launch at least 2200 of their own satellites at 400kg each.
Bare in mind that Musk really really does not want to take SpaceX public. He wants to take SpaceX to Mars, which can't be justified in dollars, so couldn't happen if SpaceX were public.
Slashdot Mirror
Indeed. That's why I'm still using my 20 year old mobile phone charger on my new phone.
Some time ago, I made my personal short list of 'hobbies which are utterly insanely dangerous'. That list is (in no particular order) base jumping and cave diving. And note that 'utterly insanely dangerous' assumes the practitioner has had lots of practice before trying the really dangerous stuff.
Presumably bids would come labelled with the time slice they are intended to act in. Anything which comes late would be ignored, not applied to the next time slice (unless the bid's labels say this should happen.)
And if the results of trades come back 1 second after the close off? Now all trades take a minimum of 1 second to resolve. How much advantage is there in the high speed trader having 1.001 second resolution of trades compared to the low speed trader's 1.5 to 6 second resolution?
Also, what information is the high speed trader trading off? If it is the results of previous trades (which I expect would normally be the case) then everyone has 5 seconds (or 4 seconds, if you delay release of trade results) in which to absorb and react to these. The high speed trader's advantage is gone.
Also, the clock tick need not be 5 seconds, it could be 30 seconds or 60 seconds or 5 minutes. What are the odds the high speed trader will get value-changing knowledge that just happens to come along in the last few milliseconds before the clock tick? If the new knowledge comes at any other time in the clock cycle, then all market participants can react equally, and the high speed trader has no advantage.
This is what I came here to say.
The economic point of share markets is to allow companies to raise capital for long term investments. If doing stuff on millisecond or microsecond timescales is profitable, then that profit is doing nothing productive and can only be leeching value from actual productive economic activity. The investors who really matter economically are those who buy and sell over timescales of months or years, who will not be hurt in the slightest by trades being on a 30 second clock tick. (I really don't know what the time quantum should be - probably somewhere between 1 second and 1 hour.)
While I like SpaceX, of the terms "robot", "AI", "ISS", "German", "IBM", "Cimon" and "SpaceX", "SpaceX" is the least important to this story.
"... as a treatment for rare forms of epilepsy that primarily afflict children."
So what happens with time?
1 They grow out of the epilepsy
2 It change to a different form in adults
3 It kill most sufferers before adulthood
4 The statement is wrong, it should say onset is in children
Lennox-Gastaut syndrome
No support for 1 or 2, refutes 3 (mortality rate on order of 5% over 10 years).
Dravet syndrome
Refutes 1 and 2.
Fallout Shelter is easily playable without paying microtransactions. I haven't played Westworld.
Diamond is so spectacular because of its high refractive index. If you want a fake diamond, cubic zirconia or silicon carbide are the favoured ways to go. Refractive indices: diamond 2.42; cubic zirconia 2.15; silicon carbide 2.65; fused silica glass 1.46.
Audio attack? This has supposedly been happening for months (in Cuba). The very first thing any competent investigator would do is put microphones on the 'targets', to confirm the hypothesis of audio attack, to start understanding where and how the attacks are taking place, and to have evidence to present to the world that the attacks are real. I've seen no claims of there being such evidence. (I'm not perfect, so if I've missed something in the news, I'm happy to be corrected.)
On the other hand, the mass hysteria hypothesis explains the known facts very well - except that we have to also assume US State Department incompetence, given that they expelled diplomats over this.
Fair point. Neil Gemmell is a specialist in mitochondrial DNA. (I'm not, but I've co-authored with him.) So I expect they'll pick out any DNA which look like they are mitochondrial by using highly conserved mitochondrial genes, and then see how that mitochondria compares to known species. If all the mitochondria they find is closely related to known fish, snails, birds etc. then this is evidence against Nessie. If they find something unlike anything known but looks like it had a common ancestor with birds or crocodiles 250 million years ago, this would be evidence for Nessie.
The general method is called metagenomics. You sequence everything, then compare the sequences to genbank, likely using the BLAST program. Any sequences which are very similar to a known sequence from genbank you conclude come from the same or similar organism to the one the genbank sequence came from. If you find a sequence which is quite close but not an exact match to lots of genbank mitochondrial sequences, that is when you might jump up and down and shout "Nessie!". (You might also get lucky with Nessie nuclear DNA.)
This explanation is simplified, partly to keep it short, and partly because I haven't done any metagenomics myself so I only know a simplified version of it.
Thanks. So by "design was tested" you mean they built part of a wing with the folding tip?
You need to apply enough force to generate enough acceleration to attain orbital velocity before you fall back into the atmosphere. Typically this means you need several km/s delta v in a few minutes. 5000m/s in 500 s requires 10 m s^-2 acceleration, or (close enough) 1g.
Unlike the EM drive, ion drives actually do work, but you can't use them to get into orbit because of this reason. They produce wonderful delta v, but lousy acceleration.
OK, I've found what your second point refers to. "The laws of mathematics are very commendable, but the only law that applies in Australia is the law of Australia."
The first point probably has so many examples I can't be bothered looking for them, but if I did, I'd start with climate change.
My understanding is that the 'thrust' comes from radiation pressure in a truncated cone cavity, and the false result comes about by accounting for radiation pressure on the ends of the cone but ignoring it on the conical sides. If you include the conical sides in your calculation, you find zero thrust.
However, it isn't actually necessary to point out the exact error. If you give me a list of numbers to add up, and all the numbers in the list is even, and I tell you I've calculated the total, and the total is an odd number, you know I've messed up. It isn't necessary to go over my calculations with a fine tooth comb to identify exactly where I went wrong. This case is the same - input physics conserves momentum, calculated result does not, calculations must be in error.
Yes, it can be, and that system is called an electrodynamic tether, and it doesn't make use of the microwave cavity which is at the heart of the EM drive (which, according to this latest experiment, wasn't doing anything in the first place.)
Once you've taken an EM drive and removed the useless cavity and microwave emitter, what you are left with is an electrodynamic tether which may indeed be useful, but doesn't owe anything to the EM drive.
The EM drive, if it works, violates conservation of momentum, which can easily be used to also violate conservation of energy. (/. commenters on previous EM drive stories have gone into this at some length.)
The EM drive was originally designed using standard physics (I think electromagnetism and possibly special relativity) and the inventor's calculations showed it would produce thrust. They did not realize that as the input physics conserved momentum but their calculation result violated it, this guaranteed their calculation was in error.
The chances of this result being real were always really tiny. I'm happy there is now a good explanation for the anomalous experimental results.
A folding wing option was offered when the 777 was first being developed. No airline wanted to pay for it, so it never happened.
Here is a discussion on why that was, and how the new 777x folding wing differs from the old rejected folding wing plan. The new folding wing section is much smaller and lighter than the old proposal. The old plan required flight controls on the folding section, which the new plan does not.
I question your claim that airlines primarily get pilots from the military. A great many come through private pilot training followed by working for regional airlines. I expect that ex-military pilots would be a minority, although a sizeable one. Feel free to try to find an authoritative source to prove me wrong.
Even of the military pilots, a minority of them will have dealt with folding wings.
But I do agree that ensuring wings are unfolded should not be a big deal. It would be simple to implement either a warning or override to prevent more than taxiing thrust to be used when wings are folded.
Almost everywhere in the world has danger of natural disaster, but we tend to become accustomed to the threats where we live, and alarmed by threats that we do not face, in other places.
Having said that, living close to Kilauea is probably more dangerous than most places, but Kilauea is high threat to property, comparatively low threat to life, as volcanos generally give you enough warning to be somewhere else (at least with modern technology they do.)
Over 23 million people live in Taiwan, with close to the highest earthquake risk in the world, and typhoon risk on top of that.
A much better (i.e. much bigger) example is Mt Tambora, 1815, and also in Indonesia (like Krakatoa.)
However the Hawaiian volcanos are the wrong type make a Krakatoa sized bang. If Hawaii wants to create a epic disaster, it would do it by an under sea landslide triggering a tsunami.
https://en.wikipedia.org/wiki/...
https://en.wikipedia.org/wiki/...
Note Hawaii does not feature on this second map, although it is for VEI 7 and 8 volcanos, while Krakatoa was smaller at merely VEI 6.
SpaceX have adopted a policy that any pre-block 5 booster will fly at most twice, and so have not been landing pre-loved boosters (called "flight proven" in SpaceX's spin.) All these boosters which would make wonderful museum pieces are being discarded into the ocean.
However, there are a few flown boosters which have not been lost. The first booster to successfully land is on display outside SpaceX's headquarters. The two side boosters from the Falcon Heavy launch were previously flown and have been recovered. I think the first booster to fly a second time was recovered, as this was before the don't-recover-used-boosters policy came into effect.
Am I correct on all these? Are there any other recovered twice-flown boosters? Does anyone know what SpaceX intends to do with them? Can I hope to see any of them in a museum one day?
I am not one of the privileged few who was on ARPANET in 1978: I was at high school and in the wrong country.
I was, however, present for a somewhat later milestone in spam history: the green card lottery spam. On 12 April 2994, a pair of exceptionally unscrupulous lawyers spammed every newsgroup on Usenet with ads for (utterly unnecessary and very expensive) assistance in entering a lottery for USA green card (permanent residence.) This generated a great deal of internet hatred.
https://www.wired.com/1999/04/...
https://en.wikipedia.org/wiki/...
SpaceX has big capital intensive plans of its own, and may not be available to bail out Tesla. Not only is SpaceX building the BFR, but they're also planning to build and launch at least 2200 of their own satellites at 400kg each.
Bare in mind that Musk really really does not want to take SpaceX public. He wants to take SpaceX to Mars, which can't be justified in dollars, so couldn't happen if SpaceX were public.