Meant to say not the mass but the chemical energy available in mass of the given propellant, e.g. in hydrazine.
33 posts • joined 20 Apr 2011
Meant to say not the mass but the chemical energy available in mass of the given propellant, e.g. in hydrazine.
No. The energy dissipated by the projectiles must be less than the fuel required to give them that energy...call it 100t of hydrazine at the upper limit of a large ICBM. The tiniest nukes generally admitted have yields of 1kton of TNT, which equates to around the same mass of Hydrazine. Yes, spreading the effects broadly is more efficient. But the dissipation of energy in reentry drops that right back to a fraction of the original 100t....IOW, no nuke.
PS a "decent" nuke means typically 100-200kton TNT equivalent. The figure is higher for most nuclear gravity bombs.
Apple is not selling you ALL of the music, just a few percent, the rest is omitted. The album you bought in CD form had 400MB of data, the Apple file has around 80MB at most. That's a bargain only for the tin-eared prole. MP3s weren't good enough for Steve Jobs, he had a great vinyl system. He never told customers that, did he?
I generally agree, though this is a huge cultural shift so I believe autonomous cars will have to demonstrate very good safety performance. But as you said, the great saving of human lives and insurance money, *AND* vehicle and petrol cost reduction will be overwhelming factors in bulldozing their adoption. Around 5 years away, like all the automakers say.
Finally, there is the terrific and generally ignored power of networked sensors on vehicles. An auto vehicle will likely have 3-4 complementary systems for navigation and safety. But the biggest safety improvement, at least on fast and/or busy roads, is the hundreds or thousands of sensors working together to avoid conflict and tragedy. That means cars will talk with cars, with roadside sensors, with pedestrians' (especially children's and pet's) wearable sensors and smart logic, and all that will work together to make driving as safe as it can be.
When that coordinating software and hardware is mature enough, the revolution will begin. I, for one, welcome our...
...(Mine's the one with the Lewis Hamilton patch.)
That's a bit harsh. The elfin electron has done quite a bit of good for us. I have a few in my shirt pocket, I count each as he or she goes off to school. Just because of the unfortunate naming of their charge, people delight in bashing them about. If they were instead positrons, a mighty row would ensue!
...with graphics sans CPU
"lossless MP3s" = D.N.E.
If mammary serves.
Heaven help me, I have no coat!
Sure, there's a good chance of it being an unstable buried shell going bang.
But the question is whether they can nail down the time of impact. That would determine conclusively whether a straggling orphan of the meteor hit. The crater tells the story of a trajectory or a in situ event. If the event's timing is nailed down, one can easily find whether any relationship exists to a parent meteor.
Another Luddite slogs for The Register on the impossibility of robotic vehicles. How about a qualified reporter with an understanding of robotics? Here are some clues: redundant, multi-spectral sensing and communication; (the following figures are for the U.S. alone) 34,000 dead last year; the waste of 6 million bbl. of oil a day with the resultant extra carbon in atmosphere; $100B+ car insurance costs; one ton of extra material per vehicle for crash protection. Nope, there is no good reason to automate vehicles.
@ ian 22
"Then we had gravel for lunch. HOT gravel."
Luxury! We lived in a matchbox in the road and were constantly run over. We woke before going to bed, and...
Three nuts on the tree of AI or A.G.I. have been cracked: Watson cracked an amazing two, natural language and world modeling. Now Google has reached a milestone in physical recognition.
How many nuts are left? 4) mobility, probably the easiest; 5) moral decision hierarchy (difficult, but less so than Watson's nuts); and 6) emotion. The last nut is actually the easiest (it is mostly a subset of nut 5), to the amazement of those outside the A.I. community.
I would donate it all to Tea Party Republicans, who would thence commence to destroy the world's economy. In glorious tatters I would then declare myself the last multi-millionaire on Planet Earth!
Well done Captain. And @Walt Leipold:
"Fireball XL-5 was the *best* show in the universe!" --- Surely that.
Finally, on Team America... what, no takers yet?!! Sigh, all right then, for you Gerry...
"I'm so lonely..."
A cruel, nihilistic, racist rant is bowdlerized and made harmless:
"All I can see now are bald eagles, stars and stripes, rednecks and McDonald's y Taco Bell. "
...that Skittles are to M&Ms like chicken s**t to chicken salad?
Mine's the one with rainbow-coloured chocolate stains.
"...just laser the nutters from space? We could have got Saddam and saved invading Iraq twice..."
Why space? Don't you get warm feelings from Predators? (Sorry.) The F-35's engine was designed to generate sufficient electrical power to operate antipersonnel directed-energy weapons. I expect that the current 700kg, ~10kW SS laser weapons are sufficient for light(sic) headaches within the "tactical range" (some kilometers) from which those weapons lit off artillery rounds in recent US tests. I expect there shall be capability in a decade (perhaps now), using a long-range UAV, to silently disable any person on earth whose position is above the surface and known. This will be merely another cold incarnation of Ray Bradbury's "mechanical hound" from Farenheit 451.
"...We could vaporize Ahmadinejad..."
Or, for artistic effect, inscribe "Haircut by Raytheon" on his noggin.
On film my vote goes easily to Blofeld. Which? The one in Thunderball, whose head is unseen but who cradles a white kitty while dispatching a thieving co-thief.
In real life the honor should not go the the most obscenely violent of men: Mao, Hitler, Stalin, or Hirohito, but only to the fifth most prolific killer (5-15 million in the Congo) of modern history, Leopold II of Belgium. Mao enjoyed violence and did not object to it, even when it took the lives of his mother and son, but Leopold managed to remain rich to the end and was even honored on a Euro coin in 2007.
...there was an 007: the late great Roy Boehm, R.I.P. He was an U.S. government assassin, a shark jumper/killer (a sad and bizarre example of species revenge), a commando, founder of Seal Team Two, hero in 3 hot wars and a human sea surface delivery vehicle (along with his buddy Lump Lump) for an American nuke expert who confirmed Soviet IRBMs in Cuba *firsthand.* Read his book First Seal to learn his story.
with a roll bar 15cm too short will not get my business. Still, good ventilation in prototype.
I can't wait to see shared self-driving vehicles so I can issue road rage provocations upon the external telly...
"The W9000 can drive up to six displays and costs a rather steep $3,999, or a buck per GIGAFLOPS single precision if you want to look at it that way, or just a little over four bucks double precision GIGAFLOPS if that is more important to your workloads."
You said Mach 6-8 and gave mph figures. One set is wrong. If the mph figures were correct, speeds were about Mach 6.9-Mach 9.2. Remember, at 12km+ altitude Mach 1 is about 660 mph.
Biggest FEL in the world, 5-6 megawatts, count 'em, just the ticket for the local defense contractors that paid for it. The EE program at UCSB is rightly considered #1.
The word is "liar." He is bright enough to know that if he had told another true story of the horrors of Darfur, Congo, N. Korea, Syria, or latter-day slavery of blacks in the deep south of the US (see "Slavery by Another Name"), he wouldn't have drawn a crowd.
I am glad to learn that Ira Glass showed backbone in the retraction because he usually sounds like a teenager in heat...bravo!
Bluetooth keyboards for phones or tablets are a great concept, but they DON'T WORK. Failure to communicate, you know. Why? It's a stupid, aggravating situation but I don't know and don't care. USB works. Jeez, just deal with the friggin wire!
So what do we need? An OS that can reside anywhere, phone, tablet, screen, keyboard. Or a group of the above for redundancy. A sturdy, snap-on hinge system that doesn't break the important bits as you hinge or unhinge or rotate. a strong keyboard, folding or not, that faces the screen while you're in transit. And finally the ability to use a touchscreen instead of a standard screen when you want to draw or write stuff longhand like equations. Finally, let it play movies or surf, etc., so long as you can turn off graphics and any other power-robbing activity with ease. So, who will build this?
@Sheluser: "According to Wikipedia the escape velocity from LEO is ~10.9 Km/s, so wouldn't must of the manned moon missions* have acheived velocities at least in that range?"
First, that 10.9km/s escape velocity applies from the *altitude* of LEO, not an object *orbiting at* LEO, which is already moving around 7.8km/s angular velocity or typically around 7.33km/s relative to the Earth's surface if flown southeastward from Florida, which is rotating at around 420(?)m/s about a different axis.
Anyway, you don't want to hit escape velocity unless you want to escape and never get back! Better to stay in elliptical orbit wrt Earth, do some brief orbits of the moon (assuming you meant moon missions) then mosey on home, wot.
@GM: "Actually that doesn't seem to take into account the amount of mass that would be lost to gravitational friction."
Essentially zero, forget it.
"...That would depend on the angle that the object entered the atmospher along with it's velocity..."
At a relative velocity of over 20km/s, as long as the entire object strikes the earth, the angle makes almost no difference. The kinetic energy transfer is over 90% and the momentum transfer is well over 50%. The object becomes effectively plasma and generates a succession of pressure waves that propagate inward and along the surface of the the Earth, with a small proportion of ejecta.
"...and more importantly its composition."
That will be pretty well known at flyby.
"As indeed would it's velocity at impact."
Yes, I heard over 20km/s.
"Since they're not quite sure what it's made of nobody can say exactly what it's mass is to start with."
Yes, but most asteroids fall within a moderate density range. Since this has no jets and is small, it's not a pile of rocks but probably a big rock, i.e. reasonably dense. Certainly moreso than water, so its mass should exceed 25 megatons for r > 300m.
So there's no way anybody could predict what the damage would be were it to hit the earth.
"...Even if it were to hit the earth it's obviously more likely that it would land at sea than on land."
If by sea, worse (waves)!
If this hit land mortality would be greater than half at 30 mile radius, like a nuke of >400 megatons without the radiation. Yeah, that's a ~7.5-magnitude earthquake except it dissipates RIGHT AT THE SURFACE. This makes it more like a 9+ scale quake at average depth. Bad for tribe:
"...According to Jay Melosh, if an asteroid the size of 2005 YU55 (~400 m across) were to hit land, it would create a crater 6.3 km (4 miles) across, 518 m (1,700 ft) deep and generate a seven-magnitude-equivalent-earthquake. ..."
@CM: The LSAT rifle is lighter than an M16A4 for long barrel or an M4 for short. It is almost as short as a bullpup of the same barrel length. The CT ammo is a HUGE advantage at >40% less weight and less barrel melt in rapid fire for both LMG and rifle. It might get a cobalt plating in the barrel for still-better heat tolerance, depending on cost. Our soldiers carry as much ammo on patrol as they possibly can, and would take much more if they could. Winning wars is, very roughly, grunt quality x leadership x ISR x logistics x weaponry x motivation IMO.
They are the LSAT rifle and LMG. 6mm or 6.5mm ammo like Grendel would be the best compromise, but to sell the low weight figure the old 5.56 caliber will probably stay, perhaps in a long range ~75 grain bullet. The new, standard 5.56 M855A1 EPR round has 3x the effective range for lethality and barrier penetration as the older M855 AP round, so that helps. The LSAT design is very good but currently suffers some in accuracy (generally elevation) compared with the M16. Barrel heating problems are absolutely reduced with LSAT. Plastic cases work fine as shown in Natec ammo, but cased-telescoped cartridges and the tilting, splitting chamber present new challenges to alignment of the bullet as it hits the barrel grooves: the design has a lot of accuracy-robbing "headspace." This is probably one reason why the LMG is the first application. Belt- or magazine-fed LMG ammo can be different from rifle ammo without much loss of safety, they seldom are interchanged. Anyway, this system is a major breakthrough in the sad science of war weapons. It arose from ingenious creative design, not new materials (except plastics) or electronics.
The mass figure is wrong. 6.2 kg could be the seeker + warhead, but the rocket motor accounts for at least 6kg by itself. 15kg is more like it. But that's worlds lighter than a Hellfire, innit?
@AC: "...A FnF on a ground attack heli makes a LOT of sense. It has somewhere to hide and "go to ground". A navy helicopter has no such place. If the target has the means to defend itself it is dead meat. So this is all a big waste of money. As usual. Shiny new toys. Budget. Dosh. Pork."
You forgot the thing called LAND, over which naval (especially Marine Corps) helicopters often fly. Also, Stingers and Strelas are not naval weapons on boats or ships (not "navalized"), though they sometimes can be found there. The new weapons in this guided 70mm class would also have the range advantage that launch altitude brings.
Reread: "...the 22nm Tri-Gate provides up to a 37 per cent performance increase at a low voltage compared to its 32nm planar transistor...The transistor also consumes less than half the power as a 32nm planar transistor at the same performance level... ...The cost of building the chips with the new transistors...is two to three per cent higher per wafer."
The 22nm wafers contain about 2x as many transistors, so the price per transistor is about halved vs. 34nm wafers. The the power use per transistor is halved, so you get nearly a doubling of transistors per dollar (cost to intel) and a corresponding doubling of performance per watt for the consumer.
At best this could give a ~4x performance boost per dollar (purchase price) and a ~2x improvement in performance per watt (recurring cost for users), i.e. pretty impressive.
The tech to do it exists in all its pieces but not as a whole. Of course we should do this, to argue otherwise is to condemn the countless people to accidental death on the roads. A decent system should cut crashes by 90%, then 90% of that over the years. And car ownership would be silly for most. How much do you pay to drive? Gas, car payments, parking, garages, carports, massive parking lots, and insurance? Would you like to cut that (and pollution) by at least 2/3 and also save lives and also be able to work or sleep or otherwise while you normally drive? No? Are you nuts? I love cars and F1 racing on TV, but I would drop *my* driving in a second if given the chance.
There are many large obstacles (opportunity costs) to adoption, as some posters here have shown. The biggest is probably trust of the system, which will sometimes fail. I suggest that transition systems will be the answer: you choose whether you drive or the car drives. Your will would be absolute in this instance, though signals indicating driver malice or incompetence would go out immediately along with lights, comms, etc. to give warning to others. The best means would be accessible mechanical clutches for steering and pedals. And I for one welcome.....
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