Problem: The CIA's senior management saw problems with the armed Predator as well, problems that Clarke and even Black and Allen were inclined to minimize. One (which also applied to reconnaissance flights) was money. A Predator cost about $3 million. If the CIA flew Predators for its own reconnaissance or covert action purposes, it might be able to borrow them from the Air Force, but it was not clear that the Air Force would bear the cost if a vehicle went down. Deputy Secretary of Defense Wolfowitz took the position that the CIA should have to pay for it; the CIA disagreed. Second, Tenet in particular questioned whether he, as Director of Central Intelligence, should operate an armed Predator." This was new ground,"he told us. Tenet ticked off key questions: What is the chain of command? Who takes the shot? Are America's leaders comfortable with the CIA doing this, going outside of normal military command and control? Charlie Allen told us that when these questions were discussed at the CIA, he and the Agency's executive director, A. B." Buzzy" Krongard, had said that either one of them would be happy to pull the trigger, but Tenet was appalled, telling them that they had no authority to do it, nor did he. Third, the Hellfire warhead carried by the Predator needed work. It had been built to hit tanks, not people. It needed to be designed to explode in a different way, and even then had to be targeted with extreme precision. In the configuration planned by the Air Force through mid-2001, the Predator's missile would not be able to hit a moving vehicle. White House officials had seen the Predator video of the "man in white." On July 11, Hadley tried to hurry along preparation of the armed system. He directed McLaughlin, Wolfowitz, and Joint Chiefs Vice Chairman Richard Myers to deploy Predators capable of being armed no later than September 1.

Question: "Why did the Hellfire warhead need work?"

Answer: "It had been built to hit tanks, not people"
Answer: yes

Problem: Sound waves are mechanical waves. They can travel only through matter. They cannot travel through empty space. This was demonstrated in the 1600s by a scientist named Robert Boyle. Boyle placed a ticking clock in a sealed glass jar. The clock could be heard ticking through the air and glass of the jar. Then Boyle pumped the air out of the jar. The clock was still running, but the ticking could not be heard. Thats because the sound couldnt travel without air particles to transfer the sound energy. Is there any other place where sound cannot be heard? Here is a hint: is there any other place that does not have air molecules? Thats right, in space sound cannot be transferred. So can astronauts hear each other? Yes, they can, because they are in enclosed space stations or pressurized suits.In both cases, they are surrounded by air molecules. If they left their space ship and did not use their electronics, they would not be able to hear each other. Next time you watch a science fiction movie, think about this factoid. When spaceships are destroyed by hostile alien beings, there would be no sound heard. Sound waves can travel through many kinds of matter.

Question: "What can sound waves move through?"

Answer: "matter."
Answer: yes

Problem: General relativity includes a dynamical spacetime, so it is difficult to see how to identify the conserved energy and momentum. Noether's theorem allows these quantities to be determined from a Lagrangian with translation invariance, but general covariance makes translation invariance into something of a gauge symmetry. The energy and momentum derived within general relativity by Noether's presecriptions do not make a real tensor for this reason. Einstein argued that this is true for fundamental reasons, because the gravitational field could be made to vanish by a choice of coordinates. He maintained that the non-covariant energy momentum pseudotensor was in fact the best description of the energy momentum distribution in a gravitational field. This approach has been echoed by Lev Landau and Evgeny Lifshitz, and others, and has become standard. The use of non-covariant objects like pseudotensors was heavily criticized in 1917 by Erwin Schrodinger and others.

Question: "When did the standard approach to energy momentum become criticized?"

Answer: "1971"
Answer:
no