Although the British Council took the trouble to provide the full English text and Hebrew translation of astrophysicist Prof. Stephen Hawking's 45-minute abstruse lecture to 200 pupils of science on Sunday, the main impression left on most of his teenage audience was the message printed on the back of the gift T-shirts they received: "I Met Stephen Hawking: 10 December 2006." The message on the shirt front - showing the formula Rs=2MG/c2 for a black hole and how it "warps spacetime" - went way above the heads of the vast majority of his listeners, as did his speech about Wheeler-Feynman electro-dynamics, the Euclidian approach to quantum gravity, "naked singularities" and the "Cosmic Censorship hypothesis." Even a senior staffer at Jerusalem's Bloomfield Science Museum, which hosted the man called "the greatest physicist since Einstein" for his first public appearance since arriving on Thursday night, couldn't make head or tail of his lecture. When the 64-year-old Hawking - here for eight days to promote Israeli appreciation of British scientific achievements, among the general public and especially among young people - arrived an hour after pupils were seated in the auditorium, members of the audience were mesmerized by his entrance. An assistant pushed his wheelchair up a special ramp to the podium as the genius scientist sat completely motionless, except for occasional spasms of his left leg. An aide followed the lecture on his laptop at the lectern to ensure that the audio part coincided with the visual parts on the screen behind him. Hawking's head, tilted permanently to his right shoulder and held in place by a semicircular headrest, did not move, and his face was expressionless - all the result of 43 years of increasingly worsening amyotrophic lateral sclerosis (or Lou Gehrig's disease), the incurable neurological condition that was supposed to kill him in his mid-20s. It is diagnosed in one or two per 100,000 people, but the cause is not known. His speech, apparently one he delivers to young people on his visits all around the world, was pre-recorded and sounded out in a mild Irish accent synthesized by a computer that takes dictation from Hawking when he opens and closes his eyelids. Sadly, those are the only parts of his body he can move voluntarily, except for two fingers of one hand. Through much of the lecture - as the screen flashed photographs of colleagues and his two children, Lucy and Tim, scientific formulas and some graphic humor - Hawking appeared to be half asleep. But unlike their British counterparts, Israeli teenagers call their teachers by their first names and prefer personal stories, to be touched by the heart and not just overwhelmed by a towering intellect. How did he feel locked up in an unmovable body, his every need met by helpers? Would he rather die if his ability to move his eyelids and breathe on his own were to disappear? How was he able to push his indomitable imagination and curiosity beyond the helplessness of his physical existence? What would he say to other disabled people who aspire to be scientists? None of these unasked questions was answered. Hawking clearly has a sense of humor. The last paragraph of his speech - a rare purely personal statement - elicited the greatest laugh of appreciation: "It has been a glorious time to be alive and doing research in theoretical physics. Our picture of the universe has changed a great deal in the last 40 years, and I'm happy if I have made a small contribution. I want to share my excitement and enthusiasm. There's nothing like the Eureka moment of discovering something that no one knew before. I won't compare it to sex, but it lasts longer!" Questions submitted in advance by three pupils in the audience, which included previous winners and finalists of the Intel-Israel Young Scientists Competition, pupils from Jerusalem, Tel Aviv, Nazareth and other locations received short replies in pre-recorded answers from Hawking's synthesizer. When Yonatan Shelah, a 17-year-old Hemda Science Center participant in Tel Aviv, asked how he felt about changing a theory about black holes after years of preaching the opposite, Hawking said: "Scientists do not correct themselves as often as they should, but more often than politicians." Prof. Hanoch Gutfreund, senior theoretical physicist and former Hebrew University president, said that although a few pupils had been invited to prepare questions for Hawking to answer spontaneously (and laboriously) on the spot, it was not possible at the Bloomfield event. But he quoted a previous interview in which Hawking was asked about coping with his devastating physical disability. "He said: 'If I were a soccer player, it would have been a problem. But as a theoretical physicist, all I need is my brain.'" "I didn't understand what he said, but he is a great physicist," said one disappointed pupil at the Hebrew University High School. "I was able to follow most of the English, but not the scientific terms he used," said a 17-year-old science buff from the north. "I will tell my classmates that I saw Stephen Hawking, but I won't be able to explain what he said."