Slouching in profile, draped in black and moving no more than an eyelid to send his words to a mesmerized audience of 6,000, Dr. Hawking ruminated on the origin of the universe as the headliner of an international physics conference.

"We are close to answering an age-old question," he concluded. "Why are we here? Where did we come from?"

Participants listen attentively to Stephen Hawking in the Great Hall of the People in Beijing June 19, 2006. [NYtimes]

But as weighty as his speech was, his mere presence was a powerful symbol of what China is and would like to be.

China wants to stand up scientifically, as it is beginning to economically, and it is pouring money and talent into the sciences, particularly physics. Jie Zhang, director general of basic sciences for the Chinese academy, said his budget had been increasing 17 percent a year for the last few years as China tried to ramp up research spending to about 2.5 percent of its gross domestic product. By comparison, the United States spends slightly less than 2 percent, according to the National Science Foundation.

Among the big-budget items on the table, Dr. Zhang said, are a giant 500-meter-diameter radio telescope in China's outback to study microwaves from the Big Bang and a multinational particle-physics project, known as the Daya Bay Reactor Neutrino Experiment to study the ghostly elementary particles known as neutrinos.

To keep track of all this activity, the United States National Science Foundation opened an office in Beijing last month. The foundation noted that China had gone from fourth in the world to third in research and development expenditures from 2000 to 2006.

While some scientists express doubts that China is open enough to foster top-tier science, others are enthusiastic.

"China is changing at a rate that is truly amazing," said David J. Gross, the director of the Kavli Institute for Theoretical Physics in Santa Barbara, Calif., and a recent Nobel Prize winner, who has been visiting to help reorganize the Beijing theoretical institute into a model that can be used for future research institutes.

Dr. Hawking's talk was part of the very public kickoff of Strings 2006, which has drawn 800 of the world's brightest and most ambitious physicists here for a week to take stock of string theory, their vaunted "theory of everything" that says the elementary constituents of nature are submicroscopic vibrating strings.

Imagine, several string theorists in the audience mused, if a physics conference in the United States started in the House of Representatives.

As he opened the conference, Chun-Li Bai, the executive vice president of the Chinese Academy of Sciences, stressed that basic scientific research had a "high visibility" in the most recent of China's five-year plans. "The next 50 years will be of beauty for the development of Chinese science and technology, as well as economic development," he said.

Calling string theory the cutting edge of curiosity, Shing-Tung Yau, a Harvard mathematics professor and the meeting's chief organizer, said he hoped to make China more involved in the field. "I want to put on a good show," he said.

Dr. Hawking, 64, is always a good show, and his arrival set off a stellar burst of camera flashes worthy of any rock star. A cosmologist at the University of Cambridge, he has been in a wheelchair for most of his life because of amytrophic lateral sclerosis, or Lou Gehrig's disease. But he has nevertheless become one of the leading gravitational theorists, an avatar of mysteries of black holes and the origin of spacetime, as well as a best-selling author, a father of three, an indefatigable world traveler and a guest star on "The Simpsons" and "Star Trek: The Next Generation."

He speaks with the aid of a computer-driven voice synthesizer. He used to operate it with his thumb but is now so weak that he has to use an infrared device that tracks his eye movements. So the camera flashes were potentially catastrophic, and Dr. Yau ordered the photographers away.

Dr. Hawking's star turn, across the street from the large portrait of Mao Zedong, also had historic resonance. In the Cultural Revolution, Mao denounced Einstein and his work as reactionary and bourgeois. Groups of scientists and scholars were set up to criticize relativity because it appeared to collide with Marxist dogma that the universe was infinite and endless, eternally embroiled in a sort of cosmic class struggle.

History has buried those aspects of Marxist thought. Chinese leaders now are technocrats, not "cosmocrats," as Yinghong Cheng, a historian at Delaware State University who has studied the cultural revolution, put it. Prime Minister Wen Jiabao wished good health to Dr. Hawking.

Hardly a week goes by without an announcement of another research initiative or new investment in a building or an institute. It is hard to find an American physicist who is not on his way to China to consult or collaborate, or has just come from China, glowing about the experience.

"The Chinese are so smart they knock your socks off," said Andrew Strominger, a Harvard string theorist who visits here often. "The impression you get when you go over there is that China is going to take over the world soon."

This week, Fred Kavli, the inventor and philanthropist whose foundation has endowed 10 research institutes in the West, announced that he would endow two new Kavli institutes in Beijing ¡ª at the Institute for Theoretical Physics at the Chinese Academy of Sciences and at Beijing University's Institute for Astronomy and Astrophysics ¡ª for several million dollars each. Both will be linked in a network with the others. Every summer, hundreds of Chinese-American scientists, so-called overseas Chinese, leave their posts in the United States and elsewhere to return to help out, lured by lucrative salaries, prestige and the chance to "help China."

Marvin I. Cohen, a professor at the University of California, Berkeley, who is president of the American Physical Society, said physics had come in for special attention in this effort, for its centrality to science and what he calls its rigorous approach.

Dr. Cohen was impressed by an up-to-date physics building that he saw in Beijing. "Someone writes a $10 million check, and they build the building in Beijing that we wanted in Berkeley," he said.

Putting up buildings is easy compared with filling them with the right people. Despite all the hype, most researchers say, their best students are so far staying in the United States. The system, everyone seems to agree, is rife with politics, and the sudden influx of money has created opportunities for corruption and fraud.

Last month, a star chip designer, Jin Chen, was fired by Shanghai Jiaotong University after a Web site run by a biochemist in San Diego, Shi-min Fang, disclosed that his design for a ballyhooed new signal-processing chip had been stolen.

That and similar incidents led 120 biologists to sign a letter written by a researcher at Indiana University, Xin-Yuan Fu, calling for a government office to investigate science misconduct. The Education Ministry has since set up a special commission to study misconduct. Dr. Yau said he was pleased to see China take the problem seriously, adding that there were many more incidents of fraud.

"They want to catch up too fast," Dr. Yau said. "They want to leapfrog."