First, the development of physics would likely have been significantly slower. Einstein's work on the theory of relativity was a major breakthrough that revolutionized our understanding of the universe. Without his contributions, it is likely that physicists would have taken much longer to develop similar theories. This could have had a ripple effect on other fields of science, such as astronomy, cosmology, and quantum mechanics.
Second, the United States may not have developed nuclear weapons as quickly as it did. Einstein played a key role in the Manhattan Project, the secret government project that developed the atomic bomb. His involvement was crucial in convincing President Franklin D. Roosevelt to authorize the project and in recruiting other top scientists to work on it. Without Einstein, the Manhattan Project may have been delayed or even abandoned, which could have had a profound impact on the outcome of World War II and the subsequent Cold War.
Third, the civil rights movement in the United States may have been less successful. Einstein was a vocal supporter of civil rights and used his fame to speak out against discrimination. He also worked closely with Martin Luther King, Jr., and other civil rights leaders. Without Einstein's support, the civil rights movement may not have been as successful as it was.
Of course, it is impossible to say for sure how history would have been different if Albert Einstein had not lived. However, it is clear that his work had a profound impact on science, society, and politics. Without him, the world would be a very different place.