Sir Isaac Newton, in his landmark 1687 scientific work Philosophiae Naturalis Principia Mathematica, wrote,“If a leaden cannon ball is horizontally propelled by a powder charge from a cannon positioned on a hilltop, it will follow a curving flight path until it hits the ground … You can make it turn 10 degrees, 30 degrees and 90 degrees before it touches the ground. You can force it to circle the Earth and even disappear into outer space, going away to infinity.”

On the evening of October 4, 1957, Newton's hypothesis was proven correct. At 1912 Greenwich Mean Time, an R-7 intercontinental ballistic missile lifted off from the Baikonur Cosmodrome, on the steppes of Kazahkstan in the former Soviet Union, carrying a 23-inch (58-centimeter) polished steel sphere called Sputnik. About 100 minutes later, the 184-pound (93-kilogram) Sputnik (translated as “satellite” or “traveling companion of the Earth”), trailing four metal antennas, passed through the skies over the launch site confirming that a human-made moon was now orbiting the Earth. The “Space Age” had begun.

Launch of Sputnik 1. Baikonur, USSR.

Word of the successful launch was relayed to Radio Moscow, and within minutes, terse bulletins flashed from news agencies around the world announcing the historic event to an unsuspecting and somewhat stunned populace. Shortwave radio operators soon picked up a persistent “beep … beep … beep” signal broadcast from the satellite as it passed silently overhead, travelling at 17,400 miles per hour (28,003 kilometres per hour). 

As news of the Soviet accomplishment quickly spread by radio and television reports, untold millions climbed onto rooftops, ventured into city parks, or ambled out to dark backyards, all scanning the heavens for a brief glimpse of a rapidly moving star. It was a communal experience that would later become known simply as “Sputnik Night.”

In his best-selling book, Rocket Boys, author (and retired NASA engineer) Homer H. Hickam, Jr. described the night he first observed Sputnik as a 14-year-old. “I saw the bright little ball, moving majestically across the narrow star field between the ridgelines. I stared at it with no less rapt attention than if it had been God Himself in a golden chariot riding overhead. It soared with what seemed to me inexorable and dangerous purpose, as if there were no power in the universe that could stop it. All my life, everything important that had ever happened had always happened somewhere else. But Sputnik was right there in front of my eyes in my backyard in Coalwood, McDowell County, West Virginia, U.S.A. I couldn't believe it,” Hickam recollected.

The teenaged Hickam's feelings were shared by one of the most powerful individuals in the U.S. government, then-Senate Majority Leader Lyndon Baines Johnson. In his memoir, The Vantage Point, Johnson recalled Sputnik Night with a sense of unease and apprehension. “In the open West, you learn to live with the sky. It is a part of your life. But now, somehow, in some new way, the sky seemed almost alien,” wrote Johnson.

The world's shocked reaction to the launch of Sputnik caught the Soviet government by surprise. The October 5, 1957, issue of the official Communist party daily newspaper Pravda barely acknowledged the event in a brief column halfway down the front page. However, the Soviets were quick to capitalize on the enormity of what The New York Times described in an editorial as “one of the world's greatest propaganda-as well as scientific-achievements.” The following day's issue of Pravda featured the banner headline “World's First Artificial Satellite of Earth Created in Soviet Nation.”

Sputnik was launched as part of the United Nations-sponsored International Geophysical Year (IGY), a collaboration by 67 nations to explore the unknowns of the physical world that actually 18 months, from July 1, 1957 to December 31, 1958. During this period the United States had announced its intention to launch a scientific satellite, Vanguard, possibly as early as November 1957. The publicized target launch date for the American satellite was likely the driving factor in the Soviet decision to launch Sputnik first in October.

The plans for a Sputnik, however, had been widely reported in both Soviet and Western publications for several years, and publicly acknowledged by the Soviets four months before the actual launch. An official paper presented to IGY participants in June 1957, by the Soviet Academy of Sciences predicted that a satellite would be launched within months and clearly outlined the satellite's approximate launch site and anticipated speed.

The dog Laika was a passenger on Sputnik 2.

On August 27, 1957, a Soviet scientist, speaking at a conference in Colorado, indicated that his Nation's satellites would pass over higher latitudes than their American counterparts and broadcast on frequencies of approximately 20 and 40 megahertz. The clues were all in place, but were generally disregarded by most in government and scientific circles because of what British astronomer Sir Bernard Lovell called “American blind disbelief in the powerful advance of Soviet science and technology.”

The American response to Sputnik bordered almost on panic. The Chicago Daily News declared that if the Soviets “could deliver a 184-pound ‘moon' into a predetermined pattern 560 miles out into space, the day is not far distant when they could deliver a death-dealing warhead onto a predetermined target almost anywhere on the earth's surface.” Newsweek magazine dolefully predicted that several dozen Sputniks equipped with nuclear bombs could “spew their lethal fallout over the U.S. and Europe.” Senator Lyndon Johnson envisioned a day when the Soviets would be “dropping bombs on us from space like kids dropping rocks onto cars from freeway overpasses,” while Senator Mike Mansfield ominously announced, “What is at stake is nothing less than our survival.”   

The one notable exception to the immediate post-Sputnik hysteria was President Dwight D. Eisenhower. Although he had American nuclear-armed bombers remain constantly airborne just four days before Sputnik's launch in response to Soviet development of the intercontinental ballistic missile (which had been used to launch Sputnik), Eisenhower did not even comment publicly on the launch until October 9, when he issued a statement congratulating the Soviet achievement.

Eisenhower's staid composure concealed an ulterior motive. The president and the U.S. intelligence community had been evaluating proposals for an orbiting reconnaissance satellite, but had been grappling with the political ramifications of Soviet reaction to over flights of its territory. The launch of Sputnik effectively ended those concerns, allowing the United States to pursue a policy of space as an “open platform,” establishing that national boundaries did not extend into space. Donald Quarles, Eisenhower's assistant Secretary of Defence, noted on October 7 that the Soviets “have, in fact, done us a good turn, unintentionally, in establishing the concept of freedom of international space,…”  a principle which the Soviets could not now refute since they had launched first.

The launch of Sputnik II on November 3, 1957, ended any slim public perception of short-term American parity in the emerging Space Race. As the United States was still struggling to launch its IGY scientific satellite Vanguard, weighing all of 3.25 pounds (1.5 kilograms), Sputnik II tipped the scales at 1,118 pounds (507 kilograms) and carried a living passenger, a mongrel dog named Laika, along with sufficient life support supplies to keep the little dog alive for 100 hours.

The United States' official response to Sputnik was multi-pronged. School curriculum's with an emphasis on science and mathematics were quickly established to prepare students for the challenges ahead; the National Defence Education Act was enacted to provide hundreds of millions of dollars in student loans, scholarships, fellowships, and the purchase of scientific equipment for schools; support was expanded for the National Science Foundation, and the Advanced Research Projects Agency was created.