"It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957."
The first artificial satellite to be launched into space by the Soviet Union in 1957, marking the beginning of the Space Race.
The Space Race: A competition between the United States and Soviet Union to explore space and demonstrate technological superiority.
The Cold War: A political and ideological struggle between the United States and Soviet Union that defined the global landscape after World War II.
Soviet Space Program: A government-funded space program established by the Soviet Union in the 1950s, which led to the development of Sputnik as well as the first manned space flights.
Sputnik 1: The first artificial satellite to be placed in orbit around the Earth, launched by the Soviet Union on October 4, 1957.
Launch Vehicles: Rockets used to launch satellites, including the rockets used to launch Sputnik 1.
Orbital Mechanics: The study of the motion of satellites and other objects as they orbit around the Earth.
Radio Transmission: The means by which Sputnik 1 communicated with ground stations and relayed scientific data.
International Reaction: The response of the United States, Europe, and other countries to the launch of Sputnik 1, including concerns over Soviet military capabilities and efforts to close the perceived "space gap".
Scientific Discoveries: The data and observations gathered by Sputnik 1 and subsequent Soviet space missions, including studies of the Earth's atmosphere and magnetic field.
Legacy and Impact: The lasting effects of early space exploration, including the development of satellite technology, communication systems, and international cooperation in space exploration.
"Its radio signal was easily detectable by amateur radio operators."
"It sent a radio signal back to Earth for three weeks."
"Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958."
"The satellite's success was unanticipated by the United States. This precipitated the American Sputnik crisis and triggered the Space Race."
"The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave data about the ionosphere."
"It was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now known as the Baikonur Cosmodrome)."
"The satellite traveled at a peak speed of about 8 km/s (18,000 mph)."
"It took 96.20 minutes to complete each orbit."
"It transmitted on 20.005 and 40.002 MHz."
"The signals continued for 21 days until the transmitter batteries ran out on 26 October 1957."
"On 4 January 1958, after three months in orbit, Sputnik 1 burned up while reentering Earth's atmosphere."
"Having completed 1,440 orbits of the Earth."
"It was a polished metal sphere 58 cm (23 in) in diameter."
"It had four external radio antennas to broadcast radio pulses."
"The word sputnik is Russian for traveller when interpreted in an astronomical context; its other meanings are spouse or traveling companion."
"The launch was the beginning of a new era of political, military, technological and scientific developments."
"The 65° orbital inclination made its flight path cover virtually the entire inhabited Earth."
"Travelling a distance of approximately 70,000,000 km (43,000,000 mi)."
"Its three silver-zinc batteries ran out." Please note that the provided quotes may not be exact, as the text was paraphrased for brevity.