Chapter 01 of 5
Beeps From Space
How listening to Sputnik led to satellite navigation.
- 1957
Sputnik's Beep
On October 4, 1957, the Soviet Union launched Sputnik 1, the first artificial satellite. Its radio beeps could be heard around the world.
- Listening In
Two Young Physicists
At the Johns Hopkins Applied Physics Laboratory, physicists William Guier and George Weiffenbach tracked Sputnik's signal.
- The Clue
The Doppler Effect
As the satellite approached, the pitch of the signal rose. As it moved away, the pitch fell, like a passing siren.
17 more cards in this chapter
Could you answer this?
What clue let scientists work out Sputnik's orbit from its radio signal?
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🛰️ Why Your Phone Needs Einstein
- 01Beeps From SpaceHow listening to Sputnik led to satellite navigation.
- 02Four Satellites and a StopwatchHow a phone works out where it is by timing radio signals.
- 03A Billionth of a SecondWhy GPS depends on atomic clocks and timing measured in nanoseconds.
- 04Einstein in OrbitThe relativity corrections that keep your blue dot on the right street.
- 05Lost in the CityUrban canyons, jamming and how your phone fills the gaps.