In essence, atomic clocks can correct themselves. "It's the reason atomic clocks can reach a performance level beyond mechanical clocks." "The fact that the energy difference between these orbits is such a precise and stable value is really the key ingredient for atomic clocks," Eric Burt, an atomic clock physicist at JPL, said in the statement. The energy required to make an electron do this jump is unique to each element and consistent to all atoms of that element. While the number of electrons each type of atom has can vary, the electrons occupy distinct energy levels, and a jolt of exactly the right amount of energy can cause an electron to jump to a higher energy level around the nucleus. The atoms of each element have a distinct structure, with a different number of protons in the nucleus. It may not be surprising to learn that atomic clocks take advantage of the structure of atoms, which are composed of a nucleus of protons and neutrons surrounded by electrons. Related: A NASA Atomic Clock on SpaceX's Next Falcon Heavy Will Pioneer Deep-Space Travel Tech It would take 10 million years for the clock to be wrong by a whole second, according to NASA. NASA's Deep Space Atomic Clock will use mercury atoms and be off by less than a nanosecond after four days and less than a microsecond after 10 years. That much error would have a huge impact on measuring the position of a fast-moving spacecraft, NASA said.Ītomic clocks combine quartz crystal oscillators with certain types of atoms to create better stability. After six weeks, they may be off by a full millisecond, which translates at the speed of light to 185 miles (300 kilometers). The vibrations act like the pendulum in a grandfather clock.īut, by the standards of space navigation, quartz crystal clocks aren't very stable at all. These take advantage of the fact that quartz crystals vibrate at a precise frequency when voltage is applied to them, NASA said in the statement. Modern clocks, from those we wear on our wrists to those used on satellites, most often keep time using a quartz crystal oscillator. While you'd think that clocks always measure the same length of time as a "second," clocks have a tendency to drift and slowly mark longer and longer times as a "second." For measuring the locations of spacecrafts in distant space, astronomers need their atomic clocks to be consistent to better than a billionth of a second over days and weeks. "Stability" here refers to how consistently a clock measures a unit of time. They also need clocks that are extremely stable. By sending multiple signals over time, scientists can calculate a spacecraft's trajectory - both where it was and where it's going.īut in order to know a spacecraft's location within a small margin of error, astronomers need very precise clocks that can measure billionths of a second, according to NASA. That's because the signal is traveling at the speed of light, so armed with the time it took to go to the spacecraft and back, finding distance is but a simple calculation away. The time of that round trip tells scientists the spacecraft's distance from Earth. They send a signal to the spacecraft, which sends it back to Earth. Astronomers already use clocks to navigate in space.
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