Why in the News?
Researchers conducted the most precise global comparison of 10 Optical Atomic Clocks to pave the way for redefining the second by 2030, replacing Caesium Clocks with more accurate Optical ones.
Definition of a Second:
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About Caesium Atomic Clocks:
- Overview: Caesium atomic clocks are devices that define the current SI unit of time (second) using the oscillation frequency of caesium-133 atoms.
- SI Second Standard: One second is defined as the duration of 9,192,631,770 cycles of microwave radiation corresponding to the transition between two energy levels of the caesium-133 atom.
- Working Principle: These clocks work by tuning microwave signals to resonate with caesium atoms and then counting the resulting waves to measure time precisely.
- Stability and Usage: They are highly stable and have been used since 1967 to set international time standards.
- Applications: They are used in GPS systems, telecommunications, scientific research, and by national metrology institutions like India’s National Physical Laboratory (NPL).
- Accuracy: A typical caesium atomic clock loses about one second every 300 million years.
What are Optical Atomic Clocks?
- Overview: They are advanced timekeeping devices that use optical (visible light) frequency transitions in atoms like Strontium (Sr) or Ytterbium (Yb).
- Measurement Basis: These clocks measure time based on the oscillation of light emitted when atoms transition between energy levels at hundreds of trillions of Hz.
- Example Frequencies:
- Strontium: ~429 trillion Hz
- Ytterbium ions: over 642 trillion Hz
- Precision Tools: They require lasers and optical frequency combs to count these rapid oscillations accurately.
- Future Standard: They are being tested worldwide and are expected to replace caesium clocks by 2030 for redefining the SI second.
How Optical Atomic Clocks are Better than Caesium ones?
- Higher Frequency Operation: Optical clocks operate at much higher frequencies, allowing division of time into finer intervals.
- Improved Precision: By counting 10,000 times more oscillations per second, optical clocks achieve significantly higher precision and stability.
- Unmatched Accuracy: An optical atomic clock using strontium reportedly drifts by less than one second in 15 billion years, compared to 300 million years for caesium clocks.
- Advanced Applications: Their precision is critical for: Next-gen GPS systems, Gravitational wave detection, Climate monitoring and research etc.
- Ultra-High Synchronization: Optical clocks enable cross-continental synchronization at 18 decimal place accuracy, essential for global time coordination.
- Noise Resilience: They offer greater resistance to environmental noise and external disturbances, improving long-term reliability.
| [UPSC 2023] Which one of the following countries has its own Satellite Navigation System?
Options: (a) Australia (b) Canada (c) Israel (d) Japan* |
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