Orders of magnitude (time) facts for kids

An order of magnitude helps us understand how big or small something is by comparing it to powers of 10. Imagine a ladder where each step is 10 times bigger than the one before it. That's an order of magnitude! For example, 100 is one order of magnitude larger than 10, and 1,000 is one order of magnitude larger than 100. This idea helps scientists talk about incredibly tiny things, like the time it takes for a particle to decay, or incredibly huge things, like the age of the universe.

Understanding Time's Scale

Time can be measured in many ways, from the blink of an eye to the age of stars. Using orders of magnitude helps us grasp these vast differences. We often use seconds or years as our main units.

Tiny Moments: Seconds and Smaller

When we talk about very short periods of time, we use special prefixes with the word "second." These names help us describe things that happen faster than you can imagine!

• Planck time (about 10⁻⁴⁴ seconds): This is the smallest amount of time that physics can currently describe. It's so incredibly tiny, it's almost impossible to picture!
• Yoctosecond (10⁻²⁴ seconds): This is a quadrillionth of a second (in the long scale) or a septillionth of a second (in the short scale).
  • A top quark particle decays in about 1 yoctosecond.
  • It takes about 1 yoctosecond for a quark to release a gluon.
• Zeptosecond (10⁻²¹ seconds): This is one trillionth of one billionth of a second.
  • The outer neutron of helium-9 has a half-life of about 7 zeptoseconds.
  • Gamma rays and X-rays have very short cycles, around 17 zeptoseconds.
• Attosecond (10⁻¹⁸ seconds): This is an extremely short time.
  • The shortest time ever measured is 100 attoseconds.
• Femtosecond (10⁻¹⁵ seconds): This is the time it takes for light to travel a very short distance.
  • Light that is 390 nanometres long (which is the boundary between visible light and ultraviolet light) completes one cycle in about 1 femtosecond.
• Picosecond (10⁻¹² seconds):
  • A bottom quark particle has a half-life of about 1 picosecond.
  • Some supercomputers can do one calculation cycle in just 4 picoseconds.
• Nanosecond (10⁻⁹ seconds):
  • An Intel Pentium 4 1 GHz computer chip can do one calculation cycle in about 1 nanosecond.
  • Light travels about 1 foot (30 cm) in 1 nanosecond.
  • There are 1,000,000,000 nanoseconds in 1 second!
• Microsecond (10⁻⁶ seconds):
  • An older computer chip like the Intel 80186 could do one calculation cycle in 1 microsecond.
  • Older minicomputers took 4 to 16 microseconds for one machine cycle.
• Millisecond (10⁻³ seconds):
  • It takes about 50-80 milliseconds to blink your eye.
• Centisecond (10⁻² seconds): This is one hundredth of a second.
• Second (10⁰ seconds): This is our basic unit of time.
  • Saying "One Mississippi" takes about 1 second.
  • There are 60 seconds in 1 minute.

Longer Stretches: Seconds to Years

As we move to longer times, we use different prefixes or switch to larger units like minutes, hours, days, and years.

• Kilosecond (10³ seconds): This is 1,000 seconds.
  • 1 hour is 3,600 seconds (3.6 kiloseconds).
  • 1 day is 86,400 seconds (86.4 kiloseconds).
  • 1 week is 604,800 seconds (604.8 kiloseconds).
• Megasecond (10⁶ seconds): This is 1,000,000 seconds, or about 11.6 days.
  • A month is about 2.6 megaseconds.
  • A year is about 31.6 megaseconds.
• Gigasecond (10⁹ seconds): This is 1,000,000,000 seconds, or about 32 years.
  • A century is about 3.16 gigaseconds.
  • A millennium (1,000 years) is about 31.6 gigaseconds.
• Terasecond (10¹² seconds): This is 1,000,000,000,000 seconds, or about 32,000 years.
• Petasecond (10¹⁵ seconds): This is 1,000,000,000,000,000 seconds, or about 32 million years.
  • The approximate age of the Universe is about 435 petaseconds (13.8 billion years).
• Exasecond (10¹⁸ seconds): This is 1,000,000,000,000,000,000 seconds, or about 32 billion years.
  • The best guess for the age of the Universe is about 0.43 exaseconds.
• Zettasecond (10²¹ seconds): This is 1,000,000,000,000,000,000,000 seconds, or about 32 trillion years.
• Yottasecond (10²⁴ seconds): This is 1,000,000,000,000,000,000,000,000 seconds, or about 32 quadrillion years.

Long Stretches: Years and Beyond

For very long periods, especially in geology or astronomy, we often use years as our main unit.

• Planck time (about 10⁻⁵⁰ years): The shortest time interval that has meaning in physics.
• Yoctoannum (10⁻²⁴ years): A very, very tiny fraction of a year.
• Zeptoannum (10⁻²¹ years): Another incredibly small fraction of a year.
• Attoannum (10⁻¹⁸ years): Still too small for us to easily imagine.
• Femtoannum (10⁻¹⁵ years): Getting slightly "larger" but still tiny.
• Picoannum (10⁻¹² years):
• Nanoannum (10⁻⁹ years):
  • 1 second is about 3.17 × 10⁻⁸ years.
• Microannum (10⁻⁶ years):
  • 1 minute is about 1.90 × 10⁻⁶ years.
  • 1 hour is about 1.40 × 10⁻⁴ years.
• Milliannum (10⁻³ years):
  • 1 day is about 2.73 × 10⁻³ years.
  • 1 week is about 1.91 × 10⁻² years.
• Annum (10⁰ years): This is simply 1 year.
  • A decade is 10 years.
  • A century is 100 years.
• Kiloannum (10³ years): This is 1,000 years, also known as a millennium.
• Megaannum (10⁶ years): This is 1,000,000 years.
  • An epoch in geology can be millions of years long.
• Gigaannum (10⁹ years): This is 1,000,000,000 years, also known as an eon.
  • The approximate age of the Universe is 13.7 gigaannums (13.7 billion years).
• Teraannum (10¹² years): This is 1,000,000,000,000 years.
• Petaannum (10¹⁵ years): This is 1,000,000,000,000,000 years.
• Exaannum (10¹⁸ years): This is 1,000,000,000,000,000,000 years.
• Zettaannum (10²¹ years): This is 1,000,000,000,000,000,000,000 years.
• Yottaannum (10²⁴ years): This is 1,000,000,000,000,000,000,000,000 years.