Days to Aeons (d to Gyr)
1 day equals 2.737907007×10⁻¹² aeons (rounded).
How to convert days to aeons
To convert days to aeons, multiply the number of days by 2.737907007×10⁻¹². The factor is rounded to 10 significant digits. To go the other way, multiply aeons by 365,242,500,000.
aeons = days × 2.737907007×10⁻¹²
Example: 10 days = 2.737907007×10⁻¹¹ aeons.
Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.
About these units
Day (d)
24 hours or 86,400 seconds. The mean solar day; the actual rotation of the Earth is about 4 minutes shorter (see sidereal day).
Old English dæg is the root of our day, with close cousins in German Tag, Dutch dag and Icelandic dagur, all descending from Proto-Germanic dagaz. It is the oldest unit here, because the cycle of light and dark needs no instrument. Yet the day we count is a constructed average: the actual interval from one noon to the next varies through the year by up to about 7.9 seconds, because Earth's orbit is elliptical and its axis is tilted.
Astronomers smooth this out with a fictitious mean Sun, giving the mean solar day, and the day in the SI sense is fixed at exactly 86,400 seconds. Reality has drifted slightly: the mean solar day has recently averaged about 86,400.002 seconds, and tidal drag from the Moon is lengthening it by about 2 milliseconds per century. That is why 27 leap seconds were added to UTC between 1972 and 2022. One rotation measured against the distant stars is shorter, about 23 hours 56 minutes 4.09 seconds, and a year contains one more of these sidereal days than solar days.
1 day = 86,400 seconds (exactly).
Sources: Wikipedia: Day; BIPM: SI Brochure, 9th edition
Aeon (Gyr)
One billion years. The Earth is about 4.5 aeons old.
Aeon comes from a Greek word meaning life, vital force, or an age, and its Latin cousin aevum lies behind English words such as eternal and medieval. In ordinary speech it means any very long, indefinite stretch. Philosophical and religious traditions use it differently, with Buddhist and Hindu texts sometimes rendering kalpa as aeon and Gnostic writers using it for divine emanations.
Astronomers fix a definite size, defining an aeon as a billion years. The figure used here is therefore 10 to the power of 9 Gregorian years, about 3.16 times 10 to the power of 16 seconds, which is a convention rather than a measured length. Geologists use the closely related spelling eon for the largest divisions of Earth's history, namely the Hadean, Archean, Proterozoic and Phanerozoic, and these are not billion-year blocks, since the Phanerozoic covers only about 538.8 million years. With Earth about 4.54 billion years old, it is roughly 4.5 aeons old.
1 aeon = 3.1556952×10¹⁶ seconds (exactly).
Sources: Wikipedia: Aeon; Wikipedia: Geologic time scale
Related conversions
- Aeons to days (reverse)
- Days to seconds
- Days to minutes
- Days to hours
- Days to weeks
- Days to months
- Days to years
- Days to milliseconds
- Days to microseconds
- Days to nanoseconds
- Days to decades
- Days to centuries
- Days to millennia
- Seconds to aeons
- Minutes to aeons
- Hours to aeons
- Weeks to aeons
- Months to aeons
- Years to aeons
See all time units.