Definitions of common eras and time scales.
eras() lists all available era definitions. eras(label) looks up a
specific era by its unique, abbreviated name (e.g. "cal BP").
Value
A table of era definitions. This can be passed to era() to construct an
era object.
See also
Other era definition functions:
era()
Examples
# List all available eras
print(eras(), n = Inf)
#> # A tibble: 33 × 6
#> label epoch name unit scale direction
#> <chr> <dbl> <chr> <era_year> <int> <dbl>
#> 1 BP 1950 Before Present Gregorian 1e0 -1
#> 2 cal BP 1950 Before Present Gregorian 1e0 -1
#> 3 BC 1 Before Christ Gregorian 1e0 -1
#> 4 BCE 1 Before Common Era Gregorian 1e0 -1
#> 5 AD 0 Anno Domini Gregorian 1e0 1
#> 6 CE 0 Common Era Gregorian 1e0 1
#> 7 a 1950 annum Gregorian 1e0 -1
#> 8 ka 1950 kiloannum Gregorian 1e3 -1
#> 9 Ma 1950 megaannum Gregorian 1e6 -1
#> 10 Ga 1950 gigaannum Gregorian 1e9 -1
#> 11 kya 1950 thousand years ago Gregorian 1e3 -1
#> 12 mya 1950 million years ago Gregorian 1e6 -1
#> 13 bya 1950 billion years ago Gregorian 1e9 -1
#> 14 b2k 2000 years before 2000 Gregorian 1e0 -1
#> 15 uncal BP 1950 uncalibrated Before Present radiocarbon 1e0 -1
#> 16 RCYBP 1950 Radiocarbon Years Before P… radiocarbon 1e0 -1
#> 17 bp 1950 Before Present (uncalibrat… radiocarbon 1e0 -1
#> 18 bc 1950 Before Christ (uncalibrate… radiocarbon 1e0 -1
#> 19 bce 1950 Before Common Era (uncalib… radiocarbon 1e0 -1
#> 20 ad 1950 Anno Domini (uncalibrated) radiocarbon 1e0 1
#> 21 ce 1950 Common Era (uncalibrated) radiocarbon 1e0 1
#> 22 AD O.S. 0 Anno Domini (Old Style) Julian 1e0 1
#> 23 BC O.S. 1 Before Christ (New Style) Julian 1e0 1
#> 24 H 622. Hijra Islamic lunar 1e0 1
#> 25 AH 622. Anno Hegirae Islamic lunar 1e0 1
#> 26 BH 623. Before the Hijra Islamic lunar 1e0 -1
#> 27 SH 621. Solar Hijri Nowruz 1e0 1
#> 28 BSH 622. Before Solar Hijri Nowruz 1e0 -1
#> 29 AM -3760. Anno Mundi Hebrew lunisolar 1e0 1
#> 30 HE -10000 Holocene Era Gregorian 1e0 1
#> 31 BHE -10000 Before Holocene Era Gregorian 1e0 -1
#> 32 AL -4000 Anno Lucis Gregorian 1e0 1
#> 33 ADA -8000 After the Development of A… Gregorian 1e0 1
# Look up a specific era by label
eras("cal BP")
#> # A tibble: 1 × 6
#> label epoch name unit scale direction
#> <chr> <dbl> <chr> <era_year> <int> <dbl>
#> 1 cal BP 1950 Before Present Gregorian 1 -1
# With partial matching
eras("cal")
#> # A tibble: 1 × 6
#> label epoch name unit scale direction
#> <chr> <dbl> <chr> <era_year> <int> <dbl>
#> 1 cal BP 1950 Before Present Gregorian 1 -1