- A year is the time
taken for
astronomical objects to
complete one orbit. For example, a year on
Earth is the time
taken for
Earth to
revolve around the...
-
Million years ago,
abbreviated as Mya, Myr (me****ear) or Ma (
megaannum), is a unit of time
equal to 1,000,000 years (i.e. 1×106 years), or approximately...
-
Megaampere (MA), a
multiple of the SI unit of
electric current, the
ampere Megaannum (Ma), one
million years Milliampere (mA), a
multiple of the SI unit of...
-
periods are then
expressed by
using metric prefixes with the annum, such as
megaannum (Ma) or
gigaannum (Ga).[citation needed] The SI unit of
angle is the radian...
- Ga)
Hadean Eon (4–4.6 Ga) ka =
kiloannum (thousand
years ago); Ma =
megaannum (million
years ago); Ga =
gigaannum (billion
years ago). See also: Geologic...
- Ga)
Hadean Eon (4–4.6 Ga) ka =
kiloannum (thousand
years ago); Ma =
megaannum (million
years ago); Ga =
gigaannum (billion
years ago). See also: Geologic...
-
International Chronostratigrahpic Chart are
represented by the unit Ma (
megaannum, for 'million years'). For example, 201.4 ± 0.2 Ma, the
lower boundary...
- Ga)
Hadean Eon (4–4.6 Ga) ka =
kiloannum (thousand
years ago); Ma =
megaannum (million
years ago); Ga =
gigaannum (billion
years ago). See also: Geologic...
-
photosynthesis c. 2.3 Ga:
Oxygenated atmosphere,
first snowball Earth 730–635 Ma (
megaannum:
million years ago):
second snowball Earth 541 ± 0.3 Ma:
Cambrian explosion...
- fish
discovered in
rocks from the
Ordovician period about 485 to 444 Ma (
megaannum,
million years ago), with
jawed vertebrates emerging in the following...
