22 relations: Astronomy, Astronomy & Astrophysics, Before Present, Billion, English language, Epoch (astronomy), Geology, Geophysics, Giga-, Gray (unit), Harvard University Press, Julian year (astronomy), Long and short scales, Myr, Orders of magnitude (time), Paleontology, Physical cosmology, Second, Sidereal year, Unit of measurement, Year, 1,000,000,000.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics.
Before Present (BP) years is a time scale used mainly in geology and other scientific disciplines to specify when events occurred in the past.
A billion is a number with two distinct definitions.
English is a West Germanic language that was first spoken in early medieval England and is now a global lingua franca.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
Geology (from the Ancient Greek γῆ, gē, i.e. "earth" and -λoγία, -logia, i.e. "study of, discourse") is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time.
Geophysics is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis.
Giga is a unit prefix in the metric system denoting a factor of a (short-form) billion (109 or 000).
The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI).
Harvard University Press (HUP) is a publishing house established on January 13, 1913, as a division of Harvard University, and focused on academic publishing.
In astronomy, a Julian year (symbol: a) is a unit of measurement of time defined as exactly 365.25 days of SI seconds each.
The long and short scales are two of several large-number naming systems for integer powers of ten that use the same words with different meanings.
The abbreviation myr, "million years", is a unit of a quantity of (i.e.) years, or 31.6 teraseconds.
An order of magnitude of time is (usually) a decimal prefix or decimal order-of-magnitude quantity together with a base unit of time, like a microsecond or a million years.
Paleontology or palaeontology is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene Epoch (roughly 11,700 years before present).
Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its origin, structure, evolution, and ultimate fate.
The second is the SI base unit of time, commonly understood and historically defined as 1/86,400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.
A sidereal year (from Latin sidus "asterism, star") is the time taken by the Earth to orbit the Sun once with respect to the fixed stars.
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity.
A year is the orbital period of the Earth moving in its orbit around the Sun.
1,000,000,000 (one billion, short scale; one thousand million or milliard, yard, long scale) is the natural number following 999,999,999 and preceding 1,000,000,001.