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  2. Power of 10 - Wikipedia

    en.wikipedia.org/wiki/Power_of_10

    Power of 10. Visualisation of powers of 10 from one to 1 trillion. A power of 10 is any of the integer powers of the number ten; in other words, ten multiplied by itself a certain number of times (when the power is a positive integer). By definition, the number one is a power (the zeroth power) of ten. The first few non-negative powers of ten are:

  3. Earth's rotation - Wikipedia

    en.wikipedia.org/wiki/Earth's_rotation

    The angular speed of Earth's rotation in inertial space is (7.292 115 0 ± 0.000 000 1) × 10 ^ −5 radians per SI second. [ 35 ] [ n 4 ] Multiplying by (180°/π radians) × (86,400 seconds/day) yields 360.985 6 °/day , indicating that Earth rotates more than 360 degrees relative to the fixed stars in one solar day.

  4. Minute and second of arc - Wikipedia

    en.wikipedia.org/wiki/Minute_and_second_of_arc

    A minute of arc is ⁠π 10 800⁠ of a radian . A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol ″, [2] is ⁠ 1 60 ⁠ of an arcminute, ⁠ 1 3600⁠ of a degree, [1] ⁠ 1 1 296 000⁠ of a turn, and ⁠π 648 000⁠ (about ⁠ 1 206 264.8⁠) of a radian. These units originated in Babylonian astronomy as ...

  5. Order of magnitude - Wikipedia

    en.wikipedia.org/wiki/Order_of_magnitude

    An order-of-magnitude estimate of a variable, whose precise value is unknown, is an estimate rounded to the nearest power of ten. For example, an order-of-magnitude estimate for a variable between about 3 billion and 30 billion (such as the human population of the Earth) is 10 billion. To round a number to its nearest order of magnitude, one ...

  6. Radian - Wikipedia

    en.wikipedia.org/wiki/Radian

    A similar calculation using the area of a circular sector θ = 2A/r 2 gives 1 SI radian as 1 m 2 /m 2 = 1. [10] The key fact is that the SI radian is a dimensionless unit equal to 1. In SI 2019, the SI radian is defined accordingly as 1 rad = 1. [11] It is a long-established practice in mathematics and across all areas of science to make use of ...

  7. Degree (angle) - Wikipedia

    en.wikipedia.org/wiki/Degree_(angle)

    10. A degree (in full, a degree of arc, arc degree, or arcdegree ), usually denoted by ° (the degree symbol ), is a measurement of a plane angle in which one full rotation is 360 degrees. [ 4] It is not an SI unit —the SI unit of angular measure is the radian —but it is mentioned in the SI brochure as an accepted unit. [ 5]

  8. Angstrom - Wikipedia

    en.wikipedia.org/wiki/Angstrom

    Portrait of Anders Ångström [15]. In 1868, Swedish physicist Anders Jonas Ångström created a chart of the spectrum of sunlight, in which he expressed the wavelengths of electromagnetic radiation in the electromagnetic spectrum in multiples of one ten-millionth of a millimetre (or 10 −7 mm.) [16] [17] Ångström's chart and table of wavelengths in the solar spectrum became widely used in ...

  9. Density of air - Wikipedia

    en.wikipedia.org/wiki/Density_of_air

    Air density, like air pressure, decreases with increasing altitude. It also changes with variations in atmospheric pressure, temperature and humidity. At 101.325 kPa (abs) and 20 °C (68 °F), air has a density of approximately 1.204 kg/m 3 (0.0752 lb/cu ft), according to the International Standard Atmosphere (ISA).