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  2. Newcomb's Tables of the Sun - Wikipedia

    en.wikipedia.org/wiki/Newcomb's_Tables_of_the_Sun

    Newcomb gives the Right ascension of the fictitious mean Sun, affected by aberration (which is used in finding mean solar time) as [10] τ = 18 h 38 m 45.836 s + 8 640 184.542 s T + 0.0929 s T 2. Authors citing this expression include McCarthy & Seidelmann (p. 13) and the Nautical Almanac Offices of the United Kingdom and United States (p. 73).

  3. Earth's orbit - Wikipedia

    en.wikipedia.org/wiki/Earth's_orbit

    One complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). [2] Ignoring the influence of other Solar System bodies, Earth's orbit, also called Earth's revolution, is an ellipse with the Earth–Sun barycenter as one focus with a current eccentricity of 0.0167. Since this value ...

  4. Orbital speed - Wikipedia

    en.wikipedia.org/wiki/Orbital_speed

    In gravitationally bound systems, the orbital speed of an astronomical body or object (e.g. planet, moon, artificial satellite, spacecraft, or star) is the speed at which it orbits around either the barycenter (the combined center of mass) or, if one body is much more massive than the other bodies of the system combined, its speed relative to the center of mass of the most massive body.

  5. Earth's rotation - Wikipedia

    en.wikipedia.org/wiki/Earth's_rotation

    It is not until a little later, at time 3, that the Sun is overhead again (1→3 = one solar day). Earth's rotation period relative to the International Celestial Reference Frame, called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is 86 164.098 903 691 seconds of mean solar time (UT1) (23 h 56 m 4. ...

  6. Sun-synchronous orbit - Wikipedia

    en.wikipedia.org/wiki/Sun-synchronous_orbit

    A non-Sun-synchronous orbit (magenta) is also shown for reference. Dates are shown in white: day/month. A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, [1] is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time.

  7. Orders of magnitude (speed) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(speed)

    Escape speed from Earth by NASA New Horizons spacecraft—Fastest escape velocity. 17,000: 61,000: 38,000 0.00006: The approximate speed of the Voyager 1 probe relative to the Sun, when it exited the Solar System. [25] 29,800: 107,280: 66,700 0.00010: Speed of the Earth in orbit around the Sun. 47,800: 172,100: 106,900 0.00016

  8. Do You Need to Worry About an Asteroid Hitting Earth? - AOL

    www.aol.com/news/worry-asteroid-hitting-earth...

    A single astronomical unit is the distance from the sun to the Earth, or 93 million miles. ... when its flight path carries it around the sun, making it impossible to see until June of 2028 ...

  9. Milky Way - Wikipedia

    en.wikipedia.org/wiki/Milky_Way

    The Sun moves through the heliosphere at 84,000 km/h (52,000 mph). At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit). [113] The Solar System is headed in the direction of the zodiacal constellation Scorpius, which follows the ecliptic. [114]