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  2. Proper motion - Wikipedia

    en.wikipedia.org/wiki/Proper_motion

    This motion is caused by the movement of the stars relative to the Sun and Solar System. The Sun travels in a nearly circular orbit (the solar circle ) about the center of the galaxy at a speed of about 220 km/s at a radius of 8,000 parsecs (26,000 ly) from Sagittarius A* [ 5 ] [ 6 ] which can be taken as the rate of rotation of the Milky Way ...

  3. Local standard of rest - Wikipedia

    en.wikipedia.org/wiki/Local_standard_of_rest

    The Sun follows the solar circle (eccentricity e < 0.1) at a speed of about 255 km/s in a clockwise direction when viewed from the galactic north pole at a radius of ≈ 8.34 kpc [4] about the center of the galaxy near Sgr A*, and has only a slight motion, towards the solar apex, relative to the LSR.

  4. Peculiar velocity - Wikipedia

    en.wikipedia.org/wiki/Peculiar_velocity

    In galactic astronomy, peculiar motion refers to the motion of an object (usually a star) relative to a Galactic rest frame. Local objects are commonly examined as to their vectors of position angle and radial velocity. These can be combined through vector addition to state the object's motion relative to the Sun.

  5. Speed - Wikipedia

    en.wikipedia.org/wiki/Speed

    Average orbital speed of planet Earth around the Sun: 29 783: 97 713: 107 218: 66 623: The fastest recorded speed of the Helios probes: 70,220: 230,381: 252,792: 157,078: Recognized as the fastest speed achieved by a man-made spacecraft, achieved in solar orbit. Orbital speed of the Sun relative to the center of the galaxy: 251 000: 823 000: ...

  6. Oort constants - Wikipedia

    en.wikipedia.org/wiki/Oort_constants

    Figure 1: Geometry of the Oort constants derivation, with a field star close to the Sun in the midplane of the Galaxy. Consider a star in the midplane of the Galactic disk with Galactic longitude at a distance from the Sun. Assume that both the star and the Sun have circular orbits around the center of the Galaxy at radii of and from the Galactic Center and rotational velocities of and ...

  7. Speed of light - Wikipedia

    en.wikipedia.org/wiki/Speed_of_Light

    From the angular difference in the position of stars (maximally 20.5 arcseconds) [97] it is possible to express the speed of light in terms of the Earth's velocity around the Sun, which with the known length of a year can be converted to the time needed to travel from the Sun to the Earth.

  8. Solar apex - Wikipedia

    en.wikipedia.org/wiki/Solar_apex

    The solar apex is in the constellation of Hercules near the star Vega. [1]For more than 30 years before 1986 the speed of the Sun towards the solar apex was taken to be about 20 km/s [2] but all later studies give a smaller component in the vector toward galactic longitude 90°, reducing overall speed to about 13.4 km/s. [3]

  9. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    The Sun, taking along the whole Solar System, orbits the galaxy's center of mass at an average speed of 230 km/s (828,000 km/h) or 143 mi/s (514,000 mph), [167] taking about 220–250 million Earth years to complete a revolution (a Galactic year), [168] having done so about 20 times since the Sun's formation.