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  2. Light-year - Wikipedia

    en.wikipedia.org/wiki/Light-year

    The centre of the Milky Way is about 26 000 light-years away. [35] [36] 1 × 10 5 ly: The Milky Way is about 100 000 light-years across. 1.65 × 10 5 ly: R136a1, in the Large Magellanic Cloud, the most luminous star known at 8.7 million times the luminosity of the Sun, has an apparent magnitude 12.77, just brighter than 3C 273. 10 6: 2.5 × 10 6 ly

  3. Speed of light - Wikipedia

    en.wikipedia.org/wiki/Speed_of_Light

    A light-year is the distance light travels in one Julian year, around 9461 billion kilometres, 5879 billion miles, or 0.3066 parsecs. In round figures, a light year is nearly 10 trillion kilometres or nearly 6 trillion miles. Proxima Centauri, the closest star to Earth after the Sun, is around 4.2 light-years away. [89]

  4. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    Distance light travels in one day – Light-year: 63,241 – Distance light travels in one Julian year (365.25 days) – Oort cloud: 75,000: ± 25,000: Distance of the outer limit of Oort cloud from the Sun (estimated, corresponds to 1.2 light-years) – Parsec: 206,265 – One parsec. The parsec is defined in terms of the astronomical unit, is ...

  5. Timeline of the far future - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_the_far_future

    Voyager 1 passes within 1.8 light-years of Gliese 445. [174] 46,600 Pioneer 11 passes within 1.9 light-years of Gliese 445. [174] 50,000 Estimated atmospheric lifetime of tetrafluoromethane, the most durable greenhouse gas. [175] 90,300 Pioneer 10 passes within 0.76 light-years of HIP 117795. [174] 100,000+

  6. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    Also called "megayear". 1000 millennia (plural of millennium), or 1 million years (in geology, abbreviated as Ma). petasecond: 10 15 s: About 31 709 791 years. galactic year: 2.3 × 10 8 yr: The amount of time it takes the Solar System to orbit the center of the Milky Way Galaxy (approx 230 000 000 years [2]). cosmological decade: logarithmic ...

  7. List of nearest stars - Wikipedia

    en.wikipedia.org/wiki/List_of_nearest_stars

    With the release of Gaia's observations of the star, it has since been refined to a much closer 0.178 light-years (0.055 pc), close enough to significantly disturb objects in the Oort cloud, which extends 1.2 light-years (0.37 pc) from the Sun. [74]

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    mail.aol.com

    Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

  9. Julian year (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Julian_year_(astronomy)

    In contrast, the Julian year is defined in terms of the SI unit one second, so is as accurate as that unit and is constant. It approximates both the sidereal year and the tropical year to about ±0.008 days. The Julian year is the basis of the definition of the light-year as a unit of measurement of distance. [2]