When.com Web Search

  1. Ad

    related to: distance to light years calculator converter hours left to school month

Search results

  1. Results From The WOW.Com Content Network
  2. Light-year - Wikipedia

    en.wikipedia.org/wiki/Light-year

    A light-year, alternatively spelled light year (ly or lyr[3]), is a unit of length used to express astronomical distances and is equal to exactly 9,460,730,472,580.8 km (Scientific notation: 9.4607304725808 × 10 12 km), which is approximately 5.88 trillion mi.

  3. Comoving and proper distances - Wikipedia

    en.wikipedia.org/wiki/Comoving_and_proper_distances

    Comoving distance and proper distance. Comoving distance is the distance between two points measured along a path defined at the present cosmological time. For objects moving with the Hubble flow, it is deemed to remain constant in time. The comoving distance from an observer to a distant object (e.g. galaxy) can be computed by the following ...

  4. Light-second - Wikipedia

    en.wikipedia.org/wiki/Light-second

    The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly 299 792 458 m (approximately 983 571 055 ft or 186 282 mi). Just as the second forms the basis for other units of time, the light-second can ...

  5. Hubble's law - Wikipedia

    en.wikipedia.org/wiki/Hubble's_law

    (The numerical value of the Hubble length in light years is, by definition, equal to that of the Hubble time in years.) The Hubble distance would be the distance between the Earth and the galaxies which are currently receding from us at the speed of light, as can be seen by substituting D = cH −1 into the equation for Hubble's law, v = H 0 D .

  6. 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]

  7. Time in physics - Wikipedia

    en.wikipedia.org/wiki/Time_in_physics

    Andromeda galaxy is two million light-years away. Thus we are viewing M31's light from two million years ago, [14] a time before humans existed on Earth. Galileo, Newton, and most people up until the 20th century thought that time was the same for everyone everywhere. This is the basis for timelines, where time is a parameter.

  8. Parsec - Wikipedia

    en.wikipedia.org/wiki/Parsec

    3.261 56 ly. The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to 3.26 light-years or 206,265 astronomical units (AU), i.e. 30.9 trillion kilometres (19.2 trillion miles). [a] The parsec unit is obtained by the use of parallax and trigonometry ...

  9. Equation of time - Wikipedia

    en.wikipedia.org/wiki/Equation_of_time

    During a year the equation of time varies as shown on the graph; its change from one year to the next is slight. Apparent time, and the sundial, can be ahead (fast) by as much as 16 min 33 s (around 3 November), or behind (slow) by as much as 14 min 6 s (around 11 February). The equation of time has zeros near 15 April, 13 June, 1 September ...