Light Year - Light - The Free Encyclopedia - Wikipedia

Alight-year, also light year orlightyear(symbol: ly) is usually a size , identical to just simply under 10 kilometres (10 1015 metres, 10 petametres as well as regarding 6 trillion miles). As described because of the International Astronomical Union (IAU), a light-year will be mileage which mild travels from a in one .

Numerical value Other values History Distances around light-yearsList of jobs with specifications to get lengthScale (ly) Value Item 10 9 40.4 10 nine of all Reflected sun energy from the Moon 's floor calls for 1.2 1.3 seconds to get information the length on the Earth 's surface. (The surface area with the Moon is roughly 376,300 kilometres through the surface of the Earth, upon average. 376,300 km 300,000 km/s (roughly your speed involving light source ) 1.25 seconds) 10 a few 15.8 10 some ly One astronomical system (the range through the towards Earth ). It will take around 499 seconds (8.32 minutes) for light going this kind of distance. 127 10 a few of all The lands upon plus transfers images from it's area 1200 thousand kilometres towards Earth. 10 several 3.2 10 3 ly The most remote living space probe , , seemed to be about sixteen light-hours far from the Earth at the time of 2011. It will administer about 17,500 years to arive at one light-year during its recent swiftness with regarding 17 km/s (38,000 mph) relative for you to this Sun. one hundred 1.6 100 ly The Oort fog up is about not one but two light-years inside diameter. Its interior boundary is speculated to end up being with 50,000 AU, with its exterior edge with 100,000 AU. 2.0 100 ly Maximum amount of the mountain sphere /interstellar carrier . 4.22 100 ly The local regarded (other approach Sun), , is around 4.22 light-years away. 8.60 100 of all Sirius , the brightest star in the night sky. Twice because huge and also 25 times more than your Sun, this outshines more lustrous superstars credited that will its comparative proximity. 20.5 100 ly Gliese 581g , the initial found out extrasolar prospect with regard to habitable planet. Three or four periods seeing that substantial because Earth, it is in the middle on the habitable zone involving celebrity Gliese 581 . 310 hundred ially Canopus , subsequent throughout brightness inside the terrestrial mist just that will Sirius, a sort F 15,000 occasions extra lustrous as opposed to Sun. 103 twenty six 103 ly The middle involving our own galaxy , the Milky Way , is approximately 26 kilolight-years away. 100 103 of all The Milky Way is around 100,000 light-years across. 165 103 of all Large Magellanic Cloud , probably the most luminous star regarded at 8,700,000 occasions the 3C 273 106 2.5 106 ly The Andromeda Galaxy is something like 2.5 megalight-years away. several 106 ly The M33 ), at in relation to 3 megalight-years away, may be the a lot of far-away item visible to the undressed eye. 59 106 of all The nearest substantial galaxy bunch , this , is going 59 megalight-years away. 150 106 a pair of 106 of all The lies at a mileage of a place involving 150 and also 250 megalight-years (the late appearing essentially the most recent estimate). 109 1.2 109 of all The Sloan Great Wall (not for being baffled by using this ) have been measured that they are approximately one particular gigalight-year distant. 2.4 109 ly 3C 273 , optically your cleverest , connected with apparent size 12.9, only dimmer than . 46.5 109 ially The comoving mileage with the Earth towards frame of the apparent market is definitely regarding 46.5 gigalight-years within every direction; this can be a comoving seen galaxy . This is actually larger as opposed to get older on the market formed because of the cosmic foundation radiation ; view dimensions with the universe: beliefs intended for why it is possible. Light-month See in addition References

^ , International Astronomical Union, gathered 2008-07-05

IAU Recommendations related to Units

Astronomical Constants web site K6 of the Astronomical Almanac .

ISBN 0-935702-68-7

Basic Constants

Marc Sauvage,

Basic Constants

Astrophysical Quantities (third edition, London: Athlone, 1973) 16.

Allen's Astrophysical Quantities (fourth edition, New York: Springer-Valeg, 2000) 12. ISBN 0-387-98746-0

Astronomical Constants

KEK B Astronomical Constants

Applied dimensional research along with modeling (New York: McGraw-Hill, 1997) 60.

IERS Conventions (2003) , Chapter 1, Table 1-1.

NASA : Cosmic Distance Scales - The Nearest Star

, Encyclopedia involving Astrobiology, Astronomy, along with Spaceflight

F. Eisenhauer, et al., " " (pdf, 93KB), Astrophysical Journal 597 (2003) L121-L124

McNamara, D. H., et al., " " (pdf, 298KB), The Publications from the Astronomical Society with the Pacific,112(2000), pp. 202 216.

52(6): 1021 26,

Compact Extragalactic Radio Sources, Proceedings in the NRAO workshop stored at Socorro, New Mexico, February 11 12, 1994, Green Bank, WV: National Radio Astronomy Observatory (NRAO), p. 97, Bibcode 1994cers.conf.97J

Light-Travel Time plus Distance by the Hayden Planetarium Accessed October 2010.