<P> Although modern astronomers often prefer to use the parsec, light years are also popularly used to gauge the expanses of interstellar and intergalactic space . </P> <P> Distances expressed in light - years include those between stars in the same general area, such as those belonging to the same spiral arm or globular cluster . Galaxies themselves span from a few thousand to a few hundred thousand light - years in diameter, and are separated from neighbouring galaxies and galaxy clusters by millions of light - years . Distances to objects such as quasars and the Sloan Great Wall run up into the billions of light - years . </P> <Table> List of orders of magnitude for length <Tr> <Th> Scale (ly) </Th> <Th> Value </Th> <Th> Item </Th> </Tr> <Tr> <Td> 10 </Td> <Td> 7008382213511092264 ♠ 40.4 × 10 ly </Td> <Td> Reflected sunlight from the Moon's surface takes 1.2--1.3 seconds to travel the distance to the Earth's surface (travelling roughly 7005350000000000000 ♠ 350 000 to 7005400000000000000 ♠ 400 000 kilometres). </Td> </Tr> <Tr> <Td> 10 </Td> <Td> 7011149479541466776 ♠ 15.8 × 10 ly </Td> <Td> One astronomical unit (the distance from the Sun to the Earth). It takes approximately 499 seconds (8.32 minutes) for light to travel this distance . </Td> </Tr> <Tr> <Td> 7012120151277001776 ♠ 127 × 10 ly </Td> <Td> The Huygens probe lands on Titan off Saturn and transmits images from its surface, 1.2 billion kilometres from Earth . </Td> </Tr> <Tr> <Td> 7012476820815818072 ♠ 504 × 10 ly </Td> <Td> New Horizons encounters Pluto at a distance 4.7 billion kilometres, and the communication takes 4 hours 25 minutes to reach Earth . </Td> </Tr> <Tr> <Td> 10 </Td> <Td> 7013192998901640648 ♠ 2.04 × 10 ly </Td> <Td> The most distant space probe, Voyager 1, was about 18 light - hours away from the Earth as of October 2014 . It will take about 7004175000000000000 ♠ 17 500 years to reach one light - year (7015946073047258080 ♠ 1.0 × 10 ly) at its current speed of about 17 km / s (7004169875200000000 ♠ 38 000 mph) relative to the Sun . On September 12, 2013, NASA scientists announced that Voyager 1 had entered the interstellar medium of space on August 25, 2012, becoming the first manmade object to leave the Solar System . </Td> </Tr> <Tr> <Td> 10 </Td> <Td> 7016151371687561292 ♠ 1.6 × 10 ly </Td> <Td> The Oort cloud is approximately two light - years in diameter . Its inner boundary is speculated to be at 7015747989353500000 ♠ 50 000 au, with its outer edge at 7016149597870700000 ♠ 100 000 au . </Td> </Tr> <Tr> <Td> 7016189214609451616 ♠ 2.0 × 10 ly </Td> <Td> Maximum extent of the Sun's gravitational dominance (Hill sphere / Roche sphere, 7016186997338375000 ♠ 125 000 au). Beyond this is the deep ex-solar gravitational interstellar medium . </Td> </Tr> <Tr> <Td> 7016399242825942909 ♠ 4.22 × 10 ly </Td> <Td> The nearest known star (other than the Sun), Proxima Centauri, is about 4.22 light - years away . </Td> </Tr> <Tr> <Td> 7016813622820641948 ♠ 8.60 × 10 ly </Td> <Td> Sirius, the brightest star of the night sky . Twice as massive and 25 times more luminous than the Sun, it outshines more luminous stars due to its relative proximity . </Td> </Tr> <Tr> <Td> 7017112582692623711 ♠ 11.90 × 10 ly </Td> <Td> HD 10700 e, an extrasolar candidate for a habitable planet . 6.6 times as massive as the earth, it is in the middle of the habitable zone of star Tau Ceti . </Td> </Tr> <Tr> <Td> 7017193944974687906 ♠ 20.5 × 10 ly </Td> <Td> Gliese 581, a red - dwarf star with several detectable exoplanets . </Td> </Tr> <Tr> <Td> 7018293282644650004 ♠ 310 × 10 ly </Td> <Td> Canopus, second in brightness in the terrestrial sky only to Sirius, a type A9 bright giant 7004107000000000000 ♠ 10 700 times more luminous than the Sun . </Td> </Tr> <Tr> <Td> 10 </Td> <Td> 7019283821914177424 ♠ 3 × 10 ly </Td> <Td> A0620 - 00, the nearest known black hole, is about 7003300000000000000 ♠ 3000 light - years away . </Td> </Tr> <Tr> <Td> 7020245978992287100 ♠ 26 × 10 ly </Td> <Td> The centre of the Milky Way is about 7004260000000000000 ♠ 26 000 light - years away . </Td> </Tr> <Tr> <Td> 7020946073047258079 ♠ 100 × 10 ly </Td> <Td> The Milky Way is about 7005100000000000000 ♠ 100 000 light - years across . </Td> </Tr> <Tr> <Td> 7021156102052797583 ♠ 165 × 10 ly </Td> <Td> 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 . </Td> </Tr> <Tr> <Td> 10 </Td> <Td> 7022236518261814520 ♠ 2.5 × 10 ly </Td> <Td> The Andromeda Galaxy is approximately 2.5 million light - years away . </Td> </Tr> <Tr> <Td> 7022283821914177424 ♠ 3 × 10 ly </Td> <Td> The Triangulum Galaxy (M33), at about 3 million light - years away, is the most distant object visible to the naked eye . </Td> </Tr> <Tr> <Td> 7023558183097882267 ♠ 59 × 10 ly </Td> <Td> The nearest large galaxy cluster, the Virgo Cluster, is about 59 million light - years away . </Td> </Tr> <Tr> <Td> 7008150000000000000 ♠ 150 × 10--7024236518261814520 ♠ 250 × 10 ly </Td> <Td> The Great Attractor lies at a distance of somewhere between 150 and 250 million light - years (the latter being the most recent estimate). </Td> </Tr> <Tr> <Td> 10 </Td> <Td> 7025113528765670969 ♠ 1.2 × 10 ly </Td> <Td> The Sloan Great Wall (not to be confused with Great Wall and Her--CrB GW) has been measured to be approximately one billion light - years distant . </Td> </Tr> <Tr> <Td> 7025227057531341939 ♠ 2.4 × 10 ly </Td> <Td> 3C 273, optically the brightest quasar, of apparent magnitude 12.9, just dimmer than R136a1 . 3C 273 is about 2.4 billion light - years away . </Td> </Tr> <Tr> <Td> 7026432355382596942 ♠ 45.7 × 10 ly </Td> <Td> The comoving distance from the Earth to the edge of the visible universe is about 45.7 billion light - years in any direction; this is the comoving radius of the observable universe . This is larger than the age of the universe dictated by the cosmic background radiation; see here for why this is possible . </Td> </Tr> </Table> <Tr> <Th> Scale (ly) </Th> <Th> Value </Th> <Th> Item </Th> </Tr>

How many lightyears is the sun from earth