how many miles in a light year wiki
Light-year The light-year is a unit of length used to express astronomical distances. It is about 9.5 trillion kilometres or 5.9 trillion miles.[note 1] As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days).[2] Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time.
Perihelion and aphelion Earth is about 147.1 million kilometers (91.4 million miles) from the Sun at perihelion around January 3, in contrast to about 152.1 million kilometers (94.5 million miles) at aphelion around July 4 â€” a difference of about 5.0 million kilometers (3.1 million miles). (These dates change over time due to precession and other orbital factors, which follow cyclical patterns known as Milankovitch cycles. For a table of these dates for various years, see Apsis.)