The term "light year" is actually a unit of distance, not time. It represents the distance that light travels in one year, which is approximately 9.46 trillion kilometers (5.88 trillion miles). The speed of light in a vacuum is about 299,792 kilometers per second (186,282 miles per second).
The Earth's orbital period around the Sun, which takes approximately 365.25 days (one year), is not directly related to the definition of a light year. The concept of a light year arises from the fact that light has a finite speed and takes time to travel across vast distances of space. It is a convenient unit for measuring astronomical distances, especially when discussing objects at great distances from Earth.
If the Earth's orbital period were different, for example, 265 days instead of 365.25 days, it would not affect the definition or mathematical calculation of a light year. The definition of a light year would remain the same, as it is based on the speed of light and not directly tied to the Earth's orbital period. The value of a light year would still represent the distance traveled by light in one year, regardless of the specific time it takes for the Earth to complete its orbit.
It's worth noting that the Earth's orbital period has been determined based on various astronomical observations and is not a fundamental factor in the definition of a light year.