Mercury is not measured in light years. Light years are used to measure vast distances between stars and galaxies, not within our solar system.

Here's why:

* Light year: The distance light travels in one year (approximately 5.88 trillion miles or 9.46 trillion kilometers).

* Mercury's distance from Earth: Mercury's distance from Earth varies depending on their positions in their orbits. It's closest at about 47 million miles (76 million kilometers) and furthest at about 135 million miles (219 million kilometers).

Therefore, it's more accurate to say that Mercury is between 47 million and 135 million miles away from Earth.