The phrase “quanti sono 18 anni luce” asks for the distance corresponding to 18 light-years in a more familiar unit. An “anno luce” is the distance light travels in one year, about 9.4605 × 10^12 kilometers (or about 5.8786 × 10^12 miles). Therefore:

• 18 light-years ≈ 18 × 9.4605 × 10^12 km ≈ 1.7029 × 10^14 km.
• In meters, that's ≈ 1.7029 × 10^17 m.

If you prefer miles, 1 light-year is about 5.8786 × 10^12 miles, so 18 light- years ≈ 1.0581 × 10^14 miles. Would you like the conversions in a specific unit (km, m, miles, or astronomical units) or a precise figure with more significant digits?