Complex sentence: With an estimated diameter of, P4 is the smallest known moon of Pluto and current observations suggest a circular, equatorial orbit with a radius of approximately 59,000 km (about 37,000 miles).
Split into simpler sentences: With an estimated diameter of, P4 is the smallest known moon of Pluto. Current observations suggest a circular, equatorial orbit with a radius of approximately 59,000 km (about 37,000 miles).