Question: Part A Pluto was first observed in 1930, and its largest moon, Charon, was discovered in 1978. A ...

Part A

Pluto was first observed in 1930, and its largest moon, Charon, was discovered in 1978. A few years after Charon’s discovery, astronomers were able to observe a series of eclipses as Pluto and Charon passed in front of one another. By studying how the brightness of Pluto and Charon changed as they eclipsed each other, astronomers were able to measure the masses and radii of both Pluto and its moon. What did these measurements imply about the average densities of Pluto and Charon?

Pluto and Charon have average densities that are expected for objects made mostly of water ice.

Pluto and Charon have average densities that are expected for objects made of rock.

Pluto and Charon have average densities that are expected for objects made mostly of gas.

Pluto and Charon have average densities that are expected for objects made mostly of liquid.

Part B

Since the early 1990s, observations of the solar system beyond Neptune, where Pluto resides, have revealed numerous objects orbiting the Sun. This collection of objects is known as the Kuiper belt. More Kuiper belt objects are being discovered each year, providing astronomers with a better understanding of their physical and orbital properties. From the list below, identify which properties are characteristic of Kuiper belt objects.

Select all that apply.

About 25% of Kuiper belt objects have the same orbital period as Pluto.

Kuiper belt objects are large, icy bodies.

No Kuiper belt objects have the same orbital period as Pluto.

Kuiper belt objects orbit the Sun at great distances.

Kuiper belt objects are bright.

Kuiper belt objects have a low relative brightness when observed from Earth.

Kuiper belt objects are small, icy bodies.