The study by the University of Washington and the University of Liege measured the densities of the seven Earth-sized planets in the Trappist-1 system. These planets, located 40 light-years away in the constellation Aquarius, are similar in size to Earth but orbit closer to their ultra-cool red dwarf star. The study found that the planets are about 8% less dense than Earth, suggesting different compositions. Three hypotheses were proposed: the planets may have a rust-covered surface, a smaller iron-rich core, or a deep ocean layer. The outer four planets might have water accounting for 5% of their mass, while the inner three could have water-heavy clouds if they possess a dense atmosphere like Venus.

What is the significance of the habitable zone in the Trappist-1 system?

• It is the region where rocky planets are most likely to have liquid water.

• It is the area where planets are closest to the star.

• It is the area with the most planets in the system.

• It is the zone where planets have the highest density.

How do the Trappist-1 planets compare to Earth in terms of density?

• They are denser than Earth.

• They have the same density as Earth.

• They are about 8% more dense than Earth.

• They are about 8% less dense than Earth.

Which of the following is a proposed hypothesis for the lower density of Trappist-1 planets?

• They are composed entirely of gas.

• They have no iron content.

• They have a larger iron-rich core than Earth.

• They have a rocky surface with a smaller iron-rich core.

What is a possible characteristic of the outer four planets in the Trappist-1 system?

• They have a deep ocean layer on their surface.

• They have a dense atmosphere like Venus.

• They are closer to the star than the inner planets.

• They have no water content.

What atmospheric condition might the inner three planets of Trappist-1 have?

• No atmosphere at all.

• An atmosphere with high oxygen levels.

• A thin atmosphere with no clouds.

• A dense atmosphere similar to Venus.