Which statement best describes what astronomers have learned about planets in the universe?

Which statement best describes what astronomers have learned about planets in the universe?

• A. The universe contains many planets beyond stars.
• B. Planets are rare.
• C. There is no life anywhere.
• D. Earth is at the center.

Answer: (A)

Planets around other stars are common. Observations from missions like Kepler, along with follow-up radial-velocity measurements, have detected thousands of exoplanets orbiting a wide variety of stars. Given the vast number of stars in our galaxy, this abundance shows that planets form frequently and are not rare, so the statement that the universe contains many planets beyond the Sun best matches what we’ve learned. The other ideas don’t fit as well. We haven’t found planets to be rare based on the current data; instead, planets appear to be a common outcome of star formation. The claim that there is no life anywhere extends beyond what we can know or prove right now, since we haven’t yet discovered life elsewhere. The notion that Earth sits at the center contradicts centuries of astronomical evidence and modern understanding that the Sun is the center of our solar system and that planetary systems are common around other stars.

Planets around other stars are common. Observations from missions like Kepler, along with follow-up radial-velocity measurements, have detected thousands of exoplanets orbiting a wide variety of stars. Given the vast number of stars in our galaxy, this abundance shows that planets form frequently and are not rare, so the statement that the universe contains many planets beyond the Sun best matches what we’ve learned.

The other ideas don’t fit as well. We haven’t found planets to be rare based on the current data; instead, planets appear to be a common outcome of star formation. The claim that there is no life anywhere extends beyond what we can know or prove right now, since we haven’t yet discovered life elsewhere. The notion that Earth sits at the center contradicts centuries of astronomical evidence and modern understanding that the Sun is the center of our solar system and that planetary systems are common around other stars.