Astronomy Astrobiology and the Search for Life 1 — Questions and Answers
Question 1: What term describes the region around a star where liquid water could exist on a planet's surface?
- Frost line
- Habitable zone (Correct answer)
- Roche limit
- Magnetosphere
Correct answer: Habitable zone
The habitable zone, sometimes called the Goldilocks zone, is the orbital range where surface temperatures allow liquid water to exist.
Question 2: Which molecule, when detected alongside oxygen in a planetary atmosphere, is considered a strong biosignature?
- Carbon dioxide
- Nitrogen
- Methane (Correct answer)
- Argon
Correct answer: Methane
Methane and oxygen coexisting in an atmosphere is a strong biosignature because they react and destroy each other, so a continuous biological source is needed to maintain both.
Question 3: NASA's TESS mission, launched in 2018, is designed primarily to:
- Map the cosmic microwave background
- Search for exoplanets transiting nearby stars (Correct answer)
- Study dark matter distribution
- Measure solar wind intensity
Correct answer: Search for exoplanets transiting nearby stars
TESS (Transiting Exoplanet Survey Satellite) monitors nearby bright stars for periodic dimming caused by planets crossing in front of them.
Question 4: Organisms that thrive in extreme environments such as high heat, high acidity, or intense radiation are called:
- Anaerobes
- Autotrophs
- Extremophiles (Correct answer)
- Lithotrophs
Correct answer: Extremophiles
Extremophiles are organisms adapted to conditions that would be hostile to most life, demonstrating the wide range of environments where life can survive.
Question 5: Which of Jupiter's moons is considered a top candidate for harboring life due to its confirmed subsurface liquid water ocean?
- Io
- Ganymede
- Callisto
- Europa (Correct answer)
Correct answer: Europa
Europa has a global subsurface ocean of liquid water beneath its icy crust, kept liquid by tidal heating from Jupiter's gravity, making it a prime astrobiology target.
Question 6: The Drake Equation was developed to estimate:
- The age of the universe
- The number of communicating extraterrestrial civilizations in the Milky Way (Correct answer)
- The speed necessary for interstellar travel
- The probability that life originated by panspermia
Correct answer: The number of communicating extraterrestrial civilizations in the Milky Way
Frank Drake formulated the equation in 1961 to quantify the factors governing how many technologically advanced civilizations might be detectable in our galaxy.
Question 7: The RNA World hypothesis proposes that RNA preceded DNA as the primary genetic molecule because:
- RNA is chemically more stable than DNA
- RNA can both store genetic information and catalyze chemical reactions (Correct answer)
- RNA does not require water to function
- RNA is found exclusively in ancient microfossils
Correct answer: RNA can both store genetic information and catalyze chemical reactions
RNA is unique in that it can store information like DNA and act as a catalyst (ribozyme) like proteins, suggesting it could have jumpstarted life before the DNA-protein system evolved.
Astronomy Astrobiology and the Search for Life 1
What term describes the region around a star where liquid water could exist on a planet's surface?