1. Which of the following best describes gravitational redshift?
- A) Light shifts to shorter wavelengths when moving into a gravity well
- B) Light loses energy and shifts to longer wavelengths when escaping a gravity well
- C) Light bends around a massive object, magnifying the source
- D) Light intensity decreases with distance from a star
Answer: B) Light loses energy and shifts to longer wavelengths when escaping a gravity well
According to general relativity, photons lose energy as they escape a massive object’s gravitational field, stretching their wavelength toward the red end of the spectrum.
2. What is the TRAPPIST telescope best known for?
- A) Detecting gravitational waves from merging black holes
- B) Capturing the first direct images of an exoplanet atmosphere
- C) Measuring cosmic microwave background fluctuations
- D) Discovering the TRAPPIST-1 system of Earth-sized exoplanets orbiting an ultra-cool dwarf star
Answer: D) Discovering the TRAPPIST-1 system of Earth-sized exoplanets orbiting an ultra-cool dwarf star
The Belgian-operated TRAPPIST telescope made headlines in 2017 with the discovery of TRAPPIST-1, a system of seven Earth-sized planets, three of which are in the habitable zone — making it one of the most exciting exoplanet finds to date.
3. In exoplanet detection, what information does the transit duration provide?
- A) The density of the host star
- B) The size of the planet relative to its star
- C) The orbital speed and geometry of the planet
- D) The atmospheric temperature of the planet
Answer: C) The orbital speed and geometry of the planet
The length of a transit depends on the planet’s orbital velocity and the angle of its orbit. Combined with stellar properties, it helps determine orbital distance and inclination.
4. What is the primary reason globular clusters are composed of old stars?
- A) They are shielded from supernovae that trigger new star formation
- B) They formed early in galactic history and lack the gas needed to form new stars
- C) They orbit only in the galactic halo, preventing new stars from forming
- D) They consume new stars through gravitational collapse
Answer: B) They formed early in galactic history and lack the gas needed to form new stars
Globular clusters are ancient, dense collections of stars. Having used up or lost their gas billions of years ago, they can no longer create new stars, leaving only old, metal-poor populations.
5. What does Hubble’s Law state about distant galaxies?
- A) Their speed of rotation increases with distance from the galactic center
- B) Their recession velocity is proportional to their distance from Earth
- C) Their luminosity decreases with the square of their distance
- D) Their mass is directly proportional to their redshift
Answer: B) Their recession velocity is proportional to their distance from Earth
This law describes the expanding universe: galaxies farther away are receding faster, a discovery that revolutionized cosmology and supported the Big Bang theory.