Question 1: Red Shift refers to the phenomenon where light from distant galaxies shifts towards the red end of the spectrum. This is primarily caused by the relative motion of galaxies moving away from us, resulting in an increase in the wavelength of emitted light.

Answer: Red Shift is the increase in wavelength of light from distant objects caused by their motion away from the observer, indicating the universe's expansion.

Question 1: Define Red Shift in the context of astronomy.

Answer: Red Shift is the phenomenon where the light from an object in space shifts towards longer wavelengths, indicating the object is moving away from the observer.

Question 2: Explain how the Doppler effect causes Red Shift in light from distant galaxies.

Answer: The Doppler effect causes the wavelength of light emitted by a moving object to stretch if the object is moving away, resulting in a shift towards red in the light spectrum. This increase in wavelength corresponds to a decrease in frequency, which is observed as Red Shift.

Question 1: A galaxy's light shows a red shift such that the observed wavelength is 520 nm, while the emitted wavelength is 500 nm. Calculate the red shift (z). Use the formula z = (λ_observed - λ_emitted) / λ_emitted.

Answer: z = 0.04

Question 2: Using the red shift calculated above (z = 0.04), and assuming the speed of light is 3.00 × 10^8 m/s, estimate the recessional velocity of the galaxy. Use v ≈ z × c for small z.

Answer: v ≈ 1.2 × 10^7 m/s

Question 1: Describe a basic observational method used by astronomers to detect Red Shift in distant galaxies.

Answer: Astronomers use spectroscopes to analyse the light from galaxies, looking for shifts in the spectral lines towards the red end of the spectrum.

Question 2: List two variables that could affect the accuracy of Red Shift measurements in an astronomical observation.

Answer: Interference from Earth's atmosphere and calibration errors in the spectroscope.

Question 3: Propose a safety or ethical consideration when conducting astronomical observations of distant galaxies.

Answer: Ensuring that observational equipment does not interfere with or damage the environment, and that data is handled responsibly to respect cultural and scientific integrity.

Question 1: A survey of 50 distant galaxies shows that their average red shift is 0.05. What does this suggest about the overall expansion of the universe?

Answer: It indicates that galaxies are generally moving away from us, supporting the idea that the universe is expanding.

Question 2: Discuss how understanding Red Shift is important for estimating the age of the universe.

Answer: Red Shift observations allow astronomers to determine the rate of expansion of the universe. By measuring how fast galaxies are receding, scientists can extrapolate backwards to estimate when the universe began, thereby estimating its age. This forms the basis of models such as the Big Bang theory.

Question 3: Identify a modern technological application that utilises principles of Red Shift in its operation.

Answer: Cosmic microwave background observatories and modern spectroscopic telescopes used for measuring galaxy velocities.