Question 1: Red shift is the phenomenon where light from an object in space shifts towards the red end of the spectrum. It occurs when the source of light is moving away from the observer, causing an increase in wavelength. This effect provides evidence for the expansion of the universe.

Answer: Red shift is the increase in wavelength of light from objects moving away, indicating the universe's expansion.

Question 2: Explain why observing red shift in light from distant galaxies supports the idea that the universe is expanding.

Answer: Because red shift shows galaxies are moving away from us, and the farther they are, the faster they recede, indicating the universe is expanding.

Question 1: Describe the Doppler effect and how it relates to red shift in astronomy.

Answer: The Doppler effect is the change in wavelength or frequency of a wave due to relative motion; in astronomy, it causes light from objects moving away to shift towards the red end of the spectrum.

Question 2: What is the significance of the wavelength increase in light from distant galaxies?

Answer: It indicates that these galaxies are moving away from us, providing evidence for the universe's expansion.

Question 1: A galaxy's light has a wavelength of 700 nm when observed. If the emitted wavelength was 680 nm, calculate the red shift (z). Use the formula z = (λ_observed - λ_emitted) / λ_emitted. Express your answer to three decimal places.

Answer: z = 0.029

Question 2: If a galaxy is receding at 30,000 km/s, what is its red shift (z)? (Speed of light, c = 300,000 km/s). Use the approximation z ≈ v / c for small z.

Answer: z ≈ 0.100

Question 1: Describe a basic experiment that astronomers might perform to measure red shift in light from a galaxy. Include the variables involved and safety considerations in theory.

Answer: Astronomers use spectroscopes to measure the wavelength of light from a galaxy. The independent variable is the galaxy's velocity, and the dependent variable is the observed wavelength. They must ensure the spectroscope is properly calibrated and handle equipment carefully to avoid damage. The data allows calculation of red shift, which indicates the galaxy's speed relative to Earth.

Question 2: Explain how understanding red shift helps scientists estimate the age and size of the universe.

Answer: Red shift shows galaxies are moving away, allowing scientists to estimate the rate of expansion (Hubble's Law). By extrapolating backwards, they can estimate the universe's age and size.

Question 3: Identify one limitation of using red shift to determine the speed of distant galaxies.

Answer: Red shift can be affected by other factors like gravitational influences, which can complicate the interpretation of the galaxy’s speed.