(a) Name the galaxy that contains the Sun.
Correct Answer: Milky Way
Detailed solution: The Sun is one of billions of stars located within a specific spiral galaxy. According to the syllabus (Section 6.2.2), this galaxy is identified as the Milky Way.
Correct Answer: Big Bang (Theory)
Detailed solution: The observation that light from distant galaxies is shifted towards the red end of the spectrum indicates they are moving away from us. This expansion of the Universe provides key evidence supporting the Big Bang Theory.
Correct Answer: shortly after the Universe was formed
Detailed solution: Cosmic microwave background radiation is the remnant heat from the initial hot, dense state of the Universe. As stated in the syllabus, it was produced very shortly after the Universe came into existence.
Correct Answer: Universe has expanded (radiation) has been redshifted (to the microwave region of the electromagnetic spectrum)
Detailed solution: As space itself has stretched and expanded over billions of years, the wavelength of the original high-energy radiation has also been stretched. This cosmological redshift has shifted the radiation from the visible or higher frequency spectrum down into the much longer microwave region we detect today.
