Stars & The Universe

9.What is the name of the galaxy that contains the Sun?

10.What is a protostar?

11.What is the ultimate fate of a very massive star (more than 8 solar masses) after a supernova?

12.A galaxy is at a distance of 9.0 × 10⁷ light-years from Earth. The Hubble constant is 2.2 × 10^−18 per second. What is the recessional speed of this galaxy in m/s? (1 light-year = 9.5 × 10¹⁵ m)

13.The spectrum of light from a distant galaxy shows a dark line at a wavelength of 656 nm. The same line from a laboratory source on Earth is at 656 nm. What can be concluded about the galaxy?

14.The graph shows recession velocity vs distance for several galaxies. What does the gradient of the best-fit line represent?

15.The Sun is a stable star. Which two forces are in equilibrium during this stage?

16.A star with a mass 15 times that of the Sun is in its stable phase. What will be its final evolutionary stage?

17.The Hubble constant is 2.2 × 10^−18 per second. What is the approximate age of the Universe in seconds?

18.Which of the following is NOT evidence for the Big Bang theory?

19.A distant galaxy has a recessional velocity of 1.5 × 10⁶ m/s. Using H0 = 2.2 × 10^−18 per second, what is its distance from Earth in metres?

20.What is the main source of energy in a stable star like the Sun?

21.Cosmic microwave background radiation (CMBR) is detected in all directions. What is its current wavelength region?

22.A student investigates the relationship between the recessional velocity of galaxies and their distance from Earth. Which two measurements are needed to determine the Hubble constant?

23.A galaxy is observed to have a recessional velocity of 1.2 × 10⁶ m/s. Using H0 = 2.2 × 10^−18 s^−1, what is the distance to this galaxy in metres?

24.The diagram shows the spectrum of light from a distant galaxy compared to a laboratory spectrum. The dark lines are from hydrogen. What does the shift in the dark lines indicate?

25.The Hubble constant is estimated to be 2.2 × 10^−18 s^−1. What is the approximate age of the Universe in years? (1 year = 3.15 × 10⁷ s)

26.Which of the following is the correct order of stages in the life cycle of a star with a mass similar to the Sun after the stable star phase?

27.A supernova in a distant galaxy has the same peak brightness as a known standard candle. Its apparent brightness is measured to be 1/100 of the standard candle's brightness at a distance of 10 parsecs. What is the distance to the galaxy? (Assume brightness follows inverse square law)

28.What is the approximate diameter of the Milky Way galaxy?

29.The table shows the distance of three galaxies from Earth. | Galaxy | Distance from Earth (m) | |---|---| | A | 1.0 × 10²³ | | B | 5.0 × 10²² | | C | 2.0 × 10²³ | | D | 8.0 × 10²² | According to Hubble's law, which galaxy has the greatest recessional velocity?

30.What is the definition of a light-year?

31.The Sun is a star. Which two elements does it consist mostly of?

32.A galaxy is at a distance of 5.0 × 10²² m from Earth. The Hubble constant is 2.2 × 10^−18 per second. What is the recessional velocity of this galaxy?

33.A student measures the spectrum of light from a distant galaxy. A hydrogen absorption line that is normally at 656 nm on Earth is observed at 662 nm. What can be concluded about the galaxy?

34.The Sun consists mostly of hydrogen and helium.

35.A light-year is a unit of time.

36.What is the initial stage in the life cycle of all stars?

37.The greater the observed redshift of a galaxy, the closer it is to Earth.

38.Cosmic microwave background radiation (CMBR) is evidence for the Big Bang because it is the redshifted radiation from the early hot Universe.

39.The age of the Universe can be estimated as 1/H₀, where H₀ is the Hubble constant.

40.Arrange the following stages in the life cycle of a low-mass star (like the Sun) in the correct order, starting from the earliest stage.

41.Match each object with its correct description.

42.Which of the following are pieces of evidence for the Big Bang theory? (Select all that apply.)

43.The Hubble constant H₀ is 2.2 × 10⁻¹⁸ per second. A galaxy is at a distance of 1.5 × 10²³ m. Calculate the recessional velocity of the galaxy in m/s.

44.Complete the sentence about star formation.

45.Describe and explain what can be deduced about the history of the Universe from the cosmic microwave background radiation (CMBR).

46.The Hubble constant H₀ is 2.2 × 10⁻¹⁸ per second. A galaxy is at a distance of 1.5 × 10²³ m. Calculate the recessional velocity of the galaxy in m/s.