Which of the following indicates that the universe is expanding? aThe spectra of Cepheid variables, which are found in all galaxies, are red shifted. bThe spectra of Cepheid variables, which are found only in our galaxy, are red shifted. cThe spectra of Cepheid variables, which are found in all galaxies, are blue shifted. dThe spectra of Cepheid variables, which are found only in our galaxy, are blue shifted.

While examining the spectrum of a galaxy you find all the hydrogen lines are shifted to longer wavelengths. This galaxy isGroup of answer choicesmoving away from us.moving towards us.expanding explosively.not forming new stars.blue shifted.

The spectral lines from a galaxy are shifted towards the red end of the spectrum. Which statement is true?Group of answer choicesthe galaxy is not movingthe galaxy is moving towards usthe galaxy is moving away from usthe galaxy is cooling

Which of the following statements is incorrect?Red-shift is the observed decrease in the frequency of the light which we receive from distant galaxiesRed-shift is the observed increase in the wavelength of the light which we receive from distant galaxiesRed-shift leads to a decrease in the amount of red light and an increase in the amount of light of other wavelengths which we receive from distant galaxiesRed-shift occurs when a light source is moving away from the observer2When we look at the spectrum of the Sun or any star, we find that light of certain wavelengths (colours) appears to be missing.  These missing wavelengths appear as a series of black lines on a spectrum.  What causes this light to be ‘missing’ from a spectrum?Light of these wavelengths is absorbed by the atmosphere of the starLight of these wavelengths is not produced by the starLight of these wavelengths is incapable of travelling the huge distance from the star to the EarthLight of these wavelengths is absorbed by the atmosphere of the Earth3Which of the following statements is NOT supported by the observation of red-shift in the light we receive from other galaxies?The Universe is expandingThe Universe (may have) started with the Big BangOur galaxy is at the centre of the Universe(Most) galaxies which are further from us are moving away from us more quickly4According to theory, how long has passed since the Big Bang occurred (in other words, how old is the Universe)?15.2 billion years4.5 billion years10.3 billion years13.8 billion years5Which of the following is NOT stated by the Steady State theory?The density of the Universe remains constantNew galaxies are not created within the UniverseThe Universe didn’t start with a big bangThe Universe has no beginning, middle or end6Which of the following statements about Cosmic Microwave Background (CMB) radiation is incorrect?It tells us that the Universe is cooling as it expandsIt is a form of electromagnetic radiationAs the Universe expands, the wavelength of this radiation decreasesIt can be thought of as leftover radiation from the Big Bang

The expansion of the universe can be explained as:

How did Hubble know that the galaxies he observed were moving away from us? aThe spectra of the stars were red-shifted which indicates they were moving away rapidly. bThe spectra of the stars were blue-shifted which indicates they were moving away rapidly. cThe spectra of the stars were violet-shifted which indicates they were moving away rapidly. dThe spectra of the stars were green-shifted which indicates they were moving away rapidly.