Expanding Universe

What is the main tool used by cosmologists to explore and study the universe?

• Telescopes

• Microscopes

• Satellites

• Radar

What can the distinctive emission spectrum from distant objects reveal?

• The object's composition

• The object's size

• The object's age

• The object's location

What is the name of the effect that causes the pitch of sound to change when an object is approaching or receding?

• Doppler effect

• Newton's effect

• Einstein's effect

• Galileo's effect

What can the Doppler shift of light from an object tell us?

• What the velocity of the object is

• How far away the object is

• How old the object is

• How big the object is

What did Edwin Hubble discover about the universe?

• The universe is expanding

• The universe is contracting

• The universe is static

• The universe is shrinking

What gases did the early universe consist of according to the Big Bang theory?

• Hydrogen and helium

• Oxygen and nitrogen

• Carbon dioxide and methane

• Water vapor and ammonia

What is believed to be causing the acceleration of the expansion of the universe?

• Dark energy

• Dark matter

• Gravity

• Electromagnetic radiation

A galaxy is moving away from the Earth at a velocity of 1·20 × 10^7 m s -1. Light of wavelength 450 nm is emitted from this galaxy. When detected and measured on Earth this light has a wavelength of

• 425 nm

• 432 nm

• 468 nm

• 475 nm

• 630 nm

Galaxies at different distances from the Earth have been found to have different speeds. The graph shows data for some distant galaxies.

A student studies this graph and makes the following statements.

I The speed of distant galaxies varies inversely with their distance from the Earth.

II The gradient of the line gives the value of Hubble’s constant.

III The unit for Hubble’s constant is s-1. Which of these statements is/are correct?

• I

• II

• III

• II, III
• I, II

An astronomer observes the spectrum of light from a star. The spectrum contains the emission lines for hydrogen. The astronomer compares this spectrum with the spectrum from a hydrogen lamp. The line which has a wavelength of 656 nm from the lamp is found to be shifted to 663 nm in the spectrum from the star. The redshift of the light from this star is

• 0.011

• 0.50

• 0.99

• 2.0

• 94