The Hγ line has a wavelength of 434.0 nm when observed in the laboratory. If the Hγ line appears in a stars spectrum at 434.5 nm, what is the radial velocity of the star?

300-nm light has a lower frequency than 500-nm light.

Light rays from a distant source __________________, assuming the light does not pass through any cloud-like nebulae.

During one day and night in the mid-northern hemisphere, the stars near the north celestial pole

In the designation α Canis Majoris, which part refers to the star and which part refers to the constellation?

At any point in its orbit, exactly one half of the Moon is illuminated by the Sun.

The geometry of an ellipse is described by two numbers: the ____ which is half the longest diameter of the ellipse and the ____ which tells us the shape of the ellipse.

If the period of a body’s orbit is doubled, then the distance from the host has ___________. Assume the units of period are years and the units of distance are A.U. Choose the best answer.

An absorption spectrum is also called a bright-line spectrum.

The total amount of illumination changes during the lunar cycle of phases.