Grazing incidence optics are critical to focusing __________ .

It is diffraction that limits the ________ of a telescope of a given objective diameter.

When Earth overtakes Mars, the outer planet retrogrades near __________ .

A fatal flaw with Ptolemy’s model is its inability to predict the observed phases of:

According to Newton’s third law, when the Voyager probes passed Jupiter in 1979, they exerted exactly the same force on Jupiter as the giant planet did on them.

The __________ blows out of the coronal holes.

At its current rate of consuming hydrogen, the Sun can stably shine for__________ .

A total solar eclipse will only occur when the new moon is both on the ecliptic and at its greatest distance from Earth.

The proton storms in the solar wind travel at almost the speed of light.

The Sun’s mass is over a million times that of the Earth.