Unit Conversions
There are this many centimeters in one meter.
What is 100?
This is the point directly overhead in the sky.
What is the zenith?
When it is summer in the Northern Hemisphere, it is this season in the Southern Hemisphere.
What is winter?
The Moon is waxing when it is doing this.
What is getting more illuminated?
Tides are mainly caused by the gravitational pull of this object.
What is the Moon?
Convert 5 minutes into seconds.
What is 300 seconds?
The imaginary line that divides the celestial sphere into northern and southern hemispheres.
What is the celestial equator?
Earth’s seasons are caused by this tilt of its axis.
What is 23.5 degrees?
During which phase is the Moon located between the Earth and the Sun?
What is new moon?
When the Sun, Moon, and Earth are aligned, we get these stronger tides.
What are spring tides?
Light takes about 8 minutes to travel from the Sun to Earth. How many seconds is that?
What is 480 seconds?
Right ascension is measured in these units.
What are hours, minutes, and seconds?
The longest day of the year in the Northern Hemisphere happens around this date.
What is June 21 (summer solstice)?
Sometimes you can faintly see the dark part of the Moon glowing because of sunlight reflected from Earth. What is this effect called?
What is Earthshine?
When the Sun and Moon are at right angles, we get these weaker tides.
What are neap tides?
Convert 2 hours into seconds.
What is 7,200 seconds?
What are the altitude and azimuth of the North Star as viewed from the Bay Area?
About 38° altitude, 0° azimuth (north).
Suppose an exoplanet has an axial tilt of 45°. Compared to Earth, would its seasonal changes be weaker, stronger, or the same? Why?
Stronger, because the tilt is more extreme.
A first quarter moon is highest in the sky at about this time of day.
What is 6:00 p.m.?
Suppose you’re in Northern California, and you see a waxing crescent moon at the zenith. What kind of tide is it likely to be?
A neap tide (Sun and Moon at right angles).
A car travels 60 kilometers in one hour. How many meters per second is that speed?
What is about 17 m/s?
What are the right ascension and declination of the Big Dipper at 9:00 p.m. on January 14, 2026?
Around 11h RA and +55° Dec (high in the northern sky, circumpolar).
Imagine a planet tilted 90° on its side, with its pole pointing at the Sun during part of its orbit. How would seasons on this planet be different from Earth’s?
Each hemisphere would get half a year of constant daylight followed by half a year of darkness, with extreme transitions at the equinoxes.
A waxing gibbous moon is highest in the sky at about this time of night.
What is 9:00 p.m.?
You’re standing on the California coast, looking at a waxing crescent Moon at an altitude of 15 degrees above the horizon. Are the tides now getting higher, lower, at high tide, or at low tide?
What is getting lower?