ASTRO 7N EXAM 1 INTRODUCTION TO
ASTRONOMY PRACTICE QUESTIONS AND
SOLUTIONS 2026 COMPLETE LEARNING
RESOURCE
◉ Kepler's Third Law
Answer: p^2=a^3, where P is the orbital period (a planets year,
given as a multiple of Earths years) and A is the semimajor axis
(average distance from Sun, given in AU)
◉ Mercury
Answer: Can only see close to sun (hard to see with naked eye)
Smaller than earth, similar to mars in mass and radius, only a little
bigger than Earth's moon: surface gravity less than earth
Temp is extremely high on side day and low on night side due to lack
of atmosphere to distribute heat evenly around
Many craters, some are permanently shadowed to hold ice deposits
Density is about 5 grams per cubic centimeter
◉ Mercury's rotation
Answer: 59 earth days; has a short year-88 Earth days to orbit the
sun
, ◉ Mercury's atmosphere
Answer: No significant atmosphere; sky appears black
◉ Venus
Answer: Closest planet to earth; visible in western ski in evenings
near sun, and in eastern sky just before sunrise; looks like a bright
star
Slightly smaller than earth mass (82%) radius (95%)
Very hot surface, bc of large amounts of greenhouse gasses in
atmosphere
◉ Venus's rotation
Answer: Longer rotational period 243 days its year is 225 earth days
Venus rotation is in the opposite direction to its orbit around the Sun
◉ Venus's atmosphere and surface
Answer: Dense atmosphere- mostly CO2- of gases produced by
volcanic outgassing, but not dissolved in ocean like on earth, sulfuric
acid clouds
Active volcanoes, huge lava flows and channels, some large craters,
but small meteors burn up in the thick atmosphere before they can
impact to leave small craters
ASTRONOMY PRACTICE QUESTIONS AND
SOLUTIONS 2026 COMPLETE LEARNING
RESOURCE
◉ Kepler's Third Law
Answer: p^2=a^3, where P is the orbital period (a planets year,
given as a multiple of Earths years) and A is the semimajor axis
(average distance from Sun, given in AU)
◉ Mercury
Answer: Can only see close to sun (hard to see with naked eye)
Smaller than earth, similar to mars in mass and radius, only a little
bigger than Earth's moon: surface gravity less than earth
Temp is extremely high on side day and low on night side due to lack
of atmosphere to distribute heat evenly around
Many craters, some are permanently shadowed to hold ice deposits
Density is about 5 grams per cubic centimeter
◉ Mercury's rotation
Answer: 59 earth days; has a short year-88 Earth days to orbit the
sun
, ◉ Mercury's atmosphere
Answer: No significant atmosphere; sky appears black
◉ Venus
Answer: Closest planet to earth; visible in western ski in evenings
near sun, and in eastern sky just before sunrise; looks like a bright
star
Slightly smaller than earth mass (82%) radius (95%)
Very hot surface, bc of large amounts of greenhouse gasses in
atmosphere
◉ Venus's rotation
Answer: Longer rotational period 243 days its year is 225 earth days
Venus rotation is in the opposite direction to its orbit around the Sun
◉ Venus's atmosphere and surface
Answer: Dense atmosphere- mostly CO2- of gases produced by
volcanic outgassing, but not dissolved in ocean like on earth, sulfuric
acid clouds
Active volcanoes, huge lava flows and channels, some large craters,
but small meteors burn up in the thick atmosphere before they can
impact to leave small craters
