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Fast Facts

About the same age as the Sun: 4.5 billion years


Solar system

Avg. distance from the Sun

4,504,000,000 km (2,799,000,000 miles)


49,530 km (30,770 miles)


1.0247 x 1026 kg

Orbital period around the Sun

164.8 Earth years (60,150 Earth days)

Number of moons

Neptune has more than 10 moons. Its largest moon, Triton, is almost as large as Earth's moon

Distinguishing features

Neptune is smaller in diameter than Uranus, but larger in mass. It is the first planet found from calculations based on the observed positions of the other planets.

Stormy weather on Neptune

Enlarge Image


"Fast Facts: Neptune" is a table that lists Neptune's age, location, average distance from the Sun, diameter, mass, orbital period around the Sun, number of moons, and distinguishing features. A picture of the planet is included.

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Adaptable, at teacher's discretion
How to use in the classroom

Use this resource as:

A source of information. Read the table to find out about this object.

A reading activity. Give each student a planet-themed Fast Facts table. Ask students to locate specific object characteristics, such as the number of moons or the diameters of their respective planets.

A large-number recognition and ordering activity. Have students review several planet Fast Fact tables, including this one. Have students read the tables to find each planet's distance from the Sun. Then ask them to arrange the planets according to their distance from the Sun, from closest to farthest. Students also can arrange the planets according to their mass and/or diameter, from smallest to largest.

A unit conversion activity. Have students change the distances in either kilometers or miles into astronomical units. One astronomical unit (AU) is the average distance from Earth to the Sun, which equals 149,600,000 km, or 92,960,000 miles.

A compare/contrast activity. Have students review several Fast Facts tables for planets. Students match the planets to statements that describe a unique feature of each planet, such as: This planet is closest to the sun, or this is the largest known dwarf planet. Either the teacher or the students can generate the statements using information from the Fast Facts. Students also can create graphic organizers comparing the features of planets and dwarf planets.

An inquiry tool. Have students write down questions they would like answered about the image and the information in the Fast Facts table.

An engagement tool. Involve students in a discussion.

A math activity. Students can determine the relationship between a planet's distance from the Sun and its period of revolution around the Sun (Kepler's Third Law). (Recommended for grades 10-12).

Use graphing calculators to plot one variable against the other. For example, plot distance from the Sun along the x axis and period of revolution along the y axis (or vice versa). Note that since the relationship is not a straight line, the distance is not proportional to the period. Ask students what they might do to the variables to produce a straight line (or direct proportion).

Have students calculate the square and cube of the distance and the period. Then have students make three new graphs by plotting the square of the distance vs. the period, the period squared, and the period cubed. Follow this by three more graphs: the cube of the distance vs. the period, the period squared, and the period cubed. Ask students to identify which graph resulted in a straight line and what combination is a direct proportion. Answer: The relationship is that the period squared is proportional to the average distance cubed. Hint: To make the calculations a little easier, express the distances in terms of astronomical units (1 AU = 149,600,000 km = 92,960,000 miles), and use years for the periods.


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