Space Oddity Trivia Quiz

Answer: Eccentricity

Famously calculated by Johannes Kepler in the early 1600s, orbital eccentricity occurs in a range with 0 being a circular orbit, values between 0 and 1 being elliptical and values greater than 1 being hyperbolic. The moon Triton has an eccentricity of 0.00002 making it a near circular orbit around Neptune whereas the comet Hale-Bopp is near parabolic in its path around the Sun with an eccentricity of 0.9951.

In regard to the planets, Venus has the lowest eccentricity (0.0068), Earth is third lowest (0.0167), and Mercury is the most eccentric (0.2056).

Answer: Venus

Other than the Sun and Moon, Venus is the brightest object in the sky with a maximum apparent magnitude of -4.9. Additionally, Venus is one of only two planets (Neptune is the other) that has a retrograde rotation in that it rotates in the opposite direction to the Sun.

Answer: Phobos

The two moons of Mars, Phobos and Deimos, were discovered within one week of each other in 1877. Although it has a radius of just 11 km (7 mi), Phobos is seven times larger than Deimos. Phobos is so close to Mars that it orbits in just 7 hours 39 minutes and it rises and sets twice in one Martian day.

Answer: Hilda group

The 2:3 orbital resonance that the Hilda family of asteroids exhibits means that, while Jupiter takes 11.9 years to orbit the Sun, the Hilda family takes 7.9 years. The main asteroid of the Hilda group is 153 Hilda which was discovered in 1875 and named after the daughter of Austrian astronomer Theodor von Oppolzer.

Answer: Mimas

Discovered in 1789 by William Herschel, Mimas is named after a Giant from Greek mythology that was the offspring of Gaia. Incredibly the impact crater Herschel has a diameter approximately 1/3 of Mimas. The composition of Mimas is primarily water ice and rock.

Answer: Water

While other planets and some moons may have both ice water and even liquid water, Earth has a considerably higher percentage than any of the other Solar System bodies. This prevalence of water and Earth's comparatively mild climate allows life to thrive.

Answer: The mass of Jupiter is 318 times the mass of Earth.

Jupiter is by far the most massive planet in the Solar System containing more than 71% of the total planetary mass. Saturn is the second-most massive planet with over 21% of the total planetary mass. Earth is the most massive of the four inner planets which are tiny in comparison to the gas giants as they comprise less than 0.5% of the total planetary mass.

Answer: Rhea

Rhea is the second-largest moon of Saturn and is believed to contain a disk with three narrow bands of rings. In 2010, two years after the announcement of Rhea containing rings, the Cassini orbiter examined the expected ring area of Rhea but was unable to confirm the presence of rings. Even so, surface impacts on Rhea from de-orbiting ring debris have been located near the moon's equator.

Answer: Axial tilt

An object's axial tilt is also known as its obliquity. Interestingly, the planet Mercury has an axial tilt of nearly zero meaning that its rotational axis is perpendicular to its orbital plane.

Answer: Coma

Comets are typically classified as short period (less than 200 year orbit around the Sun) or long period (greater than 200 year orbit around the Sun). When both long and short period comets are within approximately three to four astronomical units from the Sun they may develop a coma that can grow as large as the diameter of Jupiter.