Geodesy of the Terrestrial Planets

Flashcards about the planets and other objects in our solar system.

What is the definition of a planet according to the IAU?

A celestial body orbiting the Sun with sufficient mass for hydrostatic equilibrium shape and has cleared its orbit.

What is a Dwarf Planet?

A celestial body orbiting the Sun with sufficient mass for hydrostatic equilibrium shape but hasn't cleared its orbit.

What belt is Pluto a member of?

Member of the large Kuiper Belt

What is the shape of the orbits of planets and asteroids?

Near-circular.

What are the inclinations of planetary orbits?

Near-zero, with exceptions being long-period comets.

What is the mean solar distance of Mars?

Approximately 1.5 AU.

What is the mean solar distance of Jupiter?

Approximately 5.2 AU.

What is the mean solar distance of Pluto?

Approximately 39.5 AU.Pluto is located far from the Sun and has a highly elliptical orbit.

What is the Astronomical Unit (AU)?

Unit of length, roughly the distance between Earth and the Sun, approximately 150 Million km.

What is the ecliptic?

The plane of the Earth’s orbit about the Sun, reference plane for Solar System objects.

What is Obliquity (axial tilt)?

The angle between a planet’s rotational axis and the orbit normal vector.

What is the precession period of Earth?

25,800 years.The time it takes for Earth's rotational axis to complete a full cycle of precession, affecting its orientation relative to distant stars.

What is the precession period of Mars?

175,000 years.The time it takes for Mars' axis to complete one full cycle of precession.

Which planet has an orbital eccentricity of 0.2056?

Mercury

Which planet has an almost circular orbit (eccentricity of 0.0086)?

Neptune

Which planet has an obliquity of 177.36 degrees?

Venus

Which planet has an obliquity of 97.77 degrees?

Uranus

Which dwarf planet has an obliquity of 122.53 degrees?

Pluto

What is the purpose of the Titius Bode Law?

Predicting the spacing between planets.

Name the terrestrial planets.

Mercury, Venus, Earth, Mars.

What are the terrestrial planets composed of?

Composed mainly of rock and iron.

What is the Asteroid Belt?

Fragments of a destroyed planet or remaining building blocks of the Solar System.

Name the Galilean Satellites of Jupiter.

Io, Europa, Ganymede, Callisto.

What are the characteristics of Jupiter?

largest planet, gas giant, 67 known satellites

Name some of Saturn's satellites.

Janus, Epimetheus, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion, lapetus, Phoebe

Which Saturn Moon is known to have a dense atmosphere?

Titan

What is Enceladus known for?

Seasonal cryovolcanism.

Who discovered Uranus and when?

Wilhelm Herschel in 1781.

What are the characteristics of the planet Uranus?

Gas giant with rotation axis almost within the orbit plane.

Name the five largest satellites of Uranus

Ariel, Umbriel, Titania, Oberon, Miranda

What are the characteristics of Neptune?

Near twin of Uranus, existence predicted.

How many known moons does Neptune have?

14

Where is the Edgeworth-Kuiper Belt?

Extending beyond Neptune to approximately 50 AU.

What is the Oort Cloud?

Cloud of planetesimals at Solar distance 2,000 – 200,000 AU, source of long-period comets

Name the most massive known TNO.

Eris

What are the characteristics of the Milky Way?

~ 100,000 Lightyears ø, containing more than 100 billion stars.

What is the Solar System's closest neighbor?

Triple star system Alpha Centauri.

How old is the Heliocentric model?

Proposed by Aristarchus as early as 300 BC.

Who published The Almagest and catalog of stars?

Claudius Ptolemy

Who is associated with the Heliocentric model during the transition of the Medieval Age?

Nicolaus Copernicus

Who created physical models of heliocentric distances, speeds, and orbital periods of planets?

Johannes Kepler

Who is considered the Father of Observational Astronomy?

Galileo Galilei

What discoveries is Galileo Galilei known for?

Observed phases of Venus, Galilean Satellites, rings of Saturn, saw craters on the Moon.

Who discovered universal gravity?

Sir Isaac Newton

How was the Solar System was formed?

Collapse of a large molecular cloud of hydrogen, helium, and heavier elements.

What is the Frost line?

Temperatures sufficiently cold for volatile icy to remain solid.

What is the Soot line?

Temperatures for carbon compounds to remain solid.

When did the Solar System form?

4.568 billion years ago

What array took images of the disc around HL Tauri?

ALMA

Concerning conjunctions and oppositions, what orbit is farthest from the sun?

Outer-planet's orbit