Lecture 11 Mercury

In size, Mercury is intermediate between:

the Moon and Mars.

Which is the correct size order, from smallest to largest?

Mercury, Mars, Venus

What is Mercury’s position in the order of planets from the Sun?

First

Which of the terrestrial planets has largest core (in an absolute sense)?

Earth

Which of the terrestrial planets has largest core relative to its size?

Mercury

From Earth, due to their motions and the fact that the Sun lights only a portion of each surface, both Mercury and Venus:

appear to go through phases

What is the reason that it is so difficult to view Mercury from the Earth?

Mercury is always very close to the Sun.

True or False: For Mercury, the tidal stress of the Sun is much greater at aphelion than at perihelion.

False

How does Mercury's rotation relate to the Sun?

Its rotation rate on its axis (its sidereal day) is 2/3 as long as its year, due to tidal resonances.

Mercury presents the same side to the Sun:

every other orbit.

True and False: The orbit of Mercury is more elliptical than that of any other terrestrial planet.

True

True and False: Two Mercury years are the same length as three Mercury sidereal days.

True

Which of the following best describes Mercury’s rotational and orbital resonance?

3:2

Mercury's orbit is unique because:

It has the highest eccentricity, and It has a 3:2 spin-orbit resonance

Mercury’s surface most closely resembles which of the following?

Moon

How do the atmospheres of the Moon and Mercury compare?

Neither body has a permanent true atmosphere.

Mercury experiences extreme high and low temperatures between night and day because:

it is so close to the Sun, and it has no true atmosphere to moderate temperatures over the globe.

Caloris is well named, for at every perihelion, it faces the Sun directly.

True

One of the effects of Mercury's very slow spin is:

extreme variations in its surface temperature

Characteristics of Mercury’s orbit:

Highly elliptical, and Shortest orbital period

Mercury's inter-crater plains are most similar to the Moon's:

maria.

Mercury's surface most resembles which of these?

the lunar far side

True or False: Mercury's inter-crater plains represent vast outpourings of lava even more extensive than those that produced the lunar maria.

True

The planet-encircling escarpment (cliff) on Mercury was probably caused by:

the interior cooling and shrinking.

The presence of a Mercurian magnetic field surprised the planetary scientists on the Mariner 10 team because:

the dynamo theory predicted that Mercury was spinning too slowly for one.

Which of the following are true about Mercury’s surface:

Has many impact craters, and Shows evidence of ancient lava flows

Evidence for past volcanism on Mercury includes:

Smooth plains, and Volcanic vents

Mercury’s surface has been shaped by:

Impact cratering, and Volcanism

Evidence that Mercury contains a surprising amount of volatile salts include:

hollows, sublimation pits and etched terrain, and the occasional presence of a comet-like tail

What is the likely source of Lunar and Mercurian ice?

impacts of meteoroids and comets

Where on Mercury is water ice primarily found?

Polar craters

What makes it possible for water ice to exist on Mercury despite its proximity to the Sun?

Polar regions remain in permanent shadow

How is water ice believed to have arrived on Mercury?

Delivered by comets and asteroids