Astronomy 109 Final Exam Study Guide - Rutgers University

What is the orbital property of Mercury?

Never far from the sun

What is the eccentricity of Mercury's orbit?

Eccentric orbit

What is the precession of the perihelion of Mercury?

First support for Einstein's general relativity theory

When is Mercury best seen?

At max elongation when it is furthest from the sun

What is the density of Mercury?

Most metal-rich planet with a density of 5400 kg/m^3

What is the rotation rate of Mercury?

3:2 spin orbit resonance (rotates 3 times every 2 times it goes around the sun)

Is Mercury tidally locked to the sun?

No, it was found in 1965 that Mercury is not tidally locked to the sun

What causes the chaotic terrain on Mercury?

Volatile materials stored underground, not seismic waves from Claoris impact

What elements are distributed on Mercury's surface?

Sulfur (S), Chlorine (Cl), and Potassium (K)

What is the recent counter theory about Mercury's crust?

Crust may cover the whole planet, craters are smooth like the moon

What do the scarps on Mercury's surface indicate?

Crust shrinkage, several hundred km long, more recent because they cut through craters

What causes the stretch marks in the Claoris basin?

Cooling from pressure on both sides

What is the interior of Mercury like?

Solid interior is larger than Earth, with a large liquid metallic Fe/Ni core

What is the magnetic field of Mercury?

Small magnetic field (1/100 of Earth) due to molten outer core

Why does Mercury rotate so slow?

The reason for its slow rotation is unknown

What is the rotation period of Venus?

243 days

What is unique about Venus' rotation?

It has retrograde rotation

What are some physical properties of Venus?

Rains sulfuric acid, hot enough to melt lead, pressure at 90 atm

How does Venus compare to Earth in terms of density, mass, radius, and gravity?

Nearly a twin of Earth in terms of density, mass, radius, and gravity

What is the morning/evening star and why is it tied to the sun?

Venus is known as the morning/evening star because it is visible in the sky shortly before sunrise or after sunset. It is tied to the sun because it is an inferior planet, meaning it orbits closer to the sun than Earth.

How does the brightness of Venus change?

The brightness of Venus changes depending on its proximity to Earth. When it is closer, it appears brighter in the sky.

What is the order of brightness in the sky after the sun and moon?

Venus is the brightest object in the sky after the sun and moon.

What can be seen during the new phase of Venus?

During the new phase of Venus, a halo can sometimes be seen around the planet.

What is the rotation of Venus like?

Venus has a slow, retrograde rotation, meaning it rotates in the opposite direction of its orbit around the sun.

What is the atmosphere of Venus like?

Venus has a dense atmosphere and thick clouds. Its surface is hot due to the greenhouse effect.

What are some features of the surface of Venus?

The surface of Venus is relatively smooth with geologic features such as continents (Ishtar Terra and Aphrodite Terra), few craters, many volcanoes, and large lava flows.

What are some types of volcanoes on Venus?

Volcanoes on Venus include shield volcanoes, pancake volcanoes, and pancake-shaped lava domes called coronae.

What are some specific volcanoes on Venus?

Some specific volcanoes on Venus are Sapas Mons, Sif Mons, and Gula Mons.

What are impact craters on Venus like?

Venus has fewer impact craters compared to the moon, Mercury, or Mars. The surface is relatively young and has been resurfaced by volcanism in the last 700 million years.

Why do impact craters on Venus occur in groups?

Impact craters on Venus occur in groups because the thick atmosphere causes the incoming meteoroids to break up and explode before reaching the surface.

What is the atmosphere of Venus mostly composed of?

The atmosphere of Venus is mostly composed of carbon dioxide (CO2).

What is the greenhouse effect on Venus?

Venus experiences a giant greenhouse effect, where the surface is heated by the reabsorption of infrared radiation. This causes the planet to become extremely hot.

What is the wind circulation like on Venus?

Venus has high altitude cells that extend from the hot subsolar point to the cooler night side. The lower altitude Hadley cells are weak and polarly unstable.

What are some characteristics of the surface of Venus?

The surface of Venus is fragmented like pack ice, shows collisional folding and crustal blocks, and has little erosion or dust on rocks.

What is the evolution of Venus like?

Venus lacks a magnetic field, rotates slowly, and does not have large-scale plate tectonics like Earth. Instead, it has smaller platelets similar to pack ice.

What is the Doppler effect?

The Doppler effect refers to the change in frequency or wavelength of a wave as observed by an observer moving relative to the source of the wave. It is used to explain the redshift of light from objects moving away from us and the blueshift of light from objects moving towards us.

What are the physical properties of Mars?

Smaller than Earth, low density, smaller radius and mass than Earth, no magnetic field, high winds on surface, smaller escape velocity

How does Mars compare to Earth in terms of size and mass?

Mars is smaller in size and has 1/10th the mass of Earth.

What is the atmosphere like on Mars?

Mars has a thin atmosphere and experiences loss of atmosphere due to its smaller escape velocity.

What are the rotational and orbital properties of Mars?

Mars is tilted, rotates, and experiences seasons like Earth. It has a similar length of day.

What are some notable surface features on Mars?

Tharsis bulge, Valles Marineris, Hellas impact basin, Olympus Mons, Martian dichotomy, Borealis basin

What evidence is there of ancient water on Mars?

River delta, Martian outflow channels, possible mud flow craters, presence of ice under the surface

What is the atmosphere like on Mars?

Dust devils, red color due to iron content, fog in low-lying areas, negative feedback loop greenhouse effect

What is the internal structure of Mars?

Solid iron core, liquid iron core, solid mantle, silicate crust, possible presence of liquid

What are the moons of Mars?

Phobos and Deimos, with circular orbits and non-spherical shapes

What is the formation of Mars' moons?

Phobos and Deimos were thought to be captured asteroids, with Phobos potentially falling back on Mars if captured by the asteroid belt

What is a debris disk?

A disk of debris formed from a collision.

How were the moons of Mars possibly formed?

From a debris disk created by a collision with Mars.

What evidence suggests the presence of a liquid silicate layer on Mars?

Vibrations detected by a seismometer.

What is Jupiter?

Largest planet in the solar system

What is the appearance of Jupiter?

Lines of clouds, great red spot, auroras

What is the great red spot?

A storm the size of Earth that has been going on for hundreds of years

What is the composition of Jupiter's atmosphere?

Mostly hydrogen and helium, with traces of methane, ammonia, and water vapor

What causes the bright zones and dark belts on Jupiter?

Vertical convection zones that are cooler and higher than the belts

What is the zonal flow on Jupiter?

Stable flow underlying the zones and bands

What are the colors of the clouds on Jupiter?

White ammonia clouds at the equator, yellow/red/brown ammonium and hydrosulfide ice, blue water ice

What is the internal structure of Jupiter?

Core, liquid metal hydrogen, molecular hydrogen on the outside

What is the magnetosphere of Jupiter?

Belts of charged particles, plasma torus, strong magnetic field

How does Jupiter compare to a star?

Too cool and small to be a star, but radiates more energy than it receives from the sun

What are the moons of Jupiter?

Io, Europa, Ganymede, Callisto

Which moon is located near the great red spot?

Io

Which moon is the most dense?

Io

How does the density of Jupiter's moons change with distance?

Density decreases as distance from Jupiter increases

What is orbital resonance?

Periodic pushing and pulling between celestial bodies.

What caused the impact of the 1994 Shoemaker-Levy 9 comet?

It struck Jupiter.

What is the interior of Io composed of?

Iron sulfur core, liquid, rocky mantle, volcanoes, possibly magma ocean.

What is the interior of Europa composed of?

Heavy materials sunk to the center, rocky mantle, water ocean under ice crust.

What is the interior of Ganymede composed of?

Iron nickel core, rocky mantle, water ocean larger than Europa, icy crust.

What is the composition of Callisto?

Icy rocky mixture.

What is unique about Io?

Densest moon, most geologically active, volcanism, close to Jupiter, tidal forces, global magma ocean, tidal heating.

What features are found on Europa?

Linear cracks, lightly cratered, Connemara chaos, pulled apart terrain suggesting water upwelling and freezing.

What features are found on Ganymede?

Grooved terrain like Earth's plates, dark regions are oldest, lightest spots are impact craters.

What features are found on Callisto?

Mostly dark, old, has Valhalla around impact crater, ice impacts, oldest surface in solar system, no grooves.

What is the size of Ganymede compared to Mercury?

Larger than Mercury.

What is the relationship between Ganymede, Europa, and Io in terms of orbital resonance?

They are in a 1:2:4 orbital resonance.

What are asteroids?

Small, eccentric objects with various locations and types.

Where are asteroid belts located?

Between Mars and Jupiter.

What are leading and lagging trojans?

Asteroids that share the same orbit as a planet, leading or trailing it.

What causes gaps in the asteroid belt?

Orbital resonances with Jupiter.

What is the composition of carbonaceous asteroids?

75% carbonaceous, rich in organic matter.

What can carbonaceous meteorites tell us?

They provide information about the age of the solar system.

Where are carbonaceous asteroids usually found?

In the outer asteroid belt with lower temperatures.

What is the significance of the Occator crater on Ceres?

It is the brightest spot on Ceres and contains ice.

What is Bennu?

An active asteroid.

What is the composition of stony asteroids?

17% silicate, derived from nickel/iron.

Where are stony asteroids usually found?

In the inner part of the asteroid belt with higher temperatures.

What are some examples of stony asteroids?

Gaspra and Ida.

What is the composition of metallic asteroids?

8% metallic, primarily iron and nickel.

Where are metallic asteroids usually found?

They are the least distributed in the asteroid belt.

What are Amor asteroids?

Near-Earth asteroids.

What is Vesta?

A minor planet.

What are Itokawa and Ryugu?

Rubble pile asteroids with high inertia and organic matter.

Mars's magnetic field is so weak because:

its core may no longer be molten.
its core contains less iron than our own.

Unlike Earth, Mars's seasons are affected (enhanced and diminished) by the distance between Mars and the Sun. This is because:
.

the orbit of Mars is significantly more elliptical.

The seasonal changes on Mars create:

great changes in the barometric pressure as the atmosphere freezes and sublimes.
changes in the dark features noted from Earth by telescopes long ago.
huge dust storms that can enshroud the planet's disk.
remarkable changes in size of the two dry ice polar caps.

Valles Marineris is the most striking example of a(n):

rift valley.

Why is the southern hemisphere of Mars believed to be older than the northern?

The southern hemisphere is more heavily cratered.

If water caused the huge outflow channels on Mars, what was the most likely process that formed them?

catastrophic but rare flooding

Venus and Mars probably evolved differently from Earth because:

they orbit at different distances from the Sun.

Compare the atmospheres of Mars and Venus.

Both are chiefly carbon dioxide, but at Mars it can freeze as dry ice.