Section 6 - Comparative Planetology and Formation

The early Solar System would have featured:

Possibly five gas giants and five or more terrestrial planets, with all of the orbits bunched closer together

Which of the following would best describe the core of a terrestrial planet?

Vast amounts of iron (over 85%) with some heavy elements like nickel and sulfur (10%) and traces of heavier metals like uranium, gold, and lead

Why is the large Kuiper Belt Object Eris considered a "dwarf planet" rather than a true planet?

It is located in a debris-filled ring of icy cometary material beyond Neptune

This is asteroid Itokawa, named after Japanese rocket engineer Hideo Itokawa. At just over 540 meters across, it is about the length of New York City's World Trade Center. Its tiny mass means that its surface gravity is only 0.002% as strong as Earth's, so a 200 pound man would register as weighing 0.00046 pounds on a scale while standing on Itokawa. What is the likely composition of asteroid Itokawa?

Silicates, rock, metal, and traces of ice

What do you think: is Pluto a true planet or not?

No, Pluto shouldn't be considered a major planet

The tallest volcano in the Solar System is:

Olympus Mons

It is hoped that one day, humans may establish a permanent colony on Mars, thought surviving the planet will require protective measures and engineering. Which of the following radiation-protective measures could feasibly be used by long-term settlers on Mars to protect against the harsh cosmic ray, ultra violet, and x-ray radiation reaching Mars's surface?

Building colonies beneath the Martian surface, in the network of lava tubes crisscrossing the crust

Scientists study an object with an orbiting probe. The probe determines that the body is fairly misshapen and heavily cratered but that it is mostly one solid, large piece of continuous, compressed material. That material is a random, somewhat even mix of minerals, rocks, crystals, silicates, and metals throughout. Which name would best describe this object?

A planetoid

The official reason Pluto was downgraded from its planet standing is:

Pluto orbits in a part of the Solar System that is relatively crowded with other large orbiting bodies

Ever wanted to bask in the diffuse glow of a Sun filtering down through thick carbon dioxide clouds filled with droplets of sulfuric acid which falls as rain but boils before it reaches the year-round all-day everywhere 900°F surface? Of course you do! Visit {THIS PLANET OR MOON} today for the vacation of a lifetime! (Paid for by the {THIS PLANET OR MOON} tourism board)

Venus

What is "top-down" planet formation?

The planetary formation process in which a very large parcel of gas collapses directly and quickly into a bloated, hot planet that cools and compresses over time

Which of the following is likely true: If you took every asteroid in the Main Asteroid Belt and combined them into one single object it would:

Form a rocky-metallic body only a little over 3% the mass of Earth's Moon

Which of the following planets have multiple "permanent" (existing in stable orbits for at least 10 million years or which have been in orbit for a billion years or more) moons?

Mars and the Jovian planets

The greenhouse effect is a critical component to sustaining life, as it allows surface heat generated during the daytime to be trapped in the atmosphere so that it doesn't filter out into space during the Sun-free nighttime hours. With a daytime high temperature of nearly 850° F and a nighttime low of -300° F, which of the following planets likely does not have the benefit of a temperature-regulating greenhouse?

Mercury

How might a protoplanet differ from a planetoid?

A planetoid is large enough body to compress itself into a solid core of mixed materials while a protoplanet is a large enough body to have undergone melting and differentiation of its interior

Which of the following planets have ring systems? (Click each which apply)

Jupiter Saturn Caelus Neptune

Which of the following general statements about planets is true?

Terrestrial planets have dense iron cores, gas giants are mostly hydrogen

What might you find at the center of a planetoid?

A solid, conglomerated patchwork of metal and silicate material

Which of the following planets do not have natural satellites?

Mercury and Venus

Which of the following are dangers that explorers on Mars might realistically have to deal with during a long duration Mars mission? (Click each which apply)

\-Dementia, caused by the destruction of brain tissue by interactions with cosmic radiation

\-Cancer, caused by unfiltered exposure to solar radiation

\-Boiling of exposed skin, caused by the low boiling temperature of water at low Martian surface pressure

\-Respiratory problems, caused by inhalation of irritating dust

Studies of proplyds (as well as studies of objects in our own Solar System, like moons and asteroids) show that their chemical composition changes with distance from the central star, with different ratios of hydrogen to helium or different ratios of oxygen isotopes, or varying ratios of water ice to methane ice to ammonia ice, so that objects that form in different sections of the Solar System will have measurably different chemical compositions. Since Moon rocks don't appear to be markedly different in composition to the Earth rocks, what theory of Moon creation does this rule out?

Moon capture

A theory of the formation of the Moon held that the Earth and the Moon simply formed from the same cloud of gas, dust, and material, close enough to one another that the smaller Moon naturally wound up locked in orbit around the larger Earth. What bit of evidence brings the co-evolution theory into question?

The Moon has a crust of igneous silicate (volcanic rock), a mantle of silicate, and a core of silicate, without much more than trace amounts of iron alloy for a core

Ishtar is the Mesopotamian goddess of love and fertility, and is a large, polar, Australia-sized swath of plains and highlands rising up above the planetary plains, making up what is called a continent. Like many features on this planet, it is named after a goddess. Where could one find Ishtar Terra?

Venus

Where did most of the water making up Mars's ancient oceans, lakes, and rivers go?

The water was boiled away by low surface pressure, the molecules were disassociated by sunlight, and the former water molecule's hydrogen atoms were swept away into space

A synestia is:

A donut shaped cloud of vaporized rock

Gas giants are mostly gas:

False, the gas giants' high pressure interiors crush the hydrogen and helium gas into deep oceans of liquid

A Lagrange point is a point in space where the equal gravitational tug of two bodies - like the Earth and the Sun - may cause particles to stably oscillate around a point in space. One of the Earth-Sun Lagrange points has a misty cloud of dust caught in the gravitational tug of war between the Earth and Sun and this causes a little reflective cloud of dust particles to follow Earth around in orbit, directly on the opposite side of Earth as the Sun. Late at night under dark, dark skies, a faint, circular glow is visible in the sky from this dust. What is the name of this fuzzy, slightly bright haze in the night sky?

Gegenshein

What created the dark "lunar maria" that are visible from Earth as large, dark gray regions on the near side of the Moon?

The planet Neptune flinging Pluto-sized comets at the Earth and the rest of the inner Solar System

Click each of the following which are true of the terrestrial planets:

\-Their most abundant element is oxygen

\-Their densities (the ratio of their masses to their volumes) are higher than the gas giants' densities

\-Their formation and present-day structure was aided profoundly by the Sun and Jupiter

In proto-Earth's earliest primitive phases - when it was still too small to be considered a 'planetesimal' but was larger than a single 'planetary embryo' - which description would best described the growing planet?

A mudball, made of small rocky grains and water slush

Over 75% of Earth and the other terrestrial planets' crusts and mantles are made of:

Silicon and oxygen

Which planet performed the Grand Tack maneuver, according to studies and simulations?

Jupiter

The best current evidence suggested that Jupiter's core is:

An amorphous churning blob of ice, rock, and hydrogen

What is the Late Heavy Bombardment?

A time in the Solar System when the planets were subject to a spike in comet collisions, likely due to the migration of the gas giants upsetting the Kuiper Belt

The celestial body known as Theia was most likely responsible for:

The creation of the Earth's moon

Which theory of the Moon's creation posited that the material of the Moon splashed off of the Earth's surface due to the rapid rotation of the planet (like turning on a blender with the cover off)?

Binary Fission

What do astronomers mean when they describe asteroids as "fluffy"?

Asteroids are not solid objects but instead are messy rubble piles of rocky metallic debris held together by their own weak gravity

Shepard moons accomplish what task in the Solar System?

Maintaining the distribution and stability of ring systems

You want to live on the Moon because, frankly, Earth isn't doing so hot. Not like, the planet itself, that thing is doing fine. But the people... that's another story. The world was probably a better place when there wasn't the daily danger that you might be subject to a teenager's opinion on something against your will. But you've also heard that the Moon dust - unlike Earth's soil, which is mostly soft pliable decaying plant matter and water - is actually microscopic shards of volcanic rock. These foreign bodies are a strong lung irritant if inhaled, like asbestos or fiberglass, and may settle into the fine tissue of your lungs and cause scarring. To avoid lunar-lung, what might be a workable solution to keeping lunar shards from embedding in your lung tissue?

Smoking a few unfiltered cigarettes a day

In the documentary The Eternals, a group of robots who don't know that they're robots were made by space-gods to protect Earth so that another space-god baby can form in the Earth's core and feed off of sentient human life and emerge from the planet, thus destroying the planet. Sounds not insane. In reality, what might you actually find in the center of the Earth?

A solid, high-temperature, high-density sphere of iron and sulfur