Astronomy Test 2

When was the Solar system believed to have been created

about 4.5 billion years ago

The Sun is __% brighter than the other stars in the Galaxy

80%

Where is the region where asteroids concentrate located?

between Mars and Jupiter

How many Earths could fit inside Jupiter?

1300

How do the jovian planets differ from the terrestial planets?

The jovian planets lack solid surfaces and instead have gaseous or liquidoceans that surround a dense core

Which planets are the only ones that don’t have moons?

Mercury and Venus

Where can the dwarf planets be found?

the Kuiper Belt

How are meteors formed

chunks of rock and cosmic dust enter and burn up in Earth’s atmosphere. When they hit the ground, they become meteorites

Which set of laws best describe the motions of the bodies orbiting the Sun?

Both Newton’s and Kepler’s

How can a planet with a solid surface be aged?

By counting the number of impacts craters its surface has. The more craters on a surface, the longer it has been since that surface was altered

What is a half-life?

The rate at which radioactive isotopes in a rock decay

What is the solar nebula?

A rotating cloud of dust and gas that our solar system had originated from

How did density stratification affect Earth’s structure

Gravity pulled the denser materials like iron and nickel to Earth’s core while the lighter materials floated to Earth’s surface

What is Earth’s crust made up of

The oceanic crust is made up of basalt, and the continental crust is made up of granite

What is Earth’s mantle made up of?

Oxygen, iron, magnesium and silicon

What is Earth’s core made up of?

Iron and nickel

Where does Earth’s magnetic field originate from?

The movement of the liquid metal outer core generates it outward from the Earth.

How are auroras made?

The Earth’s magnetosphere interacts with charged particles from the Sun (solar wind)

What are tectonic plates?

Slabs of rock that make up the lithosphere and rest on the aesthenosphere. The movement of them results in the recycling of outer layers as well as volcanic eruptions and earthquakes.

What elements are Earth’s atmosphere made up of?

78% Nitrogen, 21% Oxygen along with Ar, CO2, H2O and more

Where did the O2 in Earth’s atmosphere originate from?

It was produced by photosynthetic bacteria and accumulated in the atmosphere around 2 bya

What is the difference between weather and climate?

Weather is short-term, climate is long-term.

How big was the crater left by the Chicxulub Impact?

110 miles across and 12 miles deep

What similiarities do Mercury and the Moon share?

They are small, have no atmosphere, are primarily rocky and have surfaces that are dominated by craters

Why doesn’t our Moon have an atmosphere?

its gravity is too low

What are maria?

the large, basaltic flows (dark areas) that mark the near side of the Moon

What are the Lunar highlands

the bright, heavily cratered, and topographically elevated regions on the Moon

Why do lunar mountains lack sharp contours?

Due to the lack of water, atmosphere or tectonic plates, The Moon lacks significant erosion.

Why are the lunar highlands more heavily cratered then the lunar maria?

 

The lunar highlands were solid during the period of heavy bombardment

What were the three categories of early hypothesis for the Moon’s origin?

Capture - The Moon was a passing object that got caught in Earth’s orbit.

Sister - The Moon was a separate body formed around the same time as Earth with similar materials

Fission - The Moon separated from the Earth and formed a satellite.

What is the most consistent hypothesis regarding the Moon’s origin?

The Giant impact hypothesis - Early Earth was impacted by an object called Theia which launched large pieces of Earth’s crust and mantle into orbit, condensing into the Moon.

How small is Mercury’s size in comparison to Earth?

1/18th of Earth’s size

Mercury’s core accounts for __% of its total volume

85%

What is Mercury’s rotational period?

59 days

What are Mercury’s daytime and nighttime temperatures?

Daytime 430 C

Nighttime -170 C

What are the two main hypothesis for Mercury’s structure?

1. A Giant Impact stripped Mercury of its mantle and crust leaving only a thin layer of silicates

2. Young Sun was able to vaporize the more volatile silicate components, leaving Mercury with a largely metallic composition

What are Venus’s continents called?

Ishtar and Aphrodite

When did the lava plains on Venus cool down

Between 300 and 600 mya

What is the largest crater on Venus

Mead, which is 275 km in length

What are coronae?

bulges and distortions in the crust caused by magma upwelling

The high temperatures and thick atmosphere on Venus is believed to be the result of?

Runaway greenhouse effect, due to its atmosphere having an abundance of CO2

What does Martian basalt’s composition suggest about Mars?

that it originally had liquid oceans

What is the Tharsis Bulge?

A plateau on Mars that is about the size of North America and contains the highest elevations on the

What is the largest mountain in the Solar System

Olympus Mons which is 20 km high and 500 km in diameter

What is the Valles Marineris?

A 5000 km canyon system in the Tharsis Bulge that is 7 km deep and appears to have opened through tectonic movements rather than erosion.

What are possible pieces of evidence that Mars used to have liquid water?

Runoff and outflow channels as well as hydrated salt, lakebeds and layers of dozen water underneath the surface.

What is believed to be the explanation for Mars’ climate

Runaway refrigerator effect - loss of atmosphere resulted in lowere surface temperature

What is the ‘Grand Tour’?

An event that happens once every 175 years where the jovian planets line upclose enough

Why are Jupiter and Saturn called Gas Giants?

They are primarily made up of hydrogen and helium

Why are Uranus and Neptune called the Ice Giants?

They have more frozen chemical components

True or False: The distances between the jovian planets are greater than the distances between the terrestrial planets.

True

Which planet has such low density, it could hypothetically float in water if you had enough?

Saturn

True or False: the Ice Giants are less dense than the Gas Giants.

False

What are the outer cloud layers of each jovian planet made out of?

Jupiter - ammonia

Saturn - ammonia

Uranus - no cloud layer, only haze

Neptune - methane

How can the rotation of underlying planets be determined

Through measuring their magnetic fields

What is the most likely reason for Uranus’ 98 degree tilt?

A possible impact knocked it off its axis

Why are the Gas Giants much warmer than one would expect?

Collapse of material onto their cores during formation and slow contraction of their atmospheres generated tremendous primordial heat

What is Jupiter’s upper atmosphere made of?

clouds of ammonia and ammonium hydrosulfide

What are the lighter and darker bands on Jupiter?

Lighter bands - areas of upwelling ammonia clouds

Darker bands - layers of ammonium hydrosulfide clouds

Is Jupiter’s Great Red Spot weather or a climate?

It is weather

What constitutes a “regular moon”

They must orbit their planet in a direct orbit in an eastward direction

What features can classify a moon as “irregular?

• Eccentric orbit

• distant from planet

• retrograde motion

• high inclination

How many moons does Jupiter have?

79

Name Jupiter’s four Galilean moons

Europa, Io, Ganymede and Callisto

How many moons does Saturn have?

82

What is Saturn’s largest moon and what is special about it/

Titan. It has an atmosphere and oceans made up of hydrocarbon

How many moons does Uranus have

27 known moons

How were Uranus’ rings discovered?

occultation - light from distant stars were blocked by them

How many moons does Neptune have?

14

Which is Jupiter’s outermost moon

Europa

What is the most volcanically active object in the solar system?

Io

What are the two hypotheses for ring origins

Breakup - small moons crushed by tidal forces

Moon failure - tidal forces prevent potential moons from forming

How is Saturn’s outer F ring maintained?

The shepherd moons Pandora and Prometheus

e

How is Saturn’s outer E ring maintained?

the small icy moon Enclaudeus

When was Pluto reclassified as a dwarf planet?

2006

What are the names of Pluto’s 5 moons?

Charon (biggest), Nix, Hydra, Styx and Kerberos

What was the first asteroid to be discovered and when was it discovered?

Ceres in 1801

How much of the solar system’s asteroids are located in the asteroid belt?

75%

The three primary compositional groups

Carbonaceous, stony/silicate, metallic

What are Phobos and Deimos?

Meteors that became Mars’ two moons

What is the name of the first satellite to orbit a meteor?

Dactyl

What is special about Vesta?

Due to its high reflectivity, it can be seen drom Earth with the naked eye

What is the first interstellar asteroid?

Omuamua

What are NEOs and NEAs

Near Earth Objects and Near Earth Asteroids

How is a comet formed?

They are fomed

What did the Rosetta Mission to 67P confirm

Sublimation is restricted to small active jets on the nucleus of the comet

The period of a comet describes:

The interval of time between approaches to the Sun, based on its orbit