Unit E Section 1.4

Question 1

What is the “protoplanet hypothesis”?

Answer 1

The “protoplanet hypothesis” is a model for explaining the birth of solar systems.

Question 2

Three steps of the “protoplanet hypothesis”?

“nebular theory”

Answer 2

1. A cloud of gas and dust in space begins swirling.
2. Most of the material (more than 90%) accumulates in the center, forming the Sun.
3. The remaining material accumulates in smaller clumps circling the center. These form the planets.

Question 3

megawatt?

Answer 3

A megawatt (MW) is a million watts

The Sun releases 380 billion megawatts every second.

Question 4

What is at the center of our solar system?

Answer 4

Sun

Question 5

The temperature at the surface of the Sun

Answer 5

constantly bubbling and boiling, is about 5500°C, while the core is close to 15 000 000°C.

Question 6

What is solar wind?

Answer 6

-The Sun releases charged particles that flow out in every direction.

Question 7

How is solar wind passed to Earth?

Answer 7

This solar wind passes Earth at an average speed of 400 km/s.

Earth is protected from the solar wind by its magnetic field.

Question 8

Which gases is the sun made out of?

Answer 8

hydrogen and helium.

Packed densely at the core held
together by gravity.

Question 9

The solar system can be divided into two distinct

planetary groups:

Answer 9

• the inner planets. (terrestrial), or Earth-like, planets

- the outer, or Jovian planets

Question 10

Inner planets (terrestrial) characteristics:

Answer 10

smaller,
rockier in composition,
closer to the Sun

Question 11

the outer, or Jovian planets characteristics:

Answer 11

large
gaseous
located great distances from the Sun

Question 12

Mercury (4)

Answer 12

• has been determined by telescopes and satellite data.
• the closest planet to the Sun
• Like the Moon, Mercury has no atmosphere and therefore no protection from the bombardment of meteoroids, asteroids, and comets.
• The temperatures: from over 400°C on the sunny side to –180°C on the dark side.

Question 13

Venus (8)

Answer 13

• Venus is similar to Earth in diameter, mass, and gravity, and is often called Earth’s twin.
• Surface temperatures are kept hot due to a greenhouse effect caused by thick clouds
• Temperatures can be over 450°C
• The atmospheric pressure is about 90 times that on Earth
• The permanent clouds are made of carbon dioxide and it often rains sulfuric acid
• huge canyons, extinct volcanoes, and ancient lava flows
• Venus is one of the only planets in the solar system to rotate from east to west

Question 14

Earth (4)

Answer 14

• It is the only planet where water exists in all three
  phases: solid, liquid, and gas
• Earth’s atmosphere provides protection from cosmic rays and ultraviolet radiation that would otherwise harm life
• 70% covered in water
• is one of the few places in our solar system that has active volcanism.

Question 15

Mars (8)

Answer 15

• Two missions have successfully landed robotic probes on the surface of the planet
• referred to as the “red planet,”
• caused by the iron oxides on the planet’s surface
• has two polar ice caps, one made up of frozen carbon dioxide and water, the other of just carbon dioxide.
• The atmosphere is very thin and composed mainly of carbon dioxide
• average surface temperature is extremely cold, temperatures at Mars’s equator can reach 16°C in the summer.
• canyons, valleys, and extinct volcanoes
• two small moons, Phobos and Deimos.

Question 16

Jupiter (7)

Answer 16

• observed since the 1600s
  -16 moons
  -Jupiter is the largest of all the planets in the solar system and contains more than twice the mass of all
  the other planets combined
  -gas giant composed mainly of hydrogen and helium
  -it may have formed into a star
  -The Great Red Spot on Jupiter is a huge storm in its atmosphere.
  -Jupiter has three very thin rings.

Question 17

Saturn (7)

Answer 17

• 19 moons
• Saturn is the second-largest planet in our solar system
• most distinctive ring system
• Over a thousand rings exist, composed of pieces of ice and dust
• mostly hydrogen and helium
• wind speeds at Saturn’s equator have been estimated at over 1800 km/h.
• quick rotation

Question 18

Uranus (6)

Answer 18

• Uranus has one of the most unusual rotations in the solar system: its axis of rotation is tilted toward the plane of its orbit, making it appear to roll during its orbit
• mainly of hydrogen and helium.
• Methane in its atmosphere gives the planet a distinctive blue color.
• Uranus has a large ring system,
• 17 moons.
• rotates from east to west

Question 19

Neptune (9)

Answer 19

-The composition and size of Neptune make it very similar in appearance to Uranus.
-composed of hydrogen, helium, and methane
- bluish in color.
-Very little of the Sun’s energy reaches
-Neptune gives off about 3 times more energy than it
receives
-fastest wind speeds in the solar system, at 2500 km/h.
-its own ring system,
- eight moons.

Question 20

Pluto (7)

Answer 20

• It is a frozen ball of methane smaller than our moon
• It doesn’t fit the pattern of the outer planets, which tend to be large and gaseous, and it isn’t rocky like the terrestrial planets.
• more elliptical than that of other planets
• Pluto rotates from east to west. Between 1979 and 1999, Pluto was closer to the Sun than Neptune
• astronomers believe that Pluto and its moon, Charon, are comets captured by the Sun’s gravity from the area of debris on the outer edge of the solar system called the Kuiper Belt.

Question 21

Asteroids

Answer 21

belt of small, rocky, or metallic bodies traveling in
space between the orbits of Mars and Jupiter

range in size from a few meters to several hundred kilometers across.

Question 22

The largest asteroid?

Answer 22

called Ceres, is over

1000 km wide

Question 23

Where do asteroids come from?

Answer 23

. Scientists aren’t certain where the

asteroids came from.

Question 24

What are Comets?

Answer 24

-often described as “dirty snowballs,” are objects made up of dust and ice that travel through space.

Question 25

When do comets’ tails and bright glow appear?

Answer 25

• Their long tails and bright glow only appear when they get close to the Sun
• When that happens, the Sun heats the materials on the comet, and gases are released.
• These gases then get pushed away from the comet by the solar wind.
• The tails of some comets can be millions of kilometers long.

Question 26

What do Comets do most of the time?

Answer 26

spend most of their time slowly orbiting in the outer reaches of the solar system.

Question 27

How will the comet be pushed down to the inner solar system?

Answer 27

Only when an event, such as the close passing of
another body occurs might a comet’s path be pushed toward the inner solar system

Then a comet can end up in a regular orbit around the Sun.

Question 28

How can comets have a predictable appearance?

Answer 28

Comets that orbit the Sun will make a predictable appearance because their paths are large ellipses

Question 29

When can Haily’s Comet be visible?

Answer 29

which is visible from Earth every 76 years.

The last time it was seen was in 1986.

Question 30

What are meteoroids?

Answer 30

Small pieces of rocks flying through space with no particular path.

small as a grain of sand or as large as a car

Question 31

What is a meteor?

Answer 31

When a meteoroid gets pulled into the atmosphere by Earth’s gravity, the heat of atmospheric friction causes it to give off light

Question 32

What are shooting stars?

Answer 32

they are known to be meteors

meteor showers are predictable

Question 33

What is a meteorite?

Answer 33

If a meteor lasts long enough to hit Earth’s surface, it is called a meteorite.

Question 34

When does a solar eclipse occur?

Answer 34

occurs when the Moon, passing between the Sun and Earth, casts a shadow on Earth

Question 35

When does the lunar eclipse occur?

Answer 35

occurs when Earth passes between the Sun and the Moon, casting its shadow over the Moon.

Question 36

How are comet elliptical paths different from planetary elliptical paths?

Answer 36

comets are elliptical, too, but larger and longer than

planetary paths.