The Solar System Flashcards

1
Q

Name and categorise the 8 planets.

A

Rocky/Terrestrial
Mercury / Venus / Earth / Mars
Gas Giants
Jupiter / Saturn / Uranus /Neptune

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2
Q

What is the definition of a planet?

A

A planet is a body that:

  • Is in orbit around the Sun
  • Is large enough to be Spherical
  • Has cleared its orbit of other objects.
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3
Q

Name 6 other types of body in our Solar System.

A
  • Asteroids (Vesta / Pallas)
  • Comets
  • Centaurs (Half comet, Half Asteroid)
    Orbit between Jupiter and Neptune
  • Moons/satellites (160 known)
  • Dwarf Planets (Pluto, Ceres, Eris)
  • TNOs (Trans Neptunian Object)
    Objects orbiting beyond Neptune
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4
Q

Name 2 decisions of the IAU (International Astronomical Union) taken in 2006.

A
  • Ceres promoted from Asteroid to dwarf planet

- Pluto demoted from planet to dwarf planet.

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5
Q

What is 1 AU (Astronomical Unit) ?

A

Unit of Measurement
Based on distance between Earth and Sun
150 million km

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6
Q

Describe Mercury.

A
  • It is the closest to the sun
  • Fastest orbital period. Smallest planet
  • Heavily cratered
  • Highlands and lava filled basins.
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7
Q

What is odd about Venus?

A

It spins backwards.

Retrograde Rotation

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8
Q

Describe Venus.

A
It is a similar size to Earth
Clouds of Sulphuric Acid
Atmosphere of mostly Carbon Dioxide
Runaway Greenhouse Effect
Temp 470 degrees C
Pressure
90 x Earth’s
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9
Q

Describe Mars.

A
Iron rich rocks
Red planet
450km long water carved canyons
Mariner Valley
Highest volcano in solar system
Olympus Mons
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10
Q

What is the Great red spot on Jupiter?

A

It is an anticyclone weather system greater in size than Earth.

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11
Q

How many times bigger than Earth is Jupiter?

A

11 (approx)

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12
Q

Describe Jupiter’s equatorial bulge and explain why it has one.

A
  • Dynamic wind system splits atmosphere into belts and zones

- Bulge due to extremely fast rotation (once in only 10hrs)

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13
Q

How long is a Venus day?

A

243 Earth days.

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14
Q

Name some similarities between Uranus and Neptune.

A

-Similar Size
-They are both cold Gas Giants.
(Hydrogen / Helium / Methane / Ammonia)

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15
Q

Describe some similarities and differences between Jupiter and Saturn.

A

-Both have ring systems
(Jupiter’s not as reflective as Saturn’s)
-Both are gas giants
-Similar rotational periods
-Saturn has less visible structure to its atmosphere
(unlike Jupiter which has Great Red Spot, red/brown belts and yellow/white zones.)

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16
Q

Name some differences between Uranus and Neptune?

A
  • Uranus is almost featureless.
  • Uranus spins on its side.
  • Neptune has a Great Dark Spot.
  • Neptune has clouds of frozen methane.
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17
Q

Name 5 problems Astronauts could face if venturing beyond the Moon.

A

-Time
-Space adaptation syndrome
(No up and no down / Disorientation / Headaches / Vomiting / Poor concentration)
-Physiological problems, prolonged zero gravity causes: (Muscle wasting. Brittle bones, Reduced red cell count)
-Psychological problems: Confined spaces with the same group of people.
-Communication delays
-Radiation Risk

18
Q

Name some advantages of robotic planetary exploration.

A

Less expense
No loss of life
Safer

19
Q

Name Mars’ two small moons.

A

Deimos

Phobos

20
Q

Why do Astronomers believe that Deimos and Phobos are captured Asteroids?

A

Heavily cratered.
Irregular in shape.
Densities half that of Mars.
Compositions similar to Asteroids.

21
Q

Name 3 moons of Neptune.

A

-Triton
-Dark Proteus (Largest Irregular moon of Solar System. Orbits in the plane of Neptune’s equator.
Suggesting it was formed at the same time as Neptune.)
-Nereid. (Highly eccentric orbit, 1 orbit is 1 Earth year. Probably captured Kuiper Belt object.)

22
Q

Why do astronomers believe Triton is also a captured body?

A
  • Revolves around Neptune in the opposite direction to Neptune’s rotation.
  • Highly inclined orbit.
  • It is thought that Triton’s capture is the result of a collision with Neptune or one of it’s moons.
23
Q

Name 4 planets that have ring systems.

A

Saturn.
Jupiter.
Neptune.
Uranus.

24
Q

Why aren’t Jupiter’s rings visible like Saturn’s rings?

A

Saturn’s rings are made out of highly reflective ice particles.
Jupiter’s rings are made out of dark dust.

25
Q

How thin are ring systems?

A

All are < 1.5 km thick.

26
Q

What are the gaps in Saturn’s rings called.

A

The Cassini Division.

27
Q

Which planets have incomplete rings (arcs)?

A

Neptune.

Uranus.

28
Q

Give 4 theories on the origin of rings.

A
  • Debris left over from planet formation.
  • Large impacts between moons.
  • Moons torn apart through tidal gravitational forces.
  • Meteors striking moons creating debris.
29
Q

Are the orbits of planets circular?

A

No they are elliptical.

30
Q

What is the plain on which the planet’s orbit called?

A

The ecliptic.

31
Q

What is the Zodiacal band?

A

Because all the planets orbit on the ecliptic, they appear to move through a narrow region of the sky called the Zodiacal band.

32
Q

What are the Inferior Planets?

A

Mercury and Venus

Also known as the Inner Planets

33
Q

What are the Superior Planets?

A

Mars, Jupiter, Saturn, Uranus, Neptune.

34
Q

Where do the Inferior Planets appear in the sky?

A

Near the sun.

Best observed at sunset or sunrise

35
Q

At what time in their orbit is it best for us to see Mercury and Venus?

A

At their GEE (Greatest Eastern Elongation) or GWE (Greatest Western Elongation).

36
Q

What is the GEE and GWE?

A

At the GEE and GWE the angle between the lines planet-Earth and planet-Sun is 90 degrees.

37
Q

At GEE, when will the inferior planet be visible?

A

Shortly After Sunset.

38
Q

At GWE when would the inferior planet be visible?

A

Shortly before Sunrise.

39
Q

What is an inferior conjunction?

A

When the angle of elongation is 0.
Planet passes between Sun and Earth.
May undergo a transit. (May cross over the solar disc)

40
Q

What is a superior conjunction?

A

When the angle of elongation is 0.
When the planet passes behind the sun.
May undergo an occultation (Disappears behind sun.)

41
Q

When are the superior planets most favourably placed for observation and why?

A

At opposition, because:

  • Brighter (Fully illuminated by sun throughout night)
  • Better resolution (Closest to Earth)
42
Q

Explain Retrograde Motion.

A

-Direct motion of planet seems to stop and move backwards in a “loop the loop” pattern before stopping again and resuming its original direction.
-This is because Planets orbit the sun at different speeds (Angular, Actual)
- We therefore see planets from different viewpoints (as we also orbit the Sun).
Sometimes overtaking the inner planets
Sometimes undertaking the outer planets.