The Solar System Flashcards
Name and categorise the 8 planets.
Rocky/Terrestrial
Mercury / Venus / Earth / Mars
Gas Giants
Jupiter / Saturn / Uranus /Neptune
What is the definition of a planet?
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.
Name 6 other types of body in our Solar System.
- 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
Name 2 decisions of the IAU (International Astronomical Union) taken in 2006.
- Ceres promoted from Asteroid to dwarf planet
- Pluto demoted from planet to dwarf planet.
What is 1 AU (Astronomical Unit) ?
Unit of Measurement
Based on distance between Earth and Sun
150 million km
Describe Mercury.
- It is the closest to the sun
- Fastest orbital period. Smallest planet
- Heavily cratered
- Highlands and lava filled basins.
What is odd about Venus?
It spins backwards.
Retrograde Rotation
Describe Venus.
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
Describe Mars.
Iron rich rocks Red planet 450km long water carved canyons Mariner Valley Highest volcano in solar system Olympus Mons
What is the Great red spot on Jupiter?
It is an anticyclone weather system greater in size than Earth.
How many times bigger than Earth is Jupiter?
11 (approx)
Describe Jupiter’s equatorial bulge and explain why it has one.
- Dynamic wind system splits atmosphere into belts and zones
- Bulge due to extremely fast rotation (once in only 10hrs)
How long is a Venus day?
243 Earth days.
Name some similarities between Uranus and Neptune.
-Similar Size
-They are both cold Gas Giants.
(Hydrogen / Helium / Methane / Ammonia)
Describe some similarities and differences between Jupiter and Saturn.
-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.)
Name some differences between Uranus and Neptune?
- Uranus is almost featureless.
- Uranus spins on its side.
- Neptune has a Great Dark Spot.
- Neptune has clouds of frozen methane.
Name 5 problems Astronauts could face if venturing beyond the Moon.
-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
Name some advantages of robotic planetary exploration.
Less expense
No loss of life
Safer
Name Mars’ two small moons.
Deimos
Phobos
Why do Astronomers believe that Deimos and Phobos are captured Asteroids?
Heavily cratered.
Irregular in shape.
Densities half that of Mars.
Compositions similar to Asteroids.
Name 3 moons of Neptune.
-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.)
Why do astronomers believe Triton is also a captured body?
- 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.
Name 4 planets that have ring systems.
Saturn.
Jupiter.
Neptune.
Uranus.
Why aren’t Jupiter’s rings visible like Saturn’s rings?
Saturn’s rings are made out of highly reflective ice particles.
Jupiter’s rings are made out of dark dust.
How thin are ring systems?
All are < 1.5 km thick.
What are the gaps in Saturn’s rings called.
The Cassini Division.
Which planets have incomplete rings (arcs)?
Neptune.
Uranus.
Give 4 theories on the origin of rings.
- Debris left over from planet formation.
- Large impacts between moons.
- Moons torn apart through tidal gravitational forces.
- Meteors striking moons creating debris.
Are the orbits of planets circular?
No they are elliptical.
What is the plain on which the planet’s orbit called?
The ecliptic.
What is the Zodiacal band?
Because all the planets orbit on the ecliptic, they appear to move through a narrow region of the sky called the Zodiacal band.
What are the Inferior Planets?
Mercury and Venus
Also known as the Inner Planets
What are the Superior Planets?
Mars, Jupiter, Saturn, Uranus, Neptune.
Where do the Inferior Planets appear in the sky?
Near the sun.
Best observed at sunset or sunrise
At what time in their orbit is it best for us to see Mercury and Venus?
At their GEE (Greatest Eastern Elongation) or GWE (Greatest Western Elongation).
What is the GEE and GWE?
At the GEE and GWE the angle between the lines planet-Earth and planet-Sun is 90 degrees.
At GEE, when will the inferior planet be visible?
Shortly After Sunset.
At GWE when would the inferior planet be visible?
Shortly before Sunrise.
What is an inferior conjunction?
When the angle of elongation is 0.
Planet passes between Sun and Earth.
May undergo a transit. (May cross over the solar disc)
What is a superior conjunction?
When the angle of elongation is 0.
When the planet passes behind the sun.
May undergo an occultation (Disappears behind sun.)
When are the superior planets most favourably placed for observation and why?
At opposition, because:
- Brighter (Fully illuminated by sun throughout night)
- Better resolution (Closest to Earth)
Explain Retrograde Motion.
-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.
