Solar System Flashcards
Name all of the planets in order.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
What are the three dwarf planets and where abouts do they lie?
Ceres - between Mars and Jupiter
Pluto - after Neptune
Eris - after Pluto
Where do the centaurs lie?
Between Jupiter and Neptune.
Name two Trans-Neptunian objects and state where they lie in the Solar system.
Kuiper Belt and Oort Cloud and they lie after Neptune.
What is the atmosphere and temperature like on Venus?
Very dense, thick atmosphere of CO2 with a surface temperature of 470 degrees C - could be what Earth ends up like as CO2 traps heat.
What is the atmosphere and temperature like on Mars?
Near vacuum. Temperatures from -90 degrees to -20 degrees C.
What are some problems associated with manned missions into the solar system?
- Life support
- Radiation
- Physiological problems
- Psychological problems
- Space adaption syndrome
How were Mars’ moons formed?
Captured asteroids.
How was triton (one of Neptunes moons) formed?
Either captured or due to collision.
How was Proteus formed? (Neputunian moon)
Formed when planet formed.
How was Nereid formed (neptune moon)?
Captured object from Kuiper Belt.
What are ring systems made from?
Ice and small rocks.
How are ring systems made?
Leftover ‘stuff’ from formation - gaps in rings due to shepherd moons and gravitational resonance.
How are cometary orbits different to planetary orbits?
They are either highly elliptical or open orbits and are highly incline to ecliptic.
What does a retrograde orbit mean?
Clockwise orbit (unusual).
What evidence is there for the existence of the Oort Cloud?
Spherical ‘cloud’ of cometary nuclei.
What is the nucleus of a comet made from and how large are they?
- Ices
- Bits of rock
10 km across
What is the coma in a comet?
The cloud around the nucleus.
Describe a dust tail of a comet and how they are formed.
Curved and caused by photons.
Describe an ion tail of a comet and how it is formed.
Straight tail caused by solar wind.
What is a meteoroid? *(size and origin)
Rock 10m to 10 ^-6 metres across. Originates from asteroids colliding.
What is a meteorite? (structure and origin)
On surface of Earth - meteoroid that survives journey through Earth’s atmosphere.
What is a micrometeorite? (structure and origin)
Very small asteroids with very low terminal velocities.
What is the difference between a meteor and a fireball?
Meteors are small things like asteroids or comets whereas fireballs are meteors with an apparent magnitude less than -3.
Why do meteor showers appear to point towards a radiant?
Because it is our perspective on Earth as they come towards us or pass us and as they get further away they get closer to one point (the radiant).
What is the orbit of a potentially hazardous object like?
Within 0.05 AU of Earth.
What did Copernicus contribute to our understanding of the Solar system?
Said Earth and planets orbit sun rather than Earth being the centre (heliocentric).
What did Tycho contribute to our understanding of the Solar system?
Observed planet and their coordinates using an observatory.
What did Kepler contribute to our understanding of the Solar system?
Formulated laws of planetary motion from observation of Mars.
What three things did Galileo discover about the Solar System?
- The phases of venus
- The relief features of the Moon
- The principle satellites of Jupiter
What diagram can be drawn to illustrate Kepler’s second law?
Elliptical orbit of planet around sun. Sun - planet line sweeps out equal areas in different times as when planet is further from sun, it travels slowest.
What is Kepler’s third law?
T ^2 is proportional to R ^ 3
where T is is years and R is in AU.
In gravity, what is gravitational force proportional to?
1/R^2
How was Ceres discovered?
Asteroid discovered as a planet had been predicted in the obvious gap between Mars and Jupiter.
How was Uranus discovered?
Herschel discovered Uranus by using a telescope and observing a new ‘disc’ in Gemini constellation.
How was Neptune discovered?
Perturbations of Uranus led to prediction of 8th planet. Observed by Encke, Galle and D’Arrest in Berlin.
How was Pluto discovered?
Uranus still perturbed and led to prediction of 9th planet - Tombaugh discovered it photographically.
What does the term perihelion mean?
Point on orbit closest to Sun.
What does the term aphelion mean?
Point on orbit furthest from Sun.
What does the term greatest elongation mean?
Largest possible angle between sun and inferior planet as seen by an observer on Earth.
What does the term conjunction mean?
Conjunction occurs when the angle of elongation is zero.
What does the term opposition mean?
Opposition occurs when the angle of elongation is 180 degrees.
What does the term transit mean?
Occurs when a planet passes in front of the Sun.
What does the term occultation mean?
Occurs when a planet passes behind the Sun.
What is an inferior planet?
One which lies within the orbit of Earth.
What is a superior planet?
One which lies outside the orbit of Earth.
What is astrometry and how is it used to find exoplanets?
Observe and measure the ‘wobble’ of a star due to gravitational perturbations caused by a planet orbiting it.
How is Doppler Shift used to find exoplanets?
Same as astrometry but radial perturbations are measured.
What is the transit method?
Drop in brightness when planet passes in front of star.
What are the theories for Earths water?
- Comets
- Outgassing of volcanoes
Name three factors included in the Drake equation.
- Average rate of star formation per year in our galaxy
- Fraction of those stars that have planets
- Average number of life-worthy planets per star that has planets
What is the habitable zone called and what must it have?
The Goldilocks zone - must have water and sufficient living conditions.
