Topic 2 Flashcards
What is at the center of our solar system?
The Sun
Name the planets of the Solar System in order from closest to the Sun, to furthest
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune (My Very Easy Method Just Speeds Up Naming)
Name the dwarf planets of the Solar System in order from closest to the Sun, to furthest
Ceres (in asteroid belt), Pluto, Haumea, Makemake, Eris
What is an asteroid?
A rock greater than 10 meters in diameter. Most are in the asteroid belt between the orbits of Mars and Jupiter.
What is a comet?
Made of ice, dust, and rocky small particles. They develop a gaseous coma and tail as they sublime as they approach the Sun. Found in the Oort Cloud and Kuipler Belt .
What are Centaurs?
Celestial object which are similar to comets in composition (made of ice, dust, and rocky small particles), and similar to asteroids in size. Located between the orbits of Jupiter and Neptune.
What are Trans-Nepunian objects?
They orbit the Sun at distances greater than Neptune. They are normally found in the Kuiper Belt, Scattered Disk and Oort Cloud.
What is an astronomical unit (AU)?
The mean distance between the Earth and the Sun (150 million km)
What is the shape of an orbit?
Elliptical, not necessarily on the same plane as the Earth
What is the Zodiac band?
A band 8 degrees either side of the ecliptic and it is where all the orbits of the planets lie.
What is direct motion of planets?
When planets usually appear to move from West to East.
What is retrograde motion of planets?
When the Earth orbits near the Sun, it moves more quickly which makes other planets appear to not move at all (stationary point). Sometimes the planets appear to move backwards (retrograde).
What is the stationary point of planets?
When the Earth orbits near the Sun it moves more quickly which makes other planets appear to not move at all. This is called the stationary point.
What is the ecliptic?
The apparent motion of the Sun around the Earth
What is perihelion?
The point in which a planet is closest in its orbit to the Sun
What is aphelion?
The point in which a planet is furthest from the Sun in its orbit,
What is greatest elongation?
(tinyurl.com/earthsundiagram) Mercury and Venus are best placed for observation when they are furthest from the Sun in the sky. The positions in their orbits are known as greatest eastern elongation and greatest western elongation and at these positions, the angle between the lines planet-Earth and planet-Sun is 90°. At greatest elongation, observers on Earth can see planets half-illuminated.
What is conjunction?
(tinyurl.com/earthsundiagram) An inferior planet lies at inferior conjunction when its angle of elongation is 0°. Inferior conjunction is between the Earth and the Sun. Superior conjunction is on the other side of the Sun to the Earth.
What is opposition and why is it a good position to observe at?
(tinyurl.com/earthsundiagram) At opposition, superior planets are directly opposite the Sun in the sky and so are fully-illuminated and visible throughout the night.
What is transit?
When a planet passes in front of the solar disc while at conjunction.
What is occultation?
When an inferior planet is close to superior conjunction and it appears to disappear for a short while behind the Sun
What are 6 distinguishing features of Mercury?
1) It has no atmosphere
2) It has a temperature of 90K-700K
3) It is made of rocks and craters, similar to the Moon
4) It has a thin rock crust
5) It has a large iron core
6) It produces a small magnetic field
What are 8 distinguishing features of Venus?
1) It is geologically young
2) There is evidence of volcanic structures
3) It has a thick atmosphere
4) It spins in retrograde
5) It has an atmosphere of 96% carbon and sulphuric acid
6) It has a sunlight strength of 750K
7) It is not possible to view the surface from Earth due to 100% cloud coverage
8) It has a surface pressure 90 times that of Earth
What are 5 distinguishing factors of Earth?
1) It is covered in 71% water
2) It has an atmosphere of 78% nitrogen and 21% oxygen
3) It supports life
4) It is geologically active
5) It contains an inner and outer core which produces a magnetic field