Astrophysics Flashcards
What is the definition for a universe?
A large collection of billions of galaxies
What is the definition for a galaxy?
A large collection of billions of stars
What is the definition for solar system?
- The name for the Sun and the objects which orbit around it
- Our solar system is found in the Milky Way galaxy
What is our solar system?
- Our solar system contains a star at the centre, which is orbited by different objects
- In our solar system, there are eight planets: four rocky planets, two gas giants and two ice giants
- around these planets, moons orbit
What are the four rocky planets?
Mercury, Venus, Earth, Mars
What are the two gas giants?
Jupiter, Saturn
What are the two ice giants?
Uranus, Neptune
What is the order of the planets in our solar system from the middle to the outermost planet?
Sun, mercury, Venus, earth, mars, Jupiter, Saturn, Uranus, Neptune
What is a satellite?
- Satellite is the name given to an object which orbits around another object
- Planets are satellites that orbit around the sun
- The moon is a natural satellite which orbits around the Earth
- Since the late 1950s humans have been able to launch man-made satellites into orbit around the Earth
How do man-made satellites work?
-Satellite navigation systems (is known as satnavs) rely on the global positioning system. This system is based on satellites and provides information about location anywhere on Earth as long as there is an unobstructive line of sight to 4 or more GPS satellites.
What are comets?
- We share our solar system with comets. These orbit the Sun but have a highly elliptical (oval) path.
- Comets are a mixture of ice and other chemicals.
- As the comet nears the Sun, some of it evaporates, leaving a tail. This tail always points away from the Sun.
What has gravity got to do with the solar system?
-The gravitational force is responsible for keeping all objects in the solar system orbiting the Sun.
-in 1687 Isaac Newton suggested that there is always a force of attraction between any two objects. The size of this force of attraction is related to:
The mass: the greater the masses of two objects, the stronger the attractive forces between them.
How far they are from each other: if we increase the distance between the two objects, the weaker the attractive force between them.
What is the main concept of orbital time?
The further away a planet is from the Sun, the longer time it takes for it to orbit the Sun once.
What is the definition of a moon?
A celestial body that makes an orbit around a planet
What is the definition of a star?
A large mass at the centre of a Solar System (if there are other bodies present) that produces heat and light, eg the star at the centre of our Solar System is called the Sun.
