Topic12-The Scale Of The Universe Flashcards
The main constituents of the solar system are:
1) 1 star - the sun
2) 8 planets - mercury, Venus, earth, Mars, Jupiter, Saturn, Uranus and 3) Neptune
4) 146 moons (a moon is a natural satellite of a planet)
5) An asteroid belt - between mars and Jupiter
6) Many comets and other small lumps of rock and interplanetary dust
7) A surrounding ‘halo’ of rock, ice and dust called the Oort Cloud
What is the solar system?
The universe is a very big place - it would take 13.75 thousand million years for light to travel from the Earth to the edge of the observable Universe!
What is the pattern in the solar system?
The solar system has many patterns and trends that can be deduced from data about the planets and moons. Many of these patterns relate to the energy released by the Sun and the distance of each planet from the sun. The further away from the sun, the colder the average surface temperature of a planet. The energy from the sun spreads out as it gets further from the sun. A distant planet therefore has less energy per square metre of area than a close planet.
The greater the distance of a planet from the sun, the longer it’s year length. (The planet has to travel much further to make one orbit of the sun.)
What does Re ?
Earths radius, Re - the size of a planet is measured relative to the Earth, so the radius of Jupiter = 11Re. Comparison to the Earth’s dimensions are good measurements to use to compare the planets.
What does AU mean?
Astronomical Units, AU - this is the average distance of the Earth from the Sun. Distance in the solar system are measured using this unit. Neptune, the furthest planet, is 30 AU from the sun and the Oort Cloud stretches out to over 100,000 AU!
What does light years mean”
Light years, ly - the light year is the distance that the light travels in one year. This measurement is used to measure distances timeout nearest stars and with in our own galaxy of stars.
