Astronomical distances Announcements Keep working on projects Check

Astronomical distances

Announcements • Keep working on projects • Check powerschool for missing marks

Goal of the class • To understand the vast distances within space • Question of the day: What is the best unit of measurement within our solar system? • Previous answer: The star’s main role is to provide light and energy as well as gravity in the solar system

Astronomical distances • Astronomical distances are always measured from the Sun • Calculated in km, AU, and light years • 1 AU = 149, 000 km

Inner Planets • Mercury – Closest planet to the sun – 0. 387 AU away from the sun – • Venus – Second Planet from the solar system – 0. 723 AU away – –

Inner Planets • Earth – 1. 0 AU – – • Mars – 1. 52 AU – –

Gas giants • Jupiter (5 th planet) – 5. 20 AU away – Biggest planet – • Saturn (6 th planet) – 9. 54 AU away from the sun – Has very large rings –

Gas giants • Uranus – 19. 218 A. U. from the Sun – – • Neptune – 30. 1 A. U. from the sun – Furthest planet away

Astronomical Distances • Solar systems are very far from each other • Distances to stars are measured in light years • The current closest solar system to ours is 4. 366 light years away

Mnemonic • The order of the planets of the Solar system is: • Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune • You must create a mnemonic to remember the order and tell the class.

Vocabulary • Astronomical Unit (AU) – The distance from the earth to the sun. 149, 000 kilometers • Gas giant – a large planet mostly made of gas