The Solar System The big hot thing at

The Solar System • • • The big hot thing at the centre Rocky bits Goldilocks Bloated giants Frozen dwarfs

Sun Diameter: 1. 4 million km Mass: ~2, 000, 000, 000 kg At its core 14 million degrees C Surface 6, 000 degrees C Its light takes almost 8 minutes to travel the 150 million km to reach us

The sun calmly rises each morning in the east, just like clockwork. Credit: the Solar. Max IMAX film

Our Solar System The Sun is the center of our solar system. All the planets and comets, everything in the solar system revolves around it. At any given time about half the Earth sees the Sun and half is in darkness.

Speaking of size. . . planets

Star sizes

The changing Sun The Sun, like all stars, is a busy star. It is always active, always changing. The more we learn about it, the more we learn about all stars.

Where the action is • Nuclear activity occurs in the Sun’s core • Hydrogen atoms combine to form helium and release huge amounts of energy, radiation and light • It takes over 10, 000 years for the light to get to the Sun’s surface • The temperature there is about 15 million degrees C.

The average sunspot is about the size of Earth, though the largest can be 20 times the size of Earth.

Our Solar System

Mercury Orbit: 60 m km 88 days Diameter: 4, 880 km Temperature: -180 to 450 o. C

Venus Distance: 108 m km ~225 days Diameter: 12, 104 km Temperature: ~500 o. C Pressure: ~90 atmospheres

Distance: 150 m km 365. 24 days Diameter: 12, 756 km

Goldilocks…

Martians – the good, the bad and the ugly. . .

Mars Orbit: 225 m km ~687 days Diameter: 6, 794 km Temperature: -100 to +20 o. C

Asteroids Rock, metal

Where are the asteroids?

Jupiter Orbit: 780 m km 11. 9 years Diameter: 143, 000 km Temperature: -110 o. C 63 moons (so far)

90% Hydrogen 10% Helium Tiny fraction other

Saturn Orbit: 1425 m km 29. 4 years Diameter: 120, 000 km Temperature: -180 o. C >61 moons

96% Hydrogen 3% Helium 1% other

Uranus Orbit: 2880 m km 84 years Diameter: 51, 120 km (4 Earth) Temperature: -220 o. C

Neptune Orbit: 4515 m km 165 years Diameter: 49, 528 km (3. 9 Earth) Temperature: -220 o. C

Pluto Dwarf planet Orbit: 5925 m km ~249 years Diameter: 2, 290 km Temperature: -223 o. C

Our Solar System