Minor Bodies In Space Moons, Asteroids, & Comets

Satellite – object that orbits a larger body Natural – made when solar system was made – Moons Artificial – man made – Sputnik – first one (Russian) – Explorer 1 – first one (US) – Hubble telescope

The Moon Explored through the Apollo missions Gravity 1/6 th of Earth – So weak it cannot hold an atmosphere Surface – features called lunar features – Lighter areas - rough and high – Darker areas - smooth and flat and each is called a mar (Latin – sea)

Moon Surface Features Crater – bowl shaped depressions made by collisions Rays – bright streak extending out from young craters Ridges – long narrow elevations in dark areas Regolith – thin layer of dust from meteorites

Layers of Moon Crust – One side always dark (far side) – thicker crust and very mountainous – One side faces Earth (near side) Mantle – Mantle is thick and liquid Core – Core is small iron (not completely solid or liquid) – No magnetic field

Near side Far side The Moon

Earth Verse Moon In Size

Formation of the Moon Giant impact hypothesis – Happened 4 billion years ago – Mars size object hit Earth sending mantle out into space – Mantle clumped to form the moon – Differentiation occurred forming layers of the moon – Impacts caused craters – Lava flowed out of fissures to form marias – It has changed little in 3 billion years

Moon Formation

Movement of the Moon Rotates and revolves in 27.3 days – We see the same side of the moon Its orbit is an ellipse – Apogee – when it’s the farthest from Earth – Perigee – when it’s closest Because of the Earth’s and Moon’s movements – the moon rises or sets 50 minutes later each day

Time Lapse For 1 Month

Moon Landings

Eclipses Eclipse – when one celestial body passes through the shadow of another The shadows have two parts – Umbra – the inner part which creates a full eclipse – Penumbra – the outer part which creates a partial eclipse

Solar eclipse When the moon is between the sun and Earth Total solar eclipse – Seen over a small part of the Earth – Only lasts about 7 minutes – One is seen somewhere on Earth every 18 months Next one seen in US is 2017

Lunar eclipse When the Earth is between the sun and the moon Full lunar eclipse - when the entire moon is in Earth’s umbra Partial lunar eclipse – when part of the moon is in Earth’s umbra These take hours to complete Red moon - light reflects off Earth’s atmosphere only red reaches the moon

Phases of the moon The moon reflects sunlight – As different parts of the moon reflect sunlight we see phases New moon – the moon is between the sun and Earth (no moon seen) When the amount of the moon is increasing it’s called waxing – Waxing crescent – less than half seen – First quarter – right half is seen

– Waxing gibbous – more than half is seen – Full moon – all is seen As the amount of the moon decreases it is called waning – Waning gibbous – more than half seen – Third quarter – left half is seen – Waning crescent – most is covered

Moon’s gravity Causes tides on Earth It creates bulges – location of high tide

Bay of Fundy

Tides Neap tide – the moon and sun work against each other (low tidal range) Spring tide – the moon and sun work together (high tidal range)

Spring / Neap Tides

If No Tides Earth would spin much faster without its orbiting moon. – That's because the moon's gravity pulls on Earth's oceans, which puts the brakes on Earth's daily rotation. – At one time, the cycle of day and night was less than ten hours long. Wind patterns would likely be stronger and longer lived The polar caps would grow and recede at frightening rates.

Satellites of other planets All planets except Mercury and Venus have satellites called moons All outer planets have satellites called moons and rings

Mars Have 2 called Phobos and Diemos – Possibly captured asteroids – Tiny, irregular, cratered

Jupiter Many moons (4 large ones – called Galilean moons) – Io – have active volcanoes – Europa - have sheets of ice – Ganymede – have a magnetic field – Callisto – heavily cratered

Saturn – Most are small and icy – Titan – largest, thick atmosphere of nitrogen Neptune – Most unusual is Triton which moves backwards Pluto – Charion – similar size so called a double planet system, always in same spot in Pluto’s sky same

Rings of planets Pieces range from dust to house size Younger than the planets – possibly a shattered comet-like structure Saturn’s rings get replaced by particles of its moons

Asteroids Small, rocky objects that orbit the sun Most and are in a band between Mars and Jupiter – Asteroid belt Composition – similar to inner planets Possibly left over due to Jupiter’s gravity

Comets Small bodies of rock, ice and dust that orbit the sun They give off gas and dust in the form of a tail Halley’s Comet – passes every 76 years – next time 2061 Hale-Bopp – passes every 5-10 years

Composition – Head Core – rock, metal, ice (max 100km) Coma – cloud of gas and dust (1 million km) – Tail – gases from the ice core melting and the solar winds push it away from the head Always away from sun Over 80 million km

Meteor Meteoroid – small rocky or metal body that travels through space Meteor – bright streak of light as a meteoroid burns up in Earth’s atmosphere (shooting star) – Meteor showers occur at the same time each year when Earth passes a comets trail Meteorites – A meteoroid that hits Earth’s surface (stony, iron, or stony-iron)

Oort Cloud – cloud of dust and ice that lies far beyond Pluto – Has nuclei of billions of comets – Surrounds the solar system – Take millions of years to orbit sun Kuiper Belt – part of solar system beyond Neptune – Has objects of ice – Pluto may be part of this belt