Download Origins of the Earth Video Notes

Geography 10
Origin of the Earth Video
Ms. Ripley
How did Earth go from a raging inferno to a habitual place for complex organisms?
Solar Nebula – center of this disc pressure and temperature rose, and a star (our
sun) was born. Eventually hydrogen and helium were swept to farther ends of the
disc.
Collisions of the rocks (meteorites) in the solar system. Other times the rocks
stuck together. The larger they got, the stronger their gravity became. Because
of the gravitational attraction.
Few miles across. Some of the planetismals and then they combined – mercury,
Venus, mars and Earth. But Earth didn’t look like it does today as a newborn planet.
(Baby Earth versus a human). Weight, age…snap shot gives a good idea of what you
looked like when you were young.
Newborn planet – covered with lava, earliest times – first few hundred million
years – recycling material – rocks from the material have not survived. Clues – from
outer space to tell us about Earth. 100 million miles from earth is the asteroid belt
– enormous rocks left over from planet building. Sometimes these fall out of orbit
– they are called meteors – that sometimes collide with Earth.
NW corner of BC – Meteor comes to Earth (by the Alaska border). They sent a
sample of the frozen material to NASA. More than 400 fragments could give clues
– uncontaminated inside to when they were first formed 4.5 billion years ago.
This meteorite could tell us the dust range chemical make up.
Meteorites are windows of the past – conditions that made up of how planets are
formed. Very high water content. 90 other elements have been identified – giving
us almost a fingerprint of the earth. Radioactive elements can tell us the meteorite
age. Age of the meteorite gives the age of Earth and its neighbours. 4.5 – 5 billion
years old.
Magma ocean – liquid rock ocean – hundreds of km thick.
Current – produced north and south poles. The core is in constant motion. Snow –
northern Canada. Magnetic North Pole – moving randomly over a course of a day.
Search of the precise location of (north on a compass). Days at a time - 50degrees on the ice looking for this location. Geographic North Pole is in a fixed
position. Its position has changed dramatically (the magnetic north pole). He
measured the strength of the field and then closes in on it. Surround the magnetic
pole – triangulation is the process that they use to find the magnetic north pole. It
Geography 10
Origin of the Earth Video
Ms. Ripley
had moved 125 miles off the Canadian coast. Its movement is picking up speed. It’s
been about 10km a year. Now it’s 40km per year. It’s now moving faster and it
might move to Siberia in another 40 years.
Iron core – swirling ball of molten iron. We need that magnetic field – because of
the electrical chemicals that are bombarding the earth. Ejected from the sun –
these particles million miles an hour – solar wind. Solar wind if it reached our planet
it would strip away our atmosphere, but our magnetic field saves us because it
deflects this.
Mars – magnetic field – thick atmosphere and supported water on its surface and
it might have been home to other beings. Its iron core cooled and its molten iron –
it stopped generating the magnetic field and it was stripped away and that’s why
Mars is a desert.
12:16am: Formation of the earth’s core and the magnetic shield – our world is
hostile. Volcanoes, Earth were engulfed, steam, nitrogen and carbon dioxide, no
magnetic field – life could not happen. The moon was born.
The Moon: Millions of years younger than the earth. They found this by
examining rocks.
The moon drifted away from the Earth and the Earth’s rotation slowed down.
Seasons were caused – gravitational pull from the moon.
Once Earth was cool enough water could collect on its surface. Zircon crystals –
which are extremely rare. Every living thing requires water to survive. 100 million
trillion gallons of water. Where did it all come from? How did earth come up with
it?
They may have been there from the very beginning, just hidden away. Volcanoes
pumped steam into the atmosphere. Water may have come from outer space.
Heat of the impact – storm clouds over vast parts of the planet. Acidic rain that
continued for millions of years. The rain would have formed lakes and rivers. The
problem with this theory – there is a different chemical make up in the ocean.
Extra neutron. In the comets analyzed so far – they don’t match the composition in
our oceans. They wouldn’t fit the bill – don’t have the right properties.
Comets closer to the sun might be different and might closely match the oceans.
Getting a first hand look at this comet.