Origins: Earth is Born

Earth's iron core creates a magnetic field which protects the planet from________?

Solar winds

What are two possible sources of water on the Earth's surface today?

Steam condensed into rain and from other comets

If we imagine Earth's total 4.5 billion year history to be over the span of one day, how long ago did humans being to walk the Earth?

30 seconds

How long ago were there at least islands of continental crust on Earth?

4.4 billion years

What are scientists trying to determine when they look at the age of zircons in Australia?

When the crust of the Earth formed

How quickly is the moon moving away from the Earth?

1.5 inches away every year

The leading theory for the moon's formation involves what catastrophic event?

A large body of materials crashed into Earth

What are scientists able to calculate from the radioactive elements found in a meteorite that decay at a particular rate?

Age

Was the moon closer or farther when the Earth was younger?

Closer

What special kind of water do scientists look at in the ocean and in comets to see if the proportions match?

HDO

During this time when the Earth was liquid rock, what type of elements sank toward Earth's center?

Iron and metals

What name do scientists give to Earth when the outer surface was completely molten?

Magma ocean

What planet is believed to have once a magnetic field that disappeared when the planet's iron core cooled?

Mars

What type of objects can give us information about the conditions in which the solid planets (like Earth) formed?

Meteorites

Is the magnetic north pole's movement picking up speed or slowing down over recent years?

Picking up speed

What is the name of the small early planets, which formed through gravitational attraction reaching sizes of a few miles to eventually the size of our moon?

Planetesimals

When scientists used radioactive dating on rocks from the moon, how did the moon's age compare to Earth's age? Was the composition of the rocks same or different from the Earth's?

The moon is a million+ years younger than the Earth and it was made with the same material

When the Earth first formed, what was the Earth like?

Very hot lava, fiery ball of rock