Chapter 1 Earth Science Review

Big Bang Generally accepted theory explaining the origin of the universe. All of the mass in the universe was originally concentrated at one point (singularity) at the beginning of time. The universe expanded from that point and is still expanding today. Scientists have calculated that the universe began about 15 billion years ago!

Most of the detectable mass in the universe is…………… HYDROGEN!!

Nebular Theory Generally accepted theory of the formation of the solar system. Nebula : A cloud of gas and dust in space. Rotation of nebula caused 90% of mass to contract to the center, forming the sun. Remaining matter “clumped together” by gravity (accretion) to form the planets, moons, asteroids, etc. Our solar system (including the Earth) is thought to have formed about 4.5 billion years ago!

The Earth Forms……. Material clumps together (accretion) and gravity pulls the most dense materials to the center (core). Lighter materials float to the surface. Density Stratification: The formation of layers within a material, with each deeper layer being more dense than the layer above.

Earth’s Early Atmosphere Out-gassing from volcanoes formed the Earth’s original atmosphere and the oceans. Hydrogen, Helium, Methane, Ammonia, Carbon Dioxide, Water vapor.

1st Oxygen came from………… PLANTS!!!!

The Oceans Form Water vapor in the atmosphere condensed into clouds and rained down on the Earth. As run-off drained into rivers and streams, the moving water dissolved rocks along the way, leaving dissolved salts and other minerals in the water that eventually formed the oceans.

Biosynthesis Scientists have theorized that the 1st life on Earth may have formed from “organic building blocks” such as amino acids and nucleotides combined with sunlight.

Water cycle