GEO1: Origins of the universe

What percentage of the solar system's mass is made up by the planets?

About 0.15%.

What accounts for 99.85% of the solar system's mass?

The sun.

What are the four inner planets of the solar system?

Mercury, Venus, Earth, and Mars.

What type of planets are the inner planets known as?

Terrestrial or 'rocky' planets.

What elements mostly make up the outer planets in the solar system?

Hydrogen and helium.

How long ago did the universe begin according to current understanding?

13.7 billion years ago.

Who discovered Hubble's law, and when?

Edwin Hubble in 1929.

What does Hubble's law describe?

The movement of galaxies, stating that galaxies farther away are moving faster.

What is the formula for energy derived from frequency?

E=hv.

What process led to the formation of the Sun?

The collapse of a large mass of gas within an interstellar cloud.

What is the size of planetesimals that formed during solar system formation?

Up to a few kilometers across.

What happened to Earth after the large object collided with it during the Moon-forming impact?

Earth melted to its core and material was propelled into space.

When is the current estimate for the Moon-forming impact?

About 4.51 billion years ago.

What effect did the Moon-forming impact have on Earth's rotation?

It increased Earth's spin.

What is the age of the oldest Moon rocks brought back by Apollo astronauts?

About 4.47 billion years.

What is attributed to the tilt of Earth's axis caused by the Moon-forming impact?

Seasons on Earth.

What was left over after the formation of the planets?

Residual solid material, such as meteorites and asteroids.

What important geological feature indicates past collisions on the Moon?

The cratered surface.

What happened to the material ejected during the Moon-forming impact?

It aggregated and solidified to form the Moon.