# Earth science explained

We don't know exactly how this planet was formed. This is hotly contested based on philosophical cosmological beliefs:

1. Astronomers say gravity drew the elements from various stars, which clumped together over a very long time until it eventually became what we recognize now.
2. [Religious](religion.md) people say God formed the Earth as a finished product.

The views on creationism have a profound effect on earth science.

- If the universe was formed in a completed state, the rock strata are explained by a worldwide flood that happened 6,000 years ago.
- If the universe evolved all the way from the Big Bang, then the rock strata are the accumulation of millions of years of debris.
- Either interpretation validates the conclusions to prove an entirely different but vast body of information.

Rocks come in several forms.

- Igneous: formerly magma from volcanoes.
- Sedimentary: rocks that come from packed sediment, which can be organic or nonliving.
- Metamorphic: rocks that transformed due to extreme temperature surpassing 300-400 °F and pressure surpassing 100 megapascals.

We don't know much about what's under the surface, but are aware of splits in tectonic plates (fault lines) that span the globe.

- There are many fault lines that are completely inactive, while others are active and cause earthquakes.
- There are 3 types of faults:
  - Normal: a split between the plates that moves apart.
  - Reverse: the split involves the plates pushing together, usually with one of them being shoved above or below the other.
  - Transverse: the plates rub against each other.

## Obvious unanswered questions

- How much can we damage the ecosystem before it stops self-healing?