World History chapters 1-2

What are two key pieces of supporting evidence for the Big Bang?

The expansion of the universe and the Cosmic Microwave Background Radiation (CMBR). 우주가 팽창하고 있다는 관측 + CMBR 가 빅뱅을 뒷받침하는 핵심 증거

How long would it take to count to a million? A billion?

1 million → 약 11.6 days

1 billion → 약 31.7 years

Million = 12 days 정도 / Billion = 32 years 정도

“The cosmos is fertilized and nourished by dead stars.”

When stars die, they release elements into space. These elements can later become the ingredients for new stars, planets, and life.

→ 별이 죽으면서 원소(elements)를 우주에 퍼뜨리고, 그 원소들이 새로운 별·행성·생명의 재료가 된다는 뜻.

How many stars are in our galaxy? How many galaxies beyond ours are thought to exist?

• Milky Way: about 100–400 billion stars

• Observable universe: hundreds of billions to possibly around 2 trillion galaxies, depending on the estimate.

Explain the Goldilocks Zone in terms of our search for life beyond Earth.

The Goldilocks Zone is the region around a star where conditions may be just right for liquid water to exist on a planet's surface.

→ 별에서 너무 가깝지도, 너무 멀지도 않은 거리라서 액체 상태의 물이 존재할 가능성이 있는 영역

How is the moon thought to have formed?

The Moon is thought to have formed after a giant impact between the early Earth and a large planetary body. Debris from the collision came together to form the Moon.

→ 초기 지구가 큰 천체와 충돌 → 나온 debris(잔해)가 모임 → Moon 형성.

What two things cause the seasons?

Earth's axial tilt and its revolution (rotation) around the Sun.

→ 지구의 자전축 기울기 + 태양 주위를 공전하는 것

What was the early Earth like? Why is the period called the Hadean Era?

Early Earth was extremely hot, volcanic activity, molten rock, and frequent impacts from space. → 초기 지구 = 매우 뜨겁고 화산 활동이 많고, 운석 충돌도 많았음.

It is called the Hadean Era because conditions were thought to be hellish, like Hades. → Hades = 지옥의 신/지하세계에서 이름이 유래.

How many tectonic plates are there?

There are about 14 major tectonic plates and 50 smaller plates

At about what speed do the plates move around?

About a few centimeters per year. (손톱이 자라는 속도)

What drives the movement of the plates on Earth's crust?

Heat from Earth's interior, which drives movement in the mantle.

→ 지구 내부의 열이 맨틀의 움직임을 만들고, 이것이 plate movement와 연결됨.

What kinds of things are plate tectonics responsible for?

Earthquakes, volcanoes, mountains, and the movement of continents.

What was Pangaea? When did it exist?

Pangaea was a supercontinent where most of Earth's continents were joined together. It existed roughly 335–175 million years ago.

→ 대부분의 대륙이 하나로 붙어 있던 초대륙.

Pangaea = one giant continent

What is the name for the next Pangaea? When might it exist? What might happen here in Savannah?

Pangaea Ultima (also called Pangaea Proxima in some models), and it could form in about 200–250 million years.

Savannah could be the interior of the future supercontinent, potentially making the climate hotter and drier.

Next Pangaea → ~200–250 million years → Savannah may be farther inland → hotter/drier conditions

What is a paradox? Be able to provide two examples.

Two things seem contradictory, but both are true

Fermi Paradox: Intelligent life may exist elsewhere, but we have found no clear evidence of it.

“The more you know, the more you realize how much you don't know.”

What is a paradigm shift? How do geocentric and heliocentric relate to this?

A paradigm shift is a major change in the way people understand or think about something.

Geocentric → Heliocentric
→ Earth-centered model에서 Sun-centered model로 생각이 바뀐 것.

Paradigm shift = old way of thinking → new way of thinking

How has glass helped create Big History?

Glass made it possible to create telescopes and microscopes, allowing humans to see much farther into space and much smaller things than the naked eye can see.

→ 유리로 망원경(telescope)을 만들어 우주를 관찰할 수 있었고, 현미경(microscope)으로 아주 작은 세계도 관찰할 수 있게 됨.