Week 8 Shirley‘s Blog

Lab： We did the presentation one by one of the group, and introduce the 6 topics

1. Origin of the Universe

2. Lifecycles of Stars

3. Galaxies

Some of the most fundamental structures in the universe

Consists of stars, planets and vast clouds of gas and dust, all bound together by gravity.

Most galaxies are the age between 10 billion and 13.6 billion years old

The Milky way galaxy alone contains roughly 200-400 billion stars, but it's estimated that the observable universe has over 2 trillion  galaxies

I learned what is the central  of the galaxy? It's the black hole

4. Origin of the Earth

The universe began with Big Bang theory

The lithosphere contains the solid, rocky outer layer of the earth

Earth's core is as hot as the sun's surface

5. Black Holes

All black holes are black, Black holes "suck" everything 

Formed when a very big star is at the end of the life, can be different size

Time occurs differently near the black hole due to relativity

light cannot escape because the strength of the hole's gravitational

very dense, and can be small and large

It is good to have the image and the QR code link in case others want know more about the black holes.

6. Exploration of Space: past, present, and future

Russia is 3 days ahead than Americans who land on the moon

In 1969, Americans did sent someone to the moon

And we have the questions: 

1. if you are standing on the equator during the winter solstice for Iowa, what direction dose your shadow point? North

2. what time of day should you go outside to see a lunar eclipse?  Midnight, and the Solar eclipse is noon

3. If the sun and moon are both on the same horizon, what. phase is that moon? New moon

Lecture: I learned the origin of the universe, first one is Big Bang, which is 13.7 billion years ago there was nothing and nowhere, and expansion not an explosion. There are some Alternative theories of the Big Bang. 

Then we talked about Stars, those began to form about 12.7 billion years ago, ours is 4.65 billion years old and is 4.65 billion years old and is about half -way through its full supply.

The we talked about where did the earth come from?

It created 4.65 billion years ago, which is not in the big bang, the dust and debris most likely from a former star that exploded. Planes of the Ecliptic created planets. Formation of the Earth-4.65 Billion years ago

Galaxies: There over 2 Trillion galaxies, Three primary shapes: Spiral, Elliptical, Irregular. 

Black Holes: Super dense, Nothing, including light, can escape, center of galaxies.

Pressbook: https://docs.google.com/document/d/14_UM9ERq0ljfnH22AzZZkFbcRuTu3Nr0Iz62RgFbK4w/edit?tab=t.0 review the notes for test

History of earth

Geologic Time

Entirety of Earth’s history was represented on a clock

地球生命的起源：细菌、植物和动物

• 46.5亿年前：地球形成
• 40亿年前：地球上的第一个生命是简单的原核细菌。
• 6 亿年前：水生植物和动物开始进化。生命起源于水中，可能是因为与陆地相比，水中为早期生物提供了更稳定的温度，洋流为早期生物提供了运动，而且它们不需要对抗重力。
• 5亿年前：生命进化和多样化的重要时期，被称为寒武纪。
• 4亿年前：陆地植物和动物进化。
• 6500万至2.5亿年前：恐龙生活在中生代。
• 20万至30万年前：人类的早期祖先智人进化。

雪球地球（正反馈循环的事件）冰具有高反照率，并且非常隔热，因此阳光无法有效地加热它

地球历史上至少有三次几乎完全被冰层吞没——这一事件被称为雪球地球。这些事件发生在 5.8 亿至 7.5 亿年前。雪球地球的证据来自沉积岩。在正常的冰河时代，冰川沉积的岩石类型主要出现在地球两极附近。然而，地质学家在世界各地的两极和赤道地区都发现了类似年龄的冰川岩石。这导致了雪球地球理论的产生。

盘古大陆 

由于板块构造，地球的陆地随着时间的推移不断移动和变化。2.5 亿年前，地球的所有陆地都连成一个超级大陆，称为盘古大陆。

大陆漂移

大陆漂移理论由科学家阿尔弗雷德·魏格纳提出，是解释大陆随时间移动的原因的最早方法之一。

关键要点

地球历史时间轴：