How are stars created Make a foldable to

How are stars created?

Make a foldable to describe the process in which a star system is created and how gravity is responsible for this.

Definition: A gigantic cloud of dust and gas in the universe that clumps together to form stars and planets. Example: The eagle nebula. Facts: The gas is mostly the smallest atomshydrogen and helium. The dust is extremely small particles too small to be seen with the eye. Gravity pulls the gas and dust together. Nebula Non-example: The Milky Way galaxy which already has gone beyond a cloud of gas and dust to form a galaxy.

Definition: An explanation that is supported by a lot of evidence and which is widely accepted by scientists and other people. A theory can sum up a lot of observations and is used to make predictions. Facts: A theory is accepted as the way things are until new evidence comes along. Examples: Theory of Evolution Theory of Plate Tectonics String Theory of Gravity Non-example: Explanations for phenomena that are based on religious beliefs, myths, mysticism, folklore, hunches, etc…. Theory

Definition: A pulling force that draws things with mass together. Facts: Gravity acts over extremely large distances. Gravity acts on the smallest of particles (a molecule or bit of dust or atom) to the largest of objects (a star, a galaxy and the universe). Gravity Example: Gravity pulls the Earth and Moon towards each other and keeps the moon in orbit around the Earth. Gravity pulls the Earth and Sun together and keeps the Earth in orbit around the Sun. Non-Example: Gravity is not friction or a pushing force.

Discuss what you already know about the following: • The Sun • The planets • Our solar system • Exoplanets • Formation of earth

• Use photographs to develop an understanding of the process of solar system formation. • Recognize that gravity is the driving force behind solar system formation. • Be able to describe how stars form.

Step #1: A cloud of gas and dust began to be pulled together by gravity.

• Dust is mostly carbon like the graphite in your pencil. The dust is very, very smalltoo small to be seen with the eye. The dust came from comets and stars that exploded long ago.

Step #2: Gravity pulls the mass together. The more mass, the greater the pull. The lightest matter (hydrogen) gets pulled to the center. This pull starts the cloud spinning around. The spin makes it start to flatten out. The gravitational energy is transformed into thermal energy and the center becomes very hot.

• Step #3: Gravity pulls the light hydrogen atoms to the center. The hydrogen atoms combine or fuse together (nuclear fusion). The fusion gives off tremendous amounts of energy. This energy is electromagnetic (light) and kinetic (heat). This creates a star. This takes only a few thousand years for the star to form.

• Step #4: The other more dense matter (dust) continues to be pulled together. Some of that matter condenses into planets.

Here are some gas and dust clouds shaped like pillars. Would gravity make the gas pillars grow larger (expand) or grow smaller (condense)? Why?

How big do you think one of the gas pillars in this nebula is? Answer: 24 trillion miles tall! (24, 000, 000) (3 million Earth’s tall)

• Here is a tiny portion of one gas pillar in the Orion Nebula. Do you see the blobs? What are they? What is happening to the big blob? Is it flattening? Giving off light?

The star that is forming in the center blob could fit 8 of our solar systems in it! What will continue to happen to it?

1. 2. 3. 4.

What causes a nebula to begin to shrink? A. electric forces B. gravitational forces C. magnetic forces D. temperature

Where does a star’s energy come from? A. gravitational shrinking B. nuclear fusion C. chemical reactions D. nuclear fission

First: The fusion rate increases. This means, hydrogen atoms fuse together to become helium until all of the hydrogen is used up. Some very low mass stars never go beyond this stage. They use up their hydrogen and cool and become like a planet. They are called Brown Dwarfs. Second: In big enough stars: the temperature increases and more energy is released. Some low mass stars use up all of their hydrogen , cool, and shrink. They become White Dwarfs. Third: Some moderate mass stars get brighter when they run out of hydrogen. The outer shell expands and cools. They become Red Giants. Their outer shell gets blown away and becomes a nebula while the core becomes a White Dwarf. Really massive stars end their lives by exploding as a Supernovae. The core will then collapse and become a black hole.

5 billion years ago: 75% hydrogen 25% helium Today: 35% hydrogen 65% helium 5 billion years in the future: 0% hydrogen 100% helium Earth’s temperature will be about 40 0 F hotter. The oceans will be gone. The Sun’s outer core will expand the Sun will become a Red Giant. Theory #1: The Earth will get engulfed by the Sun and exist no more. Theory #2: When the Sun first begins to shrink, gravitational attraction between the Earth and Sun will become less. Some scientists think the Earth may move away from the Sun as gravity no longer holds them together. If this happens, the Earth will be a cold, desolate, barren rock in space.

Our Sun is one of 200 billion stars in our galaxy. We did not know this until very recently when new technology allowed scientists to see through the dust and gas to the center of the galaxy.

The Milky Way Galaxy is spiral shaped and flat. In the core is a bulge of very high density stars. This core gravitationally pulls on the rest of the mass, causing our galaxy to spin. Recent evidence shows a black hole at the center of our galaxy. We are located about 1/3 of the way from the center.

Almost everything you see when you look up in the night sky is part of the Milky Way Galaxy. The exception is a smudge of light you see that is actually another galaxy, the galaxy closest to earth, Andromeda.

• Title Page: Solar Nebula Theory • Page 1: Explain what a scientific theory is and is not. Use examples. • Page 2: Describe a nebula. • Page 3: Step 1: Draw a cloud of gas and dust (nebula). Describe how this cloud begins to contract due to gravity. • Page 3: Draw a disk with a bulge at the middle. Describe how this forms from the nebula. • Page 4: Draw a star with matter surrounding it. Describe how a star begins. • Page 5: Draw a planetary system around the star. Describe how the matter forms into planets. • Page 6: Describe the life cycle of an ordinary star.