Astronomy kdY7aA

How our Universe Formed Theory of how the universe formed called the Big Bang Theory Theory of how the universe formed called the Big Bang Theory Big Bang Theory – the universe formed from a massive expansion approximately 14 bya Big Bang Theory – the universe formed from a massive expansion approximately 14 bya The Universe is expanding and the visible edge is about 13.7 billion light years away

The universe began billions of years ago as a tiny dot that exploded into today’s huge system of stars and planets.

Support for the Big bang Theory Red shifts Cosmic background radiation –Radio signals coming from every direction in space. –Believed to be created by the big bang explosion.

The Expanding Universe 1929 – Edwin Hubble found that the universe is expanding –Estimated distances, relative brightness, Doppler red shifts

Dimmer galaxies had greater red shifts  farthest from Earth tKC3nEx2I Hubble’s Law: the more distant the galaxies have greater red shifts, therefore they are moving away at faster speeds. Milky Way Galaxy…spiral shaped!

Note: Our solar system is part of a bigger system called a galaxy. Our galaxy (Milky Way) is part of a bigger system called the universe Milky Way Galaxy…spiral shaped!

Galaxies and Stars  Galaxies – billions of star groups  more than 100 billion galaxies, each containing billions of stars Milky Way Galaxy…spiral shaped!

So, how did our Solar System form? The Nebular Theory – explains that solar system was formed from a rotating disk of dust and gas The Nebular Theory – explains that solar system was formed from a rotating disk of dust and gas Formed ~4.6 bya Formed ~4.6 bya

1.Solar System began as a giant ball of dust and gases (after the Big Bang) 2.Cloud flattened as it spun around, forming an accretion disk. ►Sun formed in the middle from all the heat in the middle of the disk 3.Cooling of the disk caused small shapes to form 4. These cool forms combined to make the 4 SOLID inner planets 5.The lighter material combined farther away, forming the 4 GASEOUS outer planets

Mercury Earth Venus Jupiter Neptune Mars Pluto Saturn Uranus

How Earth’s Formation Affected Earth Earth orbits the Sun following Kepler’s 3 laws of planetary motion Earth orbits the Sun following Kepler’s 3 laws of planetary motion 1.The path of each planet around the Sun is an ellipse 2.Equal areas are covered in equal time 3.The length of time it takes a planet to orbit the Sun is proportional to its distance from the Sun

Kepler ( ) came up with these scientific laws and they are still used in Astronomy today! om/watch?v=pJlTuv Hg6wY&feature=fvsr

1 st Law: Law of Ellipses The path of the planets around the sun are elliptical in shape with the center of the sun being located at one focus The shape of the ellipse is determined by the location of the two focus points!

2 nd Law: Law of Equal Areas This law states that an imaginary line from the sun to a planet sweeps out equal areas in equal time intervals

Kepler’s 2 nd Law of Planetary Motion

Are they the SAME? The short wide glass is holding the SAME amount of water as the tall skinny glass! The short wide glass is holding the SAME amount of water as the tall skinny glass!

Planet moves FASTER in orbit when CLOSE to the SUN, and SLOWER in orbit when FAR FROM the SUN WHY? GRAVITATIONAL PULL

Keppler’s 3 rd Law

Do Now 1.What does eccentricity measure? 2.Ms. Sterling observed the orbital path of Mars. From the data she collected, she found the focal point length to be 10 light years and the major axis length to be 22.5 light years. Find Mars’ eccentricity based on her observations. 3.Planet X has an eccentricity of and Plant Y has an eccentricity of Using these measurements explain the paths of these planets around the sun.

The Sun The sun is at the center of our solar system. You may have learned that the planets orbit the sun, but in fact the Sun and planets orbit each other around the barycenter.

The Sun Our Sun and all other stars produce their energy by a process called nuclear fusion Our Sun and all other stars produce their energy by a process called nuclear fusion Fusion is when hydrogen atoms collide to make a Helium atom; this releases lots of energy Fusion is when hydrogen atoms collide to make a Helium atom; this releases lots of energy Sun consumes 600 million tons of H each second!

What is the Difference between Fusion and Fission? Fission is the opposite idea…instead of building bigger atoms, you are breaking atoms apart Fission is the opposite idea…instead of building bigger atoms, you are breaking atoms apart Nuclear Power Plants like McGuire Nuclear Station in Huntersville do this with Uranium

Energy Produced by the Sun Most of what astronomers know about our universe is known from studying the light emitted from distant sources Most of what astronomers know about our universe is known from studying the light emitted from distant sources

Electromagnetic Spectrum Visible light is just a small portion of the energy emitted by stars…what else is there?

Gamma Rays - are produced by violent nuclear explosions in space and are absorbed by our atmosphere…good thing, they are deadly to human cells! X-rays - are also absorbed by Earth’s atmosphere, so NASA has to put x-ray telescopes into space UV Rays - are mostly blocked by the ozone layer, but some can get through and cause sunburns! Infrared Rays - cause the heat we feel from sunlight Microwaves - easily move through atmosphere and are used in with satellites and GPS Radio Waves - are used with huge telescopes to learn about the structure, composition, and motion of objects in space

The Electromagnetic Spectrum