The Big Bang, Galaxies, & Stars Astronomy The study of the Universe, stars, planets, and all other objects in space. The Big Bang, Galaxies, & Stars

The Universe Composed of empty space, energy, and matter. Matter = gasses and dust particles When matter comes together, stars, planets, meteors, asteroids, and comets form.

The Visible Universe The Hubble telescopes allows astronomers to gaze into deep space. New galaxies are discovered

How did the universe begin??? Big Bang Theory marks the origin of the universe Occurred about 13.7 billion years ago All matter and space was created Not a huge explosion that hurled matter in all directions. Technically, there was no “bang”

4 Stages of the Big bang Theory All matter and energy in the universe was once located in a single dense point called a singularity. A rapid expansion occurred. Matter and energy were propelled outward in all directions as the universe began to expand. Matter began to condense - forming galaxies and these galaxies continue to expand today.

Raisin bread analogy of an expanding universe Raisins represent stars and galaxies. According to the Big Bang Theory, all stars and galaxies are moving away from each other.

Life Cycle of Stars 1st Step: Stars form from nebulas Regions of concentrated dust and gas Gas and dust begin to collide, contract and heat up All due to gravity

Life Cycle of Stars 2nd Step: As nebula contracts, a small star is formed Called a protostar Eventually, the protostar will begin nuclear fusion Hydrogen protons attract to each other Strong nuclear force Fusion begins Necessary for stars to survive

Life Cycle of Stars 3rd Step: Star joins the main sequence 90% of stars spend life here Nuclear fusion = Hydrogen into Helium Mass of star determines location on main sequence

Life Cycle of Stars Beginning of the End: Stars begin to die when they run out of hydrogen Gravity begins to take over Star core begins to shrink; outer core of hydrogen begins to fuse Star gets bigger

Life Cycle of Stars Beginning of the End: When star gets bigger, it cools down Red giant Eventually, star can fuse helium into other elements Carbon, oxygen, and other heavier elements

Life Cycle of Stars Beginning of the End: Once star runs out of “fuel”, star shrinks under its own gravity Turn into a white dwarf, neutron star, or black hole

Life Cycle of Stars Death of Stars: What stars end up as depend on mass Low and Medium mass stars Planetary nebula --------- white dwarf High mass stars Supernova --------- neutron star or black hole

Life Cycle of Stars Death of Stars: Low and Medium Mass Main Sequence Star Red Giant Planetary Nebula White Dwarf

Life Cycle of Stars Death of Stars: High Mass Main Sequence Star Red Super Giant Supernova Neutron Star Black Hole

Black Holes What is a Black Hole??? Black Holes Info Sheet An object so massive and dense that not even light can escape its gravity The end result from a supernova of a star that has a mass greater than 3x the sun

Life Cycle of Stars High Mass Stars: Mass greater than 8x our sun Create high mass elements such as iron Neutron Star Formed if remaining star < 3x sun’s mass Black Holes Formed if remaining star > 3x sun’s mass

Life Cycle of the Sun As fusion begins to slow down, the core of the sun will contract Temperature in the core will rise The outer layers of the sun will expand, consuming in the inner planets Sun will become a Red Giant

Life Cycle of the Sun

Life Cycle of the Sun Core of the sun will begin to fuse helium into larger elements such as carbon and oxygen Continuing over the next 100 million years… Core will become entirely carbon and oxygen Core will contract Outer layers will expand Outer layers will form a planetary nebula Core of sun will become a white dwarf

The Hertzsprung-Russell Diagram An H-R diagram plots stars according to their luminosity and temperature (or spectral class) 5/23/2019

Do Now Describe the big bang theory in your own words Explain why we experience 4 different seasons every year.

EARTH'S ROTATION AND REVOLUTION

Earth’s Rotation Rotation is the spinning of the Earth on its axis. The time for one rotation is 24 hours. The speed of rotation 24,855 miles/24 hr or 1,038 miles/hr

Earth’s Rotation – Causes daily changes The spinning of earth on its AXIS the imaginary line through the planet from the North Pole to the South Pole – is its rotation The axis of the earth is tilted 23.5° Earth’s rotation West to East How many degrees is a circle? _____ How many hours in one day? _____ SO, how quickly does the Earth rotate? 15 degrees / hour

Effects of Rotation Star Trails Arc of the Sun in the sky Day/Night

How do we know the Earth is really turning? Foucault Pendulum A pendulum was set moving and will continue to swing unless an outside force was acted upon it

No force that makes pendulum rotate – must be earth that is rotating!!! Inertia and gravity make it swing straight out and straight down in a straight arc – not twist.

How do we know the Earth is really turning? Coriolis Effect – the tendency of objects moving over the earth (air, water, planes, projectiles) to be deflected (curve away) from a straight line path.

Earth’s Revolution A revolution occurs as the earth moves around the sun. Time for one revolution = 365 1/4 days = 8,766 hours The speed of earth’s revolution is about 18 miles per second.

Earth’s Revolution

Earth’s Orbit The path an object takes as it revolves around another object.

Around and Around We Go Every second, that you sit in this classroom, the Earth's orbital motion carries you about 18 miles through space.

Evidence of Earth’s Revolution around the Sun Seasonal Constellations: Because of the Sun’s annual motion, some constellations are visible at night only during certain seasons. Constellations are visible when the dark side of Earth (away from sun) faces toward the constellation.

The 13 constellations the sun appears to travel through during the year

Apparent Motion of Sun due to Rotation and Revolution Rotation: Sun – apparent daily path from sunrise to sunset has the shape of an arc moving l5° per hour. Revolution: However, the sun’s arc changes both its position and its length with the seasons

Summer maximum altitude of noon sun is 73°, Winter is 26° Spring/Autumn? (Sun 90 at 23.5 41-23.5 = 17.5 90-17.5=72.5) ( 90-41= 49) (41+23.5 = 64.5 90-64.5 = 25.5)