Down the rabbit hole

Large objects in space and the big bang theory

Star Bursts

• Artemis and you look up into a clear, moonless sky at night.

1)Your friend turns to you and asks you why stars have different colors and intensities. Your response is…

2)She also suggests that they are not moving. Do you agree or disagree? Why.

Star bursts continued

3) How do you explain the band of maximum star density (colored red) in the night sky as shown in this picture?

What do you think is meant by a red dwarf star?

Red dwarfs

• Stars that are about 40% of the size of Sol• Cooler star, different color• Burn fuel at a much slower rate• Could live 100’s of billions of years• Could have earth type planets

Suns come in different sizes

• Depends on the size of the original nebula or amount of material

• The larger the sun, the smaller its life span (rate at which fuel is used)– Yellow stars like our sun, live about 10 billion

years– Large ones, only a couple of hundred million years

or less

Our sun is an average size

• Smaller stars are more common

• Red Dwarfs have no more than 40% of the mass of our sun

• Small stars can live for very long, possibly up to a trillion years

• Not a stage of the lifecycle, but a class of star

Star color

• Strong indication of the surface temperature of the star

• Blue is hottest• White• Yellow is medium• Orange• Red means lower temps

Star classification

• Russell-Hertzsprung diagram• Classified by color, brightness (luminosity)

http://en.wikipedia.org/wiki/File:HRDiagram.png

How old is the universe?

Big bang theory

• Present theory that explains the start of our universe

• All matter exploded (bang) into the universe from a single point

• Different theories about fate of universe

Major stages of BB

• 1 second- matter cooled enough to allow creation of protons, neutrons and electrons, but not atoms – a great fog

• 300,000 years matter cools enough so first atoms appear, and the universe has light

• 1 billion years, helium, hydrogen gas cool enough to form first galaxies- quasars

Big Bang

• Occurred 15ish billion years ago• Hubble telescope is looking towards the initial point• Astronomers have located Quasars that are 12 billion

lights-years away

Galaxy• Galaxy: Large scale groups of stars that rotate about a

common axis

• Average galaxy is 100,000 light years across and contains 100 billion stars

• Astronomers estimate there are between 50 billion and 1 trillion galaxies in existence

• More stars than grains of sand on all beaches on Earth

Quasars• Some of the first objects

formed after the big-bang.

• Quasi-stellar radio source

• Most distant objects observed from earth

• Move at 90% speed of light• Star like in size, bizarre in

action• Might be the protogalaxies

What do galaxies and stars rotate about?

• What would have a large enough gravitational pull to achieve such rotation?

• Dense concentrations of stars• Black holes

• Black holes probably exist at the center of every galaxy, place where massive stars are first created and died

Black holes near us

Our galaxy’s name is

• The Milky Way

• 2000 light years thick

• Our sun is located about 30,000 light-years from the center 2/3rds of the way out

• Galaxy is Rotating, 1 cycle takes 200 million years to complete

Milky way

Milky way

Galaxy clusters

• Groups of galaxies that rotate about a specific point

Recap

• The color of the star generally indicates…• The big bang explains…• A galaxy is…• A quasar is…• The Milky Way is…• At the center of our galaxy is…• A cluster is…

Is anybody out there?

Extraterrestrial means…

Is there life in the universe besides us?

Are we alone?

How does the number of stars affect the chance for life?

How does the type of stars (or planets formed)

affect the chance for life?

How does the evolution of life affect the chances for life?

What factors are important to consider in determining the likelihood that there extraterrestrial life in our galaxy?

Factors• Number of stars• Number of planets around stars• Where star is in its sequence• Size of star• Location of planets (energy from sun)• Size of planets• Atmosphere• Water, food• Time for evolution• Chance of intelligent life• Survive our intelligence

If there is life out there, will we ever make contact?

How does the size of the universe affect the chance for our contact

with extraterrestrial life ?

Does all intelligent life evolve at the same rate?

What would it mean for contact if one party is much more evolved

than the other?

Is life spread evenly throughout the universe?

How would the density of life affect our ability to make contact?

How do you think we will make first contact with extraterrestrial life?

• What are the factors that determine the likelihood that you or I will ever come into contact with life from outside the Earth?

Factors

• How common is life• How close are we in our stage of evolution• How physically close are the life forms• Communications• Seeking each other

SETI :Search for Extraterrestrial intelligence