The Cosmic Calendar• If the entire age of the universe (12.5 billion years) was

compressed into one year, humans appeared about six minutes before midnight on the last day of the year!

How is this calculated?

Assumptions:

humans “appeared”

150,000 years ago.

One year = 525600 minutes.

Use a proportion:

minutes 525600

minutesx

years ,00012,500,000

years 150,000

Solve for x = 6 minutes

Are we the new kids on the block?

• The period of massive bombardment (the accretion era) ended 3.8 billion years ago

• Within a few million years single-celled life was reproducing like rabbits in springtime

• Multicellular organisms didn’t show up till about 800 million years ago

From Humboldt State University Museum of Natural History

Deep in TimeRead bottom left then bottom right

Why did it take so long?

• Life might have arisen here several times before the sterilization from bombardment ended—MORE LATER!

• Multi-cellular life on Earth uses Oxidation for energy, this requires oxygen in the air and water, and there wasn’t any until…

• Cyanobateria created oxygen as a waste gas.• Apparently it took nearly three billion years to build

up this level of oxygen…then BANG!--The Cambrian Explosion

For more information on the development of life on Earth:

• Check out this website:

• http://www.geocities.com/capecanaveral/lab/2948/onceupon.html

What about Other Solar systems?• Some 3rd generation Sun-like

Stars (with enough heavy elements) are up to two billion years older than the Sun

• Imagine the same timeline…intelligent animals could have been around for a billion years rather than 150,000.

• They might be more interested in Earth now if their aging star is loosing its stability.

• Can then just fly on over? Have they?

Image from: http://users.erols.com/feanor17/UFO.JPG

Looking back in time• Light, although fast, travels at

a finite speed.

• It takes:– 8 minutes to reach us from the

Sun

– 8 years to reach us from Sirius (8 light-years away)

– 1,500 years to reach us from the Orion Nebula

– 12 billion years from the edge of the observable universe

The Solar System is part of the Milky Way Galaxy

• We can’t see our galaxy from the outside, but we can see the Neighbors.

• Here is M31-the Andromeda Galaxy—over one hundred billions stars!

Look out from within the Milky Way Galaxy

This animated gif shows the streaks of meteors against the backdrop of the Milky Way--particles of space dust burning up in the air—be patient!

How large is the Solar System?• Let’s view it

to scale– say the Sun

is the size of a large grapefruit (14 cm in diamter) in Washing DC how far away would the next star (grapefruit_ be?

There is plenty of space between the stars!

The next closet star (Alpha Centauri) would be 5000 Km away—San Fransisco is the right distance!

A galaxy of stars!

Sun

Alpha Centairi

On a scale showing the entire Milky Way Galaxy, the sun and nearest star are nearly touching!

The distance from the sun to the center of the gabblaxy is about 30,000 light years

How far away is the nearest galaxy?

The Milky Way and M31 (the andromeda Galaxy are shown here side by side

If each were the size of a Compact Disk, how far apart would the two disks be?

The answer is about 2.2 meters apart (about 12 feet)

In other words, you could put about twenty galaxies between the two. The actual sepeartion is about two million light years.

What is your universal address?

• Correct address:

Your street, city, state, country, then …

The Earth

This swirling storm is Hurricane Katrina bearing down on New Orleans.

Next line: Solar System

From APOD—copyright Jimmy Westlake

Milky Way Galaxy

Image reconstruction from Spitzer Space Telescope Data.

Local Group

We are part of approximately 30 galaxies. Most are much smaller than the Milky way and M31. b

Local SuperclusterThe Virgo cluster is at the heart of the Virgo supercluster….our “local supercluster”

Universe

• Superclusters and Voids are the largest structures.

• Check out http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html

Distance Quiz

• How many Kilometers in a Mile?

Answer:

• 1.6

• You can also remember that 10 kilometers is 6 miles

• Or one kilometer is 6/10 of a mile.

• How many Kilometers in diameter is the Earth?

Answer:

• 12700 km (about 13,000)

• You can also convert this to miles:

• 12700 km x 6 miles/10 km = 7900 miles

• How Far away is the moon?

Answer:

• 384,000 km

• In scientific notion this is:

• 3.84 x 105 km

• In terms of the Earth’s diameter, how far away is the moon (in other words, how many earths can fit between the Earth and moon)?

Answer:

• 30 Earth diameters

• So if the Earth was one foot in diamter (a classroom globe) the moon would be thirty feet away!

• Pretty close, huh!

Distance Quiz continued

Compared with the distance to the moon, the sun is how much farther away?

400 times (150,000,000 km or one AU)

How long does it take light to get from the Sun to the Earth?

8 minutes

Distance quiz p3

• How many Light minutes to Jupiter?• 5 AU x 8 minutes/AU = 40 minutes• How many AU to Neptune?• 30• How many AU in one light year? • 65000• How many light years to the NEAREST star?• 4

Distance quiz –celestrial section

• How many light years away is the farthest star we can see with our naked eyes?

Answer

• About 3000 light years (Deneb is 2200)

• How far to the Center of Galaxy

Answer:

• 30,000 light years (10,000 pc)

• How far to the Andromeda Galaxy?

Answer:

• Two million light years

• Remember—about twenty times the diameter of the Milky Way

Last question!

• How far to the edge of the observable Universe?

• 12 billion light years!

• But what is the observable universe?

• It’s a sphere with a radius equal to the age of the universe in light years.

• If something is farther away than this, then light hasn’t reached yet, so we cant see it!

Time to get Moving—a universe in motion

• Contrary to our perception, we are not “sitting still.”• We are moving with the Earth.

– and not just in one direction – Note that 1500 km/hr = 2200 ft/sec

•Jump up so that you are in the air for half a second…where should you land? •Without gravity and inertia, you would land 1100 feet west of where you started.

We’re moving pretty fast around the sun…

sec 30

secmillion 30

km 1

time

distancespeed

kmspeed

billion

Our Sun moves relative to the other stars in the local Solar neighborhood!

Our Sun and the stars of the local Solar neighborhood orbit around the center of the Milky Way Galaxy every 230 million years!

The sun is about 22 Galactic years old!

The Milky Way moves with the expansion of

the Universe! • Mostly all galaxies

appear to be moving away from us.

• The farther away they are, the faster they are moving.– Just like raisins in a raisin

cake; they all move apart from each other as the dough (space itself) expands.

Time waits for no oneWe live in a changing universe, with a past and future.

As we speed around our star, it is also changing and evolving towards a violent end

Will we be around to watch?

Will humans still be around billions of years from now?

Will any life on earth have the technology to reverse the sun’s evolution, or move on to another star system?

Additional Resources:

• http://www.geocities.com/capecanaveral/lab/2948/onceupon.html

• http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html