1. Unit 6 – the universe
Grab your clickers

2. Bell Work
What are some things that would happen to you as you fell toward/into a black hole?

3. I will: Learning Goals:
understand the properties of different types of galaxies.
understand how the universe come to be what we observe today.
understand how astronomers use astronomical objects (standard candles) as a distance ladder to estimate the size of the universe and to measure large distances in the universe.
understand how astronomers determine the age and size of the universe?.
4. Complex Knowledge: demonstrations of learning that go above and above and beyond what was explicitly taught. 3. Knowledge: meeting the learning goals and expectations. 2. Foundational knowledge: simpler procedures, isolated details, vocabulary. 1. Limited knowledge: know very little details but working toward a higher level.

4. Important Questions:
How did the universe come to be what we observe today?
How do astronomers use astronomical objects (standard candles) as a distance ladder to estimate the size of the universe and to measure large distances in the universe?
How do astronomers determine the age and size of the universe?

5. Starting Point! The Speed of Light
The time it takes to travel from one point to another is a function of speed and distance between the two points.
Travel time = distance/speed
t = d/c
t=time
d=distance
c = 3 X 108 m/s

6. Why do we measure distance with time?
utube.c om/wat ch?v=W p20Sc8 qPeo&f eature= plcp

7. What is the Speed of Light?c=
Meters per second 299,792,458
kilometers per second 300,000
kilometers per hour 1,080 million
miles per second 186,000
miles per hour 671 million
astronomical units  173 per day

8. How fast is the Speed of Light?
Light travels at a constant, finite speed of 186,000 mi/sec. – no matter what
A traveler, moving at the speed of light, would circumnavigate the equator approximately 7.5 times in one second.
By comparison, a traveler in a jet aircraft, moving at a ground speed of 500 mph, would cross the continental U.S. once in 4 hours.

9. How big is a Light Year?
The light-year is a measure of distance, not time.
It is the total distance that light, moving in a straight line, travels in one year in a vaccuum.
To obtain an idea of the size of a light-year, take the circumference of the earth (24,900 miles), lay it out in a straight line, multiply the length of the line by 7.5 (the corresponding distance is one light- second), then place 31.6 million similar lines end to end!

10. How big is a Light Year? 9,460,730,472,580.8 km
One light-year is equal to:
9,460,730,472,580.8 km 
5,878,625,373,183.6 miles 
(about 6 trillion miles)
63,241.1 astronomical units
31,557,600 light-seconds

11. questions: (write the answers, not the questions)
1. how are time and distance linked in the observable universe? 2. if a star in the Andromeda galaxy (2,538,000 light years away) were to undergo a supernova explosion tomorrow, will you ever see it?

13. Your Assignment. Cars travel at an average of 60 miles/hour
Jets fly at about 600 miles/hour
rockets travel at 25,000 miles/hour.
Imagine that with new technology you can build a machine that travels at light speed, or 186,000 miles/second.

14. Travel Time – create chart on 86
Using the chart, calculate the travel time from the Earth to the highlighted destinations if you were in a rocket.
Create a scale model of the travel time from Earth to each object.
Start with Earth at 0 on one end of your model, and make the other end ??? million years.

15. Using the chart, calculate the travel time from the Earth to the highlighted destinations if you were in a rocket.
Create a scale model of the travel time from Earth to each object.
Start with Earth at 0 on one end of your model, and make the other end 3 million years.

16. Object
Distance from Earth (light years)
Time at Light Speed
300,000 km/s
Time at rocket speed
25,000 km/h
Sun
8.4 minutes
Mars
4 minutes
Pluto
5.4 hours
Alpha Centauri
4.27
4.27 years
Arcturus 36
36 years
Pleiades Cluster
400
400 years
Deneb
1,600
1600 years
Center of Milky Way
38,000
38,000 years
Andromeda Galaxy
2,200,00
2,000,000 years

17. Travel Time
???? years
0 years
EARTH
ANDROMEDA GALAXY