1. How was it formed? How old is it? What does the future hold?
The Universe
How was it formed?
How old is it?
What does the future hold?

2. What is the universe?
The sum of all matter and energy that exists, that has ever existed, and that will ever exist

3. Where did it come from?
As the universe expands, photons of radiation are stretched in wavelength
Red shift: a shift toward the red end of the spectrum in the observed spectral lines of stars or galaxies
Every galaxy is moving away from Earth
All galaxies are moving away from each other

4. The Universe is Expanding
Implies that universe was once smaller
At some time in the past (~ 13.7 billion years ago) everything in the universe was confined to a single point of enormously high temperature and density
Rapid expansion of the universe called the “big bang”, creating:
Space
Time
Matter
Energy

5. A few notes on expansion
There is no “center” or “edge” to the expansion
The universe is not expanding into space, it is creating space
Galaxies are not flying apart into the rest of the universe, they are just along for the ride

6. Cosmic Background Radiation
Theory that the expansion of matter and energy should still be detectable today as microwave radiation.
Radiation is any way in which energy is transmitted through space from one point to another without the need of a physical connection
Overall temperature of universe about 2.7 K
Also, Gamma ray → X ray → ultraviolet → radio
Using a large antenna, a background “hiss” is detectable at any time filling all space

7. Evolution of the Universe
After a few seconds: expansion cooled the universe enough for protons, neutrons and electrons to form
After a million years: hydrogen atoms form
Hydrogen fuels stars
Galaxies and planets followed soon after

8. Evolution of the Universe

9. How old is the universe?
Using the Hubble Constant (rate of universal expansion), best current estimate is:
13.7 ± 0.13 billion years

10. Where do we go from here? Still expanding, but maybe not forever
Combined gravity of all the mass in universe also pulling it inward, in direction opposite of expansion

11. Where do we go from here?

12. Depends on mass Small amount of mass = universe expands forever
Moderate amount of mass = expansion continues at a slower rate
Large amount of mass = universe will contract, eventually collapsing back on itself

13. Measuring Distance in Space
Astronomical Unit (A.U.): average distance between Earth and the Sun
1 A.U. = 1.5 x 108 km
Speed of Light: the fastest possible speed
= 299, 792 km/s (670,616,629 mph)
Light-year: the distance that light travels in one year
1 ly = 9.46 x 1012 km (6 trillion miles)

14. Viewing Objects in Space
We see the universe now as it was in the past
The further away a celestial body is, the older the light we get from that object
Light that comes from the sun takes more than 8 minutes to get to Earth