1. Basics of the Universe

2. Astronomy Cosmology the study of the universe
the branch of astronomy that deals with the origin, large-scale properties, and the evolution of the observable universe

3. The Universe
sum total of all things which can be directly observed or whose physical effects on other things can be detected
in simpler terms, space and all the matter and energy in it
major components:
galaxies
solar systems
planets

4. Early History of the Universe
Matter as we know it did not exist at the time of the Big Bang, only pure energy. Within one second, the 4 fundamental forces were separated
gravity - the attraction of one body toward another
electromagnetic force - binds atoms into molecules, can be transmitted by photons
strong nuclear force - binds protons and neutrons together in the nucleus
weak nuclear force - breaks down an atom’s nucleus, producing radioactive decay

5. Early History of the Universe
After 3 minutes, photons and neutrons began to fuse to form the nuclei of hydrogen and helium atoms
About 300,000 years later, temperatures were cool enough for complete hydrogen and helium atoms to form
Photons escaped from matter about the same time, and light existed for the first time

6. Changing Composition of the Universe
200 million years later, with expansion still occurring, stars and galaxies began forming from leftover matter - hydrogen and helium
nuclear fusion in stars has reduced the original composition of 100% H and He to 98%
when a dying star explodes, the heavier elements created by fusion are blown into space to be recycled by newly forming stars
the overall composition of the galaxies is gradually changing to the heavier elements

7. Why the Speed of Light is a Speed Limit
Energy of a Moving Object in Relativity: E = mc2
One consequence: as v approaches c, Energy goes to infinity
Also, as we approach c, Energy goes up very fast

9. Fuel Economy of a Starship
At 0.1 c, energy is 0.7% greater than Newtonian formula
At 0.5 c, 24% greater
At 0.9 c, 3 x greater
At 0.99 c, 12 x greater
At c, 43 x greater
Each extra 9 more than triples the energy
Getting our 1000 ton ship to 0.9 c takes 1.1 x 1023 joules = U.S. energy use for 1100 years

10. Astronomical Unit (AU)
unit of distance equal to the average spacing between the Earth and the Sun
equal to about 150 million kilometers (93 million miles)
light takes about eight minutes to cover this distance
The Earth animation is not rotating in the correct direction;
it should be rotating from west to east
150 million km
(93 million mi.)

11. Light Year
the distance that light travels in one year in a vacuum, which is about 9.5 trillion kilometers (6 trillion miles)
The Milky Way Galaxy is about 100,000 light years in diameter
the speed at which light travels this distance is about 300,000 km/sec (186,000 mi/sec)
The second closest star to the Earth is a little over four light years away. How far away (in miles) is the star?

12. If one parsec equals 206, 265 AU, how many miles is it equal to?
unit of distance equal to about 3.26 light years (or 206,265 AU)
If one parsec equals 206, 265 AU, how many miles is it equal to?

13. “Big Bang” Theory
the primeval explosion of space, time, matter and energy that most astronomers think gave rise to the universe as we see it today.
occurred about 13.7 billion years ago
thought to have expanded within a second from something the size of a spec of dust to the size of our solar system
Misconception Alert:
Describing this theory as
the “Big Bang” is a misnomer
because there really was not
an explosion, just a release of
energy

14. Electromagnetic (EM) Radiation
Majority of astronomy looks at EM Radiation
EM Radiation – includes all radiation (light) from Radio to Gamma Rays
Humans only see small region
Visible light – 400 – 700nm (violet to red)

15. Constellation a group of stars that form a pattern in the sky
stars of a constellation are often far apart from each other, but they appear grouped together when viewed from Earth

16. Why is it not possible to see all constellations at once?
88 constellations in the night sky
patterns of constellations are dynamic; therefore, the constellations of 100,000 years ago are quite different from today’s
a part of a constellation that forms its own pattern in the sky is known as an asterism (ex. – The Big Dipper)
Why is it not possible to see all constellations at once?

17. Edwin Hubble
determined that other galaxies exist, besides the Milky Way
observed that galaxies were moving away from each other
based on Doppler Effect
Light is shifted toward red end of spectrum meaning its moving away from us
Hubble Law – the farther away a galaxy is, the faster it is moving away from us; supports the Big Bang Theory

18. Telescope
a device that gathers and focuses electromagnetic radiation
Types:
Visible, infrared, ultraviolet – pick up visible, infrared, and ultraviolet waves
Reflecting - use mirrors that reflect the image being viewed
Refracting – using lenses, gathers light and focuses it near the opposite end of the tube; works like a magnifying glass
Radio - pick up radio waves emitted from space; not effected by variables like weather or clouds

19. Hubble Space Telescope
a reflecting telescope that was placed into orbit in 1990
sends images and measurements back to Earth electronically
Taken several long exposure images called “Deep field”
Image taken from:
What is one of the main
benefits of having the Hubble Space
Telescope in orbit, as opposed to
it being here on Earth?

20. Hubble Deep Field

21. Arno Penzias & Robert Wilson
accidentally detected faint radiation on a radio telescope in 1965
determined that the radiation was leftover thermal energy from the “big bang” about 300,000 years after it happened
Called cosmic background radiation

22. Discovery of the Background Radiation from initial Big Bang
-Long wavelength
-came from all directions
Penzias and Wilson, 1965
Arecibo Dish, Puerto Rico

23. Cosmic Background Radiation

24. Galaxy
a large assemblage of stars (and often gas and dust), typically containing millions to hundreds of billions of member stars
Star - a large hot ball of gas which generates energy in its core by nuclear reactions
estimated 100 billion galaxies in the universe each with billions of stars
held together by the gravitational attraction of all its member stars on one another
formed around 200 million years after the “Big Bang”
most large galaxies have super-massive black holes at their centers
sometimes contain very bright centers called quasars
3 major types:
Spiral
Elliptical
Irregular
What is the name
of the galaxy
we reside in?

25. 3 Types of Galaxies Elliptical
shaped like spheres or eggs; have almost no dust or gas between stars; contain old stars
Irregular
faint galaxies without a definite shape; smaller than the other types of galaxies; contain fewer stars
Spiral
have arms of stars, gas , and dust that curve away from the center of the galaxy in a spiral pattern
Ex. – Milky Way
The process of galaxies colliding to create a larger galaxy is known
as “galactic cannibalism.”

26. Our Solar System
the Sun and all things orbiting around it, including the eight major planets, their satellites, and all the smaller pieces such as asteroids and comets
formed around 4.6 billion years ago
Formation called Nebular Hypothesis Theory
Solar system formed from massive rotating disk of gas (hydrogen and helium) and dusk
What is
incorrect
or misleading
about this
visual?

27. Planet derived from a Greek word that means “wanderer”
a major object which orbits around a star
in our solar system, there are eight such objects which are traditionally called “planets”

28. Asteroids small, solid, rocky bodies that orbit close to the Sun
most found between the orbits of Mars and Jupiter in the “Asteroid Belt”
thought to be leftover material from the formation of the solar system
range in size from 1000 km or 621 miles (Ceres) to the size of pebbles

29. Meteoroid, Meteor, Meteorite
Meteoroid (asteroid)
Meteoroid – solid debris from space (asteroids) that are moving towards Earth
Meteor
a brief streak of light produced by a small particle entering Earth’s atmosphere at high speed
often referred to as “shooting stars” or “falling stars”
Begin to burn up in the Mesosphere
travel at speeds between kilometers per second (6.8 – 44.7 miles per second)
Meteorite – a small object from outer space that passes through Earth’s atmosphere and reaches the surface
Russian Meteor Strike Video
Meteor
Meteorite
The Earth animation is not rotating in the correct direction;
it should be rotating from west to east
What causes a meteor shower to occur?

30. Comet
a small body of ice and dust (“dirty snowball”) that orbits the Sun
contain a head (coma) followed by a tail(s) of gas and dust
the tail always points away from the sun and can be millions of kilometers long (but the amount of matter it contains can be very small)

31. Satellite an object that orbits a more massive object (i.e. – moons)
probes we launch into orbit around the Earth are called “artificial satellites”
The Earth animation is not rotating in the correct direction;
it should be rotating from west to east

32. Universe Video
Latest Hubble Deep Field

33. Edwin Hubble at Mt. Wilson
Hubble’s observations at the 100 inch during the
1920’s led him to the conclusion that the universe
is expanding, and that an object’s recession velocity
is proportional to its distance from the observer.
Hubble guiding the Hooker
100 inch telescope in 1923.
The Hooker 100 inch telescope atop Mt. Wilson
near Pasadena, CA. It was the largest telescope in the world from

34. Deep Hubble Space Telescope Image
A deep image of an “empty”
portion of the sky with the
Hubble Space Telescope
reveals that the universe is
filled with galaxies- many just
like our own. The light
we see from the most distant
galaxies has traveled approx-
imately 10 billion years to
reach us.

35. Using the Doppler Effect to Measure Velocity
Redshift
Blueshift

36. Galaxy Spectroscopy Spectra of a nearby star and a distant galaxy
Star is nearby, approximately at rest
Galaxy is distant, traveling away from us at 12,000 km/s
Stellar Spectrum
Sodium
Magnesium
Galaxy Spectrum
Calcium

37. Origin of the Universe - Did It Begin with a Big Bang?