Chapter 26 ASTRONOMY THE SCIENTIFIC STUDY OF SPACE / THE UNIVERSE.

Galactic address Planet StarThe Sun Star System/GalaxyThe Milky Way Galactic GroupLocal Group Galactic SuperclusterVirgo Supercluster

GALACTIC ADDRESS

Measuring distances in the Universe Astronomical Unit (AU) = 150 million km ( = 149,597, km ) – The average distance from the EARTH to the SUN. Light year = 9,460,700,000,000 km ( = x km ) This is based on the speed of light = 186,000 mi/s = 300,000,000 m/s - The distance that light travels in one year. Parsec = 3.26 light years = 19 trillion miles.

Astronomical Distances and Scales

Units of Distance Astronomical Unit – The average distance from Earth to the sun ~ 150,000,000,000 meters Light Year – The distance light travels in 1 year ~ 9,500,000,000,000,000 meters

Powers of 10

Scientific Notation Step 1: Find decimal point (3000 = ) Step 2: Move decimal point to where it is directly to right of first non-zero digit. Count the number of spaces the decimal point moves Step 3: Write down the new number with x10 on the end, put the number of spaces the decimal point moved at the top right corner of the x10 (it is a positive number if point moved left and it is a negative number if point moved right)

Examples

Looking at distant objects is like looking back in time.

Observing space The electromagnetic spectrum represents different types of energy, each having different wavelengths, traveling at the speed of light. Link

Telescopes REFRACTINGREFLECTING Optical telescope Uses lenses to bend light (refraction) Optical telescope Uses a curved mirror (reflection) to gather and focus light Problems: *Focuses different colors of light at different distances. *Ability to see distant objects is based on the size of their objective lens. Advantages: *Can be made larger, can gather more light, can see more distant/fainter objects. *Less distortion *Eliminates color differences

National Radio Astronomy Observatory (NRAO) Green Bank, West Virginia

Robert C. Byrd Green Bank Telescope (100 meters in diameter)

Keck Telescopes – 10m OWL (Overwhelmingly Large Telescope) – 100m - optical and near-infrared Only Proposed!

Gran Telescopio Canarias

Human Space Exploration National Aeronautics and Space Administration (NASA)

100,000 Stars

Supernova in Messier 82

Ant Nebula Horsehead Nebula

Comet ISON

Solar Prominence

Uranus

Jupiter’s triple solar eclipse event