Microwave

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Slide 1

Parvaneh, Shelby & Marleena

Microwave

Telescopes

Slide 2

Discovery (domestic use)

Microwaves have wavelengths range from centimeters to those closer to a foot in length.

Longer are for heating food.

Shorter waves Doppler radar

Microwaves were first utilized by British the 1940s during WWII.

Sir John Randall and Dr. H. A. Boot, invented a device called a magnetron (Radar) using microwaves to detect Nazi warplanes.

1945, examining the magnetron, Percy Spencer’s candy bar melted

Product was marketed, thank goodness Percy was a chocolate lover!

www.sabers.org/STELLA%20CANDY%20BAR.JPG

Slide 3

Cosmic Microwave Background (CMB)

1960's at scientists at Bell Laboratories detected background noise using a special “low noise” antenna.

This static noise came from every direction and did not vary in intensity.

The scientists soon realized they had discovered the cosmic microwave background radiation.

“This radiation, which fills the entire Universe, is believed to be a clue to it's beginning, something known as the Big Bang.”

Slide 4

Big Bang Model

Universe was once much smaller, hotter, and denser

Based off of Einstein’s theory of general relativity

Expansion of the universe – 1929

Lightest elements

Deuterium, helium, lithium

CMB

oldwww.internet2.edu/apps/html/archives.html

Slide 5

What the CMB tells us about the Universe

The geometry of the universe

Whether the universe will expand or collapse

How much matter there is in the universe

Amount and nature of dark matter and energy

Expansion rate of the universe

Age of the universe

The origins of galaxies and galaxy clusters

Slide 6

Origins of the CMB

Universe cooled as expanded – became less dense

Density variations affected temp. of photons

Dense regions = hot spots in CMB

300,000 years – cooled enough to form atoms

Photons traveled through – form relic radiation

Gravitational collapse – 1 billion years

Created galaxies

Slide 7

Brief History and COBE

“The cosmic microwave background radiation is a remnant of the Big Bang and the fluctuations are the imprint of density contrast in the early universe.”

COBE (November 18, 1989- 1993)

Frequent observations were made over 6 mo. periods for 4 years.