outer cosmos the big bang hubble's law galaxies. big bang theory a scientific theory - with a...
TRANSCRIPT
Outer Cosmos
The Big Bang
Hubble's Law
Galaxies
Big Bang Theory
• A Scientific Theory - with a capitol “T”
• At one time, the entire universe was confined to a dense, Hot, Super massive ball of hydrogen.
• Then a violent exposition triggered the rapid expansion of that Massive ball of Hydrogen
Universal Timeline
• 13.7 billion years ago (bya) The Big Bang – a violent explosion occurred spewing Hydrogen
in all directions.
• 13.5 bya first Stars formed– Over time Stars form the elements on the
Periodic Table
• 4.6 bya Solar System formed– Universe has enough elements to create the
conditions for complex life in 2-3 – billion years
Evidence
• Theory is designed to explain and connect observations – Hubble’s Law – Background Radation
Redshift & Blueshift
When a star’s spectrum is compressed from the Doppler Effect the spectrum will either shift to the red or blue end of the spectrum
• Blueshift– Moving towards you
• Redshift– Moving away from you
• The amount of compression can also tell us speed
• Galaxies are in Red shift: – deep space objects are moving away from us, the
degree of shift tells us speed
• Galaxies are retreating from us at a speed that is proportional to their distance – AKA: the further away they are the faster they are
moving
• Indicates that the universe is expanding
Hubble’s Law:
Cosmic Background Radiation
• Faint Radio Waves coming from every direction in space, though to be remnants of the Big Bang.
Galaxies
• Groups of stars, dust, and gas held together by gravity
• The universe contained hundreds of billions of galaxies
• Each containing hundreds of billions of stars
Galaxy Classification• Spiral
– Disk shaped with arms circling the center
• Barred spiral – Disk shaped with a bar through the center
and arms coming off the bar
• Elliptical– Mass of stars ranging from circular to oval
with no arms (oldest stars)
• Irregular – No discernible shape (youngest stars)
M81NGC 1300M87NGC 4449
The Milky Way• Our Galaxy, a Barred Spiral
• 100,000 light-years wide
• 1,000 - 10,000 light-years thick