Transcript The Big Bang Theory

The Big Bang Theory
Astronomy, not the tv show
Description
• In the distant past, the universe (space) was
hotter and denser; today space is expanding
and cooling.
– NOTE: No mention of…
• Where the universe came from (no data to support any
theory)
• An explosion (it’s more like a light turned on)
• The universe has no boundaries and no
middle.
• It looks the same everywhere and in every
direction
Evidence for the BBT
• Red Shift: A star that is moving away from us
appears to give off different colours than it
actually does – their spectra are shifted
towards red in ROYGBIV.
– The stars send out a wave of light:
– But they’re moving, so it stretches the wave:
Evidence for the BBT
• Cosmic Microwave Background Radiation
(CMBR)
– When you point a satellite at the sky, you always
pick up a faint buzz
– This buzz is CMBR – echoes of the original light
produced when the universe first began to exist light that has red-shifted
way down to microwaves
Evidence for the BBT
• Location of galaxies:
– The Hubble Telescope has shown that galaxies are
spread out in all directions
– So everywhere is expanding at a similar rate – so
going back in time, it must have started hot & dense
Evidence for the BBT
• Lots of other observations support the BBT’s
mathematical predictions about what
happened when space time began, but it’s
next-level stuff 
• Interested? Check this website:
• http://www.talkorigins.org/faqs/astronomy/bi
gbang.html
So, what happened at the beginning of
space time?
• http://www.youtube.com/watch?v=PV0ACIyk
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