The Beginnings … Of the Universe & Our Solar System

Where did the universe come from? People have always wondered where we have come from People have always wondered where we have come from Until recently, there was not enough evidence to support any scientific theories Until recently, there was not enough evidence to support any scientific theories In fact, until 1920, scientists didn ’ t realize that there were other stars outside our galaxy In fact, until 1920, scientists didn ’ t realize that there were other stars outside our galaxy 2 key pieces of evidence have led to our current theory of the origin of the universe 2 key pieces of evidence have led to our current theory of the origin of the universe

The Red Shift Astronomers know what colours of light stars give off (spectrum) Astronomers know what colours of light stars give off (spectrum) Edwin Hubble discovered in the early 20 th century light coming from distant galaxies looked strange … Edwin Hubble discovered in the early 20 th century light coming from distant galaxies looked strange … Called the “ Red Shift ” Called the “ Red Shift ” ExpectedObserved

The Red Shift Con ’ t Just like with sound, this means that the distant galaxies are moving further away from us Just like with sound, this means that the distant galaxies are moving further away from us It was also noticed that the further a galaxy is away from us, the faster it is moving away from us It was also noticed that the further a galaxy is away from us, the faster it is moving away from us

The Universe is glowing! In 1964, scientists pointing special telescopes at the sky noticed that it is faintly glowing everywhere In 1964, scientists pointing special telescopes at the sky noticed that it is faintly glowing everywhere Called the Cosmic Microwave Background (CMB) Called the Cosmic Microwave Background (CMB) That is, radiation is coming to Earth from all directions That is, radiation is coming to Earth from all directions

Cosmic Microwave Background

The Theory Cosmologists combined these two ideas to come up with the Big Bang Theory Cosmologists combined these two ideas to come up with the Big Bang Theory Between 13.6 and 13.8 billion years ago, all matter in the universe was packed into a small, extremely dense, hot mass under enormous pressure Between 13.6 and 13.8 billion years ago, all matter in the universe was packed into a small, extremely dense, hot mass under enormous pressure That mass then expanded rapidly – called the Big Bang That mass then expanded rapidly – called the Big Bang Over time, this matter cooled and formed everything else around us Over time, this matter cooled and formed everything else around us

How do the Red Shift & CMB Fit??? Red Shift Red Shift If all galaxies are moving away from each other, then it makes sense that they were all together once If all galaxies are moving away from each other, then it makes sense that they were all together once CMB CMB The glowing is the left over of the Big Bang “ Explosion ” The glowing is the left over of the Big Bang “ Explosion ”

Unanswered Questions The theory can explain what happened a millionth of a second after the big bang, but not during the big bang or before it The theory can explain what happened a millionth of a second after the big bang, but not during the big bang or before it The theory is likely to be refined over the next few decades as scientists gain more knowledge The theory is likely to be refined over the next few decades as scientists gain more knowledge

New Ideas: Dark Matter The stars in galaxies and galaxies themselves are travelling faster than conventional physics would suggest The stars in galaxies and galaxies themselves are travelling faster than conventional physics would suggest Astronomers have concluded that there is about 10 times more matter than we can see Astronomers have concluded that there is about 10 times more matter than we can see It is called Dark Matter since it does not emit or absorb light It is called Dark Matter since it does not emit or absorb light Very little is known about the properties of Dark Matter Very little is known about the properties of Dark Matter

New Ideas: Dark Energy Gravity would seem to eventually slow down and stop the expansion of the Universe Gravity would seem to eventually slow down and stop the expansion of the Universe Observations in 1998 say that is not so Observations in 1998 say that is not so The rate of expansion is increasing! The rate of expansion is increasing! A new kind of energy, called Dark Energy is theorized to work against the crush of gravity A new kind of energy, called Dark Energy is theorized to work against the crush of gravity VERY little is known about Dark Energy VERY little is known about Dark Energy

The Future of the Universe? Cosmologist believe that the gravity and Dark Energy have been battling since the Big Bang Cosmologist believe that the gravity and Dark Energy have been battling since the Big Bang About 5 billion years ago, the expansion of the universe has increased About 5 billion years ago, the expansion of the universe has increased It seems Dark Energy is winning now It seems Dark Energy is winning now If that is so, the Universe will continue to expand until all matter is extremely far apart and the Universe will be nothing but cold, dark, nearly empty, space If that is so, the Universe will continue to expand until all matter is extremely far apart and the Universe will be nothing but cold, dark, nearly empty, space

Where did our solar system come from? The Big Bang explains where the matter in the Universe came from, but what about our solar system? The Big Bang explains where the matter in the Universe came from, but what about our solar system? According to the Solar Nebula Theory, our solar system started out as a nebula According to the Solar Nebula Theory, our solar system started out as a nebula A spinning mass of gas and dust A spinning mass of gas and dust

Where did our solar system come from? Con ’ t Perhaps triggered by a nearby supernova, the nebula started to contract Perhaps triggered by a nearby supernova, the nebula started to contract One collection of gases formed a protostar that would eventually be our Sun One collection of gases formed a protostar that would eventually be our Sun As more matter fell in, the protostar rotated faster (think figure skater pulling his arms in) As more matter fell in, the protostar rotated faster (think figure skater pulling his arms in) Other matter rotated around the protostar in a disk Other matter rotated around the protostar in a disk

Where did our solar system come from? Con ’ t Once the Sun started the fusion process, the Solar Wind pushed all the lighter elements out of the disk into the outer solar system Once the Sun started the fusion process, the Solar Wind pushed all the lighter elements out of the disk into the outer solar system Mostly heavier element were left near the centre Mostly heavier element were left near the centre The make-up of the inner and outer planets fit with this theory! The make-up of the inner and outer planets fit with this theory!

Homework Pg 384 #1, 3 Pg 384 #1, 3 Pg 397 #1, 3, 4, 6, 10 Pg 397 #1, 3, 4, 6, 10