Download Bellringer - Madison County Schools

Bellringer
Tatooine is a fictional planet that has a sunset
which contains 2 suns. This would be what kind of
star system?
The Expanding
Universe
Notes
How the Universe
Formed
• By looking at the most distant objects in
the universe, scientists can estimate the
age of the universe.
• Light from the Andromeda Galaxy took
3 million years to get to Earth, and
that’s the closest galaxy to us, out of an
estimated 100 billion galaxies.
early every visible object in this image is a distant galax
How the Universe
Formed
• Astronomers estimate the age of the universe at
13.75 billion years old.
• 13.75 billion years ago, the part of the universe
we see now was no larger than the period at the
end of this sentence.
• This tiny universe was incredibly hot and dense.
• This universe then exploded in what scientists
call the big bang.
http://www.astro.ubc.ca/~scharein/a311/Sim/bang/BigB
ang.html
How the Universe
Formed
• The Big Bang Theory states that the
universe formed in an instant, billions of
years ago, in an enormous explosion.
• As the universe expanded, it began to
cool. After a few hundred thousand
years, the first atoms formed.
• After about 200 million years after the
big bang, the first stars and galaxies
formed.
How the Universe
Formed
• The original Big Bang Theory came from a
Catholic Priest by the name of George Lemaître.
After viewing the red shift that occurs as galaxies
(and any other object) move away from us, he
concluded that the universe had to have
originated from a infinitely small singularity.
• In 1927, he originally called his theory the
“hypothesis of the primeval atom.”
How the Universe
Formed
• 2 years after George Lemaître published his
findings, Edwin Hubble confirmed his data my
viewing many more spectrums from various
galaxies, all of them showing a red doppler shift.
• Hubble confirmed that with the exception of our
local cluster, all galaxies are moving away from
us and from each other.
• Hubble’s Law states that the farther away a
galaxy is, the faster it is moving away from us.
How the Universe
Formed
• To understand how the the galaxies are
moving, think of raisin bread dough that
is rising. If you could shrink yourself to
sit on a raisin, you would see all of the
other raisins moving away from you.
• http://spiff.rit.edu/classes/phys301/lectu
res/lambda/RaisinBread.swf
•
•
•
How the Universe
Formed
In 1965, another piece of evidence to
support the Big Bang Theory was
discovered.
Two American Physicists noticed that no
matter where they pointed there radio
telescope, there was always some faint
radiation detected.
At first they thought it was bird droppings on
the telescope, but after cleaning it, they
discovered that the universe itself was
emitting this radiation from all directions.
How the Universe
was Formed
• This radiation is now known as Universal Cosmic
Background Radiation.
• The universe is microscopically warmer than
absolute zero because this radiation energy has
spread throughout the universe from the original
big bang explosion.
Wilkinson Microwave Anisotropy Probe (WMAP) image
of the entire sky, showing very little variation in the
cosmic background radiation.
How the Universe
was Formed
• To imagine this concept, pretend that
you heat up a closed oven to 700
degrees Fahrenheit. If you suddenly
opened the door, the heat would
escape from the oven and spread out
(diffuse) evenly across whatever room it
was opened into.
How the Universe
was Formed
• The Big Bang Theory has two pieces of
evidence as proof of its legitimacy and
accuracy:
• Universal Expansion
• Universal Cosmic Background Radiation
• Using these pieces of evidence, scientist have
concluded that the universe began as an
infinitesimally small singularity about 13.75
billion years ago.
Formation of the
Solar System
• As stated in “Lives of Stars,” before our
sun and solar system ever formed, a
supernova occurred right here.
• The supernova left behind a planetary
nebula - a gas cloud of hydrogen and
helium, as well as every element
needed to make the 8 planets and
everything else in this solar system,
including you.
Hubble image of a nebula in Orion in the process of
forming a sun and planets.
Formation of the
Solar
System
• Something eventually disturbed the nebula
(probably another nearby supernova), causing a
collapse of the gasses towards the center.
•
•
Because hydrogen and helium are the lightest
elements, they fly towards the center first,
eventually forming a protostar (smaller than the
original) that will become our sun, Sol.
The leftover, heavier elements begin to rotate
around the protostar, colliding with each other,
getting bigger and bigger, forming
planetesimals.
As the particles rotate around the protostar, they flatten
out (like pizza dough) into a disc shape that is called
an accretion disc.
Formation of the
Solar System
• Planetesimals eventually collided with
other planetesimals to form planets.
• The protostar eventually begins nuclear
fusion, becoming a full-fledged star.
• When fusion begins, the star blows out
the most of the leftover particles. These
particles are now the Oort Cloud.
QuickTime™ and a
decompressor
are needed to see this picture.
The Future of the
Universe
• There used to be two opposing views
as to how the universe would die:
• Expanding forever, eventually turning
dark and cold.
• The Big Crunch, where the universe
begins to shrink back into its original
Big Bang state.
The Future of the
Universe
• Two recent discoveries have eliminated
that down to one.
• Dark matter is matter that does not
give off EM radiation, therefore cannot
be seen. But studying the gravity of
galaxies, it is estimated that about 23%
of the entire universe is made of dark
matter.
The Future of the
Universe
• Dark Energy is a force that opposes
the gravitational attraction of matter. In
other words, it pushes outward.
• It is estimated that dark energy
accounts for 73% of the known
universe.
The Future of the
Universe
• Okay, so we’ve got two forces in
opposition:
• All matter and dark matter tend to
reverse universal expansion, and form a
Big Crunch.
• The original Big Bang expansion energy
and dark energy tend towards continued
expansion.
• So which one is greater?
The Future of the
Universe
• The most recent discoveries have
concluded that not only is the universe still
expanding, but it is actually accelerating expanding faster.
•
•
Therefore, the only logical end to the
universe is to continue to expand, stars will
explode, and there won’t be enough gravity
to collapse them back together.
The universe will eventually grow cold, grow
dark, and die.