Our Universe:
Creation, Galaxies, Stars and Celestial
Objects
Big Bang Theory
•Our universe began with one huge
exploding atom that relapsed all
the energy and matter that exists in
the universe today.
•The Big Bang occurred 13.8-15
Billion years ago.
•Hydrogen and Helium, the makeup of stars, were the first two
elements formed in less than a
quarter of a second!
•The explosion was so enormous,
that all objects in the universe are
still moving outward today from
the initial blast from billions of
years ago!
•The radiation from this
tremendous explosion is also still
traveling across our universe in the
form of microwaves (a specific type
of energy that travels in forms of
waves)
Big Bang Timeline
Evidence to Big Bang
Background Radiation
•Background radiation is the
aftermath of gas, dust and energy
from the initial explosion that is
found in every part of our
universe.
•It proves that there definitely was
some explosion beyond
enormous, billions of years ago!
Red shift
•Red shift is a shift towards the red
end of the spectrum of colors given
off by objects in space.
•This RED shift demonstrates that
object is moving away from us and
everything else.
•The red shift is evidence of the
“push” from the initial Big Bang.
•BLUE shift would demonstrate that
an object is moving TOWARDS us!
Future of the Universe
Open Universe
•This theory states that
everything in the universe
will continue to move
outward and away with
continual expansion
infinitely.
•Eventually, all stars
would burn out leaving
our universe with empty
darkness.
Closed Universe:
The Big Crunch
•This theory supports the
idea that eventually that
outward expansion from the
initial Big Bang will wear.
•At this point, the force of
gravity will begin to pull
everything back together
again.
•Then, another Big Bang
will occur!
Flat Universe
A flat universe results
if the expansion slows
to a halt in an infinite
amount of time but
never contracts.
Expansion occurs so
slow that it appears to
have stopped.
3 Types of Galaxies
Galaxy- a cluster of billions and trillions of stars bound
together by gravity
Elliptical Galaxyround and flattened
ovals
(This is the most
common type of galaxy)
Irregular Galaxysmaller galaxies with
no distinct shape.
Spiral GalaxyGalaxies with spiraling
arms that rotate
around a central bulge
of massive substance
in the center.
Our Galaxy:
The Milky Way
•Our Milky Way is a spiral galaxy.
•The center of our galaxy is full of
extremely massive, Red SuperGiant Stars.
•The center is over 28,000 light
years away. Which means it takes
28,000 years for the light of the
stars in the center to travel
through space and be seen by our
planet!!!
•The direction towards the center
is toward the constellation
Sagittarius
•1 light year (which is measure of
distance NOT time) is the distance
light travels in a year. Light travels
at a speed of 9.5x1015 m/s!!!
•Our galaxy contains over 200
billion stars!
Sun orbital
speed around
the center is
220km/s, orbital
period is 240
million years.
The sun will
complete 20
revolutions
around
center in its
lifetime.
Sun
It is believed that there may be a massive
black hole at the center of our galaxy
pulling the massive supergiants in!!
Most stars in the Milky Way are 207,000 AU (AU=
distance between sun and earth) apart, but in the
center they are only 1000Au apart!!!
Life Cycle of a Star
White dwarf will
eventually stop
nuclear fusion
and become a
black dwarf”Dead Star”
Medium
Star
Gravity condenses the
star to shrink
(Where protostars are
formed)
Giant Star
Nebula- the birth of a star
Orion Nebula
Lagoon Nebula
Horsehead Nebula
A Nebula is a cloud of cosmic gas and
dust where stars are formed.
•The gases of these nebulas are mostly
hydrogen and helium.
• These are the two gases that make
up all stars!
•Gravity begins to pull the gases inward
during the birth of a star.
•Then, with gravity, the density of the
gases increases which causes the
pressure and temperature to increase,
until the star finally stabilizes.
•A star can exist anywhere from 1
Million to 30 Billion years! (depending
on size)
•Our Sun has around 5 Billion years
remaining. It is predicted to only exist
for 10 Billion total years.
Young Stars
Protostar:
•A baby star
•These are formed in the nebulas after the gases
have condensed enough to begin nuclear fusion.
•Nuclear Fusion is the process that occurs in the
cores of all stars.
•In Nuclear fusion, hydrogen atoms are
converted into helium, releasing the ENORMOUS
amount of energy that causes stars to become so
very hot! The amount of energy released per
gram of mass is equal to the amount of
energy released by 22,000
tons of TNT. (The nuclear
explosion at Hiroshima only
released an amount equal
to 13,000 tons of TNT)
Medium Star:
•
•
•
•
Temperature= 6000°C
Color = yellow/orange
Example= Our Sun (closest star is
proxima centauri)
Size= over 90 million miles in
diameter! (actually measured in solar
radii)
Giant and Supergiant Stars
Giant Stars
•Color= Red or Blue
•Temperature= 4500°C
•Size= 10 x time the size of the Sun
Red Super Giant Stars
•Color= Red
•Temperature= 3000°C
•Size= 1000 x the size of the Sun!!
As size increases, the temperature decreases because the heat of nuclear
fusion is spread out over such an enormous volume!
Supernova or
Planetary Nebula
•If a star is extremely massive, the
extreme density of the core
collapses under the gravity
causing a stellar explosion known
as a supernova.
•The catastrophic explosion
releases elements and cosmic
dust for millions of the years.
•These explosions are more
intense than 1 million nuclear
bombs!
•Why are supernovae important
to us? These explosions create
the heavier elements that are
used and make up humans!!!
•If a star has a lower mass, it will
eventually shrink to a planetary
nebula.
•The planetary nebula then
condenses to a white dwarf and
eventually a black dwarf.
Computer Animation
Actual
Supernova70 mill light years
away and
occurred millions
of years ago!
White and Black Dwarf Stars
White Dwarf Stars:
Black Dwarf or “Dead Stars”
•Color = White
•Temperature= 15,000°C
•Size= Average around the size of Texas
•These are stars that have burned out and
nuclear fusion is no longer occurring,
therefore these stars are creating no energy.
•Pressure causes these stars to become
extremely dense, similar to squeezing an
aircraft carrier into a glass jar!
Both images are computer
animations. Black Dwarfs do not
give off any light to be seen.
Neutron Star
Color: Blue
Temperature: 35,000°C
Size: A little larger than New York City
(5-10 Miles)
•The Neutron Star is extremely
dense and small.
•As the star decreases in size, the
pressure increases so immensely
that the temperature increases
dramatically.
•As temperature increases, so
does brightness.
•A Neutron Star is almost 1.5
million times brighter than our
Sun!
•Density of a neutron star is 10 x
1015 g/cm3
•10,000,000,000,000,000 g/cm3
Black holes
•A black hole is a theoretical space
where the gravitational pull is so
incredibly strong that no radiation,
including heat and light, cannot exist.
•These black holes are a million to a
billion times more massive than our
sun!
•Is there a black hole in the center of
our Milky Way- YES!
•The fundamental descriptions of
black holes are based on equations in
the theory of general relativity
developed by the German-born
physicist Albert Einstein. The theory
was published in 1916.
•The surface of a black hole is known
as the event horizon. This is not a
normal surface that you could see or
touch. At the event horizon, the pull of
gravity becomes infinitely strong. Thus,
an object can exist there for only an
instant as it plunges inward at the
speed of light.
These are computer animations- true black
holes cannot be seen because light cannot
reflect off them to create a shape.
Galactic Blackholesweighing a few billion times
the mass of the sun, most
galaxies have a
supermassive Blackholes in
their center. (ours is slightly
smaller than our solar
system!)
This is an actual black hole
in the center of our galaxy.
The black hole cannot be
seen but we can see its
gravitational pull “eating”
everything around it
Hertzsprung-Russel Diagram
Variable Stars
•Variable Stars- stars that pulsate in
brightness because of the expansion
and contraction of their outer layers,
or the blocking of their light by
another object.
•Variable stars are brightest at their
largest diameter and dimmest at their
smallest diameter.
DON’T COPY: ONLY EXAMPLES
•RR Lyrae Variable Stars are stars
that have periods of pulsation
between 1.5 hours and 1 day, and on
average, they have the same
brightness.
•Cepheid Variable Stars have
pulsation period between 1 and 100
days and the brightness (luminosity)
doubles form dimmest to brightest.
Dark Matter and Dark Energy
• This is a “force” that is believed
to be like an anti-gravitational
force.
• Compared to water on the
Earth, 78% of universe is dark
matter!!!
• Dark matter and dark energy
are still undefined today.
• We believe dark matter
consists of subatomic particles,
smaller than protons and
neutrons!
• Scientists recognize the effects
of dark energy, but they still do
not know exactly what it is.
Celestial Objects: Asteroids,
Meteors, Meteorites and
Comets
A.
Asteroids- large pieces of rocky
debris, some larger than our
moon.
A.
B.
B.
Computer animated
asteroid impact
Images of
asteroids in space
Meteors and Meteorites:
A.
B.
C.
Most asteroids in our solar
system are located in the
asteroid belt between Mars and
Jupiter.
Asteroids do not have a specific
orbit, they cluster in the belt
and are continuously knocked
out or pulled in my Jupiter.
Meteors- pieces of rock that
burn up in our atmosphere.
(shooting star)
Meteorite- pieces of rock that
survive burning up in our
atmosphere and land on the
surface of the Earth.
Kuiper belt
Halley’s Comet
(Every 76 years)
Comets- balls of ice and dust in a
specific orbit in space.
A.
Kuiper Belt and Orrt Cloudsthese are two areas at the edge
of our solar system where
comets are located until
knocked into a new, closer orbit.
Meteor Shower
Meteorite
What if one hits us???
Asteroids and other objects come close to our planet EVERY
DAY! Most of the time we never notice them, but with improving
technologies we are detecting more of them, and detecting
them earlier.
In fact, on Wednesday Sept. 8th, 2010
NASA telescopes spotted 2 asteroids (both
around 30 feet in diameter) that came very
close to Earth. One actually passed
between the orbit of Earth and the Moon.
Neither would have been large enough to
cause large scale damage. The majority of
these asteroids would burn up while
entering our atmosphere.
-This blue ring is
the Oort cloud,
nearly a light year
away (to put it in
perspective)
-Sedna is the
furthest known
object to orbit our
sun. The IAU
(International
Astronomy Union)
has yet to define it
as a planet/dwarf
planet/asteroid.
1
4
2
3