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Astrophysics
Introduction to the Universe
What is it we can see in
the sky?
Our Solar System
Image source: http://web.eps.utk.edu/research/images/SolarSystem.jpg
Planets
Types of planets:
Jovian - gas planets
Jupiter, Saturn, Uranus & Neptune
Terestrial
Mercury, Venus, Earth, and Mars
protoplanets
celestial objects the size of a moon
exoplanets - Exoplanet Overview
Image Source:
http://www.bcssa.org/newsroom/scholarships/great8sci/Photos/Space_Photos/Solar_Syste
mB.PNG
Astronomical Unit
•
When we talk about
distances inside the solar
system:
•
Astronomical Unit (AU) :
distance between the Earth &
the sun or 93 million miles.
Need to know terms:
•
•
Revolution: how long it takes a planet
to go around the sun.
Rotation: how long it takes a planet to
turn once on its axis.
Light Year
•
Light Year:
the distance
light travels in
one year or 6
trillion miles
Trivia: The Sun
is so far away
The Inner Planets
The Outer Planets
What is a galaxy?
•
•
•
Large grouping of stars, gas, and
dust in space that are held together
by gravity.
The largest galaxies contain more
than a trillion stars. Smaller
galaxies may have only a few
million.
Scientists estimate the number of
stars from the size and brightness of
the galaxy.
Spiral
Main Types of
Galaxies
Irregular
Elliptical
Our solar system is located in the outer reaches of the Milky
Way Galaxy, which is a spiral galaxy. The Milky Way Galaxy
contains roughly 200 billion stars. Most of these stars are not
visible from Earth. Almost everything that we can see in the
sky belongs to the Milky Way Galaxy.
Barred Spiral
Earth in the Milky Way
Our Sun
Our Sun: Extreme Ultraviolet Imaging Telescope (EIT) image of a huge, handle-shaped prominence taken on Sept. 14,1999 taken in the
304 angstrom wavelength - Prominences are huge clouds of relatively cool dense plasmasuspended in the Sun's hot, thin corona. At
times, they can erupt,escaping the Sun's atmosphere.
http://www.nasa.gov/multimedia/imagegallery/image_feature_21.html
Before we start exploring,
let’s talk about distances
•
•
The distances between
most objects in space
are huge, and mind
boggling.
Because of the vast
distances in space we
use 2 measurements.
Our Moon
Moon Aglow: Framed by the Earth's horizon and airglow, the full moon floats in the blackness of space in this photo from the Expedition
10 crew on board the International Space Station.
http://www.nasa.gov/multimedia/imagegallery/image_feature_290.html
Large body
Made of gas:
hydrogen & helium
Stars
Gives off light:
Nuclear fusion
White Dwarfs:
small as Earth
Giants: can be 10
to 1000 times
larger than Earth
The galaxy cluster 1E 0657-56 (known as the Bullet Cluster) lies 3.8 billion light-years away. It's one of hundreds that appear to be carried
along by a mysterious cosmic flow.
http://www.nasa.gov/centers/goddard/news/topstory/2008/dark_flow.html
Comets
Ablaze with Infrared Light: Siding Spring streaking across the sky, as seen by NASA's Wide-field Infrared Survey Explorer, or WISE. This
movie stitches together five frames taken by WISE as it orbited Earth during its ongoing infrared survey of the whole sky. The images
span about eight hours of time.
http://www.nasa.gov/mission_pages/WISE/multimedia/pia12836v.html
Asteroids
Spitzer Surveys Dozens of Near-Earth Asteroids: This image, taken by NASA's Near Earth Asteroid Rendezvous mission in 2000,
shows a close-up view of Eros, an asteroid with an orbit that takes it somewhat close to Earth.
http://www.nasa.gov/mission_pages/spitzer/multimedia/eros.html
Meteors
Perseid Power: This bright and colorful fireball meteor flashed through skies over Japan in the early morning hours of August 12. Ending
at the upper right, the meteor's trail points down and to the left, back to the shower's radiant point between the constellations of
Perseus and Cassiopeia.
http://www.nasa.gov/multimedia/imagegallery/image_feature_206.html
Hubble Space Telescope
Hubble floating above Earth during servicing mission 3B, March 2002.
http://hubblesite.org/the_telescope/hubble_essentials/image.php?image=hst-above
International Space Station
A View From Above: Backdropped by a colorful Earth, this full view of the International Space Station was photographed from the Space
Shuttle Discovery during the STS-114 Return to Flight mission, following the undocking of the two spacecraft.
http://www.nasa.gov/multimedia/imagegallery/image_feature_390.html
Astrophysics
the branch of astronomy concerned with the
physical and chemical properties of celestial bodies
Terrestrial Planets and Moons
Image source: Terrestrial Planets Interiors - http://www.nasaimages.org/
Jovian Planets and Moons
Image source: Gas Giant Interiors - http://www.nasaimages.org/
Image source: Moons of the Solar System - http://www.nasaimages.org/
What’s in our Solar
System?
1 Sun
8 Planets ( 170 Moons)
5 Dwarf Planets
1 Asteroid Belt
Various
Comets
Meteoroids
Asteroids
Left over debris (Kuiper
Belt)
Introduction to the Universe
E.1.1Outline the between
E.1.2Distinguish
general structure
a stellar of
cluster
the solar
and asystem
constellation
Globular Cluster
• M80 (NGC 6093),
• 147 known globular star clusters
•
•
•
•
•
•
in the Milky Way galaxy.
about 28,000 light-years away
hundreds of thousands of stars,
about 15 billion years old
range of stellar masses.
more highly evolved than, or in a
few rare cases more massive
than, our own Sun.
bright red giants, nearing the
ends of their lives.
Image Source: http://kepler.nasa.gov/multimedia/AnimationsandMore/animations/?ImageID=36
Introduction to the Universe
E.1.1Outline the between
E.1.2Distinguish
general structure
a stellar of
cluster
the solar
and asystem
constellation
Open Cluster
• NGC 265 in the Small Magellanic
Cloud.
• The image taken with the Advanced
Camera for Surveys onboard the
NASA/ESA Hubble Space Telescope
• The brilliant open star cluster, NGC
265, is located about 200,000 lightyears away and is roughly 65 lightyears across.
• similar age and chemical composition,
the effects of other stellar properties
are more easily determined than they
are for isolated stars.
Image Source: http://spacetelescope.org/images/heic0603b/
Introduction to the Universe
E.1.1Outline the between
E.1.2Distinguish
general structure
a stellar of
cluster
the solar
and asystem
constellation
•
Constellations
•
Historically speaking - pattern in the sky with a pattern
•
•
•
•
Modern beliefs - internationally defined area of the
celestial sphere
Stellar Clusters - very useful in studying stellar
evolution
Open Cluster - similar age and chemical composition
Globular clusters - have the same age but cover a range
of stellar masses.
Introduction to the Universe
E.1.1Outlinethe
E.1.2Distinguish
E.1.3Define
thelight
between
general
yearstructure
a stellar of
cluster
the solar
and asystem
constellation
What is a light year?
The distance light travels in a vacuum in
one Julian year. (365.25 days)
exactly 9,460,730,472,580.8 km
about 5,878,625,373,183.608 miles
(about 6 trillion miles)
about 63,241.1 astronomical units
about 0.306601 parsecs
Astrophysics
IB Physics HL
Dublin Jerome High School
C. Crawford
So how do we start to
understand the universe
Understanding the places
and distances
Introduction to the Universe
E.1.4Compare
E.1.1Outline
E.1.2Distinguish
E.1.3Define
the
the
the
light
between
general
relative
yearstructure
adistances
stellar of
cluster
between
the solar
and stars
asystem
constellation
within a galaxy and
between galaxies, in terms of order of magnitude
It is important for us to know what else there is
beyond our solar system
•
•
In order to do that, there must be a way to
replicate measurements
In order to do that we have to make ourselves
a system of identification
Introduction to the Universe
E.1.4Compare
E.1.1Outline
E.1.2Distinguish
E.1.3Define
the
the
the
light
between
general
relative
yearstructure
adistances
stellar of
cluster
between
the solar
and stars
asystem
constellation
within a galaxy and
between galaxies, in terms of order of magnitude
closest star Alpha Centauri, located about 4.37 light
years away (41.5 trillion km).
closest planet - HD 189733b - 63 ly from sun
status of the voyager 1 and 2
Introduction to the Universe
E.1.5Describe
E.1.1Outline
E.1.2Distinguish
E.1.3Define
E.1.4Compare
the
the
the
the
light
between
general
apparent
relative
yearstructure
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stellar
motionof
cluster
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and
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within a galaxy
over aand
period
between
of
a nightgalaxies,
and overina terms
periodofoforder
a year,
of and
magnitude
explain these observations
in terms of the rotation and revolution of the Earth
Read “Mask of the Black god”
Introduction to the Universe
•
celestial sphere
Introduction to the Universe
E.1.4Compare
E.1.1Outline
E.1.2Distinguish
E.1.3Define
the
the
the
light
between
general
relative
yearstructure
adistances
stellar of
cluster
between
the solar
and stars
asystem
constellation
within a galaxy and
between galaxies, in terms of order of magnitude
• View the Milky Way at 10 million light years from the
Earth.
• Then move through space towards the Earth in
successive orders of magnitude until you reach a tall
oak tree just outside the buildings of the National High
Magnetic Field Laboratory in Tallahassee, Florida.
• After that, begin to move from the actual size of a leaf
into a microscopic world that reveals leaf cell walls, the
cell nucleus, chromatin, DNA and finally, into the
subatomic universe of electrons and protons.
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
What else
is it we can see
in the sky?
Galaxies!!!
Objects in the sky
Galaxies
• collection of a very large number of stars
• mutually attracting each other through the
gravitational force
• stay together
• number of stars varies between a few million and
hundreds of billions.
• There approximately 100 billion galaxies in the
observable universe.
Objects in the sky
Spiral galaxies
consist of a rotating
disk of stars
Galaxies - Spiral
and interstellar
medium
along with a central
bulge of generally
older stars.
Extending outward
from the bulge are
relatively bright
arms.
Image Source: http://www.spacetelescope.org/images/potw1006a/
The Milky Way Galaxy
Our Sun is just one out of over 200 billion stars in our galaxy, the Milky Way. The Sun is located in the Orion arm of our
galaxy about 25,000 light years from the center of the Galaxy. Kepler will be examining over 100,000 stars in our
neighborhood of our galaxy in the Cygnus and Lyra constellations. Most of these stars will be somewhere between 500 and
3,000 light years from our solar system.
http://kepler.nasa.gov/multimedia/AnimationsandMore/animations/?ImageID=36
Objects in the sky
Galaxies - Elliptical
Elliptical cross-section and
no spiral arms.
They range in shape from
nearly spherical to highly
flattened ellipsoids
size from hundreds of
millions to over one trillion
stars.
In the outer regions, many
stars are grouped into
globular clusters.
Image Source:
http://www.calvin.edu/academic/phys/observatory/images/Astr110.Fall200
5/Feyen.html
Objects in the sky
Galaxies - Irregular
Irregular galaxies
have no specific
structure.
The Large and Small
Magellanic Clouds,
the nearest galaxies
Image to the right is
known as the Bird
Galaxy
Image Source: http://anneminard.com/2009/04/05/day-72-galaxies-of-saltand-other-stellar-teaching-moments-from-huntsville-alabama/
Astrophysics
Nebulae
Objects in the sky
Nebulae
•Nebula
plasma.
is an interstellar cloud of dust, hydrogen gas and
It is the first stage of a star's cycle but it can also
refer to the remains of a dying star (planetary
nebula).
Originally nebula was a general name for any extended
astronomical object,
Nebulae often form star-forming regions, such as in the
Eagle Nebula.
Nebulae