Name: ______Period: ______
Astronomy Notes
Astronomy is the study of all physical subjects ______Earth.
Light-year: a unit of length equal to the distance that light travels through space in 1 year.
· The speed of light is approximately 300,000 kilometers per second (about 186,000 miles per second)
Astronomers
· Ptolemy – believed the Earth was at the ______of the universe.
· Copernicus – the ______is at the center of the universe.
· Galileo Galilei: first to use a ______to observe celestial bodies.
· Isaac Newton: explained that ______is the force that keeps planets orbiting the sun and moons orbiting planets.
Constellations are sections of the sky that contain recognizable star ______.
· Different ______named the constellations after their gods or objects in their daily lives.
· The constellations change from season to season because of Earth’s revolution.
Telescopes
A telescope is an instrument that collects electromagnetic radiation from the sky and ______it for better observation.
· Types
· Refracting: a curved objective ______bends light and focuses the light to be magnified by the eyepiece.
· Reflecting: light enters the telescope and is reflected from a large, curved ______to a focal point above the mirror.
· Hubble Space Telescope: an optical telescope that is in ______.
o Provided clearer images in space than any ground based telescope.
· Chandra X-ray telescope is the most powerful X-ray telescope ever built.
o Launched in 1999.
Our Place in the Universe
· The Universe - 93 billion light years in ______
o Virgo Supercluster: 110 million light years in diameter. This is a group of about 100 galaxy groups.
§ The Local Group - ______million light years in diameter. This is a group of over 50 galaxies.
· The Milky Way Galaxy - 100,000 light years in diameter
o Our Solar System - the Sun's gravity extends out to around 2 light years. So it is about 4 light years in diameter.
§ Earth – 3rd planet to our Sun
Study Jams Universe Video
Quiz Score: ______
Inner Planets – all terrestrial (have land)
· Mercury- terrestrial
o Closest to the Sun
o Can be as hot as 427° C
o Its year is only ______Earth days long!
· Venus – terrestrial
o About the same size, mass, and density as ______.
o Rotates in the opposite direction than Earth.
o It's day (243 Earth days) is longer than it's year (about 225 Earth days).
o Hottest planet: Averages 464 ° C because there is so much greenhouse gas.
· Earth – terrestrial
o Just the right distance from the ______.
o Allowed water to develop which is the key to life.
· Mars – terrestrial
o The ______Planet
o Cold planet, ______atmosphere, very low pressure
o There is ice found on Mars.
Study Jams Inner Planets Slide Show: Quiz Score: ______
Outer Planets – all gas giants
· Jupiter- gaseous
o ______planet. Has the Great Red Spot (a spinning storm)
o Made of primarily hydrogen and helium.
o Takes almost 12 years to revolve!
· Saturn- gaseous
o Second largest planet
o Similar composition to Jupiter.
o Rings are made of ______particles.
· Uranus- gaseous
o Bluish-green color.
o Made of mostly hydrogen and methane.
o Very dense and it’s axis is tilted almost ______° !
· Neptune- gaseous
o ______color
o Temperature is -225 °C
o The atmosphere has belts of clouds
· Pluto – like a terrestrial planet
o ______from the Sun. Has a moon called Charon
o Now considered a ______planet because it is more like an asteroid.
o Half the size of Mercury
o Made of rock and ice. Atmosphere is mostly methane.
Study Jams Outer Planets Slide Show : Quiz Score: ______
Comet: a small body of ______, rock and cosmic dust loosely packed together.
· “Dirty ______”
· Comet tails: gas and dust that the comet gives off when solar radiation heats it.
· They orbit in an elliptical shape.
· Scientists believe comets come from outside our solar system (Oort Cloud).
Asteroids are large rocky bodies in ______around the sun.
· Irregularly shaped.
· Most orbit in a region between Mars and Jupiter called the asteroid ______.
Meteoroid/Meteorite/Meteor
· A meteoroid is a ______, rocky body orbiting the sun.
o They are smaller than an asteroid.
· A meteorite is when a meteoroid enters the Earth’s atmosphere and strikes the ground.
· A meteor is the bright streak of light caused by a meteoroid or comet dust burning up in the atmosphere.
A star is a hot, brilliant ball of ______.
· Stars go through a life cycle.
· Absolute magnitude is the actual ______of a star.
· The H-R (Hertzsprung-Russell) diagram is a graph showing the relationship between a star’s surface temperature and it’s absolute magnitude.
· Our sun is an average star (dwarf star).
Hertzsprung-Russell (HR) Diagram
The Sun
· Our sun is an ______star (dwarf star).
· The energy from the sun is produced by fusion.
· Sun spot- cool, dark spots on the sun
· Solar flare- giant storm on the surface of the sun.
o Can affect ______
Old Stars
· Supernovas: ______of a large star by explosion.
o Produces silver, gold, and lead.
· Neutron Stars: a star formed from the left over materials a ______.
o Extremely dense.
o Particles inside the star become ______.
· Pulsars: a ______neutron star.
· Nebulae: a cloud of ______and dust that is created by the energy of the supernova explosion. New stars can be born here. (stellar nurseries)
· Black Holes: an object that is so ______(in other words, has enough mass in a small enough volume) that its gravity is strong enough to prevent light or anything else from escaping.
o Astronomers theorized that these are created after a supernova and when the universe began.
A Stars’ Life Cycle Video:
What are stars made of (it is the fuel for the star)? ______
What does a star’s life cycle depend on? Circle one: It’s size or Where it’s born
What will our sun turn into after it runs out of fuel? ______
Galaxies
A galaxy is a large ______of stars in space (billions to trillions of stars)
· Types:
o ______- bulge at the center and spiral
§ Most galaxies are this type.
§ The Milky Way is thought to be this type
o Elliptical- bright centers and very little dust and gas.
§ Contain only ______stars.
o Irregular
§ No definite shape
The Big Bang Theory:
The scientific theory, discovered by ______, that the Universe was born from a single point in a violent explosion and has been expanding ever since.
What is 1 thing you learned from the Big Bang Theory video? ______
______