Exploring the Universe

Harcourt ScienceUnit D

Chapter 4

Mrs.Strand6th grade Lockwood Middle School

Life Cycle of Stars

• Terms– Fusion– Main sequence– Nebula– Nova– Supernova

Life Cycle of Stars

• Brightness of stars– Distance affects the brightness of stars– What we see is called the apparent

magnitude– Absolute magnitude is a measurement of the

brightness as if the distance from the earth was 32.6 light years away. A uniform distance, so it’s the real brightness.

– Besides the sun, the brightest star is Sirius

Types of Stars

• All stars are made up of hot, glowing gases

• Stars can appear red, blue or yellow based on surface temperature– Hottest stars are blue, coolest are red– Hertzspurg-Russel diagram classifies stars

• 90° of stars are called the main sequence• Other stars include red giants, supergiants, and

dwarfs

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http://www.lpl.arizona.edu/~rhill/alpo/images/

Birth & Death of StarsStars form in huge, cool, dark clouds of dust

and gases. When there is enough matter, the particles fuse into nebula.This fusion is where the stars get their energy. The centers are called protostars and determine how the star starts its life.

The mass may be really hot which leads to high-mass blue stars.The mass may be cool which leads to low-mass red stars.The mass also determines how the star will die.

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http://www.phobos.pcm.hr/slike/Helix%20Nebula%20NGC7293.jpg

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Birth & Death of Stars

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http://www.seasky.org/cosmic/assets/images/starlife.jpg

Types of Stars

• Terms– Galaxy– Galactic cluster

Types of starlight• Knowledge about stars is indirect based

upon electromagnetic radiation (light & sound,infrared rays, ultraviolet rays, x-rays)

• Stars are viewed with telescopes, radio-wave receivers, and x-rays

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http://www.yorku.ca/eye/spectru.htm

What are galaxies?

• A large system of stars

• Our galaxy has our sun and billions of stars

• Our galaxy is 100,000 light-years across

• Other galaxies include Andromeda, but there are billions!

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http://en.wikipedia.org/wiki/Groups_and_clusters_of_galaxies

Shapes of galaxies

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http://www.damtp.cam.ac.uk/user/gr/public/gal_class.html

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http://www.damtp.cam.ac.uk/user/gr/public/gal_class.html

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http://curious.astro.cornell.edu/galaxies.php

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http://www.seds.org/messier/xtra/ngc/lmc.html

Models of the Universe

• The universe is everything that exists!

• How do we know how big it really is?

• What do we know about black holes?

How do we study space?

• Terms:– Refracting telescope– Reflecting telescope

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http://www.eurocosm.com/Application/images/telescopes/675-telescope-lg.jpg

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Refracting & Reflecting telescopes

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http://www.indepthinfo.com/telescopes/reflecting-telescopes.shtml

Optical telescopes

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How do we study space?• People used to navigate

by the starswe are always wanting to know where we come from and where we are going

• Galileo developed a refracting telescope

• 60 years later, Newton developed a reflecting telescope

People VS No People

• What are some potential problems with people in space?

• What are some things that only people can do in space?

Click Here for Timeline ofSpace Exploration

Advanced Telescopes

• Very sensitive instruments

• Hubble Space Telescope

• Compton Gamma Ray Observatory

• Cosmic Background Explorer

• Radio Telescopes

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http://quest.nasa.gov/hst/photo.html

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http://imagine.gsfc.nasa.gov/docs/science/know_l2/emspectrum.html

Investigate Further