Do Now: Write down five things you know about the sun in your notes… Do Now: Write down five things you know about the sun in your notes…

Gives off energy in the form of electromagnetic waves (see esrt p15) Gives off energy in the form of electromagnetic waves (see esrt p15) Luminous Luminous Can be classified according to the Hertzsprung-Russel Diagram (our sun is a typical star) Can be classified according to the Hertzsprung-Russel Diagram (our sun is a typical star) Energy produced by the nuclear fusion of 2 hydrogen atoms to helium Energy produced by the nuclear fusion of 2 hydrogen atoms to helium Takes 27 days to rotate Takes 27 days to rotate

Sunspots were first observed by Galileo Sunspots were first observed by Galileo Cooler areas on the surface of the sun Cooler areas on the surface of the sun Occur in a cyclic manner-every 11 years reach a maxima or a minima Occur in a cyclic manner-every 11 years reach a maxima or a minima

8 planets (see esrt p15) 8 planets (see esrt p15) Meteors Meteors Asteroid Belt (Mars and Jupiter Asteroid Belt (Mars and Jupiter Kuiper Belt (Pluto is the king) Kuiper Belt (Pluto is the king) Inner (rocky) Inner (rocky) Outer (gas giants) Outer (gas giants)

The Milky Way- our home galaxy The Milky Way- our home galaxy Milky Way Local Group- The Milky Way is not an island universe, but a member of a small cluster of galaxies called the Local Group. The Local Group contains about 3 dozen known galaxies, clumped in two subgroups around two massive spiral galaxies - -the Milky Way, and the Andromeda Galaxy. In several billion years it is possible that the Milky Way and Andromeda will collide and merge to form one huge elliptical galaxy.(Credit: NASA/CXC/M.Weiss) Milky Way Local Group- The Milky Way is not an island universe, but a member of a small cluster of galaxies called the Local Group. The Local Group contains about 3 dozen known galaxies, clumped in two subgroups around two massive spiral galaxies - -the Milky Way, and the Andromeda Galaxy. In several billion years it is possible that the Milky Way and Andromeda will collide and merge to form one huge elliptical galaxy.(Credit: NASA/CXC/M.Weiss)

Milky Way Galaxy: Face-on ViewSchematic, face on illustration of the Milky Way galaxy, showing the prominent spiral arms, the central galactic bulge and the location of the Sun. (labeled & unlabeled) (Credit: NASA/CXC/M.Weiss ) Milky Way Galaxy: Face-on ViewSchematic, face on illustration of the Milky Way galaxy, showing the prominent spiral arms, the central galactic bulge and the location of the Sun. (labeled & unlabeled) (Credit: NASA/CXC/M.Weiss )

Consists of billions of stars clustered together Consists of billions of stars clustered together Spiral shaped Spiral shaped 100,000 light yearts across 100,000 light yearts across Mapped by radiotelescopes –x-ray telescopes (Chandra) Mapped by radiotelescopes –x-ray telescopes (Chandra) Rotates Rotates Virgo Cluster- our local group Virgo Cluster- our local group Andromeda is the nearest galaxy to us Andromeda is the nearest galaxy to us

Light years-distance light travels in one year Light years-distance light travels in one year 10 trillion km 10 trillion km Our universe is 25 bilion light years in diameter and billion years old Our universe is 25 bilion light years in diameter and billion years old closest star to us is Proxima Centauri light years away closest star to us is Proxima Centauri light years away

Proposed by George LeMaitre (a roman catholic priest) 1927 Proposed by George LeMaitre (a roman catholic priest) 1927 Says universe began from a primordial hot and dense state which exploded material out into space Says universe began from a primordial hot and dense state which exploded material out into space Is still expanding outward today Is still expanding outward today

Yes Yes Evidence for expansion was first provided by Edwin Hubble- red shift (1929) Evidence for expansion was first provided by Edwin Hubble- red shift (1929) And Background (cosmic microwaves)Radiation from space (1964) And Background (cosmic microwaves)Radiation from space (1964)

Light Spectra

Science tries to answer them all Science tries to answer them all What is the fate of our universe? Will it continue to expand or undergo the Big Crunch? What is the fate of our universe? Will it continue to expand or undergo the Big Crunch? There are many models to that try to explain this There are many models to that try to explain this ??????? ???????

Wrap up? use the following to determine.... Universe Solar system Milky way Virgo cluster USA NY Rm 227 What is our Cosmic Address?