What do you think of when you look at the night sky?

http://www.astro.ufl.edu/~lada/ast3018/lectures/ast3018lecturestarform.pdf

What is Space?• Not really empty• Stars, planets, etc.• Interstellar medium

• Dust and Gas• Nebulas

Orion Nebulahttp://hubblesite.org/gallery/album/nebula/pr1995044a/

Large Magellanic Cloudhttp://hubblesite.org/gallery/album/nebula/pr2006055a/

Nebular Hypothesis

• Random collisions of atoms

• Areas of growing mass• Spherical shape• Pull in more matter• Increase in

• Temperature• Pressure

• Spin• Creates a bulge in the sphere

http://physics.uoregon.edu/~jimbrau/BrauImNew/Chap06/FG06_17.jpg

Nuclear Fusion

• High temperatures• 2 particles become 1• Releases a lot of energy• Video clip

• Particle accelerators• Man-made• Create new elements• Find smallest particles

Fermi National Labhttp://www.wired.com/playbook/2012/08/olympics-physics-hammer-throw/

http://www.universetoday.com/52696/nuclear-fusion-power-closer-to-reality-say-two-separate-teams/

Spectroscopy Activity

•Draw the lines that you see• Make sure the # of lines, color of the lines and order is accurate

•Write a conclusion – based on your observations what can you conclude about the different materials and light you see the material produce

Warm Up #1

•Clicker Quiz •Compare conclusions from the spectroscopy activity

What does a spectrum tell us?• Each chemical/atom has a unique spectrum• Like a fingerprint

• What chemicals are present

http://www.umsl.edu/~physics/Lab%20Connection/Electricity%20and%20Magnetism%20Lab/12-lab13.html

How is a spectrum created?• All objects emit light• Pure light from a source• Continuous spectrum

• If light passes through gas or dust• Light absorbed• Excites/heats atoms• Emit own light• Makes an emission spectrum

• Unique

https://www.cfa.harvard.edu/~jbattat/a35/cont_abs_em.html

How do astronomers use spectra?• Look at light from

• Stars (gas in outer layers)• Nebula• Planets

• Determine chemical composition• Can also determine movement of object• Activity

http://www.eso.org/public/outreach/eduoff/cas/cas2004/casreports-2004/rep-236/

Warm Up #2

•Why are emission spectra important?•How are emission spectrum created?•What 2 things can astronomers learn by looking at the spectrum from a star?

H-R Diagram Graphing Activity

•Look for patterns

http://www.rootstown.sparcc.org/mattjust/h-r-diagram

Color and Temperature• What did you see as a pattern?• Objects give off a variety of light• Peak depends on temperature

• Peak shows most common type of light

http://docs.kde.org/stable/en/kdeedu/kstars/ai-colorandtemp.html

Main Sequence Stars• Find group on H-R

diagram• Wide variety• Highest # of stars• Stars stay here the

longest• Actively fusing hydrogen

into helium• Outward pressure from

fusion• Inward pressure from

gravity• Equal in these stars• Maintain size

http://www.rootstown.sparcc.org/mattjust/h-r-diagram

http://www.thenakedscientists.com/HTML/articles/article/the-science-of-the-supernova/

What happens to our Sun?

• Form red giants• Fusing helium• Core collapsing• Outer layers

spread out• Cools

http://flightline.highline.edu/iglozman/classes/astronotes/media/2paths.jpg

http://www.physics.uc.edu/~hanson/ASTRO/LECTURENOTES/StarLife/Page7.html

What then?• Forms a white dwarf

• Ran out of helium• No more fusion

• Outer gasses moving away• Planetary nebula

• Leaves a hot, dense corehttp://chandra.harvard.edu/xray_sources/white_dwarfs.html

Ring Nebulahttp://hubblesite.org/gallery/album/nebula/planetary/pr2004032d/

Cat’s Eye Nebulahttp://hubblesite.org/gallery/album/nebula/planetary/pr2004027a/

Warm Up #3

•What makes a star a main sequence star?

•Why does the size of the core of a main sequence star not change?

•What will eventually happen to our Sun and why?

What about the fate of larger stars?• Become red supergiants

• Fuse elements larger than helium• All the way to iron

• Short lives

• Supernova• No more fusion• Core violently explodes• Fuses heavier atoms• Very bright, short time• Spreads out material

http://flightline.highline.edu/iglozman/classes/astronotes/media/2paths.jpg

http://hubblesite.org/gallery/album/nebula/supernova_remnant/pr2005037a/

What then?

• Forms a neutron star• If a lower mass core• Very dense

• Not very big• Lots of gravity

• Can produce gamma and x-rays when it pulls items into it

Neutron star in supernova Cassiopeia Ahttp://www.space-pictures.com/view/pictures-of-space/pictures-of-stars/neutron-star/index.php

http://www.clccharter.org/maya1/Supernova/supernova.html

Or…• Forms a black hole

• Higher mass cores• Infinitely dense• Need to travel faster than the speed

of light to escape

• How can we see?• Will bend light from nearby stars• See dust and gas swirling around

• Hot enough to give off x-rays

• Probably at the center of most galaxies• Including ours!

• Video

Whirlpool Galaxyhttp://hubblesite.org/gallery/album/pr2001010a/

http://www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html

Warm Up #4

• What is happening inside a red supergiant star?

• What happens in a supernova?• How is a neutron star different from a black hole?

• Why should we not be able to see a black hole?

• Why can we “see” a black hole?

Warm Up #5

•Clicker Quiz

Metric System Olympics

• Create a data table to organize the following items (one per group)• You will be doing the following “events” – paper plate “discus”, straw “javelin” and long jump

• For each “event” you will need a measurement, then you will change that measurement to another unit, and you will write this last unit in scientific notation

How do we know how far away that is?• Parallax effect

• Compare distant stars to nearby stars

• Measure shift as Earth orbits the Sun

• Calculate the distance

• Further away = less of a shift

• Better technology = see smaller shifts = measure larger distances

http://lifeng.lamost.org/courses/astrotoday/CHAISSON/AT301/HTML/AT30105.HTM

http://astronomy.nmsu.edu/aruiter/ASTRONOMY110/parallax.gif

Looking Back in Time• If a star is 10 light years

away• How old is the light we see

today?• Is that star still there

today?

• If an alien is on a planet 10 million light years away• If they could see with the

Earth with great detail, what would they see right now?

• When we observe light from a star 2 billion light years away….what does that mean?

http://www.spacetelescope.org/images/heic1214c/

How has our “picture” of the universe changed?

• Greeks• Rotating spheres

• Earth centered

Early Scientists

•Galileo•Copernicus•Kepler•Newton

• Mathematical laws about movement of planets

• First telescope• Calculation of gravity

• Sun centered universe

Next generation of scientists…• Einstein

• Calculations• Universe changing size• Disbelieved

• Added a constant to his equations

• Results = static universe

• Friedmann• Russian• Removed Einstein’s constant• Universe changing shape• Won Einstein’s approval

http://wouterdeheij.wordpress.com/2013/04/27/famous-innovation-quotes-from-steve-jobs-gunter-pauli-einstein-henry-ford-and-many-others/

http://en.wikipedia.org/wiki/File:Aleksandr_Fridman.png

The Big Bang Theory

• Lemaitre• Priest and physicist• Universe began as a

single point• Expanded since that time

• Hubble• Astronomer• Published around same

time• Provided evidence

http://scienceblogs.com/startswithabang/2011/01/05/q-a-how-is-the-universe-so-big/

Hubble’s Evidence - Redshift• Change in emission spectrum

• Same pattern• Shifted from where it should be

Same thing happens with sound…• Doppler effect• Object moving past a stationary object• Waves get shortened in front

• Higher pitch

• Waves get longer in back• Lower pitch

• Inside the source – no change

http://archive.ncsa.illinois.edu/Cyberia/Bima/doppler.html

Relating back to light…• Blue-shift

• Wavelength shortens• Moving towards us

• Red-shift• Wavelength lengthens• Moving away from us• Bigger the shift the further

away it has come from• Hubble only saw red-shifted

spectra

Hubble’s Conclusions• Universe

moving away from us

• Things further away are moving away faster

• Expansion rate has

since beginning

https://www.e-education.psu.edu/astro801/book/export/html/1967

Warm Up #6