Astronomy Unit Review

Topics Solar system(planets, asteroid belt, meteor, meteoroid, meteorite, comet etc) Measurement (AU and Light Years) Sun (structure; features of the Sun--> Sunspots, Solar Flares & Prominences) Star ( Brightness, Colour, Temperature, Composition, Mass) Star Formation and Death ( Life Cycle of a star handout!!!!) Star Spectrum Types of Galaxies, Galaxy structure, Milky way Galaxy, Big Bang Theory (Expanding Universe, Hubble’s Law, redshift, Evidence of the theory) Dark Matter

Mark Breakdown Knowledge --22 marks ( M/C & short answer) Thinking/ Inquiry marks (graph, fill in chart, short answer) Communication-- 10 marks ( labeling, short answer) Application-- 8 marks

Order of the planets What’s the order of our solar system? What is the structure of the Sun?

Features of the Sun Sunspots Darker areas of lower temperatures that appear on photosphere Solar Flares as sunspots age, nearby areas may violently erupt produces stream of high-speed, sub-atomic particles --> SOLAR WINDS at earth, can interfere with electronic communication interaction with Earth’s magnetic field produces auroras Prominences corona throws streamers of gas into space can flow straight out or loop back into sun

Properties of Stars Electromagnetic Spectrum other types include radio wave, microwaves, UV rays and X-Ray different wavelengths of the e-m spectrum carry different amounts of energy Brightness of Stars depends of size & distance closest stars not necessarily the brightest luminosity measures the energy radiated per second, a true measure of brightness Temperature of Stars bluish, white, yellow, orange, red e-m spectrum red stars are cooler yellow stars are hot (sun) blue stars are very hot! Composition of Stars use colour to determine elements in the star

Properties of Stars H-R Diagram want to find an patterns in star data Stars mass determines its brightness, colour, size and life cycle plotting luminosity and colour (temperature) showed some order in types of stars main sequence accounts for 90% of known stars, including the Sun other 10% fell to either side of the main sequence bright but cool --> red giants(larger, bright, cool stars) and supergiants dim but hot --> white dwarf hottest, luminous and very large---> Blue Supergiants Upper Right & left corner----dim & hot ; Luminous & cool

Birth of a Star Stars are formed in Nebula interstellar clouds of dust and gas (mostly hydrogen). When a the nebula ( clouds of dust and gas) crosses the spiral arm of a galaxy, it begins to from clumps. Gravity pulls material together More material pulled in = more pressure and increase in temperature. Hydrogen fuses into helium. Nuclear fusion begins ( formation of the star begins) Star has “ turned on”. ---> creating a Protostar Protostar - massive concentration of gas and dust thought to eventually develop into a star after the nebula collapse

Death of a Star Small -Medium Stars Consume hydrogen slowly(up to100 billion years swells to becomes a large, cool, red giant Death- Outer layer of gas drift away and the core shrinks to become a small, hot, dense white dwarf star Remains- White dwarf star eventually cools and fades

Death of a Star Large and Massive Stars Consumes hydrogen rapidly Mass of stars determine how long a star will “live” Use up hydrogen and other fuels and swells to becomes a red supergiant Large Star--- core collapses inward, sending the outer layers exploding as a supernova. Core remains as a Neutron star Massive Star-- core collapses, sending the outer layer exploding as a very larger supernova. Black hole is the remaining product.

Galaxies Open star clusters- younger stars, spread out Globular star clusters- older stars, highly concentrated in the middle Types of galaxies---> Elliptical, Spiral, Lenticular, Irregular How do the galaxies look when you observe them from different angles. Milky way

Big Bang Theory Big Bang Theory- A cosmological theory holding that the Universe originated approx 20 billion years ago from the violent explosion (EXPANSION) of a very small amount of matter if extremely high matter of extremely high density and temperature Universe began as one small object, called a singularity, that contained all the mass & energy of the universe Singularity rapidly expanded and began to cool down Hubble Law--- Redshift! Redshift- object is moving away from us, the pattern shifts towards the red end of the spectral Most objects in the distant parts of the universe exhibit a red shift, indicating that the universe is expanding.

Dark Matter Recent discovery of dark matter Characteristics of dark matter. cannot be seen directly with telescopes does not absorb light or emit light structure of the universe we know about dark matter because of its gravitational effect. Still know a little about it