2StarsA star is a hot, glowing ball of gas (mainly hydrogen) that gives off light energy.Very hot stars look blue, while cooler stars look red.In the 1920's, Ejnar Hertzsprung and Henry Norris Russell compared the surface temperature of stars with its brightness (luminosity).Stars fall into distinct groupings.
8SupernovaAn enormous explosion that marks the death of a massive star.Fusion has stopped and the star runs out of fuel.Gravity causes the star to collapse upon its self.The outer part of the star explodes with a shock wave.
9Black HolesA highly dense remnant of a star in which gravity is so strong that not even light from radiation going on inside the remnant can escape.Event horizon – point at which light cannot escape.Invisible to telescopes.This shows how the path of a beam of light bends in the vicinity of a non- rotating black hole.
10Star GroupsConstellations are the groupings of stars we see as patterns in the night sky.There are 88 constellations and many are explained in Greek Mythology.Asterisms are also groupings of stars but are not officially recognized as constellations.
11GalaxiesA galaxy is a grouping of millions or billions of stars, gas and dust.Held together by gravity.The Milky Way Galaxy is the galaxy our solar system is a part of.It is shaped like a flattened pinwheel, with arms spiralling out from the center.
13Types of GalaxiesSpiral – long curved arms radiating out from a bright central core – older to younger at the armsElliptical – football or egg – mostly old starsIrregular – no notable shape – smaller size – mixture of young and old stars
15The Sun The Sun emits charged particles in all directions. This solar wind bombards the Earth at 400km/s, but the magnetic field of the Earth protects us.
16Protoplanet hypothesis 1. A cloud of gas & dust in space begin swirling2. Most of the matter (more than 90% of it) accumulates in the center - forming the Sun3. The remaining materials accumulate (forming planets) and circle the Sun
17The Planets: Mercury Closest planet to the Sun Surface similar to our moonNo atmosphereHigh temperature – 400oC sunny side- 180oC dark side
18The Planets: Venus Similar in size, mass, and gravity to earth High surface temperature – 450oC (melt lead)90 x atmospheric pressure to EarthCO2 cloud coverRotates opposite to other planets – east to west
19The Planets: EarthOnly planet where water exists in solid, liquid, and gasOnly planet to support lifeAtmosphere provides protection from the Sun70% surface covered in waterActive volcanism
20The Planets: MarsRed planet – orangish – caused by iron oxides on surfaceTwo polar ice caps (One of Co2 + H2O and one of CO2)Extremely cold surface temperatureVaried surface topography2 moons
21The Planets: Jupiter Largest of all planets Twice the mass of all other planets combinedComposed of mainly hydrogen and heliumGreat Red Spot – atmospheric stormThree thin rings28 moons
22The Planets: Saturn 19 moons Second largest planet 1000+ rings surround equatorComposed mostly of hydrogen and heliumHigh wind speeds over km/h due to fast rotation
23The Planets: UranusUnusual axis of rotation – tilted toward the plane of its orbit –making it appear to roll its orbitComposed mostly of hydrogen and heliumMethane in atmosphere gives it its blue colourLarge ring system17 moons
24The Planets: NeptuneComposed mostly of hydrogen and helium, and methaneMethane in atmosphere gives it its blue colourLittle light reaches this planetFastest wind speed – km/hOwn ring system8 moons
25The Planets: Pluto Cold frozen ball of methane Disqualified as a Planet due to its obit around the sun at 17.2o – more ellipticalRotates east to west rather than west to eastSome astronomers believe it and Charon (moon) are comets that have been captured by the gravity of the sunOriginated from the Kuiper Belt
26Other Celestial Bodies Asteroids – rocky , metallic bodies ranging in size of a few meters to hundreds of kilometresComets – dirty snowballs – dust and ice and heat up when they come close to the sun, releasing gasComets have predictable paths – large ellipses
27Other Celestial Bodies Meteoroids – small pieces of rock flying through space with not particular pathMeteor – a meteoroid that gets pulled into the atmosphere by gravity – heats up and gives off lightMeteorite – a meteor that hits the surface
28Hyper LinksSolar SystemSpace Videos National Geographic
29Describing the Position of Objects in Space Section 1.5Pages
30Altitude Altitude gives you the "how above the horizon it is” The point straight overhead has an altitude of +90 degreesStraight underneath, an altitude of -90 degrees.Points on the horizon have 0 degree altitudes.An object halfway up in the sky has an altitude of 45 degrees.
31AzimuthAzimuth determines "which compass direction it can be found in the sky."An azimuth of zero degrees puts the object in the North.An azimuth of 90 degrees puts the object in the East.An azimuth of 180 degrees puts the object in the South, and one of 270 degrees puts the object in the west.Zenith is the position in the sky directly overhead.
33Motion of Objects in Space The path in the sky along which the Sun takes is called the ecliptic.The Celestial Sphere is the name given to the very large imaginary 'sphere of sky' surrounding the Earth.