Astronomy Universe: all of space and everything in it Most (90%) of the universe is made up of: dark matter: stuff we think is there due to amount of mass we think is there but is not detected by the instruments we have available at this time http://media.skysurvey.org/interactive360/index.html
Nebula: large amount of gases spread out in an immense volume All stars start as part of a nebula
Star: large amount of glowing gas in a small volume mostly hydrogen It creates energy through nuclear fusion of hydrogen to helium in its core. We see and feel this release of energy as sunshine
Globular cluster: a group of 10,000 to 1 million stars (that s a LOT)
Galaxy: a giant structure that contains hundreds of BILLIONS of stars 3 main types: 1. spiral 2. elliptical 3. irregular
1. spiral: have arms that spiral outward like a pinwheel Milky Way: our galaxy We are on an outer arm.
2. elliptical: looks like a flattened ball; 3. irregular: No regular shape
Galactic cluster: groups of galaxies held together by gravity The Milky Way is part of a galactic cluster with 30 other galaxies traveling together called, The Local Group.
Life Cycles of Stars
Supernova: explosions of dying large stars. Can be seen without a telescope. Neutron star: extremely small, dense leftovers from a supernova supernovae shrink into neutron stars
Black hole: what remains after the most massive stars die gravity is so strong that nothing can escape (not even light) many scientists think the center of Milky Way contains a black hole Artist s rendition. Not a real photograph!!
How we get information about space: (no man has ever been farther than the moon) One way: space telescopes! the Hubble Space Telescope (looks at distant galaxies & at planets in our solar system) Kepler Space Telescope (looks for planets around other stars (exoplanets))
How do we measure movement and distances in space Within our solar system we use radar and the formula for speed: Speed = distance/time Speed of light = 186,000 mi./sec or 300,000km/sec. That s around Earth 7 ½ times in one second! ALL EM waves travel at the speed of light.
Measuring Distance within our Solar System. Astronomical Unit (AU): distance between the Earth and Sun Approximately 93,000,000 miles Used only within our solar system to measure distances between planets and the sun
Takes about 8 minutes for sunlight to reach Earth Takes about 4 years for starlight from next nearest star to reach Earth.That star is 4 light-years away! Alpha Centauri Measuring Distance outside our Solar System. Light-year: distance light travels in one year at the speed of light. If Speed of light = 186,000 mi./sec, then a Light-year = 5.9 trillion miles (5,900,000,000,000 miles)
Parallax: the apparent change in position of an object when you look at it from different places used to measure distance to nearby stars smaller shift = greater distance.
Doppler effect Red shift - longer wavelenghts : moving away from you. Blue shift- shorter wavelengths: moving toward you. Red -away ; blue toward you.
Doppler effect Red shift Blue shift
Telescopes collect and focus different types of electromagnetic radiation, including visible light. OOptical telescopes are used to see distant or faint objects by magnifying the amount of light they emit. Isaac Newton's telescope Hubble Telescope
Radio Telescopes collect radio waves from space to convert to images so we can see the source. easily detects waves through our atmosphere. Robert C. Byrd Green Bank Telescope (GBT)
Infrared Telescopes Can be on the ground or above atmosphere. Used to measure temperature of celestial objects, their composition and to locate planets around other stars. Exoplanets IInfrared telescopes on Mauna Lea in Hawaii Robert C. Byrd Green Bank Telescope (GBT)
Ultraviolet Telescopes Placed outside Earth s atmosphere. Detect hot, young stars in other galaxies Galex UV Telescope Robert C. Byrd Green Bank Telescope (GBT)
X-Ray Telescopes Are placed outside Earth s atmosphere. Observe supernova remnants, X-ray pulsars, black holes, neutron stars, and hot galactic clusters. Chandra X-ray Telescope Robert C. Byrd Green Bank Telescope (GBT)
Gamma Ray Telescopes Are placed outside Earth s atmosphere. Gamma rays often come from objects like black holes and exploding stars Fermi Gamma Ray Telescope Robert C. Byrd Green Bank Telescope (GBT)