4Arecibo Radio Telescope Globular cluster M13 was chosen as a target for one of the first radio messages addressed to possible extra-terrestrials. This message was sent by the giant radio telescope of the Arecibo Observatory in Puerto Rico, at a ceremony to mark the remodeling of the telescope on November 16, 1973.
5What is the Arecibo Message? It will take 25,000 years for the message to reach M13 and if any reply were to be received it would take another 25,000 years to reach Earth, a total of 50,000 years. The Arecibo message was more a symbolic event to demonstrate the capabilities of the newly installed equipment than an actual attempt at communication.
7What is the origin of our universe? Big Bang Theory: As used by cosmologists, the term Big Bang generally refers to the idea that the Universe has expanded from a primordial hot and dense initial conditionOccurred around 13.3 to 13.9 billion years ago and continues to expand to this day.
8What Evidence exists for the Big Bang Theory? First of all, we are reasonably certain that the universe had a beginning.Second, galaxies appear to be moving away from us at speeds proportional to their distance. This is called "Hubble's Law," named after Edwin Hubble ( ) who discovered this phenomenon in This observation supports the expansion of the universe and suggests that the universe was once compacted.Third, if the universe was initially very, very hot as the Big Bang suggests, we should be able to find some remnant of this heat. In 1965, Radioastronomers Arno Penzias and Robert Wilson discovered a Cosmic Microwave Background radiation (CMB) which pervades the observable universe. This is thought to be the remnant which scientists were looking for. Penzias and Wilson shared in the 1978 Nobel Prize for Physics for their discovery.Finally, the abundance of the "light elements" Hydrogen and Helium found in the observable universe are thought to support the Big Bang model of origins.
10Comparing the PlanetsInner Planets: Mercury, Venus, Earth, Mars (also known as terrestrial planets)Outer planets: Jupiter, Saturn, Uranus, Neptune (also known as gaseous planets or gas giants)Which planet is largest? Smallest?How does size affect gravity? Weight? Mass?
11What other objects exist in our solar system? Asteroids: Any of numerous small celestial bodies composed of rock and metal that move around the sun (mainly between the orbits of Mars and Jupiter)Comets: A relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit
12Structure of a Comet Parts of a Comet Nucleus: solid part of comet Coma: A halo of evaporated gas (water vapor, ammonia, carbon dioxide) and dust that surrounds the nucleusPlasma (Ion) Tail: Electrically charged gas molecules that are pushed away from the nucleus by the solar wind.Dust Tail: Dust particles that evaporate from nucleus. Always faces away from sun!
13Where do comets come from? The Kuiper Belt is a disk-shaped region past the orbit of Neptune extending roughly from 30 to 50 AU from the Sun containing many small icy bodies. It is now considered to be the source of the short-period comets.
14What is the Oort Cloud?Comet orbits come in two varieties, long and short period.There are about 600 comets with known orbits. About 100 have orbits that lie within the solar system with periods less than 200 years.The majority of comets have long elliptical orbits that are randomly oriented in space. These are the long period comets. These long period comets come from a place called the Oort cloud.
16What are meteoroids?Meteoroids: Small bodies that travel through space. They are smaller than asteroids; most are smaller than the size of a pebble.Meteors: Meteoroid that has entered the Earth’s atmosphere.Meteorites: Meteor that hits the Earth’s surface
17WHAT PROPERTIES OF STARS DO SCIENTISTS STUDY? COLOR (COMPOSITION)TEMPERATURE: RED, ORANGE, YELLOW, WHITE, BLUEMASSLUMINOSITY (BRIGHTNESS)SIZE (RADIUS)AGE
18ANATOMY OF OUR SUN Corona: (atmosphere) Chromosphere (outer atmosphere)Photosphere: (inner atmosphere)Prominence: arches of gasSolar Flares: Explosions on surfaceSun spots: cooler, darker regionsNuclear fusion: putting together atoms
19HOW WILL OUR SUN EVOLVE? MEDIUM STARS: RED GIANT TO WHITE DWARF LARGE STARS: SUPERGIANT, SUPERNOVA, NEUTRON STARMASSIVE STARS: SUPERGIANT, SUPERNOVA, BLACK HOLE
20BIRTH & DEATH OF STARSNEBULA: Cloud of dust and gas where stars are bornBlack Hole: is a region of space from which nothing, including light, can escape. It is the result of the deformation of spacetime caused by a very compact mass.NEUTRON STAR: A neutron star is about 20 km in diameter and has the mass of about 1.4 times that of our Sun. This means that a neutron star is so dense that on Earth, one teaspoonful would weigh a billion tons!White Dwarf: A white dwarf is what stars like our Sun become after they have exhausted their nuclear fuel.Pulsars: Rotating neutron stars
22What are comets and asteroids? Comets: collection of ice, dust and rocky particlesNucleus: Center solid regionComa: glowing atmosphere as the comet approaches the sunTail: trail of burning gas and dust particlesAsteroids: debris that did not form planetsMeteoroids: smaller than asteroidsMeteors: when meteoroid enters Earth’s atmosphereMeteorites: Any piece that hits Earth’s surface