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Physical Science
The Universe
| Question | Answer |
|---|---|
| The study of the _____ is the oldest science. | stars |
| Our _____ is a star and is what provides the energy for the generation of life on the Earth. | sun |
| _____ are born, they radiate energy, and then they expand, contract, possibly explode, and die out. | stars |
| We know this because of the study of the ______and by applying the laws of science from many diverse fields. | atomic nucleus |
| The Sun is held together by its own _____and energized by the nuclear reactions in its interior. | gravity |
| The sun moves through space with its solar system at a rate of 250 km/s in the direction of the constellation | Lyra. Study the diagram on page 467 and make sure you know about the layers of the Sun. |
| Solar wind – | the flow of radiation from the Sun outward through the solar system. |
| Heliosphere – | the volume of space over which the solar wind extends. |
| Sunspots – | patches of cooler material on the surface of the Sun. Usually indicate areas of magnetism. |
| They are on a 22-year cycle. Every 11 years the magnetic north and south swap around. | sunspots |
| The core of the Sun is made up mostly of | Hydrogen nuclei, or protons. |
| Neutrino – | an elementary particle that has no charge, very little mass, travels at or about the speed of light, and hardly ever interacts with other particles such as electrons and protons. |
| Scientists believe that the Sun has been radiating for about | 5 billion years and that it will continue to do so for about another 5 billion years. |
| The hydrogen atoms that are fusing together will eventually form a | helium atom. Some excess matter results from this and this excess is what is given off as energy. The three reactions that cause this to happen make up the proton-proton chain. P. 469-471 |
| Celestial sphere – | the background of stars. P. 472 |
| Celestial Equator – | the imaginary line in the sky that is directly above the Earth’s equator. It divides the sky into north and south. In order to locate a position of a star, it must some coordinates assigned to it. |
| Declination (DEC) – | the angular measure in degrees north or south of the celestial equator. |
| Degrees north are given a | positive (+). |
| Degrees south are given a | negative (-). |
| Right ascension (RA) – | is the angular measure in hours, with hours divided into minutes and seconds. It begins with 0 hour at the celestial prime meridian and continues eastward to a maximum value of 24 hours, which coincides with the starting point. |
| Celestial Equator – | runs from north to south, perpendicular to the equator. It crosses the equator at the point of the vernal equinox (first day of spring) March 21st. The distance coordinate is measured in astronomical units, parsecs, or in light years. |
| Light year (ly) – | the distance traveled by light in one year. |
| 1 ly = | 6.0 x 10 ^12 miles |
| 1 parsec = | 3.26 ly or 206,265 AU |
| AU = | astronomical unit = distance from the Earth to the Sun = 93,000,000 miles. |
| There are | 88 constellations. Your latitude and the time of year determine which ones you see. |
| Asterism – | a group of stars that is part of a constellation. Ex/ the Big Dipper is NOT a constellation. It is an asterism. It is part of Ursa Major, the Big Bear. |
| During the ecliptic the Sun passes through the constellations that make up the 12 signs of the | Zodiac. |
| Zodiac – | the word means the circle of animals. There is only one sign of the zodiac that it is not an animal and it is Libra. Libra is a set of scales. |
| Magnitude – | term that refers to the brightness of a star. It is a numerical scale. The smaller the number, the brighter the star. |
| Binary star – | system where two stars are orbiting each other. |
| Nova – | “new” star. Star that is undergoing a drastic change. It goes from very dim to very bright in a matter of hours. It is the result of an explosion on the surface of a white dwarf caused by matter falling onto its surface from the atmosphere of a larger |
| Supernova – | a gigantic explosion in which a star throws off large amounts of material. It may be so great that the star is destroyed. |
| Only ____ supernovae have been observed in our galaxy. | 3 The best known is Crab Nebula in the constellation Taurus. |
| The greater the mass of a star the faster it moves through its | life cycle. |
| Neutron Star – | made up of about 99% neutrons. It is a very dense star. A teaspoon of the neutrons would weigh about 1 billion tons. |
| Pulsar – | rapidly rotating stars giving out radio waves in pulses. |
| black hole | an object whose gravity is so strong that the escape velocity is equal to or greater than the speed of light; thus no radiation can escape from the object |
| brown dwarfs | low-mass objects that are larger than a typical planet but do not have enough mass to sustain fusion in their cores. Also called "failed stars" |
| celestial prime meridian | an imaginary half-circle running from the north celestial pole to the south celestial pole and crossing perpendicular to the celestial equator at the point of the vernal equinox |
| celestial sphere | the apparent sphere of the sky on which all the stars seem to appear |
| cosmic microwave background | the microwave radiation that fills all space and is believed to be the redshifted glow from the Big Bang |
| cosmological redshift | the shift toward longer wavelengths caused by the expansion of the universe |
| cosmology | the study of the structure and evolution of the universe |
| dark energy | A mysterious energy that seems to be causing the expansion of the universe to accelerate |
| dark matter | the as-yet-unidentified nonluminous matter in the universe |
| declination | the angular measure in degrees north or south of the celestial equator |
| ecliptic | the apparent annual path of the Sun on the celestial sphere |
| galaxy | A large-scale aggregate of stars (plus some gas and dust) held together by gravity. Galaxies have a spiral, elliptical, or irregular structure. Each contains, on average, 100 billion solar masses |
| parsec (pc) | the distance to a star when the star exhibits a parallax of one second of arc. This distance is equal to 3.26 light-years or 206,265 astronomical units |
| Big Bang | theory of the origin of the universe that states that the known universe was concentrated in a point of energy that exploded approximately 13.7 billion years ago |
| globular cluster | a large, spherical group of gravitationally bound stars; usually found in the outlying regions of a galaxy |
| H-R diagram | a plot of the absolute magnitude versus the temperature of stars Hubble's law the recessional speed of a distant galaxy is directly proportional to its distance away |
| Local Group | the cluster of galaxies that includes our own Milky Way |
| magnitude (absolute) | the apparent magnitude that a star would have if it were placed 10 parsecs from the Earth |
| magnitude (apparent) | a measure of the brightness of a star as observed from the Earth |
| main sequence | a narrow band on the H-R diagram on which most stars fall |
| nebulae | vast clouds of interstellar gas and dust |
| neutron star | an extremely high-density star composed almost entirely of neutrons |
| nova | a white dwarf star that suddenly increases dramatically in brightness for a brief period of time |
| nucleosynthesis | the creation of the nuclei of elements inside stars |
| photosphere | the Sun's outer surface, visible to the eye |
| planetary nebula | a luminous shell of gas ejected from an old, low-mass star proton-proton chain |
| red dwarfs | small, cool, red, type M stars, whose color and size give them their name |
| red giant | a relatively cool, very bright star that has a diameter much larger than average |
| right ascension | a coordinate for measuring the east-west positions of celestial objects. The angle is measured eastward from the vernal equinox in hours,minutes, and seconds |
| singularity | the center of a black hole. The point to which the entire mass of a star has contracted |
| supernova | an exploding star |
| universe | everything that is-all energy, matter, and space |
| white dwarf | a white star that has a much smaller diameter and much higher density than average. It is believed to be the final stage of low-mass stars |
| The Sun rotates on its own internal axis with a period of about | 25 days |
| The thin, red, outer layer of the Sun's surface that can be seen only for a few seconds during a solar eclipse is called the | chromosphere. |
| The measurement of angular distance north or south of the celestial equator on a celestial sphere is referred to as | declinaiton. |
| Which of the following units of distance is the largest? | the parsec. |
| The brightness of a star as seen from Earth is referred to as the star's | apparent magnitude. |
| A very large star whose surface temperature is several thousand degrees cooler than that of the Sun's photosphere is referred to as | a red giant. |
| A rapidly rotating neutron star that has been detected on Earth by observing its regular bursts of radio emission is known as | a pulsar. |
| The mass of a black hole is believed to be concentrated in a very small central region referred to as | a singularity. |
| Hubble's law expresses a relationship between the distance from Earth to a galaxy and that galaxy's | radial velocity. |
| We believe that quasars are very distant objects because astronomers have been able to measure their | large red shifts. |
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malrey3
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