Details Title: Astro things 2:. Description: N/A Total Flash Cards: 66 Created: 06/04/2009 14:52:18		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Astronomy Flashcards
Cards in this set: Term Kepler's FIrst Law of Planetary Motion Definition 1. Planets follow elliptical orbits; sun is at one focus. Term Kepler's Second Law of Planetary Motion Definition 2. The planets sweep out equal areas of their orbits in equal time Term Kepler's Third law of Planetary Motion Definition Period squared equals the semi-major axis cubed. Term Newton's First law of Motion Definition Law of Inertia; An object will remain at rest or in uniform straight motion unless acted upon by an external force Term Newton's second law of Motion Definition the rate of change of momentum of an object is equal to the external force applied to it. f=ma Term Newton's Third law of Motion Definition action-reaction law. for every force applied by one body on another, an equal and opposite force is applied on the first body by the second. Fsub1=-Fsub2 Term Newton's Universal Law of Gravitation Definition curved orbits imply a force which we know to be gravitational F= - G x Mm/r^2 Term Angular Momentum Definition A planet in orbit about the Sun has an angular momentum = m v r...it's a constant, so if the radius increases, the velocity will decrease, and vice versa. Mass stays the same! Term Copernican Revolution Definition The laws of physics that are true on the earth are true everywhere. Made earth like every other planet. Big change! Term First Postulate Definition laws of physics are the same for all observers Term Wavelength Definition distance over which wave repeats itself (distance between two peaks or troughs) Term Speed of Light Definition 300000 km per second Term NM Definition nanometers (1 x 10^-9 meters) Term Herz Definition units in cycles / s Term frequency Definition number of crests that passes a point in one second Term Optical light spectrum Definition From Violet (short wavelength, high frequency) to Red (the opposite) Term The Electromagnetic Spectrum Definition From low to high frequency: Radio, microwaves, infrared, optical, ultraviolet, x rays, gamma rays. Term Not all of the EM spectrum makes it through the atmosphere... Definition Good to know! Term Time Dilation Definition time is not a constant; clocks of observers Term LGP Definition Light Gathering Power- Dsub1^2/Dsub2^2 ...answer is how many times brighter something will seem. Term Apparent Brightness Definition 1/d^2 Term Tycho Brahe Definition extremely accurate, used quadrants to measure the positions of the planets GEOCENTRIC....moon orbited earth, other planets orbited sun while it orbited earth. Term Tycho's Nova Definition a bright star that appears on the sky that was not there before, no parallax....cellestial sphere changes?! Term Galileo Galilei Definition first to utilize the telescope for astronomy, recognized uniform acceleration of objects Term Moons of Jupiter Definition Lo, Europa, Ganymede, Castillo, other revolutions exist! Geocentricity? No thank you! Term Galileo noticed what with telescopes? Definition Moons of Jupiter, Craters on Moon, Sunspots, Saturn's Rings, Milky Way Galaxy, Phases of Venus (shouldve been only crescents) Term Who invented the telescope? Definition Hans Lippersay Term Foucault's Pendulum Definition plane of pendulum wants to maintain the same orientation, and will rotate to counteract earth's rotation. Term Johannes Kepler Definition inherited Tycho's observations, and came up with laws of planetary motion! Term Sir Isaac Newton Definition wrote Principia, estables laws of motion and law of gravity, and calculus... Term Bound orbits Definition circular or elliptical Term Unbound orbits Definition parabolic and hyperbolic Term Albert Einstein Definition Helped lay foundations for Quantum Mechanics (energy is quantized or kept in bundles) and that light is made of photons. Term second postulate Definition speed of light is a constant; 3 x 10^8 m/s Term Velocity Addition Laws Definition add both together Term Consequence of Relativity Definition E=mc^2, where mass can be converted into energy, and back... Term First Postulate - principle of equivalence Definition observer cannot distinguish locally between the forces of acceleration or gravitation (elevator) Term Second Postulate of SR Definition Mass determines the curvature of space-time, and the curvature of space-time tells mass how to accelerate. Term Gravitational Dilation Definition as curvature of space-time increases due to the distance of a mass, time slows Term Deflection of Light Definition light falls toward gravitational body the same as a mass. Term Longitudinal Waves Definition sound -alternating regions of high and low densities DIRECTION OF TRAVEL Term Transverse waves Definition Displacement perpendicular to motion of travel! Term Light waves Definition transverse waves of electric and magnetic fields Term Wavelength Definition (h) Distance over which wave repeats itself Term Frequency (v) Definition number of crests that passes a point in one second (period of wave= 1/v) Term Frequency versus Wavelength Definition hv=c Term Refracting Telescopes Definition collects light and bends light to a focus; pros: no central obstruction, great resolution/contrast... Cons: expensive, glass sags, size limit Term Chromatic Aberration Definition when focus might not refract all certain wavelengths the same, and you get different colors; stars with halos of red. Term Achromatic Lens Definition two lenses of different glass to counteract the Chromatic Aberration Term Reflecting Telescopes Definition invented by Newton; primary mirror collects light, cage at primary focus Pros: No Chrom. Ab., cheap, only one surface, can be supported from backside, no size limit....Cons: central obstruction, poor resolution and contrast Term Newtonian Style Definition uses flat secondary mirror to divert light to side Term Cassegrain Definition Uses curved secondary mirror Term German Equatorial Mount Definition designed to align rotation of telescope with Earth's rotation axis; can attach a "clock" that moves telscope to counteract earth's rotation. Term Right Ascension Definition Analogous to Longitude on the CS; increases eastward from Vernal Equinox (measured in degrees (360) or 24 hours) Term Declination Definition Latitude on celestial sphere; Celestial Poles have 90deg N/S Dec Term Alt-Az mounts Definition cheaper, dont align with rotation axis; requires computer control to follow stars, most large telescopes use this... Term Alt-Az Altitude Definition angle above the horizon Term Alt-az Azimuth Definition angle measured from North Cp toward East Cp (north to east...90 degrees....north to south....180....etc.) Term Telescope detectors Definition Photographic Plates (inefficient but cover large areas of sky) Charge-coupled device (CCD)(used by modern instruments) Term Luminosity Definition total light emitted by an object L= 4pi x d^2 F where F(flux)= the amount of light that passes through a unit area Term Absolute Magnitude (M) Definition brightness of a star located 10 Parsecs away. Term (m-M) (Apparent Magnitude-Absolute Magnitude) Definition distance modulus Term Surveyor's Method Definition used to measure the distance to an object (also known as Triangulation) Term Stellar Parallax Definition used to measure distance to stars; only used on nearby stars. d=1/p (p-parallax in arcseconds) Term 1 Parsec Definition 206265 AU Term Spectral Classification Definition Annie Jump Cannon, OBAFGKM (high temp to low temp)