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DSST Astronomy

Flashcard Created for Astronomy DSST

TermDefinition
Ptolemaic solar System model A geocentric model of the solar system, with a balancing point called the "equant"
Constructed first observatory Tycho Brahe
First type of telescope Galileo's refraction telescope with concave and convex lenses.
Equation for power of telescope Focal length of the optical lens, divided by the focal length of the eyepiece.
Kepler's First Law Planets in the solar system orbit in an elliptical pattern
F=ma Newton's Second Law. Motion is proportional to the force acting on an object and the object's mass.
Newton's Law of Inertia An object traveling through space will continue in the same manner unless another force acts on it.
Einstein's Special Theory of Relativity Time is relative, described in the equation E=mc2. A person experiences time more slowly at the speed of light.
Age of Earth Based on meteorite studies, the Earth is 4.5 billion years old.
cause of oxygen in Earth's atmosphere Cyanobacteria generate oxygen as a natural byproduct.
New Moon Phase when the moon is positioned between the Earth and the Sun.
Declination of the north star +90 degrees
Year measurement The time it takes for a planet to orbit around the Sun. The longest planet year is 165 Earth years.
spring tide Occurs when the Moon and Sun are on the same side of the Earth. Their combined gravity cause a higher tide.
Highest frequency of electromagnetic waves Gamma rays. They cannot be viewed using mirrors or telescopes and cannot penetrate the Earth's Atmosphere.
Cause of seasons Axial tilt. Different hemispheres are tilted nearer and closer to the Sun.
Speed of light 300 million m/s
Parsec The parallax of an arc second, approximately 3.3 light years in length.
Refraction Light distortion that occurs when light changes using a transparent medium.
Electromagnetic spectrum order Radio, Microwave, Infrared, Visible Light, Ultraviolet, X-Rays, Gamma.
Common cause of infrared radiation Heat, all object NOT at absolute zero emit infrared radiation proportional to their warmth
Spectral signatures Continuous, emission and absorption are the spectral signatures created as light bends through a prism.
Planets in blue-shift Moving towards the Earth. Their light waves are compressed, which makes the shift towards the blue end of the visible spectrum.
Io Jupiter's moon, unique for its volcanic activity.
Main component of Mars' atmosphere 95% Carbon Dioxide.
Main Belt The asteroid belt between Mars and Jupiter. It separates the terrestrial and gas-based planets.
Local Group A cluster of galaxies that the Milky Way galaxy belongs to.
Age of the Sun Based on relative levels of hydrogen and helium, it is 4.5 billion years old.
Flare Occurs when an explosion within the photosphere ejects great amounts of solar material into the air. (solar storms)
Main component of the Sun Hydrogen. The Sun is 75% Hydrogen.
Planet with the most moons Saturn (62)
Triton A moon that orbits Neptune. Triton is the largest moon in the solar system with retrograde movement; it has seasons.
Ice Giants Uranus and Neptune
Milky Way Galaxy Type Barred Spiral galaxy with four arms.
Closest Star to the Sun Alpha Centauri aproximately 4 light years away.
Most Common Galaxy Type Elliptical galaxies.
Brown Dwarf Failed stars that emit light, but their pressure is too low for hydrogen fusion.
Result of a Type II Supernova Black Holes. Heavy elements build up at a star's core. The pressure causes it to collapse.
Neutron Stars A supernova caused protons and electrons fuse at a star's core resulting in an extreme gravitational pull.
Population I star movement Uniform and circular orbits that keep stars on the main plane of the galaxy bound in open clusters.
Order of spectral classes from hottest to coolest is: O, B, A, G, B, K, M
First multicellular organisms Eukaryotic cells.
Four most likely locations for life in the Milky Way Titan, Europa, Enceladus, and Mars.
Fermi Paradox Life has the potential to be more common in the universe, but no evidence of it is observed.
Percent of universe that is dark matter 27%
Basis of spectral class color.
Singularity of a black hole The point at which all of it's mass is centered. The mass contained is drawn to the singularity
Most common element in the universe Hydrogen.
Heliocentric Theory Places the Sun at the center of the solar system with all other bodies orbiting it.
Nicolaus Copernicus Father of Heliocentric Theory, he correctly predicated the movement of planets.
Hans Lippershey Inventor of the telescope. He was a German Dutch Lens Maker.
Galileo Galilei First to use telescope for Astronomy. Saw 4 moons of Jupiter using a telescope. Believer of Heliocentric theory.
Tycho Brahe Disproved the celestial sphere theory. He proved this by observing a supernova
Kepler Mathematician who developed the three laws of Planetary motion.
Kepler's first Law of Planetary Motion Planets orbit in an elliptical nature.
Kepler's Second Law of Planetary Motion Planets move faster as they approach the sun and slow as the go away from the Sun.
Isaac Newton Invented the reflective telescope. Proposed the three laws of motion and the law of universal gravitation.
First Law of Motion An object at rest will stay at rest unless acted upon by and outside force. Called the law of Inertia.
Second Law of Motion An object's mass is directly proportional to how much force is going to be needed to move an object.
Third Law of Motion For every action there is an equal and opposite reaction.
Law of Universal Gravitation Everything in the universe has a gravitational field that affects other objects.
Max Planck German scientist who worked with Einstein. Credited with creating Quantum Mechanics. His Quantum Theory revolutionized science and won him a Nobel Prize in 1918.
Edwin Hubble Confirmed the existence of other galaxies in 1919. Discovered the degree of Doppler shift in those galaxies and how they increased. Hubble's law allows the observation of the universe expanding.
Big Bang Theory Theory which explains the origin of all matter in the universe as the result of an original cosmic explosion and is constantly expanding.
Arno Penzias and Robert Wilson Discovered cosmic microwave background radiation in 1964. Necessary evidence for the Big Bang Theory.
Universe Contraction theory Belief that the universe will contract and the Big Bang Theory will reverse itself.
Solar Mass One solar mass is equal to the size of the Sun.
Astronomical Unit Distance between the Earth and Sun, equal to 93 million miles.
Light Year The distance light travels over one year, 6 trillion miles or 63,000 AU.
Parsec Equal to 206,000 AU or 3.2 light years.
Absolute Magnitude measure of intrinsic brightness use for celestial objects.
Spectroscope Used to measure light over the electromagnetic spectrum. Breaks down light into individual wavelengths.
Absorption Lines When a certain shade of color on that strip is black, indicating that a particular frequency of light has been blocked. Designated by a sudden black line.
Emission Lines Indicated the emission of a particular wavelength of light. It shows up as a bright line on a spectrum.
Angstrom Used to measure wavelengths of electromagnetic radiation.
Doppler Effect How a wave's frequency changes based on the motion of the observer in relation to the source of the wave. Using the Doppler Effect, astronomers can detect the relative motion of celestial objects and even determine their speeds.
Radial Velocity Radial Velocity is the speed at which an object is moving towards or away from the viewer here on Earth.
Parallax The apparent shift in the position of an object when the angle of viewing is changed.
Triangulation Astronomers note a stars position, then wait a period of time to measure its angle again. Using Trigonometry they can determine the distance.
Refractive Telescope Used by Galileo, it has two different lenses. The objective and the eyepiece lens. Cannot see the entire spectrum of light due to the glass and lens size.
Reflective Telescope Uses two curved mirrors to reflect gathered light to form an image.
Radio Telescope Used to see celestial bodies on the radio spectrum. Radio interference on Earth stops these waves from reaching Earth. Radio Telescopes are usually set in space.
X-ray Telescope X-rays are absorbed by the Earth's atmosphere. Telescopes sit in space and can be used to observe black holes.
Quasar One of the most luminous objects in the universe. They are the most distant objects observed. One quasar is the equivalent of a trillion suns. Caused by supermassive black holes.
Supermassive Black Hole Believed to be at the center of most galaxies.
Galaxy Cluster Usually consists of 50 to 1,000 galaxies in a cluster.
Local Group Cluster of galaxies containing the Milky Way and Andromeda.
Nebula Where stars begin, collection of hot gasses and interstellar dust.
Protostar Dust and gas condense and begin to heat up. Hydrogen fuses to form Helium and it turns into a main sequence star. If the mass is not large enough to begin fusion, it becomes a Brown Dwarf instead.
Red Giant & Blue Giant a main sequence star that has fused all of its hydrogen into helium. The star will cool and swell. It will eventually become a Red Giant or Blue Giant.
White Dwarf Comparable to the Earth in size, but extremely dense. Powered by the leftover energy in the core. Less luminous than the Sun.
SuperGiant A star of larger mass. It expands rapidly around the core and can be 1000 times the diameter of the sun. A SuperGiant ends in a violent explosion where the core collapses creating a Supernova.
Supernova When a massive star collapses due to gravity. It creates a supernova explosion with extreme luminosity. If the star survives it forms a Neutron Star or a Black Hole.
Neutron Star Remnants of a dead star. Small and dense, less than three solar masses in size.
Black Hole a gravitational vacuum from which no light can escape. Formed from a supernova whose core collapses upon itself. Black holes consume all nearby matter.
Pulsar Neutron star that emits radiation that appears to pulse when observed from Earth.
Binary Star A star made up of two stars orbiting around a common center point.
Blue star A class O star, hottest of the Main Sequence stars. A blue Supergiant, which can have a surface temperature around 40,000 degrees Kelvin. Blue stars burn hotter than red stars.
Cepheids Pulsating variable stars. They change luminosity at a very regular intervals and by very regular amounts.
Population I stars Youngest and highest in metal content, the Sun is a population I star.
Population II stars Oldest of today's observed stars formed from the remnants of a population I star.
Population III stars Lowest in metal content and the oldest. Formed when metal levels in the universe were low.
Star cluster a group of gravitationally bound stars.
Globular custer contains old stars, and can contain millions of stars in a very small region. Yellow and red stars are present with very rare blue star.
Open cluster Made up of young stars, burning brighter and hotter than globular clusters. Blue stars are more common in an open cluster.
Fusion The process when stars convert hydrogen to helium. Two types of fusion Proton-Proton Chain Reaction for small stars, and CNO cycle for larger stars.
Proxima Centauri Closest star to our own Sun. Only 4.2 light years from the Sun.
Age of Solar System 4.5 billion years old
Orion Arm location of the solar system in the Milky Way galaxy.
Comet ball of ice, rock and dust originating in the Kuiper Belt or Oort Cloud.
Oort Cloud a hypothetical cloud of many billions of icy objects on the outskirts of the solar system.
Planets with rings Jupiter, Saturn, Neptune, and Uranus.
Gas Planets Jupiter, Saturn, Neptune and Uranus.
Terra planets Mecury, Venus, Earth and Mars.
Earth's Age 4.5 billion years.
Earth's Rotation 23 hours and 56 minutes.
Precession The Earth is tilted as it rotates around the Sun, as it spins it makes a small circle. It's the apparent wobble of the Earth.
Equinox Occurs twice a year when the Earth is neither tilted towards nor away from the Sun.
Vernal Equinox Occurs in March (beginning of Spring in Northern Hemisphere)
Autumnal Equinox Occurs in September (beginning of fall in the Northern Hemisphere)
Solstice When the Earth is tilted most towards the Sun.
Meteoroid Rocky or metallic debris that is smaller than an asteroid which travels through the Solar System.
Meteor When a meteoroid is traveling towards Earth and enters the atmosphere.
Meteorite When a Meteoroid survives and hits Earth.
Asteroids bodies of rock and metal that are contained within the asteroid belt between Mars and Jupiter.
Mars 95% carbon dioxide atmosphere.
Titan Largest moon of Saturn. Has a fully developed atmosphere.
Uranus Is tilted on its side.
Sunspot Area of the Sun with lower heat caused by magnetic activity. Appears darker than surrounding areas.
Plage A bright region in the Sun's Chromosphere.
Corona The Sun's atmosphere that extends millions of miles into space.
Solar Apex The direction the Sun is traveling in relation to other stars.
Neap tides Occurs when the moon is at the first or last quarter. The moon and sun cancel each other out resulting in a lower tide.
Spring Tides When the sun and the moon are lined up on the same side of the Earth resulting in higher tides.
Lunar Eclipse When the Earth is between the Moon and Sun.
Solar Eclipse When the Moon is between the Earth and Sun.
Lunar Phases New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent, New Moon,
Perihelion When the Earth is closest to the Sun in orbit.
Aphelion When the Earth is furthest away from the Sun in its orbit.
Created by: Jcandres