Space Flashcards
EM Electromagnetic Spectrum
Range of wavelengths of EM Radiation, extending from radio waves, to gamma waves, including visible light.
EM Electromagnetic Radiation
Energy emitted from matter, w/ electromagnetic waves that travel at speed of light.
Sun Diagram (inner to outer)
Core Radiative Zone Convective Zone Photosphere Chromosphere Corona Solar Flare Solar Prominence
Sun’s Effects on Earth
Gases of Sun swirl around, causing solar storms & winds.
Auroras
Communication Disruptions
Radiation Hazards
Auroras
Earth’s surrounded my magnetic field - strongest near North & South poles
Solar winds travelling toward Earth follow lines of magnetic force, winds come in contact with particles in Earth’s atmosphere near poles, producing display of light in night sky.
Communication Disruptions
Solar activity at Sun’s surface can affect artificial satellites.
Temperature & density of Earth’s upper atmosphere sometimes increased by solar radiation and storms.
Friction caused by dense atmosphere slows down satellites and alters orbital path.
Radiation Hazards
Charged solar particles entered Earth’s atmosphere & disrupted signals from communications satellites orbiting planet.
Airplanes could receive higher than usual dose of radiation due to higher altitude
Solar System Order
Inner, terrestrial planets: Mercury Venus Earth Mars
Outer, gas giant planets: Jupiter Saturn Uranus Neptune
Smaller Components, Dwarf Planets
Orbits Sun, spherical shape, DOES NOT dominate its orbit.
Asteroids
Composed of rock & metal
Orbits sun, small, irregularly shaped
Meteroids
Piece of rock & metal
Smaller than asteroid, usually size of dust particles but can be as large as car/building
Friction causes them to burn up, creating bright streak of light across sky ‘shooting star’
Comets
Chunk of ice & dust & rock
Orbits sun
When close enough to Sun, outer surface begins to sublimate (solid to gas), icy nucleus heats up, gases & dust escape - can be pulled in by planet’s gravity.
Earth’s Rotation
Causes apparent motion of Sun in sky
Each day, earth makes complete rotation (west to east)
Portion facing sun - daylight
Portion facing away - darkness
Earth’s Revolution
Earth is elliptical
Each year, earth makes one complete revolution
Distance of each planet from Sun changes as it completes its orbit around Sun due to how Sun is located closer to one end of elliptical path
Shape and size of orbit affects time it takes to complete a revolution around Sun, value called an Orbital period.
Larger orbits takes longer to orbit Sun
Orbital Radius
Average distance from planet and Sun
Earth to Sun = 1 AU
Earth’s Tilt
Rotational Axis tilted 23.5 degrees from vertical
Affects average daytime temperature of Earth’s hemispheres
Reasons for Seasons
Because of Earth’s tilt
When hemispheres revolve around Sun
Earth farthest from sun & northern hem tilted toward sun & sunlight spreads over small area, causes intense heating, sun appears to travel highest path in sky-more hours of daylight
Earth closest to sun & northern hem tilted away from sun & sunlight spreads over larger area, causes less heating, sun appears to travel lower path in sky-fewer hours of daylight.
Solstice
When earth’s axis is most inclined toward/away from Sun
Winter // Summer
Equinox
Time of year when hours of daylight and darkness are equal
Autumn // Spring
Lunar Eclipse
When earth is positioned between Sun & Moon, casting shadow on Moon
Can appear red/orange - caused by refraction of sunlight
Solar Eclipse
When moon is aligned between Earth & Sun, blocking sun from being observed from earth
Only possible during new moon phase - quite rare
Only corona visible ( total solar eclipse )
Position & Function of Different Satellites: NATURAL SATELLITE
Earth has one: Moon - orbits around earth
Position & Function of Different Satellites: ARTIFICIAL/HUMAN-MADE SATELLITE
Help forecast weather & monitor agriculture & aid in telecommunication/navigation & Aassist military activities & explore Universe - orbits around Earth
Used in astronomy & space exploration
Stays in stable orbit because of balance between between its forward velocity & Earth’s gravitational pull
Position & Function of Different Satellites: Low Earth Orbit
Revolves at around Earth at altitude up to 2000km
Special type: polar orbit, travels at altitude 200-900 km taking over north & south pole, allowing to view all parts of earth, provides best global coverage
Position & Function of Different Satellites: Medium Earth Orbit
Travels altitude up to 35000km
Many part of Global Positional Systems GPS, travels at about 11000km
Aid in navigation by transmitting signals down to GPS receivers on ground, providing precise geographical coordinates of location
Position & Function of Different Satellites: Geostationary Orbit Satellite
Orbits at 35790km, tenth of way to Moon
Provides orbital period equal to period of rotation of Earth
GEOSTATIONARY ORBIT when satellite orbits directly above equator
Appears motionless in sky
Weather satellites track weather in this manner, used by communication industries to broadcast TV & radio, can be linked to antennas on earth
LY
Distance travelled by light in one year
Describing Stars: LUMINOSITY
Total amount of energy produced by a star per second
Apparent Magnitude
Brightness from Earth
Absolute Magnitude
Brightness located 33 ly from Earth
Describing Stars: Colour & Temperature
Hottest to Coldest:
Blue White Yellow Orange Red
Describing stars: Composition
Use spectrograph to analyze spectrum
Spectrograph splits light energy into patterns of colours for observation
Each element emits light energy only at certain characteristic frequencies - influenced by unique electron energy levels within each atom
Can tell which elements make up star & be indicator of star’s temperature
Describing stars: Mass
Mass of sun - 1 solar mass
Used to compare
Does not always reflect its size
Red Shift
Discovered by Hubble
Light from galaxies shifting toward red end of visible spectrum, indicating galaxies & milky way are moving away from earth - evidence universe is expanding
Farther away the galaxy, greater the red shift, faster it appeared to be moving
Hubble’s Discoveries
Each galaxy emits its own distinctive spectrum of light
Light spectra shift, depending on whether light source is moving/stationary
How and where stars are formed
Begins with nebula: cloud of gas & dust (primarily hydrogen & helium)
Formed when parts of nebulas collapse in on themselves
Gravity pulls gas & dust particles together, causes clumps -forms protostar
Increase of mass & gravity causes atoms that become so tightly packed that pressure in core rises and nuclear fusion begins
Low to Medium Mass
Star’s hydrogen converts to helium by nuclear fusion-results in helium-rich core, surrounded by outer layer of hydrogen
With less hydrogen to burn, core begins to contract
Contraction heats core-while core contracts and gets hotter, outer layers of star expand and then cool, becoming red giant or super red giant
High mass - consumes hydrogen much faster resulting in short life cycles
Fuses helium into carbon when runs out of hydrogen for fusion
What happens when stars die? Low-medium mass
Death of star less than or equal to 1 solar mass
Stars die when nuclear fusion stops occurring, core begins to collapse due to own gravity
Remains is white dwarf-emits UV light that collides with gas & dust
Energy illuminates clouds of gas and dust, creating planetary nebula
Black dwarf when white dwarf continues radiating energy into space, becoming cooler & dimmer until light goes out
What happens when stars die? High Mass
Once fusion stops, stars collapse under own gravity, iron core increases temperature
Explodes in supernova - explosion that sends series of shockwaves
Rapidly expands nebula of gas & dust
Death of star between 10 and 30 solar masses: Core left behind becomes neutron star-extremely dense star composed of tightly packed neutrons
Death of star larger than 30 solar masses: core so massive it forms a black hole - matter so dense w/ gravity so strong that light can’t escape
Big bang theory
Theory that Universe began in incredibly hot dense, expansion approx 13.7 billion years ago
Extremely hot universe spread energy outward very quickly.
As it cooled, energy began turning into matter(mainly hydrogen)
Over hundreds of millions of years, this matter formed clumps eventually forming stars & galaxies seen today
Big Bang Theory Evidences
In 1965, physicists Arno Penzias & Robert Wilson kept detecting radiation from all directions in Universe from supersensitive antennas, interfering w/ radio experiments.
Scientists determined static interference represented remnants of energy released by initial expansion of space that followed Big Bang
In 1889, satellite COBE Cosmic Background Explorer, precisely measured temperature of background microwave radiation. Measurements matched evidence collected by Penzias & Wilson. Temperature variations are similar to an imprint of beginning of structure in Universe
In 2001, NASA launched cosmological satellite WMAP Wilkinson Microwave Anisotropy Probe which detects variations in temperatures in space. Data collected provides more info about early stages of universe. WMAP found evidence that first stars began to shine about 200-300 million years after Big Bang
