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what is electromagnetic radiation?
- radiation consisting of electromagnetic waves that travel at the speed of light(such as visible light, radio waves, and x rays)
what is a refracting telescope?
- a telescope that usues a lens to collect the light from an object
what is a reflecting telescope?
- a telesope that uses a mirror to collect the light from an object
what is a satellite?
- an artificial (human-made) object or vehicle that orbits earth, the moon, or other celestial bodies, also, a celestial body that orbits another of larger size (for example, the moon is earths natural satellite)
what are orbiters?
observatories that orbit other celestial objects
what is the solar nebula theory?
the theory that describes how stars and planets form from contracting, spinning disks of dust
what is a star?
- a celestial body made of hot gases, mainly hydrogen and some helium
- the sun is the closest star to earth
what is a protostar?
a hot, condensed object at the center of a nebula
what is nuclar fusion?
the process of energy production in which hydrogen nuclei combine to form helium nuclei
what is a photosphere?
- the surface layer of the sun
what is a sunspot?
- an area of strong magnetic fields on the photosphere
- it is cooler than the rest of the sun and looks a different shade!
what is solar wind?
- a stream of fast moving charged particles ejected by the sun into the solar system (solar flare)
- -eventually aurora borealis forms (when it enters the earths atmosphere it is considered solar wind)
what is a black hole?
- the remnant of a supernova explosion with a gravitational field so strong that nothing can escape its pull
what is luminosity?
a stars total energy output per second; its power in joules per second (J/s)
what is a nebula?
a vast cloud of gas and dust, which may be the birthplace of stars and planets
what is absolute magnitude?
- the magnitude of a star that we would observe if the star were placed 32.6 light-years from Earth
- the absolute magnitude of the sun is about 4.7
what is a spectroscope?
- an optical instrument that produces a spectrum from a narrow beam of light, and usually projects the spectrum onro a photographic plate or digital detector
what are spectral lines?
certain specific wavelengths within a spectrum characterized by lines; spectral lines identify specific chemical elements
what is a Hertzsprung-Russel (H-R) diagram?
- a graph that compares the properties of stars
what is a main sequence?
- a narrow band of stars on the H-R digram that runs diagonally from the upper left (bright, hot stars) to the the lower right (dim, cool stars); about 90% of stars, including the sun, are in the main sequence
what is a white dwarf?
- a small, dim, hot star
what is a supernova?
a massive explosion in which the entire outer portion of a star is blown off
what is a neutron star?
a star so dense that only neutrons can exist in the core
what are solar flares?
- can occur where there are complex groups of sunspots.
- magnetic fields explosively eject intense streams of charged particles into space.
- usually result in beautiful auroras
what is the importance of the sun?
- the sun is needed for all life on earth.
- the suns energy drives most processes on earth like sufficient food and shelter.
- solar energy powers the winds and ocean currents
- drives all weather
- drives photosynthesis (provides oxygen)
how do low-mass stars evolve?
- red dwarfs have less mass than the sun
- consume their hydrogen slowly over a period as long as 100 billion years
- lose significant mass
- all that remains is a fain white dwarf
- takes tens of billions of years for them to cool down
how do intermediate mass stars involve?
- the sun is an intermediate mass star
- consume their hydrogen over about 10 billion years
- the core collapses when hydrogen is used up
- as this happens, temperature increases and outer layers expand and are cooler, so they turn red
- turn into red giants, eventually the sun will be a white dwarf
how to high mass stars dissolve?
- have 12 or more solar masses
- consume fuel faster than intermediate mass stars
- die more quickly and mre violently
- the core heats up to higher temperatures, heavier elements from, star expands into supergiant
- iron forms in core, the core collapses violently, shock waves travel through star
- outer portion explodes (supernova)