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15 Cards in this Set
- Front
- Back
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nebular theory
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the detailed theory that describes how our solar system formed from a cloud of interstellar gas and dust
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solar nebula
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the piece of interstellar cloud from which our own solar system formed
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condensation
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the formation of solid or liquid particles from a cloud of gas
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rocks
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materials common on the surface of the Earth that are solid at temperatures and pressures found on Earth
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metals
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elements that condense at fairly high temperature
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frost line
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the boundary in the solar nebula beyond which ices can condense; only metals and rocks can condense within the frost line
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accretion
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the process by which small objects gather together to make larger objects
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planetesimals
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the building blocks of planets formed by accretion in the solar nebula
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solar wind
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a stream of charged particles ejected from the Sun
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heavy bombardment
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the period in the first few hundred million years after the solar system formed during which the tail end of planetary accretion created most of the craters found on ancient planetary motions
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giant impact
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a collision between a forming planet and a very large planetesimal
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radiometric dating
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the process of determining the age of a rock by comparing the present amount of a radioactive substance to the amount of its decay product
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radioactive isotope
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a substance whose nucleus tends to fall apart simultaneously
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radioactive decay
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the spontaneous change of an atom, in which its nucleus breaks apart or a proton turns into an electron, thereby changing it into a different element
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half life
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the time it takes for half of the nuclei in a given quantity of a radioactive substance to decay
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