chapter 18 physical science
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- the elements heavier than hydrogen and helium of which planets are composed came from
- debris of supernova explosions that occured before the solar system came to be
- soon after it came into being, the universe contained
- slightly more matter than anitmatter
- current ideas suggest that what is responsible for the observed properties of a quasar is a massive
- black hole
- quasars dont
- occur in the solar system
- the red shift in the spectral lines of light reachin us from other galaxies implies that thes galaxies
- are moving farther apart from one another
- clouds of luminous gas and dust in our galaxy are called
- galactic nebulas
- cosmic rays carry energy to the earth at about the same rate a
- starlight
- the origin of the most energetic cosmic rays is
- unknown
- today the universe apparantly contains
- only matter
- the globular clusters of our galaxy
- contain around a million stars each
- it is likely that the planets, satellites, and other members of the solar system were formed
- together with the sun
- cosmic rays
- are trapped in our galaxy by magnetic fields
- the stars in our galaxies
- are revolving around the center
- the age of the universe is
- 13.7 billion years
- compared with the population II stars in globular clusters, the population I starsin the galactic disk are
- richer in heavier elements
- supernova explosion have no connectiton
- quasars
- the matter in the early universe that eventually condensed into galaxies and then into stars consisted of
- hydrogen and helium are approx 3 to 1 ratio
- in the past several billion years the rate of expansion of the universe has
- decreased
- radiation from the early history of the universe was stretched by the expanison of the universe until today it is in the form of
- radio waves
- primary cosmic rays are composed largely of very fast
- protons
- a radio telescope is basically a
- directional attena connective to a sensetive radio reciever
- the least likely reason why planetary systems have not been directly observed around stars other than the sun is that
- planetary systems are rare
- radio waves from space never originate in
- cosmic rays
- the population II stars in globular cluster
- are mostly very old
- present evidence suggests that the major ingredient of the universe is in the form
- dark energy
- according to einstein's general theory of the universe
- must be either expanding or contracting
- the milky way is
- the galaxy of which the sun is a member
- it is least likely that the universe will
- stop expanding and maintain constant size
- the number of stars our galaxy is approx.
- 200 billion
- the stars in space are
- mostly contained within widely seperated galaxies
- relative to the center of our galaxy
- its stars revolve
- in the next phase of its evolution the sun will
- be a red giant
- planets are small compared with stars because
- the planets would then be stars themselves
- the age of the earth is
- 4.6 billion years
- spiral galaxies
- are usually similar to our galaxies
- our galaxy is shaped roughly like a fried egg who diameter
- 10 times its thickness
- our galaxy is approxomately
- 130,000 lightyears across
- evidence of various kinds suggest that at the center of our galaxy is a
- black hole
- each cubic centimeter of space between the stars in our galaxy contains an average about
- 1 atom or molecule
- the term big bang refers to
- the origin of the universe
- our galaxy has
- 4 main spiral arms