Exploring the Universe

Subdecks (2)

Cards (60)

  • It's unlikely we would have a science of astronomy if the laws of nature were not the same everywhere (and everywhen) in the universe
  • We interpret what we see in more distant parts of the galaxy and the universe (and therefore also at different times in the history of the universe) by the laws of nature we've determined through experimentation and direct observation on Earth and in our solar system
  • If the laws of nature were different in other regions of the universe, we would have great difficulty interpreting our observations
  • Light-year
    The distance light travels in a year
  • The finite time light takes to travel from objects in the universe to the Earth allows astronomers to look directly into the universe's past
  • Large telescopes allow us to see further away in the universe and to observe fainter objects
  • We are able to see the planets in our solar system because they reflect light from the Sun
  • Interstellar dust blocks our view of more distant parts of the galaxy, just as smog obscures the view in big cities on Earth
  • Astronomers have been able to look about 10 billion years into the past
  • The air we breathe is about 10^19 times denser than interstellar gas
  • Humans appear in the "cosmic year" on the evening of December 31st
  • Science is… • a system of knowledge held together by a particular worldview • this worldview is a philosophy of science
  • science = is the search for truth about the material universe • follows the scientific method • follows all the evidence • is based on trust in natural laws
  • hypotheses must be testable through experiment or observation
  • Astronomy is an observational science Mostly uses inductive reasoning to reach conclusions Inductive: going from the specific to the general
  • Theory = A set of principles on which to base action, e.g. “A theory of business practices” 2. An idea used to account for a situation, e.g. “My theory is that gremlins mess up my room every night while I’m sleeping 3. Used to describe would is supposed to or could happen, e.g. “In theory, this should work” 4. A scientific system of ideas that explain a physical phenomenon, e.g. “Quantum field theory”