Astronomy 1,2

 What is Astronomy?

  • A body of knowledge and a method of how we learned that knowledge
  • Science tells us that stuff we know may not be perfectly known; it may be partly or entirely wrong.
  • Understanding that our understanding might be wrong is essential, and trying to figure out the ways we may be mistaken is the only way that science can help us find our way to the truth, or at least the nearest approximation to it.

"Focus On...": Astronomers

  • Who are we? What do we do?
  • Astronomers are programmers, programmers, and programmers
  • Once the data from a telescope is taken and analyzed, you have to know what to do with it
  • Do the observations fit the physical model of how stars blow up, galaxies form, or the way gas flows through space?

An astrophysicist is someone who studies the sky and uses telescopes and detectors to test hypotheses.

  • Astronomers don't actually use the telescopes themselves, but someone who's trained in their specific use does that for them.
  • Some of those instruments go into space, and some go to other worlds, like the moon and Mars.
  • We need astronomers and engineers and software programmers who can build those, too.
  • And then, at the end, we need people to tell you all about it.

Humans began to notice that when certain stars appeared in the sky, the weather started getting warmer

  • When other stars were seen, the days would get longer, and nights get colder
  • This became important to farmers because it told them when to plant seeds, and when to harvest.

Astrology means "study of the stars"

  • It originated as a formal method of studying nature, but has changed over time to mean "law or culture of stars".

now it's pretty well understood that astronomy is science, and astrology isn't

  • Millennia ago, astrology was as close to science as you got

Geocentrism

  • It is patently obvious that the ground you stand on is fixed, rooted if you will, and the skies turn above us. The sun rises, the sun sets. The moon rises and sets, the stars themselves wheel around the sky at night. Clearly, the Earth is motionless.
  • The sky, however, is what is actually moving.

The cosmos is actually made up of nested spheres, some of which are transparent, maybe made of crystal, which spin once per day

  • The stars may just be holes in the otherwise opaque sphere, letting sunlight in
  • If you don’t have today’s modern understanding of how the cosmos works, this whole multiple-shells-of-things-in-the-sky thing actually does make sense.

How We Got Here

  • A few centuries ago, Copernicus came up with the idea that the sun was the center of the solar system, not the Earth.
  • Then along came Tycho Brahe and Johannes Kepler, who modified that system, making it even better.
  • Then Isaac Newton invented calculus partly to help him understand the way objects moved in space.
  • Finally, photography came along and we could capture much fainter objects on glass plates sprayed with light-sensitive chemicals, which revealed stars otherwise invisible to us, details in galaxies, beautiful clouds of gas and dust in space, and digital detectors were invented which allowed computers to analyze observations.
  • And where are we now?.

The U.S. system is filled to overflowing with worlds more bizarre than we could have dreamed

  • Nature has more imagination than we do. It comes up with some nutty stuff.
  • We're clever too, we big-brained apes. We've learned a lot... but there's still a long way to go.

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