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In this section of the class, we'll be talking about the fundamental principles
of matter and radiation that underlie the subject of astronomy.
We'll talk about the structure of matter, the distinction between atoms,
molecules, ions, and isotopes, and also how atoms are put together,
from tiny compact nuclei and large clouds of negatively charged electrons.
We'll also talk about new information on the sub-structure of matter,
indicating that protons and neutrons are not fundamental particles but
made of quarks and hinting at an even deeper level of
structure which may be interpretable in string theory.
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We'll look at radiation as well and the equivalence of matter and
radiation in terms of Einstein's famous equation E equals MC squared.
Well consider the different forms of energy which in
the universe are interchangeable.
The most profound form of energy that we'll deal with in this class is light and
other types of electromagnetic radiation.
They're all unified in terms of being electromagnetic waves travelling at
the same speed 300 thousand kilometers per second in a vacuum.
Radiation is fundamental to how we understand the universe.
Astronomers not only collect radiation, but they disperse it
by wavelength into spectra, and spectroscopy is a key tool of astronomy.
So we'll look at what can be learned from spectroscopy, which enables us to remotely
diagnose the composition, temperature, and even density of remote astronomical
objects, such as stars, compact remnants of stars, and even entire galaxies.
Then, we'll look at matter.
And in particular, the theory of gravity that underlies all the structure of
the universe, from planets to stars to galaxies.
The theory of gravity, from Isaac Newton,
applies in almost every location in the universe.
But in the early 20th century Einstein developed a new concept of
gravity that applies more accurately in regions where the gravity is strong.
This is general relativity and we need it to understand not only black holes and
neutron stars but also the entire universe and its evolution.
Chris ImpeyDistinguished Professor
