This is known as cosmology.

So cosmology is now a precision science.

Let's now consider what's called, Milne Cosmology.

Now let's look at the effect of cosmology.

Is sensitive to cosmology in two different ways.

So, where, really cosmology started as a branch of astronomy, astronomy as a whole and certainly cosmology became a branch of physics.

It's a kind of cosmology, and I have to develop a cosmology of my own universe, as the creator of that universe.

This last view of cosmology is called the relational view.

Welcome to the Coursera class on Galaxies amp amp Cosmology.

But first of all, let us define what is cosmology.

Unlike most other sciences, cosmology has only one object to study.

Observational cosmology really started blossoming from 1970's onward. And thanks

In Japanese cosmology we refer to 8 million when speaking about infinity.

Now we talk about precision cosmology. Two important paths will happen there.

Martin Reese suggested that cosmology today is now developing in two directions.

So next time we will talk about cosmology Cosmic microwave background fluctuations.

Hello, again. Let us now review briefly the history of modern cosmology.

Hello. We now continue our quick overview of the history of cosmology.

The cosmic micro background remains as one of the touchstones of cosmology.

However, measuring the distances in cosmology is, a very difficult thing to do.

Einstein's theories of general relativity, some ideas in cosmology about how galaxies form.

So that is both Aristotelian cosmology, and in a certain sense, medieval society.

1990s, mid 1990s really saw return to the classical cosmology or cosmological tests.

One was the supernova cosmology project, at Lawrence Berkeley Lab, led by Saul

And not only that, they make the analogy to relativity theory and cosmology often.

So far, at least, magnetic fields do not play an important role in cosmology.

Then super novae come in, and those are currently favorite ways of measuring distances in cosmology.

So trying to understand why this is, was one of the first important paradoxes in cosmology.

Hello, again. So far, we introduced Friedmann Equation, which is the basic equation of relativistic cosmology.

Let us now complete this brief survey of history of cosmology with some more modern developments.

At some distance from us, things no longer appear smaller, this is specific to relativistic cosmology.

But we keep an open mind, that's what makes theoretical physics and cosmology so much fun.

So, the inverse of the Hubble constant is the characteristic time unit of cosmology. The Hubble time.

And this turns out to be actually far more sensitive to cosmology then just simple galaxy counts.

The first science of cosmology that was anything like science was Aristotelian science, and that was hierarchical.

We now turn to cosmological tests, which in some sense, are at the very heart of cosmology.

The most basic unit in astronomy and cosmology is the distance from the sun to the earth.

As you can see, they condense to the value that we always quote for the concurrence cosmology.

Cosmology responds to the basic human need to understand the big picture. Where is it all coming from?

One of which he compared to chess, which is theoretical elegant cosmology, which is very precise and clean.

You see, the typical redshifts of interest in modern cosmology, it's of the order of ten Hubble lengths.

And it's what really led us into the era of precision cosmology. The basic idea is as follows.

So, that was forgotten for a little while. Then in 1930's, relativistic cosmology really started to flourish.

The existence of the cosmic microwave background is one of the two great predictions of the Big Bang cosmology.

But then, things change considerably. Galaxy evolution really became forefront of cosmology in 1970, or late 1970s and 1980s.