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The First Galaxies in the Universe

Credit: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit

Credit: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit

By Stuart Wyithe

By measuring the spatial distribution of cosmic hydrogen, the SKA will help to answer some of the biggest missing pieces in our knowledge of the universe’s history, including when the first galaxies formed and how they influenced the universe around them.

The full text of this article can be purchased from Informit.

As part of the fundamental quest to define our existence, astronomers seek to understand the origin and evolution of our universe. A great deal of progress towards this goal has been made in the past decade as astronomers have measured the mass, expansion rate and age of the universe with unprecedented precision. At the same time, enormous surveys of galaxies over volumes that span the far reaches of cosmic distance and time have increased our understanding of how galaxies live and die.

However, our knowledge of the first generations of galaxies remains limited. We do not know how the first galaxies formed. We do not know what they looked like, or how big they were. Indeed, we do not even know when galaxies first appeared in our universe.

Fortunately, astronomy has a great advantage when it comes to studying the distant past. Because it takes light a finite amount of time to travel from the first galaxies to our telescopes, astronomers study the distant universe not as it exists today but rather as it looked at a much earlier time. Thus, by looking out to ever-larger distances, astronomers are able to construct a fossil record of the history of our universe. Uncovering this fossil record is a key goal driving the development of the SKA.

Currently, our best theory is that the universe began with the Big Bang, which left small ripples of density in...

The full text of this article can be purchased from Informit.