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# 1.26 Astronomy

The subject of Astronomy is the study of all the kinds of matter and radiation beyond the Earth. Astronomy is an excellent vehicle for studying science because of the sheer diversity of the universe. The primary backdrop for astronomy is physics, which describes how the material of the universe interacts and behaves. And while the interaction of matter and radiation might sound a little forbidding, in astronomy it leads to sights as beautiful as the northern lights and the rings of Saturn. The subject of geology deals with the composition and history of the Earth and the planets. Astronomy also involves chemistry, which is the study of the way that the fundamental elements in the universe interact and combine. The existence of life on the Earth, and possibly beyond, involves biology, the study of the function and form of living organisms. The language of astronomy and all science is mathematics, which describes the manipulation of numbers and symbols and which provides efficient shorthand for conveying many scientific ideas.

This is a Hubble Ultra-Deep Field image. This includes some of the most distant galaxies to have been imaged by an optical telescope, existing shortly after the Big Bang (June 2014). (This photo has the same field of view as the 2012 XDF, but NASA reverted to the older moniker of HUDF with the photo's release.). Click here for original source URL.

For an example that illustrates the scope of astronomy consider the digital image of a swarm of remote galaxies as revealed by deep observations from the Hubble Space Telescope. Each fuzzy blob contains many millions of stars. The existence of so many stars beyond the Sun leads us to wonder about our relationship to the larger universe around us. The stars in those faint galaxies are many trillions of miles away, yet each operates according to the laws of physics that apply to the Sun and the nearby stars we see in the night sky. The images also make us wonder how we "know" in astronomy. After all, in terms of direct exploration, humans have only made the small jump to the Moon, and our spacecraft emissaries have barely left the solar system. Yet with large telescopes, we have studied radiation that has traveled for billions of years through space to reach us from distant, ancient galaxies.

LH 95 stellar nursery in the Large Magellanic Cloud. Click here for original source URL.