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Recent Podcast
Tour of Chandra Deep Field South
Tour of Chandra Deep Field South
What happens when astronomers use Chandra to take a long look at the same patch of sky? (2017-01-06)
Audio Podcasts: "Touch the Invisible Sky"

Simon Steel reads "Touch the Invisible Sky" Braille book (Introduction)


The Universe is huge. Almost everything that we know about distant objects in the Universe comes from studying the light that is emitted or reflected by them. On Earth, geologists can study rocks by collecting them. Astronauts traveled to the Moon in 1969 and collected moon rocks, but the stars and galaxies are so far away that the primary way we can learn about them is from their light.

Astronomy is a little like Archaeology. This is because the light from stars and galaxies may take hundreds, thousands or even millions of years to reach our telescopes. We observe that star or galaxy as it looked when the light was emitted, hundreds or thousands or millions of years ago. For example, when astronomers study a galaxy that is 200 million light years away, they are observing that galaxy as it appeared 200 million years ago. Looking out in space is like looking back in time. Fortunately, the stream of light from those stars and galaxies contains an incredible amount of information. Simply by analyzing star light, we can tell the distance, age, size and chemical composition of a celestial object way beyond their grasp. Astronomers are space detectives, intent on solving the mysteries of how galaxies, stars and planets are born, evolve and behave. Perhaps most importantly, the story of the Universe is also the story of us. In unraveling the mysteries of the Universe, we are also beginning to understand our place in our cosmic home.

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