Understanding the Cosmos and Our Place in It
From its unique vantage point in space, the Hubble Space Telescope provides us with a clearer sense of the history of the universe and our place in it. By allowing scientists to study the origins of the universe, the earliest galaxies and the mysterious, repulsive force known as dark energy, Hubble is helping to answer age-old questions such as Where did we come from? and How will the universe end?
What Is the Big Bang?
About 13.8 billion years ago, the universe sprang into existence in an event known as the big bang. The early universe was incredibly hot — too hot for even atoms to exist — and extraordinarily dense. As the universe expanded, it it cooled and became less dense. Atoms formed, then molecules. Gravity drew the matter into greater and greater clumps, eventually bringing into existence the stars, planets and galaxies so familiar to us today.
What Is Dark Energy?
In the late 1990s, astronomers found evidence that the expansion of the universe was not slowing down due to gravity as expected. Instead, the expansion speed was increasing. Something had to be powering this accelerating universe and, in part due to its unknown nature, this “something” was called dark energy.
What Are the Hubble Deep Fields?
For 10 straight days in 1995, Hubble stared at a tiny and nearly empty patch of sky near the Big Dipper. The telescope gathered all the light it could, slowly building a picture. What emerged — the Hubble Deep Field — revealed galaxies fainter than had ever been seen before. The light from some of these has traveled for 10 billion years to reach us.