The Hubble Space Telescope is only 347 miles away, in orbit around the Earth. But in its 25 years, it has taken humanity on an astounding journey from our own smallish, out-of-the-way galaxy to the beginning of time itself.
Not bad for something that once was considered a huge blunder for NASA.
The telescope, which was launched in April 1990 by the space shuttle Discovery, had an ignoble debut when it started sending back photos a month later: They were out of focus, a problem caused by a flaw in the telescope’s mirror. But after space-walking astronauts made repairs, Hubble started sending back astonishing images.
The discoveries made with Hubble’s help have changed the way we think about the universe. Its observations have been the basis of more than 12,800 scientific papers and contributed to major breakthroughs in cosmology. And it’s a very democratic instrument: Any astronomer, anywhere in the world, can request “time” on the telescope. After one year, any findings are released to the entire scientific community.
Named for American astronomer Edwin Hubble, the telescope was able to confirm the theory of its namesake that the universe was rapidly expanding. It can see so far back in time and space that it was able to put a time stamp on the Big Bang that started it all: 13.7 billion years (plus or minus a few hundred million years, NASA says). Previously astronomers thought the universe was 10-20 billion years old.
Because it is outside the Earth’s atmosphere and free of distortion, Hubble has amazing “eyesight.” It has allowed us to see the birth of stars in immense “nurseries” and provided clues into how planets are formed. It has expanded our knowledge of black holes and mysterious “dark energy.” It has detected the farthest planets found to date and captured the first visible-light image of a planet around another star. It found that our Milky Way galaxy eventually will collide with the Andromeda Galaxy.
Its list of discoveries goes on and on. (For more information, and spectacular photographs, visit hubblesite.org.)
The Hubble’s journey will end in the next few years, probably no later than 2020, when it will fall out of orbit and plunge to Earth. But there’s good news: Another instrument, the James Webb Space Telescope, is scheduled for launch in 2018.
The Webb telescope will orbit the sun instead of the Earth in an alignment that will protect it from the sun’s radiation. Its infrared technology is expected to provide even more insight into the great questions of the universe, including the big one: Are we alone?
But this is Hubble’s moment in the sun. At 25, it has been one of the most — some would say the most — productive scientific instruments in history. Those scientists who championed the idea of a space telescope, and then fought to make it a reality, deserve our thanks.