Hubble: 20 years of unlocking the universe's secrets

The Hubble telescope marks two decades in space this month, where it has captured stunning images that have had a profound effect on our understanding of the universe.And to celebrate, NASA has released a recent image that shows a star factory in action.York University Paul
Delaney said the image of the Carina nebula, one of the largest star formation regions that exists, captures "the wonderful interplay between dust, gas and stellar embryos."Although the way stars are formed has been known for some time, there was no way to get a front-row view of the action until Hubble.

"Hubble has been able to peel aside some of the veils which have always annoyed astronomers and gotten right into the deepest parts of star formation areas," Delaney told CTV News Channel this week."It's a vindication of the stellar evolutionary theories, and that's really what Hubble has been about," he said. "It has been able to confirm, deny and advance the theories of astrophysics in such a wonderfully pictorial way."

In another photo of deep space taken by Hubble with an exposure of one million seconds, or four and a half days, nearly 10,000 galaxies are visible, Delaney said. Some of the galaxies are younger than one billion years old, which means the image allows scientists to see back 12 million years in time.Hubble looks through many different filters -- including ultraviolet and infrared ones -- to capture "the full breadth and beauty of the image," Delaney explained.

Aside from being admired for their beauty, the images Hubble has captured have also proved useful. They have helped scientists determine the age of the universe and how planets form -- and has even supported the idea that there is a mysterious form of dark energy in the universe, holding everything together.But the clarity of the images used to be a lot worse.
When Hubble was first launched into orbit on the space shuttle Discovery on April 24, 1990, the initial images it captured were distorted due to an improperly ground mirror. In 1993, corrective lenses were installed on the telescope by astronauts to fix the problem.

Also, the technology of the telescope has been updated and maintained over the years through five servicing missions, each of which has increased its power. On the last Hubble servicing mission in May 2009, it was made 100 times more powerful than when it was launched.

Earlier this year, the telescope captured images of Pluto that surprised colour astronomers -- the planet's colours were changing and its ice sheets shifting.Over the years, Hubble has looked at more than 300,000 celestial objects and built an archive of more than 500,000 images, according to NASA.Hubble, named after astronomer Edwin Hubble, is the first major optical telescope to be placed in space, a location that affords it an unobstructed view of the universe.The telescope is about 13 metres long and does not travel to any of the celestial objects it captures images of. It orbits the Earth at a height of about 570 kilometres.
Hubble will eventually be replaced by its successor, the larger James Webb space telescope. The Webb has a planned 2014 launch date. The Webb has a much larger mirror than that in the Hubble space telescope, and means that the Webb will be able to look farther into space.