The most dramatic and significant images of the universe taken by the Hubble Space Telescope have been named to mark the iconic telescope's 20th anniversary in space.

Now, to mark the observatory's 20th anniversary, scientists at NASA have selected the most dramatic and scientifically-important images it has taken.
Massive clouds of dust where new stars are born, the bursts of light released when stars die, beautiful structures of galaxies and even new planets in distant parts of the solar system are among the images to be singled out.
NASA has released the images in a new book, Hubble: A Journey Through Space and Time.
They also show how the telescope, which has cost around $10 billion to build, launch and maintain, has evolved during its 20 year history.
Ed Weiler, associate administrator for NASA's science mission directorate in Washington, said: “This book represents a sampling of 20 years of Hubble discoveries that have forever changed the view of the universe and our place within it.”
He said the upgrade of Hubble in May last year would allow the telescope to continue capturing scientifically important images.
Hubble was launched into space on April 24 1990 from the space shuttle Discovery. The first images to be sent back to Earth by the 43 foot long observatory were grainy black and white pictures of stars on 20 May 1990, which also revealed the early signs that the space telescope's mirror had been incorrectly produced, leaving images distorted.
In 1993, NASA was forced to launch an expensive repair mission to restore the telescope back to its intended quality.
It has since received five servicing and upgrade missions by astronauts and is now expected to function until at least 2014 when its successor the James Webb Space Telescope is due to be launched.
The telescope, which is named after the American astronomer Edwin Hubble, has attracted intense criticism since its launch due to its high cost and early problems.
However, it has helped to answer questions about the age of the universe, revealed information about how planets form and shown that massive black holes dwell at the centre of galaxies.
Among the most influential images to be sent back to Earth by Hubble were the so-called Pillars of Creation in the Eagle Nebula.
The towers of cold gas and dust stretch about 57 trillion miles high, and mark an area where new stars are being born.
It has also revealed the structure of rare massive stars such as Eta Carinae, a star system 100 times bigger and a million times brighter than our own sun.
Scientists have also been able to see some of the most destructive forces in the universe at work thanks to Hubble's view, undistorted by the Earth's atmosphere. It has revealed colliding galaxies such as the Antennae Galaxies and revealed that the energy released as two galaxies merge is enough to lead to the birth of new stars.
Nebula such as the Helix Nebula, which is 700 light years away and often called the Eye of God due to its distinctive structure, have revealed in fine detail the huge amount of energy released when stars reach the end of their lives.
Hubble has also taken stunning close up pictures of planets in our own solar system including Mars, but two years ago it captured the first visible light image of a planet outside our own solar system as it orbited a star.
(Source: Daily Telegraph)