Nearly half a century ago, visionary scientists decided to create a telescope that would operate in space, to transcend the blurring and obscuring effects of the Earth’s atmosphere, and to take clearer, deeper images of the Universe than ever before. On the 25th of April, the incarnation of their dream - the Hubble Space Telescope (HST) - was deployed by Space Shuttle Discovery into an orbit several hundred kilometres above the Earth’s surface. The telescope was named after Edwin Hubble, one of the most important astronomers and cosmologists of all time (and as I recently found out, an Oxford grad), who provided the first definitive proof that the Milky Way is just one of billions of galaxies in the universe. The HST weighed as much as two elephants, was about the size of a small bus, and zipped around the Earth at more than 25,000 km/h; a marvel of science and engineering. And then it started to look at the universe.

It is no exaggeration to say that the HST's impact, since its launch 25 years ago, has been nothing short of staggering. It has been as revolutionary in our time as Galileo’s telescope was in his. It has allowed us to look deeper into the universe - further back in time - than was ever thought possible; it played a critical role in the discovery that the expansion of the Universe is accelerating; and has even allowed us to to study the atmospheres of planet around faraway stars. It has made major contributions to every branch of astronomy, and data from the telescope has led to more than ten thousand science papers. But more than anything, it has given humanity a newfound appreciation for our infinitesimal place in the vast, beautiful cosmic arena.

(For my part, it was HST imagery that sparked an early-childhood interest in astronomy - an interest that eventually led to me choosing a research career in astrophysics.)

The linked IFL article contains a small collection of some of the HST’s most beautiful and celebrated images; if you’re hungry for more, also check out this astounding gallery put together by the Hubble team.

The HST’s formal successor is the James Webb Space Telescope, to be launched in 2018, and which should far surpass even the HST’s capabilities. But at the moment, NASA has no firm decommissioning date because the HST is operating better than anyone expected more than five years after its last servicing, and more than 10 years after the telescope was originally expected to stop functioning!