Hubble telescope 25th anniversary: The space secrets you didn’t know

IT’S been 25 years since the Hubble telescope was launched into space. What we’ve learned about space since Hubble’s launch will surprise you.

ITÂ’S not the biggest telescope ever built, but it certainly is the most famous. And today it celebrates its 25th birthday. The Hubble Space Telescope has spent the past quarter of a century astounding us with breathtaking views of the cosmos, and producing scientific results that have both confirmed and overturned long-held theories.

Hubble was launched into orbit aboard the space shuttle Discovery in April 1990, but its origins go much further back than that. Scientists first proposed the concept of a space telescope in 1946, almost 20 years before the first satellite was launched. The Hubble project itself was initiated in the early 1970s, and after a long development period beset by delays, the telescope finally reached orbit seven years later than planned.

But no sooner had it begun its work, than mission controllers spotted something wrong — all the pictures it was sending back were blurry. An investigation found that the telescope’s main mirror had been made with slightly the wrong curvature on its reflecting surface.

For any other space telescope (and there had been a few smaller ones before), this would have fatal. But NASA had a trick up its sleeve — Hubble had been designed to be regularly upgraded by repairmen astronauts while still in orbit. And so in 1993, the during the first of several scheduled servicing mission, astronauts installed corrective optics that completely fixed the telescope’s vision, and scientists everywhere breathed a sigh of relief.

News_Image_File: On the edge. This galaxy, 50 million light-years from Earth, is seen edge-on.News_Image_File: Things that go bump in the night. Galaxies collisions are common in the cosmos. Pic: NASA/ESA

News_Image_File: Scarred planet. Hubble watched as comet fragments hit Jupiter in July, 1994. The black blotch is the aftermath of one of those collisions. Pic: NASA.

In the years since, Hubble has been involved with many of the most amazing discoveries of the modern era. Here are just a few:

How old is the universe?

Throughout the 20th century, scientists had tried to pin down the age of the cosmos. Estimates ranged from 5 billion to 15 billion years. One of Hubble’s main tasks was to measure the expansion rate of the universe, which could then be used to backtrack and find the age. Today, we know it is 13.8 billion years, give or take a little bit.

The birth of planetary systems

Scientists had long theorised that planets form within clouds of gas and dust that swirl around infant stars. It took Hubble’s super vision to spot them.

Cosmic collisions

With its newly corrected vision, Hubble was in the box seat to witness fragments of comet Shoemaker/Levy 9 crash into Jupiter in 1994. The telescope has also monitored the weather on other planets such as Mars and Neptune.

Deep vision

Hubble’s main claim to fame is its ability to see faint things very, very far away. Several times now it has produced ‘deep fields’, where it has stared for hundreds of hours at seemingly empty patches of sky, slowing soaking up the light of distant galaxies that were in existence not long after the Big Bang.

News_Image_File: Artist’s impression of the James Webb Space Telescope, Hubble’s successor, due for launch in 2018. Pic: NASA.News_Image_File: The Hubble Space Telescope in orbit. Pic: NASA.News_Image_File: Pillars of creation. The Eagle Nebula is a complex of gas and dust clouds, inside which infant star systems are being formed. Pic NASA.News_Image_File: Deep vision. This is the Hubble eXtreme Deep Field, showing thousands of galaxies stretching back in time toward the Big Bang. Pic: NASA

Ever expanding universe

In what came as complete surprise to most of the world’s scientists, including the ones doing the research, Hubble observations of exploding stars in distant galaxies helped determine that not only is the universe expanding (as had long been known), but that the expansion seems to be getting quicker as the years go by. This result led to Nobel prizes in 2011 for the leaders of the research teams, including Australia’s Professor Brian Schmidt.

Nothing lasts forever, and within the next 5 to 10 years, Hubble will come to the end of its life. With the space shuttles gone, there is no way to get those astro-repairmen back into space. So there will be no more servicing missions for Hubble, and it will slowly die as its on-board equipment begins to fail.

Happy galaxies. A phenomenon predicted by Albert Einstein, called gravitational lensing, is responsible for the distorted shape of background galaxies in this image. PIC: NASA

But by that time it’s successor will be up there. For years, NASA has been working on the James Webb Space Telescope, or JWST (named after one of the agency’s early bosses). Due for launch in 2018, the JWST will be much bigger than Hubble, and able to see further and fainter.

Hubble has wowed us with unexpected discoveries and awe-inspiring images for the past 25 years. We can look forward to the JWST doing the same for the next quarter of a century.

Jonathan Nally has been a space writer for 30 years, and appears regularly on the Today Show on Channel 9.