The Great Barrier Reef is the largest, indeed the only living thing that can be seen from space, as images of it captured by astronauts and satellites show.
The International Space Station is mostly a giant, floating laboratory that enables scientists to carry out experiments in zero gravity over long periods of time.
But it’s also a great platform for photography.
Astronauts of many nations have used their time on the ISS to capture fantastic shots of our planet from space, including of the Great Barrier Reef.
In October 2015, one member of the Expedition 45 crew took this amazing shot of a stretch of the Great Barrier Reef, near the Whitsunday Islands, using a Nikon D4 camera and a 1150mm lens.
The image above shows an area spanning about 15km (10mi), but that’s just a tiny fraction of a system that stretches some 2,300km (1,700mi) from end to end and covers an area of around 344,000km2 (133,000mi2).
As the image reveals, the Great Barrier Reef isn’t a single object, but a system comprising over 2,900 individual reefs and over 900 small islands. The image above shows just three of those reefs.
They can be seen clearly because the water within the lagoons they form, being shallow, shows up a much lighter blue then the deeper water in the surrounding ocean.
A slightly more complete picture of the Great Barrier Reef is seen in this image by NASA’s Envisat satellite from 2008.
Protecting the Great Barrier Reef
Given its vast size, it’s no surprise the Great Barrier Reef is home to a dazzling array of marine wildlife.
Including over 1,600 different species of fish and over 30 species of whales and dolphins.
And let’s not forget that coral is, itself, an animal.
A piece of coral on a shelf might look like a rock; coral growing under the sea may look like plants
But coral reefs are vast colonies of tiny little creatures called coral polyps, which are closely related to jellyfish.
Sadly, the reef is under threat from pollution and climate change.
Efforts have been made to mitigate the situation – including the establishment of the Great Barrier Reef Marine Park Authority in 1975, and the reef being declared a World Heritage Site.
Environmentalists warn however, that more action needs to be taken if we are to avoid a huge species die-off.
It has, after all, happened before: the geological record shows that there has been a reef in this area for around 600,000 years, but that the current, living reef is a mere 20,000 years of age.
Hopefully we, as a species, get our act together before another catastrophe occurs, because the loss of the reef would be a catastrophe.
You can’t just kill off thousands of marine species and not expect consequences higher up the food chain!
The Great Barrier Reef from space is a beautiful thing, as the picture above taken by astronaut Kjell Lindgren shows.
What are your favourite pictures of Earth from space? Let us know by emailing contactus@skyatnightmagazine.com