Earth’s oceans have it all: from teeny tiny life forms to the largest animals that have ever lived. The oceans can be frozen or boiling, sunlit shallows or the deepest, darkest parts of the planet — they are the most amazing places in the world!

But most importantly, healthy oceans are essential to our survival. They help to feed us, clean the water we drink, keep the weather under control and give us a treasure trove of medicines. But most importantly, the oceans provide most of the oxygen we breathe — they are the lungs of our planet.

This is why, in June each year, World Oceans Day takes place. A day when people around our blue planet get together to celebrate and protect our shared ocean.

To mark the celebration this year, new out-of-this-world photographs have been released from the recently-launched Sentinel-3 satellite. The picture above is one of the very first images from the satellite, which is looking down on Earth from 800 km above us.

The photograph captures a rare, cloud-free day over Northern Europe. Can you spot the snow-covered mountains in Norway or a plume of phytoplankton in the North Sea? (Phytoplankton, which is pronounced ‘FIGHT-o-plankton’, are plants that live in huge groups just under the surface of the sea.)

But Sentinel-3 was sent into orbit to do more than take pretty pictures. The satellite is decked-out with the latest technology for measuring the temperature, colour and height of the sea surface.

Collecting this data over days, weeks and years lets us see how the seas are changing over time. We can check whether sea levels are rising, pollution is increasing or Phytoplankton is growing out of control. Armed with this information, we can help keep our planet’s lungs clean and healthy!