Scientists have made a surprising discovery of a mega-colony of penguins in Antarctica, thanks to NASA satellites in space.

Published in the journal Scientific Reports, the team described how they used imagery from NASA’s orbiting Landsat satellites to find patches of guano – penguin poo – at the northern tip of the Antarctic Peninsula on an archipelago called the Danger Islands.

They then used drones to survey the area, and in the process found a huge colony of about 1.5 million Adélie penguins, one of the largest ever seen. This could tell us more about penguin populations in the region, and the effects of changing temperature and sea ice.

“[T]he sheer size of what we were looking at took our breath away," Dr Heather Lynch from Stony Brook University in New York, one of the study’s lead authors, told BBC News.

"We thought, 'Wow! If what we're seeing is true, these are going to be some of the largest Adélie penguin colonies in the world, and it's going to be well worth our while sending in an expedition to count them properly.'"

The team travelled to the region in December 2015, funded by the Wood Hole Oceanographic Institution (WHOI), having first found evidence for animals there in 2014 by scouring Landsat data with an algorithm. They then used a modified quadcopter drone to take images of the Danger Islands from above, discovering the supercolony in the process.

The Danger Islands get their name from British explorer James Ross in 1842. He named them so because, according to the US Geological Survey (USGS), they appeared suddenly among heavy fragments of ice and “were almost completely concealed until the ship was nearly upon them.”

Interestingly, the number of Adélie penguins found on the east side of Antarctica is different to the west side – where this discovery was made. This could be due to greater sea ice in the area, more available food, or other factors.

It's hoped this discovery will give more support to creating protected areas near the Antarctic, such as Antarctic Specially Protected Areas (ASPAs) or Marine Protected Areas (MPAs).

“Given the large number of Adélie penguins breeding in the Danger Islands, and the likelihood that the northern Weddell Sea will remain suitable for Adélie penguins longer than the rest of the Antarctic Peninsula region, we suggest the Danger Islands should be strongly considered for further protection,” the team wrote in their paper.