Geo Facts

Do you know what the tallest mountain in the world is? Mount Everest, right? Wrong!

Mount Everest is certainly the tallest mountain above sea level, but there is a mountain that is actually much taller ... Mauna Kea. Only thing is you can't really see its height as part of it is below the sea.

Mauna Kea with its many observatories

Mauna Kea is a dormant (inactive) volcano situated on the south central part in the island of Hawaii. It is 33,465 feet (over 9,000m) from top to bottom, but only 13,796 feet (4,205m) stands above sea level and is therefore visible.

From the base to the top, Mount Everest is 29,029ft (8,848m) tall, which means that Mauna Kea beats Everest by 4436 ft. (over 3/4 of a mile). The peak which rises from the Pacific Ocean floor is also known as the highest island mountain in the world. However, Mount Everest is officially recognised as the tallest mountain in the world.

Mauna Kea is one of five volcanoes which form the island of Hawaii. Its name means "white mountain" in the Hawaiian language, which is a reference to the mountain summit being regularly snow-capped during winter. Its summit was entirely covered by a massive ice cap during the Pleistocene ice ages.

It shows evidence of four periods of glaciation over the last 200,000 years, the last ending about 11,000 years ago, when the most recent ice age finished. Dense rock is found at a quarry near the summit and this is believed to have been formed when lava erupted under a glacier.

The mountain slowly built itself up over many thousands of years through volcanic activity. However, its height has been decreasing slightly over recent years as its massive weight depresses the Pacific seafloor beneath it.

The summit of this mountain has been an astronomical observatory since ancient times, and is considered as one of the best astronomical sites in the world. Many of the world's leading observatories have been attracted to this location for that reason.

The summit is above 40 per cent of Earth's atmosphere and 90 per cent of the water vapour, which results in amazingly clear images of the night sky. Another reason is minimum man-made pollution in the area due to the low population density of the island.

Despite being a dormant volcano, having erupted last about 4,500 years ago, Mauna Kea has the capacity to erupt again. Its quiet periods between eruptions have been longer than those of the other active volcanoes in the area.

Several earthquakes beneath the mountain have been worrying geologists that an eruption could occur shortly, but such quakes do not always result in an eruption. The telescopes on top, besides looking into distant space, also have the task of detecting these ground tilts that could hint at a future eruption.