…is not Mount Everest. Though it is a bit of a cheat: Mount Everest, at 29,029 ft (8848 m) is indeed the highest mountain on Earth above sea level, but it sits on a plateau that is itself at an elevation of a good 15,000 ft (4500 m) or. So measured from its base to its summit, Mount Everest is a surprisingly second-rate 14,000′ (4300 m) tall. That statistic, of course, is rather cold comfort — emphasis on the “cold” — if you are actually standing atop Mount Everest trying to breathe.
No, the tallest mountain on the planet, as measured from its base to its summit, is Mauna Kea here on the Big Island. Again, you’ve got to be a little flexible with your definitions, because the base of Mauna Kea is the ocean floor itself, a good 15,000 ft (4600 m) below my feet as I type this. Mauna Kea’s summit is at an altitude of 13,796 ft (4205 m), which means that measured from base to summit it is roughly 29,000 ft (8800 m) tall.
Mauna Kea also has the more personal distinction of being the most important geographical feature in my life because of the many observatories at its summit and the many nights (~200) I spent using them early in my career. At that time, in the early 1980’s, there were four major observatories plus a couple of much smaller telescopes. Today, there are a dozen major observatories and a whole lot of controversy about whether building any more constitutes a desecration of the summit, which has Hawaiian religious significance. But the current controversy aside, the mountain holds a lot of history and emotional resonance for me, and so it was important that we make the pilgrimage to the top.
Getting to the summit is a lot easier than it was 30+ years ago because more (though not all) of the summit access road is paved. Even so, at that altitude you’re breathing only about 60% of the oxygen that you’ve got at sea level, so you’ve got to be very careful. Most of the car rental companies on the island forbid you from taking their vehicles to the top, a restriction that is frequently ignored by tourists, often without consequence, but sometimes to their extreme detriment when either their oxygen-starved engine conks out or their wheels lose traction on the unpaved lava gravel. (I should add that at that altitude your oxygen-starved brain and cardiopulmonary systems also lose traction; many people feel woozy and headachy and have difficulty concentrating; a few experience much more serious health consequences.)
You first ascend via paved road to Hale Pohaku, the mid-level facility that serves as a visitor center and dormitory for the observatory engineers and astronomers. Hale Pohaku sits at 9000 ft (2700 m) which, given the weather patterns of the island, is typically where the cloud layer lives that traps the island’s heat and moisture below. It’s cold and dry above that point, which is why the site is the best astronomy observing locale in the world. But that also means that you drive up through the clouds to get there.
That makes for a nasty and dangerous drive, especially on the unpaved portion of the road, but also serves up a (literally) breathtaking panorama when you break through the clouds at the top and find yourself on a sunlit Martian dessert. As you approach the very summit the road is paved again; this is to prevent vehicles from kicking up dust that could get onto the telescope mirrors. (Which, needless to say, are exquisitely precise.)
That’s Mauna Loa sticking out of the clouds at the center of the frame. It’s the same height as Mauna Kea, about 25 miles ( 40 km) to the south. It does not host any telescopes for the very sensible reason that it is an active volcano. The dome at the right side of the frame is the United Kingdom Infrared Telescope (UKIRT), where I worked for three years. It houses a 3.8 m diameter telescope.
I’ll close with a few more scenes from our visit to the summit.
The white dome at left in bottom picture is the Canada-France-Hawaii Telescope (CFHT), one of the older observatories on the mountain. The silver dome is the more recent Gemini telescope, so named because it has an identical twin sibling on an Andean mountaintop in Chile.