[Mount Everest is the tallest mountain above sea level, while Mauna Kea can certainly claim to be the world's tallest mountain (when sea level isn't taken into account). It would be difficult to make a case for Chimborazo being the tallest, but "it's all a matter of perspective," Price admitted.]
It
depends how you measure height.
By Joe Phelan
You
may be surprised to hear, then, that other peaks could conceivably be
considered Earth's tallest;
it just depends how you measure them.
So,
judging by different parameters — including tallest by altitude, tallest from
base to top and tallest based on being the farthest point from Earth's center —
what is the tallest mountain in the world?
Mount
Everest, located deep in the Mahālangūr Himāl subrange of the Himalayas, is
undoubtedly the most famous — and alluring — of all our planet's mountains.
Also known as Chomolungma, meaning "Goddess Mother of the World" in
Tibetan, Everest was first scaled on May 29, 1953 by Tenzing Norgay, a Sherpa
of Nepal, and New Zealander Edmund Hillary, and has since been successfully
climbed by around 4,000 people. The mountain has also claimed
the lives of over 300 since records started being kept in 1922, according to the Guardian.
Researchers
have measured Mount Everest many times over the past few decades, but the
latest assessment, announced in November 2021, puts it at 29,031.69 feet
(8,848.86 meters) above sea level, which is almost 5.5 miles (8.8 kilometers)
tall. It's a pretty impressive height, but it does raise a question: Why do we
use "above sea level" when determining the world's tallest
peak?
"In
order to have comparability in measurements, it is necessary to have a
consistent baseline," Martin Price, a professor and founding director of
the Centre for Mountain Studies at the University of Highlands and Islands in
Scotland, told Live Science.
"Historically,
and even now, elevation is usually given as height above mean sea level,"
Price told Live Science in an email. "However, this has to be with
reference to a standard mean sea level, which has to be defined. Sea levels are
different in different parts of the world, and they're changing due to climate change."
As
a result, "elevation is now measured in relation to the mathematically
defined geoid of the Earth," he said. The geoid is, according to the National
Oceanic and Atmospheric Administration, "a model of global mean sea
level that is used to measure precise surface elevations." This average is
used to ascertain the height of mountains, a process that sometimes requires an
aeroplane to fly "back and forth over a mountain in a series of parallel
lines to measure how much gravity pulls down on its peak," according
to GIM International. These measurements, in conjunction with
GPS readings, provide incredibly accurate elevation readings.
So,
all mountains are measured from sea level, predominantly for convenience and
consistency, but what if measurements were simply taken from base to peak?
Would Everest still top the charts?
The
answer is a mountainous "no." That honor would go to Mauna Kea, an
inactive volcano in Hawaii. Although its peak is 13,802 feet (4,205 m) above
sea level — which is less than half the height of Everest, according to National Geographic — the majority of Mauna Kea is
hidden below sea level. When measured from base to peak, Mauna Kea is 33,497
feet (10,211 m) tall, according to the United
States Geological Survey, which puts it heads and shoulders above Mount
Everest.
Should
we, therefore, regard Mauna Kea as the tallest mountain on Earth?
"It
all depends on the perspective you take," Price said. "If there were
no oceans on our planet, there would be no debate! You could draw comparisons
to the highest mountains on other bodies in our solar system, which have no
oceans."
Meanwhile,
another contender, Mount Chimborazo in Ecuador, boasts a peak that is the
farthest point from Earth's center.
Chimborazo
isn't the tallest mountain in the Andes — it's not even in the top 30 — but its
proximity to the equator is what makes all the difference. Earth is not a
perfect sphere — technically, it's an oblate spheroid — and it bulges along the
equator. This is a result of the force created by Earth's rotation. As a
result, it means there is a difference of 13.29 miles (21.39 km) between the
planet's polar radius (3,949.90 miles/6,356.75 km) and its equatorial radius
(3,963.19 miles/6,378.14 km), according to the NASA Goddard Space Flight Center.
Chimborazo
is just 1 degree south of the equator, where Earth's bulge is most prominent;
this geographical quirk means Chimborazo's summit is 3,967
miles from Earth’s core, making it 6,798 feet (2,072 m) farther away from
the planet's center than the peak of Everest.
So,
which of these three contenders for tallest mountain should take home first
prize?
Mount
Everest is the tallest mountain above sea level, while Mauna Kea can certainly
claim to be the world's tallest mountain (when sea level isn't taken into
account). It would be difficult to make a case for Chimborazo being the
tallest, but "it's all a matter of perspective," Price admitted.
Regardless
of the mountain you choose, its height will pale in comparison with Mars'
Olympus Mons, the largest known volcano in the solar system. It
has a height of around 16 miles (25 km), according to NASA,
which is almost three times taller than Everest, and a base of 374 miles (601.9 km) in diameter, which is about the same
distance separating San Francisco and Los Angeles (383.1 miles/616.5 km).
There
is also an impact crater called Rheasilvia on the asteroid Vesta, which is part
of the asteroid belt 100 million miles from Earth. At the center of this crater is a peak that scientists
believe could be anywhere between 12 and 15.5 miles (20 and 25 km) in height,
meaning it may be the tallest mountain in the solar system, according to
the NASA Jet Propulsion Laboratory.
Originally
published on Live Science.
