Tamu Massif

The largest mountain by volume on the planet Earth is a shield volcano that extends from the abyssal plain between Japan and Midway to about two kilometers below the surface of the Pacific Ocean. You can read more about it here:
Tamu Massif

Mauna Loa had long been thought to be the most voluminous mountain on Earth, and still seems to be the biggest with a peak above sea level. Though there are many places with peaks higher above sea level, the great shield volcanoes of the Hawaiian islands are much higher from base to peak than the Himalayas or the Andes. They just start out quite a bit lower. Mauna Kea reaches about 120 feet higher above the Pacific than Mauna Loa, but it's been much less active than its southern cousin in recent years, and as a result most of the bulk of the island of Hawaii is counted as part of Mauna Loa's mass. The mountain complex is in fact nearly the same size as Mars's Olympus Mons, but gravity is much stronger on here than on Mars, and Mauna Kea crushes the bedrock beneath it into a deep furrow in the Pacific Plate. On Mars, where gravity isn't quite so intense, the tops of volcanoes tower well above anything on Earth.

Tamu Massif can't compete with anything in Hawaii, or even the Maldives, when it comes to elevation above sea level, but the mountain is quite impressive when considered relative to the ocean floor. The massif measures over 14,000 feet from base to peak, comparable to the heights of the highest points in California, Colorado, and Washington, though its slope is far more gradual. With slopes rarely greater than one degree, it takes a base the size of New Mexico to reach such a height, and this gives Tamu its edge over Mauna Loa in girth if not in height.

Mauna Loa has been known to people since at least the 6th Century, and to Europeans since the 18th, but Tamu Massiff was not known to be a single mountain until this year. The deep ocean is a thoroughly hostile environment to people, and even at the peak's summit the ambient pressure is 200 times greater than that at the ocean's surface. This makes exploration of the oceans difficult, and it wasn't until significant drilling operations had been conducted throughout the region that the basalt of the massif could be shown to have a single source. Earth is much better explored and better understood than any other planet in the universe, but clearly we have a long way to go before we can say that our homeland is fully explored.

Papal Infallibility

One of the distinguishing features of the Roman Catholic Church relative to other branches of Christianity is the Church's assertion that, under very limited circumstances, people are capable of speaking without possibility of error. You can read more about that here:
Papal infallibility

In this case, the category of "people" is restricted to the Pope, and the limits of those circumstances are a bit more constricting than you might expect. The claim is that infallible statements only occur when the Pope speaks ex cathedra to define that a doctrine concerning faith or morals that must be held by all in the Church. One of my friends described speaking ex cathedra as "The Catholic equivalent of Super Saiyan;" more rigorous definitions exist in the Catechism and on Wikipedia.

The result is that infallibility is invoked very rarely, and if you encounter Catholics who believe that everything the Pope says is unquestionable (I haven't actually met any such people, but people on the internet claim this happens), they're probably confused. Pope Pius XII made the only statement that fits all the criteria of infallibility since the doctrine was rigorously asserted during the first Vatican Council in 1870, affirming the dogma of the Assumption of Mary in 1950. Before Vatican I, Pope Pius IX's definition of the dogma of the Immaculate Conception of Mary is the only teaching that Catholic theologians agree was infallible. As the current Pope Emeritus put it more recently, "The Pope is not an oracle..."

Understanding how things work is hard. People have been working relentlessly for as long as we've lived on the Earth to find ways to discern truth in a universe that seems really weird and counterintuitive most of the time. The idea of Papal infallibility is that there's another avenue by which our minds' can be graced by truth about the reality we live in. Arguments whether or not it might be true are beyond the scope of this blog (though I sometimes touch on them at my other one), but I find the idea fascinating that humans can, through reliable but sometimes fallible methods of reasoning, reach a point where they can say in confidence that truth can, in some limited, intermittent way, shine clearly, and the optimism about humanity embedded in the idea is lovely. As usual, these are just observations (and some blatant reposting from Wikipedia). The real interesting argument is outside the scope of this post.

Comet Shoemaker-Levy 9

The most violent event ever observed in the solar system happened in Jupiter's southern hemisphere between July 16 and July 22, 1994. A series of 22 comet fragments known as Shoemaker-Levy 9 collided with the planet at 60 kilometers per second, about seven and a half times faster than the International Space Station orbits Earth, and left behind a series of impact scars and mushroom clouds each similar in size to the Earth. You can read more about the event here:
Comet Shoemaker-Levy 9

Shoemaker-Levy 9 was initially about five kilometers across, comparable in size to the asteroid that caused the K-T extinction event that killed off most of the dinosaurs. Two years before the collision, the comet had approached, but just missed Jupiter, binding it gravitationally to the planet. Tidal forces from that encounter ripped the nucleus apart into a series of comet fragments that the discoverers likened to "pearls on a string." Because of this encounter, the comet wound up impacting Jupiter in a series of relatively low-speed blows rather than a single interplanetary-speed slam, but the total energy delivered to the atmosphere was still equivalent to about six trillion tons of TNT, on the order of 600 times the combined explosive energy of every nuclear weapon ever built by humans. Kinetic energy packs quite a punch at the speeds things move in space.

The string of impacts in July 1994 were tremendous not just for their awesome scale, but in their good timing. Even Jupiter, the most massive and bulky planet in the solar system, doesn't encounter an object so big very often. Shoemaker-Levy 9 was probably the first comet so big to strike any planet in the solar system since the beginning of civilization, and it came along just after the Hubble Space Telescope's flawed mirror optics were repaired, and the Galileo spacecraft, five years along on her six-year voyage to Jupiter, had a direct view of impacts on the far side of Jupiter from Earth. Observing the impact of Shoemaker-Levy 9 is the kind of once-in-a-lifetime opportunity astronomers dream about.

Like the Tunguska Event of 1908 or the Chelyabinsk meteor of this year, Shoemaker-Levy 9 is a reminder that though the skies seem changeless on a human scale, we actually live in a dynamic and potentially hostile clime where every once and a while cataclysmic intersections of planets and mountain-size icebergs occur. We'd do well to heed the warning embedded in the messages we take in through our telescopes and spacecraft.