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In 2016 the Japanese Space Agency launched a quarter-of-a-billion dollar x-ray observatory named Hitomi into Earth orbit.  The craft’s mission was to study extremely energetic processes at the far reaches of the universe.  It was hoped that the data Hitomi provided would allow astronomers to understand how the large scale structures of the universe came into being (how galactic superclusters form, for example).  The satellite initially worked perfectly, but, within 38 Earth days, the spacecraft was lost: a failure of attitude control sent it into an uncontrolled spin which caused critical structural elements to break apart.

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The full story of what destroyed Hitomi is perhaps of greater immediate interest to living beings on Earth than how the meta-structures the universe came into being.  When everything went wrong for the ill-fated space observatory it was passing over the southern part of the Atlantic ocean.  For spacefarers, this region of the Van Allen Belt is analogous to what the Bermuda Triangle or the Namib Skeleton Coast is for sailors: it is a haunted and dangerous stretch of space.  Astronauts who travel through it report strange phantasmagorical dots and streaks in their vision, even when they close their eyes.   The Hubble Space Telescope does not make observations when it passes over the south Atlantic.  Controllers turn off its delicate systems.  The region is known to the world’s space agencies as “the South Atlantic Anomaly.”  Hitomi was not its first victim–it is surmised that the South Atlantic Anomaly was responsible for the failures of the Globalstar network satellites way back in aught seven.

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The existence of the South Atlantic Anomaly was known long before that.  It was discovered in 1958 by Explorer 1, the first American satellite (which was equipped with a Geiger counter).  Perhaps the Soviets would have discovered the anomaly by means of Sputnik, but, because the Cold War made  scientific cooperation difficult, Australia did not hand over Sputnik data to the Soviets until later.  Suffice to say, the South Atlantic Anomaly is an anomaly in the Van Allen Belt, the torus-shaped field of charged particles which are held in place by the magnetic field of Earth.  Earth’s magnetosphere is important. Billions of years ago, Mars and Venus seem to have been exceedingly Earthlike, with water oceans and convivial atmospheres.  But neither Mars nor Venus has a magnetosphere and their oceans have perished and their atmospheres have changed into monstrous things….although we don’t know exactly what happened on either of our neighboring planets (and the present priorities here on Earth are to make Michel Dell and Howard Schultz as rich as possible at everyone else’s expense, not, you know, to understand what planetary scale forces could make worlds uninhabitable).

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Um, at any rate, the magnetic field of Earth is created by the mysterious processes beneath our feet at the center of the planet.  The Earth’s inner core is believed to have two layers: an outer core of molten iron and heavy metals and an inner core of solid iron nickel alloy.  The inner core is about 70% of the volume of the moon and it is nearly as hot as the surface of the sun with an estimated temperature of (5,430 °C) or 9806 °F, but the molten outer core is only as hot as the surface of an orange star (2,730–4,230 °C; 4,940–7,640 °F).  Within the outer core, eddy currents form in the superheated metal. The complex relationship between these currents, the spinning planet, and the two core layers creates a geodynamo which produces the planet’s magnetosphere which in turn captures the particles which make up the Van Allen Belts.  However, the eddy currents cause the magnetic poles to invert every few hundred thousand years (we are currently overdue for such a flip).  The South Atlantic Anomaly is a manifestation of the “weather” in the molten outer core of Earth–a prelude to the magnetic polar flip.  First generation spacecraft used solid state components and had big ungainly robust circuitry.  Additionally they were hardened against radiation.  Some of today’s craft make use of delicate & elaborate microcircuitry which is prone to failure when struck by esoteric radiation particles.  This is how what happens far beneath our feet influences what happens to craft in outer space.

An Artist’s conception of Jupiter seen from Amalthea

If you wanted to build a vacation home with a truly spectacular view, one of the possibilities you might consider is Jupiter’s moon Amalthea.  Discovered in 1892 by the American astronomer Edward Emerson Barnard (who also discovered Barnard’s star) Amalthea was the first Jovian moon discovered by someone other than Galileo Galilei.  Amalthea is the largest inner satellite of Jupiter and from its surface Jupiter would appear to take up 46.5 degrees of the sky (from the horizon to directly overhead is 90 degrees).  Amalthea is in synchronous rotation around Jupiter and so the planet would always appear in the same part of the sky (provided you were on the right part of the moon).  From Amalthea the sun would disappear behind the planet’s bulk for an hour and a half each revolution.

A digital rendering of Amalthea

The 66 known Jovian moons are largely named after the lovers and children of Jupiter/Zeus, however Amalthea is an exception: it is named for Jupiter’s step-mother the goat/nymph Amalthea who fed and cared for the young god as he quickly grew to adulthood and whose impervious skin was fashioned into the aegis of the king of the god.  The name Amalthea was used for the moon almost since it was discovered but was only formally adopted by the International Astronomical Union in 1975.

Amalthea Visited by the NASA spacecraft Galileo

Amalthea is a strange and mysterious moon which perplexes astronomers.  Its irregularly shape is somewhat like a potato and it is covered with deep craters and tall mountains.  The surface of the moon is deep red in color (in fact Amalthea is the reddest object in the solar system) however weird bright patches of green appearing on the mountain slopes–the nature of which is unknown.  The moon appears to be formed of ice and rubble, but if had formed where it now is during the early days of Jupiter, it would have melted.  The moon must have formed elsewhere and been captured by Jupiter—a recent paper speculated that it was originally a Trojan asteroid.  Since Amalthea is made of ice and heterogeneous rubble scientists are perplexed at why gravity has not rearranged its into a more spherical shape.  Since Amalthea is so close to Jupiter it’s orbit is decaying and it will one day fall into the gas giant (so you may want to get really good insurance on the vacation house I mentioned in the first paragraph).

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