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It’s an exciting new year in space exploration and today we are getting back images from the most distant object ever explored by a probe spacecraft.  Launched in January of 2006, NASA’s amazing New Horizons mission (pictured above) has been flying through the solar system ever since.  Back in 2014 it reached its primary objective, the icy dwarf world Pluto, which has been the focus of considerable interest and, arguably, of even greater controversy concerning astronomical naming conventions (“My Very Educated Mother Just Served Us….Nothing.” could arguably teach us about astronomy AND independent food preparation, I suppose).  Since that time, New Horizons has continued to fly further from the Sun and deeper into the Kuiper Belt, a dark distant band of icy pseudo-worlds at the edge of the Solar System.  New Horizons just flew past one of these Kuiper Belt objects…the distant ice ball 2014 MU69.

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This frozen miniature planet is only 35 by 15 km (20 by 10 miles in diameter) and it orbits the sun every 298 years.  The most exciting part of this body is its shape.  It is literally a snowman—a smaller spherical lump of ice frozen to a larger one.  Just look at it! You can practically see Charlie Brown half-building it and then giving up with a silent outer space “Good Grief”

Sadly, the mission has generated another astronomical naming controversy.  Scientists were dissatisfied with the way “2014 MU69” rolled off the tongue so they crowdsourced the problem to the internet to find names for this distant iceball.  The internet suggested “Ultima Thule” which was a Roman and Medieval term for the unknown icy lands beyond the periphery of the known world.  That is a pretty good name and the scientists split it into two for the weird binary snowman (the larger body is “Ultima” and the smaller is “Thule”).  Unfortunately, though, Nazi occultists also found the name “Thule” back in the thirties and they used it as a mythical place of origin for the mythical Aryan Race (sorry Nazis, we are all originally African).

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Like all good-hearted people, I despise Nazis…but this seems like a Roman name sullied by racist morons more than a millennium after its introduction.  Do you think scientists need to rename this primitive snowman world? Or should we go with Ultima Thule?  Or should we just stick with 2014 MU69 (since, frankly, unless New Horizons discovers some strange artifacts, alien beings, or something we are probably never going to think about this corner of the solar system again).

 

Artist's Interpretation of Sedna (Credit: Gemini artwork by Jon Lomberg)

After the discovery of Pluto in 1930, there was a long hiatus in discovering objects of comparable size. Then in 2003, a team of astronomers led by Mike Brown of Caltech discovered a distant icy sphere which was quickly heralded as “the tenth planet.”  Mike Brown announced the discovery on his website along with his team’s rationale for naming the object.  He wrote “Our newly discovered object is the coldest most distant place known in the Solar System, so we feel it is appropriate to name it in honor of Sedna, the Inuit goddess of the sea, who is thought to live at the bottom of the frigid Arctic Ocean.

It turns out that Sedna is only one of many similar snowball-like planetoids beyond Neptune.  In fact, Ferrebeekeeper has already described the dwarf planet Eris (named after the Greek goddess of Strife) which is the largest currently known Kuiper belt object.  Sedna was the first to be discovered since Pluto and it sparked a debate about such objects which ultimately resulted in Pluto’s downgrade to dwarf planet.  Sedna also has some unique features which make it remarkable in its own right.

The orbit of Sedna (red) set against the orbits of Jupiter (orange), Saturn (yellow), Uranus (green), Neptune (blue), and Pluto (purple)

Sedna takes 11,400 years to complete its orbit around the sun and its bizarre highly elliptical orbit has given rise to much conjecture among astronomers.  Although some astronomers believe it was scattered into a skewed orbit by the gravitational influence of Neptune, other astronomers believe it originated in the inner Oort cloud and was never close enough to Neptune to be affected by the giant’s gravity.  Some scientists speculate that its lengthy orbit may have been caused by a passing star (perhaps from the sun’s birth cluster).  A few theorists have gone one step further and conjectured that Sedna is from a different solar system and was captured by our Sun billions of years ago.  A final school contends that Sedna is evidence of an unknown giant planet somewhere in the depths of space (!).

A photo of Sedna taken from a powerful telescope on Earth

We don’t know much about Sedna except that is probably 1,200–1,600 km in diameter and that its surface is extremely red.  After Mars, Sedna is one of the reddest astronomical objects in our solar system.  This color comes from the profusion of tholins covering the methane and nitrogen ice of which the little world is formed.  Tholins are large, complex organic molecules created by the interaction of ultraviolet light on methane and other simple hydrocarbons.  It is believed that early Earth (prior to obtaining an oxidizing atmosphere) was rich in Tholins and they are one of the precursors to the rise of life.

During the 1950’s, astronomers using the first radio telescopes started discovering a mysterious class of heavenly objects.  Certain discreet points in the sky blazed brightly with low-frequency electromagnetic radiation–yet when the scientists looked at the spots through conventional optic telescopes, it was impossible to discover a source for this energy.  Some of these radio flares came from incredibly faint smudges and some issued from what seemed like empty space. Astronomers called the mystery flares “quasi-stellar radio sources” (QUASAR) because they believed such discreetly focused energy must come from stellar-like objects.  Further study revealed that the photons issuing from quasars were red-shifted, which meant that the quasars were rushing away from the solar system at high velocities.

An Artist's interpretation of a Quasar

Only in the 60’s did optical telescopes become powerful enough to associate certain quasars with the cores of extremely distant galaxies.  The reason no luminous objects were initially associated with quasars was because quasars turned out to be profoundly distant—the closest were billions of light years away.  They were visible to early radio telescopes only because of their immense energy output and their beam-like focus.

An X-ray image shows the quasar PKS 1127-145 (credit: NASA)

Scientific consensus concerning these massive energy flares did not fully coalesce until the 1980s.  Today astronomers believe that quasars are powered by accretion of material into super-massive black holes which lie at the center of dynamic young galaxies.  Such phenomena are called “active galactic nuclei” (AGN). As radio telescopes and time-space modeling grew more sophisticated it became obvious that quasars (which produce low-frequency radiation) were not the only energy flares associated with AGN.  Giant beams of different spectrums of electromagnetic radiation are possible depending on the galaxy.  Quasars and their ilk produce incomprehensible amounts of energy—the most luminous active galactic nuclei radiate exotic energy at a rate that can exceed the output of an average galaxy by a thousand times (equivalent to the energy from two trillion suns).  To produce such energy the brightest known quasars consume roughly 1000 solar masses of matter within an earth year (which is equivalent to swallowing/burning 600 Earths per minute).

Yikes

Galaxies change as they age. Today the Milky Way Galaxy is a mostly responsible middle aged galaxy (which only occasionally cuts lose with something crazy like the luminous blue hypergiant Eta Carinae) however there are reasons to think that in the past the Milky Way was a deeply troubled teen-aged galaxy ablaze with self-destructive fury just like the AGN galaxies we see at the far edges of space.  Assuming they exist, alien astronomers in galaxies billions of light years away probably see our galaxy as a blazing quasar–because they are looking at its distant violent past.

Active Galaxies Collide (painting by Don Dixon for "Scientific American")

Of course galaxies are not always quiescent.  Some astrophysicists theorize that in 3 to 5 billion years, when the Andromeda Galaxy collides with the Milky Way, the black holes in the center of one or both galaxies could begin swallowing up matter (or could merge) reigniting a super bright fountain of high energy particles again visible throughout the universe.

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