The Universe: Aliens in the Solar System Revealed (S2, E5) | Full Episode | History

lurking in the shadows of the solar system   are worlds so chemically active and  misshapen that they border on the bazaar   i think the most shocking thing was  how very different the solar system is these are the moons surrounding the planets of  the solar system moons that were once either   unknown or considered afterthoughts are now on  the cutting edge of astronomical exploration   what was surprising that they all didn't look  like our moon the so-called minor members of   the solar system are not of minor interest  what surprises await us on these alien moons our solar system has always been fertile  ground for science fiction writers   but with exponential advances in telescopic  technology and close encounters by unmanned probes   the curtain has now been lifted on a new ballet  of moons most of which are going one way around   some of which are going the other way around all  at different rates passing one another the inner   ones passing the outer ones for nearly half a  century it was believed the solar system was   home to only 32 moons they ranged in size  from jupiter's moon ganymede larger than   the planet mercury to small asteroid shaped  ones like the martian moons phobos and deimos that number has exploded in 2007  alone scientists announced the   discovery of 20 new moons around jupiter  one around saturn and three around neptune   what happened is astronomical telescopes  had available to them what are called ccd   cameras so these are digital cameras  that almost everybody has nowadays it's difficult to hold astronomers to an  exact number of moons in the solar system   as cameras become more sensitive and telescopes  more powerful more moons reveal themselves moons are classified in two distinct ways those  like our moon travel in nearly circular orbits   above their planet's equators  and are called regular moons while our moon formed from an impact all other  regular moons coalesced from the gaseous stew   surrounding their parent planets a process known  as accretion the classic example of regular moons   would be the galilean moons of jupiter io europa  ganymede and callisto the material that is going   to form jupiter too but extended a little  bit that material accumulates into the moons   moons that follow elongated orbits highly tilted  to their planet's equators are called irregular   moons most of these move in retrograde orbits  clockwise if their planet rotates counterclockwise   phoebe the newly discovered moon orbiting saturn  is a perfect example she began her celestial life   as an independent traveler orbiting the sun  before being captured by the more massive saturn whether regular or irregular moons  must fall within the gravitational   reach of their parent planet the limit of  these orbits is known as the heel sphere this phenomenon is named after george william  hill an american astronomer from the mid-1800s   so a hill sphere is this region around the  planet that moves along with the planet   inside of which the gravity of the  planet overwhelms the gravity of the sun the moons of mars deimos and phobos operate  very differently within the hill sphere   if the planet is rotating faster than  the moon it orbits like deimos the   tidal forces between the two actually  shove deimos out further and further volvos on the other hand is  rotating faster than mars rotates these small moons were discovered by  american astronomer aspeth hall in 1877.   he named phobos after the greek god of  fear and deimos for the god of terror tom duxbury was part of the mariner 9 mission that  first photographed the two potato shaped moons   in november of 1971. this was late at night in a  cold rainy dark dreary day and i looked at this   and i turned the picture sideways it looked  like a skull and it was such an eerie thing phobos is in a death spiral it orbits  just 3 700 miles from the martian surface   closer to its host planet than any moon  in our solar system if our own moon were   as close to the earth as phobos is to mars it  would look 20 times larger its orbital period   would be in hours not days like it is now but  hours and at full moon it would fill the sky   the daily tides you know rise and fall  tens of feet if not hundreds of feet   and so the earth's moon would eventually  crash into the earth in such a situation phobos predicament is caused by a  process known as secular acceleration   as phobos races faster than mars rotates a  tidal bump is raised on the martian surface   in the process mars yanks phobos  closer to its surface with each orbit the struggle between mars and phobos is similar  to the dynamics of a simple game of tetherball   imagine the ball as the moon the pole   as the planet and the rope between the pole  and the ball as the planet's gravitational pull what we see is that the gravity would pull the  moon in such a way that it speeds up it goes   faster and faster and it works its way until it  eventually hits the pole that's exactly what's   happening to phobos phobos is going around mars  faster than mars rotates that tidal interaction is   pulling phobos in closer and closer and speeding  it up in its orbit in about 50 million years we   expect phobos to be pulled in so closely it will  impact mars and disappear as the moon of mars on the other hand deimos the further out  moon is going slower than mars rotates   and so it's unwinding the string in the  opposite way and what we see is deimos   is going further and further away from  mars and eventually deimos will be pulled   away from mars by the gravity of the sun  so over time mars will become moonless because phobos outpaces the rotation of  mars it appears to rise in the west and set   in the east instead of the planet turning quickly  under it like our moon and most other moons   and thus having it rise in the east and set  in the west it races ahead of the rotation   of the planet and so it comes up on the western  horizon and races ahead and sets on the eastern horizon it will be another 50 million years  before phobos completely disappears before then   it may prove useful for the eventual colonization  of mars science fiction writer arthur c   clarke speculated on this idea in his book the  sands of mars although there is no real reason   to colonize phobos itself its close proximity  to mars makes it a natural weigh station   from a gravity standpoint it's much easier  to go to phobos which has no gravity than   it is to fight the gravity of  mars to get down to its surface from galileo to stanley kubrick the giant  planets of the outer solar system have   tantalized our imagination with their enormity but  in reality exploring them is tantamount to suicide   the overwhelming pressure from  jupiter's massive atmosphere   would make it almost impossible to function but the moons of these behemoths may provide  a more promising platform for exploration   and even future colonization   are these prisoners of jupiter's gravity  hostile worlds with little chance of sustaining   organic life or might they provide a safe haven  for future generations of planetary explorers until recently very little was  known about the moons of the gas and   ice giants most of them remained hidden  in the glare of their parent planets   today modern telescopes and unmanned space  exploration reveal a realm populated by a host   of moons from planet-like spherical worlds  to misshapen ones barely 30 miles across jupiter the largest planet in the solar  system is a moon magnet nearly four and   a half billion years ago it began as a  massive gas cloud collapsing in on itself   this process known as accretion formed the  beginnings of the jovian system while nearly all   the gas and spinning material went into forming  jupiter itself a very small percentage clumped   in small eddies within jupiter's orbit these  miniature accretions solidified into jupiter's   regular moons io europa ganymede and callisto  as jupiter coalesced its massive gravity began   adding to its menagerie little remaining  bits from the birth of the early solar system   the giant planets formed early in a gas-rich  environment when there was lots of little   flotsam and jetsam around the solar  system still to be captured into orbit   the number of jupiter's moons ranges from  60 to over 200 depending on who's counting what's clear is if you could stand at the edge  of jupiter's gaseous atmosphere and look to the   heavens you'd see a magnificent dance of lunar  objects it would look pretty cool to be able   to see the moons every so often you'd see io come  by every second time io comes by you'd see europa   at the same time and every four times io comes by  you'd see ganymede one member of this jovian cast   is so battered by jupiter's great mass that  it's literally bursting from the inside out in february of 2007 the new horizons spacecraft  eventually bound for pluto focused its cameras   on io about the size of earth's moon it  orbits 263 000 miles from jupiter's surface   what sets io apart from the other jovian  moons is its spectacular volcanism   new horizons cameras captured detailed photos  of glowing lava scattered across io's surface   a huge 200-mile high dust plume rose  above the surface of the molten moon io like all jupiter's regular moons is named  after a lover of the god jupiter from roman   mythology it was discovered by galileo in 1610  first photographed by pioneer 1 in 1974 and   again by voyager 1 in 1979 its pulsating activity  has puzzled and intrigued scientists for decades   leaving eo is about a ton per second of material  every second of every day it's a phenomenal   machine i would like to go to io even though  it'd be very dangerous and hot and sulfurous io is too small to have maintained a molten core  since its formation another mysterious process   must be responsible for its heating io's  entire interior may be molten because   it's squeezed so much as it's orbiting around  jupiter this process is known as tidal heating   the massive gravity of jupiter is  causing friction at the inner core of io much like a sculptor needs a cold lump of clay jupiter is endlessly creating its own masterpiece if a moon gets a little bit of tidal heating  it becomes malleable it can be stretched out   like clay and deformed by the gravity of  the parent planet the surface of the moon   is cold it breaks like pulling clay apart  quickly it'll break but the interior where   it's warm can literally flow and stretch be  needed by the gravity of the parent planet most regular moons have circular orbits to produce  tidal heating a moon must be in a more oblong   orbit where the distance from the host planet  changes radically during a single revolution   the only way to produce these eccentric orbits  is if another moon's gravity disrupts it when   a moon is in an eccentric orbit a non-round orbit  it gets closer and farther from its parent planet   when it does it gets squeezed it  gets pulled apart when it's closer   io is in orbital resonance with its companion  moons europa and ganymede while jupiter and io   struggle to find a synchronistic relationship  europa and ganymede are yanking io in opposite   directions jupiter yanks back and io gets  stretched and squeezed in the process   the tidal heating on io which is  responsible for its prodigious volcanoes   has a secondary side effect it creates  the largest stationary visible object   in the solar system a massive gas  cloud 500 times the size of jupiter in 1990 professor michael mandillo and his team  from boston university discovered a large gas   cloud spanning the huge distance from one side  of jupiter to the other they were the first to   photograph the entire nebula discover its origins  and the mechanism that keeps it growing now eo is   small so it doesn't have much of an atmosphere but  these volcanoes are continually providing material   that could be an atmosphere but you might ask  well why isn't having tremendous atmosphere   of all the volcanoes have been going on for  eons well it's because the material escapes   the key gas is sodium even though it only  makes up five percent of io's ejected materials   it's easily detectable by telescopes on  earth sodium emits an orange glow in fact   sodium is commonly used to illuminate street  lights in many cities across the world the sodium and the other gas molecules are pelted  by light from the sun and electrons in jupiter's   powerful magnetic field electrons and protons  are knocked off some of these particles and   ionized now in plasma form these ions are taken  on a ride by jupiter's powerful magnetosphere   its speed increases dramatically because  it's been picked up by the magnetic field it's like they're taking a ride on a cosmic  carousel the magnetic field lines are the holes   here and then every now and then a sodium atom  gets picked up along with it's an electron and   now i'm in the jupiter plasma taurus with all the  other ions and electrons that have been captured   previously and the ions and the electrons  we combine the neutral is not confined by   the magnetic field and it goes off at a much  higher speed and that's enough to escape from   jupiter and they form the largest visible cloud  of gas that's permanently in the solar system if we could see the nebula with the naked eye it  would be the size of 12 moons in the night sky   it is so enormous that to view it mandillo and  his team created their own specialized telescope   well as it turns out to get a big field of view  all you need is a small lens like a pair of   binoculars gives you a big field of view even  in 1991 the telescope may have seemed ordinary   but its camera was highly sophisticated and at  the time revolutionary the digital camera well   once you've got a picture that's in numbers you  can do all kinds of things with it mandello and   his team knew that sodium existed in the nebula  sodium also exists in the earth's atmosphere they were able to compare digital  photographs of both jupiter   and earth's atmospheres and bring  forth an image of the nebula   well that was very difficult to do if you  just had two photographs and pieces of paper   but now that we have these digital cameras we've  revolutionized the way that we can process images though io would be a fascinating  scientific and aesthetic destination   its hostile environment probably precludes that  even landing an unmanned probe would be difficult   among io's convulsing fissures but there's another  moon orbiting jupiter which may not only support   human exploration but possibly support its  own alien life forms europa is one of the   most fascinating and enigmatic objects in our  solar system really unlike any place else in the   solar system and for that matter unlike anything  on earth the surface features are such that there   are cracks in the surface there's model terrain  there's chaotic terrain and it looks like icebergs   in some areas we know europa is an alien moon  could it be home to alien life forms as well europa orbits 400 000 miles from jupiter's  surface about double the distance of io and   like its convulsive cousin it too  is molded by gravitational tides jupiter has the greatest effect its mass  like a persistent lover pulls the reluctant   moon toward its surface europa resists with its  own gravity and they form a kind of symbiosis   hundreds of thousands of miles above the gas  giant but it's not just jupiter tugging at europa   little io and larger cousin ganymede  bullet europa from different directions   it's the same orbital resonance that has such  a dramatic effect on io however the results   are far different on europa europa's surface is  cold minus 550 degrees fahrenheit in some places   yet there is heating and what rises to the surface  of europa is also what makes the moon so exciting   water this water actually a kind of glacial  ice is rising from an underground ocean and   oozing out onto the surface repaving  it as a zamboni does an ice rink   europa's ocean is thought to be shallow  only about 10 or 15 miles below the surface water was the cradle of life on earth  could the same be true on europa or   other moons icy satellite oceans could be  the most common habitat that exists in the   universe earth's might be relatively rare  but icy satellites are probably plentiful in february of 2007 the new horizon spacecraft  on its way to pluto and the outer reaches of   the solar system managed to fly close enough  to europa to send back some startling pictures   seen only as the sun is rising or setting behind  europa are enormous geological patterns that have   been dubbed crop circles they are very large if  you were to you know try to drive across one of   the circles you would very you know gently  go in and travel down to a location that's a   few hundred feet lower than the surface you came  up from and then rise back up the resemblance   of europa's crop circles to the mysterious  ones that dot the countryside here on earth   ends when you consider their size each one  is two to three thousand miles in diameter   they're too shallow and uniform to be impact  craters asteroids and comets come in different   sizes and shapes europa's crop circles are  remarkably similar geologically although   nothing has been proven it seems the great  mass of jupiter may once again be the culprit the speculation is that the icy covering  surrounding europa is not tethered to the   core of the moon rather it's floating above the  subsurface ocean like a spherical iceberg the   polar region may be somehow shaped by jupiter  and then over hundreds of thousands of years   slowly tugged toward the equator this forms a  line of small circle depressions dropping from the   polar region toward the equator if europa's ice  crust has similar structure to icebergs on earth   most of it would be under the ocean's surface  this has huge implications for future exploration   it means there has to be something like eight or  nine times that amount of ice underneath them to   allow that kind of a large-scale topography  to exist the iceberg theory lays to rest   the belief that europa's subsurface ocean can be  easily tapped through a thin crust radar mapping   and ultraviolet data will prove to be even more  important before a europa lander can make its way   down to the surface future explorers will have  to search out hot spots and places where this   mysterious ocean has weld up through the surface  and from there try to find a way to dip into it those explorers may choose instead to  set up a base of operations on ganymede   jupiter's largest moon as phobos might  serve martian exploration as a way station   ganymede might do the same for the jovian system larger than the planet mercury its gravity is  closer to that of earth's than any of jupiter's   moons and though it's an orbital resonance  with both io and europa it's far enough away   from jupiter to be less affected by the gas  giant's relentless tides and a ganymede you   could say park in some nice big crater and build  your domed protected region protected from the   charged particles in the jovian system and make  a pretty safe place to study not just ganymede   itself and its magnetic field and its interior  and its geology but the jupiter system as a whole   ganymede is the only moon in the solar  system with its own magnetic field   to have this distinction ganymede must  have sufficient mass and a hot inner   core its mass is obvious but where the  heat is coming from is a bit of a mystery ganymede is affected by both io and europa's tidal  forces but measurements on its orbit indicate   that it's round enough to avoid the  squashing and stretching that its   smaller cousins endure from jupiter the thought  is maybe something happened in ganymede's past   to change its orbit slightly and maybe its  eccentricity got kind of haywire for a little   while and generated a lot of heat within ganymede  caused the core to be hot we don't really know   what we do know is the new horizons recent flyby  of the jovian system gave us a tantalizing glimpse   at the wonders that await us on jupiter's alien  moons scientists look forward to the day a lander   touches down on one of these moons and starts to  uncover the secrets of these mysterious worlds another icy moon orbits the gas giant saturn  it's too small to hold onto its own atmosphere   but that doesn't stop it from sapping  the atmosphere of its parent planet   enceladus even though quite small is named  after a tribe of giants in greek mythology   like io and europa enceladus has an eccentric  orbit around its parent planet saturn the   tidal forces of saturn squeeze and knead  this tiny moon and create heat at its core but unlike io it doesn't regurgitate molten  material that coalesces into a massive gas cloud   water doesn't well up to the surface as it does on  icy europa nope enceladus actually spits plumes of   icy water into the atmosphere of saturn so we  don't call it a volcano it's more like a geyser   the water vapor is then in orbit around the little  tiny moon or because it's near saturn saturn's   gravity can pull it into the planet interested by  their work on the taurus of io michael mendillo   and his team at boston university began to  consider enceladus effect on saturn's atmosphere   and it turns out that water is a wonderful  catalyst to have the ions and electrons recombine   before cassini scientists relied on computer  models to determine atmospheric conditions   surrounding saturn they indicated that  saturn should have a very robust ionosphere   surprisingly cassini's data indicated  that saturn's ionosphere was only 10   of what computer models had predicted it seems  that the icy water ejected from enceladus   is neutralizing the charged  particles in saturn's ionosphere scientists had learned quite by accident the  effect water can have on earth's atmosphere in 1973 when nasa launched its skylab  workshop it launched its last gigantic   saturn v rocket the moon rocket and it had  never had a launch that allowed the space   vehicle to keep its engine burning as high  as the ionosphere well this gigantic engine   dumped a ton per second of water vapor which comes  out of a giant rocket motor into the ionosphere   and the ionosphere nearly vanished on that day  it blew a gaping hole in earth's ionosphere the   top layer of the atmosphere a hole that took  the sun's ionizing radiation 24 hours to repair   however on saturn where enceladus  continuously dumps six tons of   water per minute into its atmosphere the  long-term effects have been significant   there's no worry that enceladus will strip  away its parent planet's ionosphere completely   but this tiny moon only 300 miles in diameter has  gotten the attention of the scientific community   and saturn itself while we prepare probes  to phobos and europa and study data from   enceladus and io an entirely new set of moons  has literally just come into the picture before the 1990s most astronomers agreed that  there were only 34 moons in the solar system most   of those were regular moons like our own spherical  bodies that orbit their host planet in the same   direction it rotates but a handful of these  satellites were what's known as irregular moons   these freakish moons follow elongated  orbits their orbits are often tilted   and they rotate in the opposite  direction of their host planets   they look like flying potatoes or splinters  or misshapen lumps they've been hard to find   before now because they're very small  and they're also usually very dark the advent of digital photography  and the use of light-sensitive optics   changed the lunar terrain within a decade dr  brett gladman from the university of british   columbia discovered his first irregular  moon in 1997 at the palomar observatory   since then dr gladman has brought to light 17  previously hidden objects in the solar system   so you detect objects in the outer solar system  by observing the move relative to the background   stars and galaxies which are stationary so if you  take a picture of the sky and you wait an hour   and you take another picture of the sky none  of the stars in the galaxies will have moved   but distant objects in the outer solar system  will displace by a visible amount between the   two pictures and so by comparing the two pictures  you can see as we have here a moving target the object could be a comet or an asteroid or  if it orbits a planet in a retrograde fashion   a new irregular moon another important  distinction between regular moons and   their irregular counterparts irregular moons  are captured that is they formed independently   of their host planet and most likely were part of  the debris that originally formed our solar system phoebe the largest irregular moon orbiting  saturn is a classic example phoebe orbit saturn   very far out it has a very elliptical and very  inclined orbit it orbits in a retrograde direction voyager images suggested that this thing looks  like it could be an asteroid and so people thought   maybe it is a captured asteroid now we know  from cassini's it's a very water ice rich body   that pretty much rules out the asteroid  belt the thinking is is that phoebe could   very well have come from the kuiper belt way  out in the outer reaches of the solar system the kuiper belt is thought to be the  debris left over after the solar system   form it revolves around the  sun beyond the orbit of pluto   however another theory suggests  something altogether different it's much more likely that phoebe formed  in an independent orbit around the sun   and then was captured into orbit around saturn  whereas most of the other objects that formed near   saturn's distance were either recreated by saturn  or ejected from the solar system phoebe would   then be made of the planetary debris that was  floating around saturn at the time of its birth   and possibly it's made up of different material  than some of the irregular moons orbiting jupiter   if this is the case astro geologists  may be able to discern and compare   the different ingredients that  birth these two gas giants   three main theories currently exist as to how  phoebe and its other irregular counterparts   lost their independence two suggest the irregulars  were captured as the solar system was still   forming and the planets were still an  accreting blob of gas and debris the gas   drag theory is the most straightforward thick  gases were swirling around the accreting planet   when a comet asteroid or a shattered combination  of both passed through the gaseous mixture   we know that the giant planets built their regular  satellite systems in a large accretion disk around   each of the planets sort of like a mini little  solar system forming around each planet and the   gas and dust that was in that disk can also serve  in its outer regions as a source of friction where   passing planetesimals formed independently are  slowed down a little bit and captured into orbits   the second theory is really a variation on the  first it's sometimes called the pull down theory   here instead of an object being caught by  simply passing through the accreting gases   it is unsuspectingly pulled into the forming  planet's orbit by its growing gravitational pull   the gas drag and pull down theories of  capture work well for both jupiter and saturn   because their mixture of ingredients was massive  enough to slow down these passing objects   but what about the icy giants neptune and uranus   because of the extreme cold they formed much more  slowly and it's difficult to believe that their   icy accretion mixture contained enough mass  to snare a passing piece of the solar system yet both icy giants have their own irregular  moons hence a third theory three-body interaction   you discover that many of the objects are actually  more than one object they're usually two objects   often that because they're both more or less the  same size as the other in a binary relationship   instead of being a big object with with a small  object going in an orbit around it like this it's   two more or less similar size objects going around  a common orbit between the two of them is called   the very center a binary pair exists when two  objects of the same size are tight enough to the   berry center to prevent a third larger object  from splitting them apart but when one of the   binary pair is significantly larger than the other  the more massive third object has a greater chance   of separating them the smaller one will tend  to have the much bigger orbit swing out further   this brings the smaller object close  enough to the planet to be captured   while its partner is slung  out into an independent orbit one bizarre moon seems to defy classification   triton orbits neptune in a retrograde fashion  counter to neptune's rotation that would make   it an irregular moon except that it's  spherical and orbits close to the equator   with an almost perfectly round circumference  a classical description of a regular moon it also spews out mysterious icy plumes   with some indications that it once was  or possibly still is volcanically active before voyager 2 ventured into the outer solar  system neptune's moon triton was assumed to be   a geologically dead ball of rock about the size of  our own moon when voyager beamed back photographs   revealing a world with mountains fault lines  and fissures indicative of tectonic movement   as well as a surprisingly thick  atmosphere scientists were amazed   geologic forces usually associated with much  warmer and larger planets might be occurring   on a frozen moon slightly smaller than our own  voyager detected no active volcanoes in 1989   however like saturn's moon enceladus geyser is  periodically erupted from the planet's surface   what's really stunning about triton is not  just that it has some unique geological   processes occurring but the fact that they're  happening even though triton is in irregular mood   most large moons in the solar system  are regular satellites with the very   important exception of triton neptune's  largest moon which orbits the wrong way   so triton is thought to  have been a captured object   a captured moon that acts like a regular one how  did an object the size of triton slow down enough   not to either pass through neptune's atmosphere  or collide directly into the icy planet there's no sure bet but some  theories carry better odds   much like gamblers at the roulette wheel triton  and neptune played the odds and trusted to luck place your bets get lucky now in roulette  there are several ways to bet each one carries   different odds and like most games of chance  the longer the odds the greater the payoff there are at least three possible ways  triton could have been captured by neptune all three hypotheses are physically possible  but the first one the idea of gas drag is the   least likely simply because the period of time  which neptune had a disc of gas and dust which   could have captured a prototriton object it  was a very short period of time and so the   window opportunity was very small so that's like  betting on the green zero on the roulette table   more likely is the possibility that the  prototriton sun time in solar system history   crashed into a set of regular middle-sized icy  satellites and it was the collision which gave   us triton and that's like betting on the first  third of the numbers on the roulette table so   you have like a one in three chance of that taking  place your best bet is to bet on the even numbers   there you have a one and two chance of  things happening and and the best bet   for the capture of triton right now is this binary  capture hypothesis because there we know there are   probably thousands of objects that have existed  in the kuiper belt that would have the right   size and be partnered with another even larger  object and neptune could capture one of them no one knows for sure which number paid  in the early days of the solar system   when neptune captured triton however once triton  began orbiting neptune in an irregular fashion   it started obliterating anything that got in its  way neptune doesn't have a very regular system of   satellites it's thought that the capture of triton  disrupted what would have otherwise been a nice   regular system like the other large planets have  it's as if triton was angry at losing its freedom   and took it out on neptune's other hapless moons  but where did this headstrong moon come from data from voyager 2 indicates the  triton's density nearly matches pluto's   this suggests a kinship that no other regular moon  can claim it's suspected that pluto and triton   are both objects that originated in the kuiper  belt the outer solar system consisted of these   large objects going every which way essentially  some of them formed the giant planets themselves   and some of them were tossed out further  where they sit today in the kuiper belt   collisions accretions and even captures have  diminished what was once a major thoroughfare   of planetary building materials early in solar  system history the kuiper belt had far more   larger objects it may have once had a cumulative  mass of 50 earths whereas the current hybrid belt   mass is much less than one earth what's left of  the kuiper belt is as old as the solar system   itself the material that makes up the binary  objects shards of collisions and even some alien   moons hasn't changed in over four billion years  it's amazing how really different all the moons   of the outer solar system are when i first got  interested in astronomy as a kid in the 1960s we   hadn't seen any of these moons they were little  dots in your telescope and so we had no idea   how radically different they could be i think the  most shocking thing was how much variety there   is in the solar system i think that blew me and  everybody else away who lived through that period as we travel back home from the  frigid outskirts of our solar system   awed by the vastness of the universe  and the majesty of the planets   it's worth it to pause and take notice of the  small worlds in the shadows those alien moods that   were once considered afterthoughts hold mysteries  just waiting for human curiosity to solve you

Channel: HISTORY

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Id: bn64kiu_zR4

Length: 44min 27sec (2667 seconds)

Published: Mon Dec 07 2020