June 16th, 2010

Comets have held a high fascination for all levels of astronomers all the way back to the first civilizations that provided a recorded history through writing or picture.  Ancient civilizations first mention the presence of comets associated with dark omens of death or destruction, and it was not until 350 BC when Aristotle offered his first book, “Meteorology,” and a basic scientific explanation of comets.  Within the texts he stated that comets were a phenomenon of the upper atmosphere, where hot, dry exhalations gathered and occasionally burst into flame.  Late in the seventeenth century Sir Iisac Newton added that comets were compact and durable solid bodies moving in oblique orbits, and their tails as thin streams of vapor emitted by their nuclei ignited or heated by the sun.  While today’s scientists have largely confirmed the hypothesis of these former scholars, much about comets is still largely unknown.

What is known about comets is that they follow a predetermined path, and their inner core is comprised of rock and forms of ice.  What exactly determines a comet’s course still remains largely a mystery; some pass by the Earth every few years while others may not return for hundreds of thousands of years or more.  Recent data from the Stardust spacecraft, which returned a core sample from Comet Wild 2 in 2004, verified that the interior makeup of comets were of crystaline form, which could only be produced by the intense heat of a star or another cosmic event.  The tail associated with comets is actually the visibility of gasses from within frozen ice particles when it passes close to our Sun, and once these gases are completely expelled the comet is simply a fast moving hunk of rock that closely resembles an asteroid.  It is also noted that the gravatitional pull of larger planets can alter a comet’s flight course, and even a differential of a few feet can equate to a massive trajectory change over the life of a comet.

Comets are classified by how often they pass into our solar system.  Short period comets pass by the Earth every two hundred years or less, and they are further divided into two subcatagories.  Jupiter comets are seen every twenty years or less while those belonging to the Halley family are spotted every twenty to two hundred years.  Long period comets are those that appear more than once within their lifetimes outside the two hundred year mark, and Single Appirition comets are those that travel an unknown course that will not bring them back into our solar system.  One of the problems with classifying a comet is that their orbits can last thousands or even millions of years, and the odds of not colliding with another object and being destroyed within that time period is infintisimal. 

Of course, another problem for astrologers is the formation of new comets from nearby celestial objects.  The Kuiper Belt, which resides beyond Neptune, is thought to create many short period comets while the Oort Cloud just outside our solar system is believed to be the creator of long period comets.  Since it is near impossible to predict how comets are formed or how many of them actually enter our various means of vision in space, it is difficult to make a reasonable hypothesis of their overall travel patterns.  As technology advances tracking long period comets will become a more resaonalbe expectation and hopefully science will finally be able to provide a definitive answer regarding their true origins.

Artificial Satellites

June 16th, 2010

By definition a satellite is any object placed in orbit due to a gravitational pull of a larger entity.  Since moons and some asteroids would fall under this description, the term artificial satellite was invented to describe man-made objects in space.  Sputnik 1 was the first of its kind and launched by Russia in 1957, primarily to identify proper the proper launch coordinates required for later missions.  Two months later Sputnik 2 successfully sent a dog named Lakia into space, and by this time the space race was fully ignited around the globe.  Since that time thousands of other launches have occurred by over fifty separate countries.  Only a few hundred of those artificial satellites are still operational, and within our orbit hundreds of partially damaged satellites continue to rotate around our planet as if they were inside a type of technological graveyard.  If aliens have in fact visited our planet as so many people have attested over time, we must be viewed as the hillbillies of the universe since our space garbage has been left to idly drift for everyone to see.

There are countless uses for artificial satellites and they are relied on at all levels of civil and public government.  Many will associate satellites for spying purposes, but they are also used for communication, global navigation, weather reporting, and other various types of research.  From internet access and cellular telephones to GPS devices and television, satellites empower modern living as much as any twentieth century invention.

As useful as the technology appears, satellites are unfortunately a common object of attack as well.  Militant groups will often hack into satellite transmissions in order to broadcast their own political views or to obtain classified secrets of another world nation.  While the technology behind a satellite may appear advanced, it is no more than a computer designed to accept a variety of commands.  Since communication requires a signal to be sent to and from Earth, it is relatively simple to block, intercept, or even take control of that transmission for personal gain.  More sophisticated monitoring equipment has become available within the past decade to assist satellite operators to avoid these issues and quickly track the parties responsible, but the problem is far from being solved.

In astronomy, satellites have been used to view distant objects that would otherwise be inaccessible.  The unmanned spacecrafts Pioneer and Voyager have been sent to the outer regions of our solar system and provided detailed analysis of Saturn, Uranus, Jupiter, and Neptune.  At a total one way distance in excess of over four billion miles, these epic journeys have provided countless data for scientists on Earth and have helped explain the makeup of our solar system.  A few examples of Voyager’s many scientific contributions are the discovery of water on one of Jupiter’s moons (Europa), erupting volcanoes on another (Lo), and a massive storm on Neptune that was previously undiscovered (the Great Dark Spot).  Many of the highest resolution pictures of the outer planets have been provided by one of these two satellites, and without them our solar system would still be largely considered a mystery.

The Hubble Telescope

June 16th, 2010

The Hubble Space Telescope, designed by NASA and the European Space agency, has been capturing pictures of stunning celestial objects for the past two decades.  The concept of launching a telescope into orbit can not be fully accredited to our generation, however, since it was first proposed as early as 1923.  The Hubble project began in the late 1970’s with a proposed launch date of around 1983, but the Challenger incident and technical delays postponed the project’s completion until April of 1990.  Even then it was discovered that the main mirror had been attached incorrectly and the full capabilities of Hubble were not achieved until 1993.  Although not technically the first distant viewer in space, the Hubble Telescope is easily one of the largest and most versatile instruments of its kind and has provided more scientific data relating to astronomy than every other method used up until 1990. 

The idea of a telescope in space sounded good in theory; a good bit of sunlight reflects from the Earth’s surface and to gain a view without that interference was thought to be extremely beneficial.  Not only would clearer images be possible with such an instrument, but astronomers would also be able to view far outside of our solar system and gain a much more thorough knowledge of the universe.  Hubble’s Ultra Deep Field is the most technologically advanced system ever created and provides the most detailed visible light images ever witnessed.  By studying objects far distant from our own solar system scientists gain a more thorough understanding of how the universe was formed and at the rate it expands.

Not only has the Hubble Telescope validated or proven wrong countless hypothetical theories proposed by astronomers, but its discoveries have led to many other questions while trying to explain some of its discoveries.  Before the Hubble Telescope black holes were entirely theoretical, dark energy was not even expected,  and countless celestial bodies within our own solar system were not even known to exist.  Over eight thousand papers have been published within scientific journals with countless other observations reserved for lectures and background data. 

On top of launching Hubble in 1990 and the subsequent adjustment of the main mirror, several other modifiactions and adjustments have occurred over the years.  The last such mission was completed by the crew of Space Shuttle Atlantis in May of 2009.  Over the course of five spacewalks, Wide Field Camera 3 and the Cosmic Origins Spectrograph were installed to provide the Hubble Telescope even more viewing power.  The new systems allows astronomers a wider angle to study and up to thirty-five times more detailed viewing in ultraviolet and visible spectral ranges.  Although Hubble was originally designed to be returned to Earth for regular maintenance procedures, the retirement of the shuttle fleet make it an impossible task.  All future repairs and additions will have to be conducted from space.

Perhaps the best news about the Hubble Space Telescope is that anyone can gain access to its technology.  There is quite a waiting list and there is always more demand than actual usage time available, but all requests are considered based on the celestial object requested for viewing and the potential application for the research being conducted.  Amateur astronomers are not granted as much time now as they have been granted in previous years but the launch of Hubble’s successor, the James Webb Space Telescope, in 2014 should make it more readily available.


June 16th, 2010

Neptune is the furthest planet from our Sun and named after the Roman God of the sea.  As far as planetary bodies are concerned it is the fourth largest planet in diameter and the third largest in mass.  An interesting notation is that Neptune was the first planet ever discovered by mathematical calculation derived by French astronomer Alexis Bouvard. From visual studies he determined that there was an interruption in Uranus’s orbit that could only be caused by a gravitational field large enough to be from a separate planet, and by deducting the relative interruption in orbit he hypothesized where an additional planet should have been located within our solar system.  As director of the Paris Observatory, Bouvard vigilantly searched for the spherical object he insisted was there but he was never able to substantiate this theory.  The discovery of Neptune and its largest moon Triton was not made until after his death, but since it was located due to his mathematical research fellow scientists John Couch Adams and Urbain Le Verrier granted him the formal credit for the discovery.

Composition wise, Neptune is very similar to Uranus in that it is comprised of mostly ices formed from ammonia, methane, and water.  The methane present within its outmost regions grants the planet its blue coloration when seen from afar, and like Uranus it has extremely cold surface temperatures reaching negative three hundred degrees Ferinheight.  Since Neptune is one and a half times further from the Sun and receives only forty percent as much sunlight, it is known that the planet must exert some form of internal heat to make up for the difference.  Neptune has been found to generate almost two and a half times more energy than it absorbs from sunlight, which in itself is quite a mystery that scientists can not fully explain.

Neptune also possesses some of the most extreme weather found anywhere within the solar system, which is a bit puzzling to scientists that the furthest planet from the Sun would expel among the highest levels of energy.  In 1989 scientists discovered an anti cyclonic storm system in the Southern Hemisphere that had close similarities to the Great Red Spot of Jupiter; then in 1994 the planet was viewed with the assistance of the Hubble Telescope and a similar storm movement was spotted within the Northern Hemisphere.  Surface winds have been verified blowing as strong as thirteen hundred miles per hour, which is by far the strongest found anywhere within our solar system. 

Neptune is never visible to the naked eye due to the extreme distance from Earth and its relatively low brightness measuring between 7.7 and 8.0, but through moderately powered telescopes partial ring formations and several moons have been discovered.  The largest moon, Triton, is completely unique from previous discoveries because it rotates against Neptune’s orbit.  Because of its unnatural rotation around Neptune it could not have formed within the region, and scientists hypothesize that it was actually a dwarf planet originating from the nearby Kuiper belt.    Measured in 1989, Triton was considered the coldest object within the solar system; and because of its unnatural rotation it will eventually be destroyed by Neptune’s gravitational pull and tidal surges.


June 16th, 2010

Uranus is the second furthest planet from the Sun and is the third largest within our solar system at fourteen and a half times larger than the Earth.  As with the other gas giants it shares its distinction with, the planet’s surface is made up of rock and ice with large traces of helium and hydrogen present.  With surface temperatures reaching negative three hundred seventy-one degrees Ferinheight, Uranus is by far the coldest planet within our solar system.  Uranus can be spotted with the naked eye within darkened skies, but its glow is much fainter than other recognizable planets.  The surface is covered in a thick cloud structure saturated with water at lower levels and methane within the uppermost layer.  High winds are also experienced on the planet, which are thought to reach speeds in excess of five hundred and sixty miles per hour.

A unique feature of Uranus is the configuration of its axis, which is almost completely sideways and typically where the equator would be on other planets.  Like Saturn, Uranus does have several rings that orbit around the equator; but due to its unique positioning they instead appear above and below the target, much like the appearance of a tire on a wheel.  There are thirteen total rings in all, and from what astronomers can tell they did not form with Uranus because of their relatively low density.  A collision with the planet and one of the moons is one of the most likely scenarios for their formation.

Despite Uranus’s large size, its density is higher than only Saturn’s.  This tells scientists that a rocky core is likely, with ice contained within the mantle and an outer region made up of gaseous forms of hydrogen and helium.  Because a large portion of its interior is composed of ice or various liquids, both Neptune and Uranus are often referred to as ice giants instead of gas giants like Saturn and Jupiter.  There are those within the scientific community, however, that do not agree with these assumptions and feel the separate naming classifications are premature since other theories have been presented that could possibly account for the low density.

Another interesting feature of Uranus is its 27 moons with names contrived from characters within the works of Shakespeare and Alexander Pope, The five main satellites are Miranda, Ariel, Umbriel, Titania, and Oberon; and each of them are expected to be as much as fifty percent ice combined with rock.  From what little evidence there is available about this region within our solar system, it appears that each of these natural satellites were formed at different times.  Ariel, for example, has a very smooth surface with very few craters while Umbriel and Oberon are covered with multiple large impact zones.

As previously mentioned, much of how Uranus formed and its current makeup is still completely unkown due to a lack of concrete data.  The only time Uranus has been visited was by NASA’s Voyager Two spacecraft in January of 1986.  Although much of the planet, its rings, the atmosphere, and the five largest moons were partially mapped during that fly-by there is still much to be discovered.  There is currenty no return mission scheduled, so it is unknown when more information may become available to explain several of Uranus’s more perplexing features.


June 16th, 2010

Saturn, a large gas giant and the sixth planet from the Sun, is mainly associated with the many rings that encompass the planet.  It is the second largest planet within the solar system, smaller than only Jupiter, and shares many of the same physical properties.  Since this planet is so extremely far from the Sun, it completes one rotation every twenty-nine and a half years and makes a full rotation on its axis about every thirty days.  Due to the enormous pressure placed on Saturn it is classified as an oblate spheroid, meaning it bulges around the equator and is flattened near the poles.  Very little was actually known about this planet when compared to others within our solar system; however, additional research within the past decade has shared several additional features of Saturn.

The rings that encompass Saturn may well be the most viewed celestial object within our solar system due to their natural beauty and questionable origins.  Many scientists speculate that the ring formations were formed due to a collision between Saturn and one of its moons, while others hypothesize that they are leftover material from the planet’s creation.  The rings are mainly composed of water ice with traces of amorphous carbon, and they extend upwards of seventy five thousand miles from Saturn’s equator.  The size of the debris within this planet’s rings vary from tiny dust particles to the relative size of a modern vehicle.

The planet itself is believed to be a rocky surface surrounded by gases of hydrogen and helium, much like Jupiter is.  The extremely hot core of Saturn reaches temperatures of over twenty-one thousand degrees ferinheight, and the planet expells two and a half times more energy than it absorbs from the Sun.  Outside the core is speculated to be liquid hydrogen, and it must undergo some type of secondary reaction in order to produce such extreme temperatures.  Although this process is not completely understood by scientists it could possibly be explained by helium rising up from the center of the planet and causing friction as it passes the lighter hydrogen gasses. 

Another extrodinary study of the planet Saturn is its many moons that orbit around the planet.  Sixty-one are known to exist in all, although over three quarters of them are less than 50 km in diameter.  Each of them are named after a Greek Titan, with the name Titan reserved for the largest natural satellite.  Saturn’s second largest moon, Rhea, is believed to have its own ring system which was previously unheard of.  Since the three rings are located near the equator, meteorite impacts could in fact explain their existance. 

Saturn’s largest moon, Titan, and it is an escpecially interesting area of study due to its similarities to the Earth.  It is the only known natural satellite of its kind with a dense atmosphere, comprised of over 98% nitrogen.  An additional unique feature is the presence of hydrocarbon lakes covering Titan’s poles, this is not present anywhere else within our solar system except on Earth.  Less than one percent of the Sun’s rays penetrate the atmosphere, making it around negative two hundred ninety degrees ferinheight.  The moon also produces high quantities of Methane gas, which burns up in the atmosphere but is regenerated near the polar caps.  Due to Titan’s gravity human visitors would be able to fly across its surface, although that may not be a realistic goal to expect within our lifetimes.


June 16th, 2010

Jupiter has the distinction of being the largest planet within our solar system; it is so large that its size is two and a half times larger than every other planet in the solar system combined.  A disproportional overall mass leads scientists to believe that Jupiter could not contain any additional volume without actually shrinking in overall size, translating into theories that the massive planet has reached the absolute maximum diameter for its age and category.  Close inspection with even an amateur’s telescope shows that the planet actually bulges around the equator due to its mass and extreme magnetic properties.  Some astronomers further contemplate that Jupiter may have actually been a failed star, but since the formation patterns of multiple star systems is largely unknown it is considered speculation at best.  This theory is further supported by the fact that Jupiter radiates more heat than what is absorbed by the sun, and scientific data shows that the planet was almost twice as large and much hotter in its early stages of formation.

Much about Jupiter is still a mystery though, due to the heavy ammonium cloud cover that surrounds the planet.  The cloud bands that encompass the planet rotate is alternating patterns parallel to different latitudes across the planet, and these formations vary both in size and in color from year to year.  The overall density of these cloud bands is believed to stretch over thirty-one miles towards the planet’s surface and is made up of two individual layers.  The inner clouds have been captured discharging lightning up to a thousand times ore powerful than what we experience on Earth; this is significant because the presence of water vapor in clouds is necessary for lighting to occur.

Other types of massive storm systems have also been viewed within these bands, the most popular of them being the Giant Red Spot.  First discovered in 1831, this massive tornado like storm spins counter-clockwise twenty-two degrees south of Jupiter’s equator and has been in perpetual motion ever since (a separate claim suggests that the Giant Red Spot may have been around in 1665 but there is not enough data available to support or refute the statement).  The storm’s total mass is larger than Mercury, Venus, Earth, and Mars combined and it extends seven miles beyond the highest cloud barrier.  It has encircled the entire planet several times at varying speeds, and very little is known what causes the storm to speed up or slow down.  Consequently, in 2000 three smaller storms that were encircling the planet merged into one and are now considered Red Spot Junior, although their overall mass is still much smaller than the original.

Another interesting and unique feature of Jupiter is its moons, all sixty-three of them.  While the vast majority are only a few miles in diameter they still bear the classification for lack of an updated term There are also several within the larger moons that are both active and interesting areas of study.  Europa, for example, is believed to have liquid water beneath its surface that remains in constant motion as solid ice above it is drawn by Saturn’s magnetic pull.  Some scientists even believe that Europa could support life since several key elements are present, but research techniques are still too primitive in order to tell for certain.   Because of the strong magnetosphere, which is estimated fourteen times stronger than Earth’s, these objects are believed to have been influenced and shaped by Jupiter’s presence, much like the formation of the solar system and many asteroid belts within it.


June 16th, 2010

The planet Mars has always been a fascinating subject of interest among those who did not closely follow astronomy, especially just before the turn of the 20th century when the idea of Martians inhabiting the nearby planet were possibly sending communications through space as a warning to Earth.  Giovanni Virginio Schiaparelli, an Italian astronomer who classified much of the glowing red planet during his studies in the late 1800’s named a dense network of structures on the planet “canali,” which literally translates to channels.  A mistake in the translation led Americans to think he called them canals, which is essentially thought of as a man made sturcture.  Around the same time period, Austrian born inventor Nikola Tesla thought he picked up repetitive radio waves that could have possibly originated from the planet, and Mars Fever officially swept the nation.  Although more modern technological studies have corrected these unfounded beliefs, scientists are still unsure of whether living organisms once inhabited Mars.  Recent studies show the building blocks for intelligent life were once in place on the planet, and although the core appears largely dormant many of those properties are still in place.

Scientists can say, however, with a fair amount of certianty that there is no life on Mars at the present time, because essentally the planet has become incative and is considered dead.  While there is signifigant evidence to show that liquid water, thought to be the catalyst of life, was once abundant across much of Mar’s surface, the lack of a proper atmosphere in its current state prevents signifigant accumulations from forming and remaining on the surface.  The tectonic plates found beneath the surface of Mars are no longer active; neither are any of the volcanos that scatter across its surface.  The polar caps on the planet contain massive amounts of dry ice, and in 2007 NASA scientists determined if melted it would cover the entire planet in thirty-six feet of water.  The presence of sediments associated with water in recently explored regions of Mars could mean that there is still traces of flowing liquid on the planet’s surface, but further research would be required to either confirm or deny that theory.

In terms of size, Mars is about 1/6th  the size of the Earth, meaning the surface area is nearly equivelant to Earth’s dry land.  Much of the surface is covered with fine grains of iron oxide, commonly referred to as rust across our planet; silica-rich asalt is also present in large uantities.  Initial studies of the soil found traces of elements required in order for plants to grow but later findings have shown the presence of salt, which would inhibit such growth.  While our rotational orbits around each planet’s respective axis is similar, Mars has a longer rotation around the Sun due to its relative distance. 

Mars also posesses two separate moons, but both are thought instead to actually be asteriods.  The term moon is applied in this case only because of a lack of a better term; since they both orbit Mars they qualify by defenition.  The smaller of the two moons, Phobos, is slowly altering its orbit and expected to eventually collide with Mars or to break away from the gravitational pull completely, sending it on an unknown course across our solar system.  Both moons orbit dangerously close to the planet, their very existance and how they became associated with Mars is somewhat of a mystery to scientists.  Mars is near an asteriod belt and has suffered thousands of direct hits throughout history, so the asteriod theory is currently the most popular explaination.


June 16th, 2010

The Earth has the distinction of being the third planet from the Sun, but may be better known as the only planet ever discovered that supports life on its surface.  Scientists date the planet’s age at around four and a half billion years old, and the formation resulted from the same solar nebula that collapsed and allowed the creation of our Sun.  At that time our beloved planet would have been almost entirely molten, and it may have taken as much as twenty million years for water to form on the surface and cool it into a solid mass.  The first signs of life began to crop up about a billion years after the Earth’s formation, and the greatest mystery of the universe is why our planet accomplished this feat when thousands of other studied planets have not. 

While this question may never be fully answered within our lifetimes; the answer, or some form of it, must lie within the Earth itself.  Of the countless planets that have been studied by satellites and telescopes throughout the history of our civilizations, our planet is the only known location of water in liquid form.  While it exists as a gaseous vapor or solid ice in comets, meteors, and other planets, the relative location of the Earth from the Sun is what has allowed water to become present and initialize the presence for millions of individual life forms that have inhabited our planet since its creation. 

Our ozone layer and Earth’s magnetic field are also responsible for much of our survival, since combined they effectively block out over 91% of the Sun’s ultraviolet rays and help deter serious collisions with our planet.  These factors were not present when the Earth was initially formed since evidence exists that an object the size of Mars collided with our planet, and the debris from the glancing blow almost was eventually what led to the formation of our moon.  Since the moon’s presence also provides stimuli for hundreds of thousands of organisms within our oceans and on land, it may actually fit somewhere within the equation of our origins.

Another unique feature of the Earth is our tectonic plates, which are massive solid structures that rest atop our planet’s mantle.  Guided by the convection that occurs deep beneath the surface, tectonic plates move freely across the globe and renew the Earth’s surface with their steady movement.  They are thought to have formed most of the mountainous regions above and below sea level and could in fact hold clues as to the presence of our oceans and their salinity. 

While there are still countless mysteries regarding the Earth’s formation and how we fit in to the universe, scientists almost unanimously agree that the majority of the answers reside right here within our planet.  If other intelligent species truly inhabit the landscapes of distant planets beyond our atmosphere, then there must be some common denominator to explain it.  By studying the Earth and understanding why we are here may in fact someday provide that very answer.


June 16th, 2010

The planet Venus derives its name from ancient Babylonians around 1600 BC associating it with the Goddess of love, and it is the only planet within our solar system named after a female figure.  The original cultures to witness this planet actually believed it was two separate objects; one seen around sunrise and another at sunset referred to as the Morning and Evening Stars.  Since Venus appearance wise is very similar to the Earth in size and shape it is often referred to as our sister planet, even though until this past decade very little was known about Venus or its surface.  A thick layer of sulfuric clouds reside within Venus’s upper atmosphere that light cannot penetrate, making visibility and research from abroad near impossible.  It is thought to be the densest atmosphere of all the planets within our solar system, and therefore possibly the least likely place for humanity to colonize.  It is also one of the brightest objects within the sky around sunrise and sunset each day, and countless reports across the world have mistaken Venus for a UFO or other rare celestial object.

Whether or not we can live on Venus is almost inconsequential to scientists though, because our solar twin still holds many answers that could possibly further explain the Earth’s future.  Although the planet is currently very different from our own, research indicates that at its formation Venus had several striking similarities to our home.  Water was once abundantly present across the planet, and the planet’s core is believed to contain a crust and a mantle that is partially liquid just like our own.  Venus’s current surface is made up of mountainous regions and valleys commonly found on rocky planets, but what was unexpected was the sheer number of flat, volcanic areas that have dominated the planet’s geographical makeup.  Venus’s thick atmosphere provides ample protection from meteors and asteroids, and experts believe that even giant planetary strikes are broken down into small enough pieces to avoid the serious scarring we see from impacts on other planets.  For every question that has been answered regarding Venus two more have been presented, making this planet a popular conversation piece among astronomers.  Several future missions to study the planet in further detail have already been planned by the United States, Russia, and Japan.

What is actually known about Venus makes for an interesting astrological study.  The planet completes a full orbit around the Sun every two hundred twenty-four days in almost a perfect circular pattern, which is approximately one third faster than the Earth’s trajectory.  It rotates once on its axis every two hundred forty-three days, which by practical terms means a day on Venus last longer than what we would define as a year.  The planet also appears to be much younger than the Earth, and scientists predict its age to be around 1 billion years old.  Why this planet formed over three billion years after Earth may indeed be the greatest mystery in itself, and the answer may provide clues as to why it turned out so very different from our own planet.