What Are Astronomical Artifacts?

In a nutshell, Astronomical Artifacts are objects erected or constructed by ancient civilizations that were used in conjunction with the visible celestial bodies that orbited the planet outside the Earth's atmosphere. Such objects as the stone circles at Nabta Playa in Egypt, as well as the pyramids and the construction of Stonehenge are all considered ancient Astronomical Artifacts. The civilizations that built these monuments often used these objects for both religious ceremonies and astronomical purposes. There are some theorists that claim the enormous statues on Easter Island also had astronomical symbolism. Theories and debates over how these objects were created and what they were intended to be used for range from the simple to the extreme. Some believe these monuments were erected by civilizations that were far superior intelligently for their time in history, while others believe they provide evidence of extra-terrestrial visitation and interference with human history.
The pyramids of ancient Egypt were constructed in alignment with the pole star and the Great Temple was built in alignment with the rising of the midwinter sun. These monuments assisted the Egyptians with determining different natural occurrences, such as the annual flooding of the Nile river basin. They also assisted the temple astronomers with following the different phases, conjunctions and rising of such celestial bodies as stars, planets and their natural satellites, or moons.
Stonehenge is another Astronomical Artifact. This monument has a much storied history dating all the way back to 8,000 B.C. There is significant evidence suggesting that at some of its earliest moments in history it was used as a burial facility. Archaeologists have uncovered several grave sites around the area where the stones are actually erected. They have also found evidence to suggest that several different generations of people used the area for different purposes. Religious rituals and ceremonies were also conducted at this historical site, and several theories exist as to how the stones were actually aligned and what they were intended for, most of which surround religious theories as well as astronomical symbolism in the formation of reading and charting stars and planets.
The Antikythera Mechanism was discovered in 1900 by sponge divers off the coast of the Greek Island Antikythera when they came across an ancient Roman-era shipwreck. This bronze device is about the size of a shoebox and baffled scientists and archaeologists for years. It wasn't until very recently that a British researcher, exploring the evidence and inscriptions on the mechanism, was able to identify and establish it as the oldest surviving astronomical computer. It has 30 wheels and dials that are covered in astronomical inscriptions and texts which have been used to decipher and translate ancient Greek languages that haven't been seen or used in over 2,000 years.
One of the oldest educated and intelligent civilizations in the history of humans is the Sumerians who were also steeped in the knowledge of Astronomy for their period in time. The Mul Apin tablet is an artifact that dates back to the time of the Sumerians. This device contained astronomical information, as well as significant dates for the rising and setting of specific constellations. It also included a record of omens that were predicted by the reading and mapping of celestial objects.

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What Is Astronomy?

Astronomy is the natural science of studying objects and phenomena located outside the Earth's atmosphere. Stars, planets, comets, asteroids, meteors, nebulae as well as other galaxies are studied by Astronomers, both professional and amateur alike, that use a wide range of instruments and technology to make determinations regarding the density and chemical composition of these objects, as well as their relative distance from Earth. Astronomy is without a doubt one the oldest sciences known to man. Our earliest ancestors were fascinated with the celestial objects that were visible in the night sky, so much so that they developed navigational skills that used star locations as a means to guide them from one place to another.
Astronomy shouldn't be confused with Astrology, although they both have similar origins, they involve completely different theories and beliefs. Astrology deals with the belief that the positions of celestial objects has a direct impact on human affairs, whereas Astronomy studies the evolution and formation of the entire universe, namely the birth of a star or planet, how it was created, what the chemical composition of the object is, as well as the orbital motion it maintains in conjunction with other objects in the same galaxy.
Ancient early civilizations that began studying Astronomy were only able to observe and predict the motions of celestial objects that they could see with the unaided human eye. This process was normally carried out from positions considered advantageous, such as the top of a mountain or the highest building. Since the telescope had yet to be invented some of these civilizations actually erected enormous observatories that they used not only for astronomical purposes but for ceremonies as well. The monuments they erected were also used to determine the upcoming changes in the seasons, indicating at what times of the year crops should be planted or prepare to be harvested.
For the most part early Astronomers were only concerned with the mapping of stars and planets. It wasn't until the construction of astronomical observatories that ideas regarding the evolution of the universe were first postulated and explored. Some of the earliest beliefs revolved around the theory that the Earth was at the center of the galaxy and that all of the stars and planets were placed in orbit around it. This theory is referred to as the Ptolemaic system, which depicts a geocentric model of the universe using the Earth as the center point.
Astronomy in the modern age involves the study of unique objects such as quasars, pulsars, neutron stars and the infamous black hole. The advancements in technology we have at our fingertips today allows us the opportunity to explore the cosmos like never before, and with each consecutive step we get closer and closer to realizing how life as we know it began centuries and centuries ago. Astronomy continues to play a vital role in the search for more answers regarding who we are and where we came from. Astronomers often relate that the study of celestial objects is akin to traveling back in time. The further back we are able to go the better we will understand how the planets and stars were formed and how life came to be on this tiny little rock we call Earth.

How Are Stars Formed?

Star formation is a unique branch of Astronomy that deals with studying Interstellar mediums and GMC's or Giant Molecular Clouds to better understand how dense regions within these clouds collapse into spheres or orbs of plasma and gases and form stars, young stellar objects and new planets. Areas with higher density form clouds or nebulae. It is from these regions that stars are born or formed. These cloud structures are also referred to as 'Stellar Nurseries' since they are considered the primary source of all new stars, celestial objects and planets. These celestial objects are then ejected from the nebulae and form galaxies. These galaxies are either spiral or elliptical in nature and can even collide with one another changing the entire dynamic of both galaxies involved in the event.
Our galaxy which is known as the Milky Way has roughly 6,000 such molecular clouds, the closest nebula to our Sun which is capable of producing new stars and planets is the Orion nebula. This region of our galaxy is approximately 1,300 light years away from the Sun itself. There are smaller, or lower mass stars being formed in a region known as the Ophiuchi cloud complex which is significantly closer, ranging roughly 400-450 light years away. Bok globules, which were named after Astronomer Bart Bok, are also regions of space from which stars can be create. These globules form during the collapse of molecular clouds and appear as opaque cloud formations which are considered more compact star producing structures.
The nebulae where stars are formed consist of different molecular clouds. If one of these molecular clouds becomes so massive that the gas pressure cannot support it, the molecular cloud undergoes gravitational collapse, which results in the fragmentation of the molecular cloud. These smaller pieces and fragments condense into rotating spheres of gas known as stellar embryos.
There are several events that can result in the compression of a molecular cloud causing its gravitational collapse and subsequent fragmentation in a process referred to as triggered star formation. The collision of molecular clouds, and explosion from a close enough supernova, as well as galactic collisions can all result in the gravitational collapse of one of these molecular cloud masses. The collision of two galaxies usually results in the massive formation of multiple stars, also called starbursts, as the molecular gas clouds from each galaxy are compressed and tossed around by tidal forces created within each separate galaxy.
Stars are generally categorized as either being low mass or high mass formations which are created by slightly different occurrences. The theory of low mass star creation is supported by observational evidence, whereas the theory of massive star formation is still being studied and observed to obtain and compile significant data which will serve to better educate Astronomers on the difference between the two different creation methods. Smaller or lower mass stars are thought to be created when the cloud collapses, releasing gas and dust which rotates in what is called an accretion disk around a centrally located protostar. The amount of material in the accretion disk ultimately determines the overall size of the star when it is completed.

What Are Comets?

 

Comets are a very unique celestial object similar yet drastically different than any other objects or bodies that appear in space. They consist of a nucleus containing both ice and dust, and when they approach a sun class star they emit a tail of gas and dust particles that streak away from the object they are headed towards or near. They might also provide the presence of a coma, which is a thin, temporary atmosphere that is generated by the prevailing effects of both solar radiation and solar wind. The appearance of comets dates back several thousands, if not millions of years and have often been associated with bad omens and impending doom and destruction.
Like all other celestial bodies, comets have an orbital cycle they adhere to which can encompass a wide range of visible periods, which means that they are only visible from Earth and the naked eye during specific periods when they pass close enough to our planet or our sun. The orbital cycle of comets can range from a few years to hundreds of thousands of years. Comets with a shorter orbital cycle are thought to originate in the Kuiper Belt which lies outside and beyond the orbit of Neptune, while comets with exaggerated or longer orbital cycles are thought to originate from further out in the solar system in what has been referred to as the Oort cloud configuration, a hypothesized celestial object that is said to encompass icy bodies which plunge towards our Sun due in part to gravitational forces from some of our solar systems bigger planets.
Hyperbolic comets are celestial objects that make a single pass through our inner solar system before being hurled out into interstellar space along an escape trajectory. Spiral and elliptical trajectories like those of the planets in our solar system revolve around a central object such as our sun while maintaining a specified distance at different points along the path of orbit. A hyperbolic or escape trajectory does not follow the same laws of space/time travel. The orbital path of celestial objects such as are associated with comets allow for the object to pass significantly closer to the central gravitational field of the solar system before using that force to eject it on a path that will hurl the object out into the deepest regions of that solar system at which point it begins the journey back towards the central figure or sun.
As recently as January of 2011 there were 4,185 known comets within our solar system. On average comets are visible once a year, some are rather small and cannot be seen with the naked eye, while others that are referred to as Great Comets are extremely visible and awe inspiring episodes that light up the night sky. Comets are defined by the appearance of a coma and/or a tail which classifies them separately from asteroids; however small extinct comets can sometimes be confused with an asteroid. The origin of asteroids is thought to be inside the orbit of Jupiter whereas the origin of comets is associated with the outer reaches of the solar system our planet is a part of.
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The Andromeda Galaxy - The Nearest Member Of Our Cosmic Sisterhood

As darkness falls and the shades are drawn I sit here in the fading light on the 100th anniversary of Irish author Bram Stoker's death.
A clap of thunder. Hail bursts from lowering thunder clouds.
A shadow flits across the window... is it someone hurrying home to escape the foul weather? Maybe Stoker's creation still stalks the landscape?
Just as the Dracula of Stoker's novel required sustenance by feeding on the lifeblood of others, so too we have discovered a universe where strange creatures are nourished by matter that courses through the cosmos.
Black holes rip apart anything that strays too close to their clutches, galaxies like the Milky Way cannibalise smaller siblings, and the universe blazes with violence at high-energy wavelengths.
On a smaller scale, a white dwarf star scavenges its orbiting companion, comets are flung from the heavens to fall like Thor's hammer on an unsuspecting world, and gravitational forces cruelly warp and melt the interiors of moons.
When the sky clears and the world is silent though, we can contemplate the stillness of the night, knowing that life clings tenaciously to this blue marble despite the perils: Suddenly those celestial demons are tamed as we turn our gaze skyward and marvel.
What's the furthest thing you can see with your naked eye? The Moon? The Sun? Saturn? Maybe it's a star; they're much farther away after all. And they're all at different distances.
Not even close.
With the naked eye, in a dark sky, away from neighbourhood security lights and the neon-glow of urban skies, in the closing months of the year, overhead lies a dim patch which can just be seen...
The Andromeda Galaxy
Messier 31 (M31) as it's known, is a sister galaxy of the Milky Way, one of many but certainly its closest. This is a spiral galaxy much like our own but twice the size. Our eyes can only see the glow of the galaxy's central bulge and, when photographed it spans an area six times the width of the Moon.
Currently the Andromeda galaxy is about 2.2 million light years distant and due to the mind-warping laws of the Universe, that means the light that enters your eyes when you look at it is 2.2 million years old. You see it as it was before Man walked the Earth.
One of the consequences of light having a finite speed limit (186,000 miles per second) is that you can never see anything as it ever is, only as it was. And the further away an object, the older the light we see. So in some sense, the Universe acts as a time machine! We can only ever look into the past. We can't even actually look at the present.
There's another unsettling fact about M31 - it's careening towards our Milky Way at between 62 and 87 miles per second (about 400 light years every million years) and both galaxies are expected to collide in about 4.5 billion years.
Since there's an element of uncertainty in velocities and trajectories, it's not known for certain what will happen, but the expectation is that the two galaxies will eventually merge and form a large elliptical galaxy. Both will lose their aesthetic and beautiful spiral structures as a result.
How our solar system will fare is also unknown, should the galaxies merge. If the galaxies don't merge, then there's a small possibility the solar system could be ejected from the Milky way, out into the dark void between the galaxies. On the other hand, there's also a chance the solar system could do a cosmic swap and end up in the Andromeda galaxy rather than the Milky Way.
Whether anyone will be around when that happens is very much open to question.
So when you look up at that faint fuzzy patch on a dark and moonless night, imagine you could see the ghostly light of a galaxy, six times larger than anything else in the night sky, as it hurtles towards a cosmic kiss with the Milky Way that will change the lives of both galaxies forever.