Archive for the ‘Planets and Solar System’ Category

Mercury

Wednesday, June 16th, 2010

The planet Mercury has the distinction of being the smallest planet within our solar system, being only 40% as large as the Earth.  With a name derived from Roman mythology due to Mercury’s rapid rotation around the sun, the planet travels through space covering almost thirty miles every second.  It is also the closest planet to the sun at just over twenty-eight million miles away, making it by far the warmest planet.  A full day spent on the surface of the planet would calculate to around one hundred seventy-six days on Earth; and since it takes fifty-nine days to complete one full rotation around its axis only two actual sunrises would be visible each year.  Although the Sun would appear twice as large if standing atop the planet Mercury, the sky would appear black because of the thin atmosphere.

Since Mercury is the closest planet within our solar system to the Sun, it has by far the hottest surface temperatures ranging from three hundred to eight hundred degrees Ferinheight, with the dark side of the planet reaching temperatures as low as -300 degrees because of the lacking atmosphere to retain warmth.  This is the biggest swing in temperatures present within our solar system and is an interesting study since the surface would actually be hot enough to melt most metals during daylight hours.  The sunlight from Mercury’s surface would appear 6.5 times more intense than we experience on Earth, which means even if a person would somehow survive the extreme heat and lack of oxygen they would be virtually blinded within the brightness.

It is believed that just after the Big Bang and the formation of the Mercury, the planet received massive damage from comets and, meteors, and asteroids.  Although the planet is one of only three within our solar system that is perfectly symmetrical, the smooth rocky surface is riddled with craters showing extensive cosmic damage that occurred up to 4.6 billion years ago.  The largest of these craters stretches over eight hundred miles across Mercury’s surface and the appearance is much like our own moon for comparative purposes. 

Sunlight never reaches the polar caps of Mercury and ice has been discovered there, but the lack of a functional atmosphere would make life on the planet’s surface impossible.  The solar winds sweep away what little atmosphere is present on Mercury almost continually, which means it has little protection from damaging objects in space.  The atmosphere is constantly renewing and creates a vacuum like effect so gravity could not be present for extended periods of time.  Its iron core generates a magnetic field thought to be less than one percent as strong as what is found on Earth, making the planets similar in overall interior composition. 

The reflection qualities of Mercury are similar to our own moon, sending only about six percent of the light that strikes the surface back into space.  Because of these qualities Mercury is difficult to view from our planet, and the best times to view the planet would be around sunrise and sunset.  With the assistance of a telescope Mercury can be witnessed going through phases much like we associate with the moon in regards to its positioning between our location and the sun.

The Sun

Wednesday, June 16th, 2010

The star that we refer to as the Sun creates the possibility of life on Earth and provides so many essential functions regarding humanity’s survival that it is often taken for granted.  Without water, almost every living organism would die within days.  Move us just a bit closer to the sun and our water supply becomes vapor; move us back just a bit and now it’s solid ice.  Neither form is readily consumable for our everyday needs, and the Earth’s precise distance from the Sun is the only reason liquid water exists at all. Likewise, that same distance just discussed allows the temperature of the Earth to remain within acceptable boundaries; Venus the next closest planet to the sun and averages temperatures up to nine hundred degrees Ferinheight.  Plants use the sun to complete a process known as photosynthesis, which simply means to convert carbon dioxide and water to produce oxygen.  If just one of these factors were affected even slightly, such as the Earth changing its orbit or the sun becoming hotter or cooler, life on Earth would cease to exist.

The birth of our Sun occurred around 4.6 billion years ago with the collapse of a hydrogen molecular cloud, the same formation that eventually gave birth to our solar system and all of the objects contained within it.  Primarily composed of hydrogen and helium, the sun is a near perfect sphere that is fuelled by nuclear fusion reactions.  As far as stars are concerned the Sun is medium in size, but to give an idea of the sheer mass involved with these objects over one million planets of the Earth’s relative size could easily fit inside the Sun.  It is also classified as a population one star, meaning it has minerals present heavier than helium, and this is proven by the levels of uranium and gold found on the Earth when compared to other planets throughout the galaxy.  The Sun is thought to be brighter than about 85% of the stars within the Milky Way galaxy.

Of course, the Sun’s composition is much different from the Earth.  Within its core, temperatures are estimated to reach temperatures of twenty-seven million degrees Ferinheight and the nuclear reactions that take place keep the Sun’s outer form in constant evolution.  Within a single second over seven hundred million tons of hydrogen are converted into helium ash with the release of over five million tons of energy; which would be the equivalent of one hundred trillion tons of dynamite being detonated on Earth each and every second of the day.  This violent reaction can continue to take place as long as hydrogen exists to fuel this fission, which is expected to last another five billion years or longer.  Once the last traces of hydrogen and helium are depleted, the sun will begin to swell as it converts into a red giant.  This process will eventually swallow the Earth and all of the interior planets until suddenly the Sun will collapse and complete its life cycle as a white dwarf.

Scorpius

Wednesday, June 16th, 2010

Scorpius, long tied to Orion within Greek mythology, is the figure of a scorpion found within our evening skies.  Ancient legends depict that Orion possessed keen hunting skills and was seldom at a loss for words when it came to describing his conquests.  At one such meeting he commented to the goddess Artemis and her mother Leto that he would slay every living animal on Earth.  Since Artemis was the protector of all creatures this comment was found unacceptable, so she sent a savage scorpion to conquer Orion.  A fierce battle ensued witnessed by Zeus and many of the other Gods, and when Orion was killed there were many that felt a deep sorrow.  Zeus then decided to place both Orion and the scorpion within the evening skies as constellations for all to behold, but far enough apart so that the scorpion could never threaten Orion again. 

Scorpius is a very large constellation located relatively close to our own Milky Way galaxy, and it is perhaps one of the oldest constellations known.  It was actually once much larger in detail but its western parts that once made up the pincers are now known as Libra instead.  In fact, the two brightest stars within Libra, Zubeneschamali and Zubenelgenubi, literally translate in English to northern and southern claws.  In terms of brightness Scorpius is one of the brighter constellations viewable within the sky, with several double and variable star systems within its borders.

The brightest star within Scorpius is Antares, which is a massive red super giant and considered a first magnitude star.  There is only one other red super giant that matches its vibrance, and it happens to be Betelgeuse in the constellation Orion.  Antares is currently twelve times larger than our current sun and it is burning approximately six thousand times faster.  Although it is a relatively young star, its violent lifespan will allow an astronomically short existence perhaps as little as twelve million years.  Since our own sun is expected to have a total lifespan of around six to ten billion years, the difference is dynamic.

The other stars within the constellation of Scorpius are Graffias, Dschubba, Sargas, Shaula, Jabbah, Grafias, Alniyat, Alniyat, and Lesath.  Many of them are actually double stars with a variety of hues, but due to the brightness of this constellation many are difficult to ascertain without high powered equipment.  There are also four messier objects within the constellation; with the Butterfly Cluster and Ptolemy’s Cluster being the most prominent.  On clear nights both can be viewed with the naked eye or seen in stunning detail with the use of even a low powered telescope.

The best views of Scorpius for those in the Northern Hemisphere are in July and August since that is when the entire constellation will have cleared the Southern Hemisphere, but it can be viewed as early as March or April if you are willing to stay up late and watch it slowly clear the horizon.  In the Southern Hemisphere it is a bit trickier since it is directly overhead during the winter when the views are more difficult to see.

Polaris

Wednesday, June 16th, 2010

Polaris, better known as the North Star, has been a beacon of guidance for civilizations for thousands of years.  If a person is anywhere within the Northern Hemisphere and locates Polaris within the night skies, they will be facing almost perfectly due north while viewing it.  How could someone at the North Pole and someone in the Philippines just north of the equator both be facing due north when viewing Polaris?  As perplexing as it seems, the science behind Polaris is fairly simple even though it generates hundreds of thousands of questions from amateur astronomers, sailors, and outdoor enthusiasts every year. 

Contrary to popular belief, Polaris is not the brightest star in the northern skies, sort of.  Of all the viewable stars it currently ranks 50th in brightness from our perspective, however since it is estimated at over 430 light years away it must have a luminosity of around twenty-five hundred of our suns.  Since many of the stars we consider bright are much closer in perspective when compared to Polaris, it is an extremely bright star.  Likewise, because of its extended distance from Earth is why we can currently use it to judge which way is north.  If you placed a coin inside your bedroom and another within your kitchen then drew a straight line from each of them to your front door, in essence you would have a triangular pattern since each line is at different angels from the other.  If you drew those same lines to your neighbor’s home across the street, the angles would decrease a small portion and become a bit straighter.  If you drew those same two lines to the other side of the country, your lines would appear almost completely straight because the distance traveled directly relates to how parallel they are.  Because Polaris is so extremely far from our location everywhere on Earth faces due north when viewing the star, and because of its brightness it is an easy target to pick out of the sky and follow.

There are several easy ways to locate Polaris, which makes up a part of the Little Dipper.  Polaris is viewable year round so if the Little Dipper is not immediately spotted, it may be easier to locate the Big Dipper and use it as a reference point, since it is by far the easiest constellation to find.  When looking at the Big Dipper, find the two stars that make up the outer portion of the dipper opposite the handle.  These two stars are known as Merak and Dubhe, and because of the Earth’s rotation they continually rotate around Polaris twenty-four hours a day.  Using these two stars, draw a straight line moving away from the top of the dipper and they will lead you directly to Polaris and the Little Dipper.

Because of the Earth’s orbit, Polaris will not always be considered the North Star.  It is currently less than one degree off of true north and is slowly making its way towards perfect alignment around 2100 AD, but in the future other stars will be much closer to true north and used in Polaris’s place until it realigns with our North Pole once again.

Orion

Wednesday, June 16th, 2010

The constellation Orion rests almost exactly on the celestial equator and is viewable from anywhere in the world.  Often referred to as The Hunter, Orion depicts a kneeling hunter with a weapon drawn, ready to charge into battle; with other nearby constellations referred to as his potential targets and faithful animal companions.  With several highly visible stars and other objects making up its formation, Orion is one of the most visible constellations in the sky and is often used as a reference point for locating other constellations.  Because of its centralized location, the view we witness is nearly identical to what the ancient Egyptians and other past civilizations witnessed and it should remain that way for millions of years into the future.

Orion is made up of a series of stars easily visible within the night sky and makes it an excellent reference point for casual observers.  Betelgeuse and Rigel, two of the brightest stars from our vantage point, encompass the right shoulder and the left foot of the hunter.  Both supergiants are approaching the end of their lives and will eventually explode into a brilliant glare that will be visible even during daylight hours.  Bellatrix, Mintaka, Alnilam, Alnitak, and Saiph make up the rest of Orion’s formation.

An astronomical asterism can also be found within Orion, and it is a trio of systems known as Orion’s Belt.  Alnilam, Alnitak, and Mintaka create this highly visible celestial body and are often quick reference points to locate Orion and other nearby constellations.  These three massive star systems are also ancient relics within the evening skies with an average brightness between the trio over one hundred thousand times greater than our sun.  Orion’s Belt has been highly viewed throughout the ages and has carried with it a host of different nicknames; the best time to view this asterism is during the December and January months when it is nearest to the local meridian.

Over half of the constellation of Orion is highlighted by Orion’s Nebula, or more simply put a massive cloud of gasses and dust made up of hydrogen, helium, and plasma.  The properties of a nebula make for excellent chances of new stars being formed, and currently in the Orion Nebula there are over seven hundred of them in various stages of infancy.  Since its discovery in 1610 by Nicolas-Claude Fabri de Peiresc, the Orion Nebula has been one of the most viewed areas of the sky due to its rapid development and wondrous views.  It is also one of the most popular focuses of the Hubble Space Telescope, since scientists still actively seek data that will further explain how our solar system was formed and the possibility of intelligent life beyond our planet.

The Flame Nebula is also visible within Orion, and gives novice astronomers a fantastic view due to the overall brightness of Alnitak, the easternmost star within Orion’s Belt.  Because of its massive emission of ultraviolet light not visible to the naked human eye, the Flame Nebula appears as a great burst of red and yellow colors that is perhaps one of the most beautiful refraction nebulas within the sky.

Leo

Wednesday, June 16th, 2010

The constellation of Leo, one of the twelve zodiac symbols found within the night sky, represents the lion.   Ancient mythology shares a tale about the mighty Hercules, son of Zeus, who murdered his own family in an entranced fit of rage.  To atone for his sins, Hercules was required to complete twelve labors, one of which was to slay a mighty lion.  The ancient Greeks claimed Hercules was their greatest warrior, so when they spotted the constellation it was named Leo as a tribute to his glory.  Although other names and stories are shared by different cultures throughout the world, the name Leo has been generally accepted for several thousands of years.  During the summer in ancient Egypt, desert lions traveled to the Nile River when it flooded each year, which happened to be when the sun aligned with Leo. Others have believed this to be the name’s true origin.

The constellation of Leo is made up of several stars forming the mighty lion’s mane and its body, and is fairly easily spotted in the sky.  The trademark shape to look for appears like a backwards question mark, which is an asterism known as the Sickle.  Regulus, the twenty-fifth overall brightest star in the sky, forms the bottom of the shape and is an easy centralized point to locate the Leo if the constellation is not immediately spotted.   

The other predominant stars observed in Leo are Denebola, Algieba, Zosma, Chertan, Al Minliar al Asad, Alterf and Subra.  It is also interesting to note that the star Wolf 359 is one of the closest stars to our solar system at only 7.78 light years away.  There are also several galaxies to view within the constellation of Leo that can be viewed with low to medium powered telescopes; Messier 96, Messier 95, Messier 66 and Messier 65 are a few of the brighter ones available to look at.  The Leo Ring, made up of leftover gasses from he Big Bang, are also an object of interest since much of its contents or what constitutes its formation are still unknown.

Another interesting feature of Leo is the amount of meteor showers associated with that area of space.  The ones easiest to view are named the Leonids, and together they remain active through much of the year.  Alpha Leonid is viewable from mid January to mid February, with multiple showers being seen nightly.  Beta and Delta Leonids both happen during February to March, with Beta peaking around March 19th and Delta reaching it’s height about a month earlier.  Gamma Leonids lasts from August 14th until September 12th but is generally a milder showing.  Rho and Sigma Leonids have also been documented but are of questionable performance levels.  The peak viewing nights are around November 17th, where 15-20 meteors per hour can be spotted.

The best time of year to view Leo depends on where you are located.  Residents to the Northern Hemisphere will have the best views of this constellation during the spring season, while those in the Southern Hemisphere will have Leo above them around autumn.


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