OUR SOLAR SYSTEM: AN OVERVIEW
In this series, we will pretend we are taking a guided tour of our own solar system. Say you were an alien
coming from light years away and had never seen our system before.
What would stand out and what would be routine?
One thing that would stand out right away is our bright yellow sun. An alien race, let’s call them Centarians, would know that life is possible on least one planet of the system. Only around smaller white-yellow suns and red dwarfs are there potential for life; blue,red,white and yellow giants burn too quickly, and white, black and brown dwarfs are usually dead stars.
They would also see right away the orb cloud and Kuiper belt that surrounds our system,the several tiny exo-planets and dwarf planets that surround the outer orbits, and the many comets that travel around our sun, each on their own individual flight path. As they traveled closer, they would see the Jovian, or gas giants. They would pass through the asteroid belt to see Mars and Earth, the two most hospitable planets in the system, then the two that orbit the sun in the danger zone of Sol’s powerful radiation.
As the Centarions would know, Sol was created 4.6 billion years ago in a massive burst of energy. As it formed, there was a tremendous amount of matter left over, which formed all the terrestrial bodies we know today. As this matter collided with other matter it began to combine to form planets. Our system is in the Milky Way Galaxy, on the Orion arm, and measures 9 billion miles from the sun, 18 billion if you were to go from one end to the other. Our space travelers would have be awfully advanced to travel that distance in any reasonable amount of time. We use the measurement of Astronautical Unit, or AU, which is the distance from the Earth to the sun, or 93,000,000 miles. The solar system is approximately 50 AU.
The Centarians would know this type of solar system is not unique, and even though red dwarfs are the major prospects for life in the universe, some “yellow” stars show promise as well. There are, however, some properties that are unique to our system alone, such as orbit stability. In many other systems there is chaos, just as there was in the past and will be in our own billions of years from today.
Tomorrow we will investigate our remarkable sun, named Sol, and its amazing power. Until tomorrow, here are today’s links:
As our Centarians travel past the eight planets, they will discover our star, Sol, the giver of life and the giver of death. They will have known that it was formed like any other star, a swirling cloud and hot gases, causing the nuclear fusion that remains in its core today, and will for another 5 billion years. They will not travel too close, but are probably safe at a distance of 1.3 million miles. Any closer, they could be toast, at least by the technology we know. They may have special systems we are unaware of to protect them from the heat and radiation of the solar flares.
Looking into our cultural data banks, they can see that since man began, he worshiped the sun for spiritual reasons. The Centarians know that this practice was extremely primitive, but necessary for man to evolve into what he is today. Searching into later history, they learned that man was finally gaining an understanding of the universe that surrounded him. He learned that the sun itself was living, and had a birth, a life, and yes, a death.
In about 4 billion years, the sun will heat up and form a red giant, engulfing the three inner planets, and turning them into torched shells of worlds, or absorbing their matter. After that, it will die and cool into a white dwarf, then a black dwarf. By then, hopefully we will have moved on for our own sake.
But you may ask yourself, if the sun appears yellow on Earth, why is it red closeup, and white far away? It an optical illusion, based on wherever you are in the solar system. The reason it looks yellow to us is because of our Nitrogen rich atmosphere. In blackness of space, colors are inconsequential, because there are no spectrums of an atmosphere to judge them by. How do we even know if our aliens have eyes to see it? 70 % of the sun’s radiation and sunlight is filtered through our atmosphere and magnetosphere.
They also know that the surface is 10,000 degrees, and over 15,000,000 at its core, and Hydrogen is its main gas, as well as Helium. The corona actually extends past the dwarf planet Pluto, but some of the planets, like our own, have there own form of protection. Tomorrow, our next stop will be Mercury, named after the Greek messenger. Until tomorrow, here are today’s links:
As our hosts take us away from the fury of the sun, we travel to a world just as inhospitable. The surface temperatures reach 800 degrees in the day and -280 at night. Its surface is battered by meteorites and asteroids, much like our own moon, and has no moon of its own. It sits in the darkness as a lone reminder of how cruel the universe can be, and what can happen when there is no protection of a magnetosphere.
It makes an orbit every 88 days, and has to travel around twice to complete its solar day. It is slightly larger than our own moon, and the gravity is similar to Mars; a man weighing 100 lbs here would weigh 38 lbs. Two of our own satellites that have gone there have been the Mariner 10 in the early 70’s, and Messenger in 2004, which is still orbiting it.
Our Centarian friends would easily determine that other than its precious metals, it would be senseless to set up an outpost here. In order to mine the planet, however, aliens would have to be able to survive the extreme temperature variations, radiation and celestial objects being propelled at them. In short, it would be a waste of their time and resources. Our next stop on our tour-Venus, named after the Roman goddess of love. Here are today’s links:
Venus was named after the Roman goddess of love and beauty. As we gaze at the evening sky it is indeed beautiful, and the first star we see in the morning as well. Although it seems pretty from a distance, it is really a hot, hellish, volcanic world. As our Centarian friends know, Venus is another hostile, uninhabitable world, but once possibly had water just like Earth.
It has been called our sister planet, due to its similar size, gravity, and mass. Its dense atmosphere is 96 % Carbon Dioxide, and the pressure at its surface is as much as the bottom of the ocean. A human would implode with that much pressure. The surface reaches an incredible 865 degrees, hot enough to melt lead. Spacecraft that have landed there have lasted less than a few minutes before being destroyed. Clouds of sulfuric acid and radiation cause frequent lightning, and volcanoes shower the surface with occasional lava flows. Nice place for a vacation, isn’t it?
The planet is the closest to Earth, but rotates the opposite way of most planets. Our alien friends determine that this may have been caused by a collision of some kind in the past. It is 66,782,596 miles from the sun, and orbits every 224 days, but its day is 243 of our days. It is believed that Venus could have been similar to Mars in history as it may have contained water, but its runaway greenhouse effect caused it to evaporate to a dry, cracked, heated surface. It has no moons and no magnetosphere. Our next stop will be an interesting one because it is the only one known to support life, and that life is us. Until tomorrow, here are the links:
As our Centarian friends approach their next destination, they have found the most diverse planet in the solar system, and the only one that we know that sustains life. The planet that I’m speaking of is of course, our own-Earth, also sometimes called Terra in science fiction. It is the largest of the terrestrial planets, and the densest. It is 93,000,000 miles from the sun, has a convenient 24 hour day, and has a rotation of 365.6 days. It has an atmospheric composition of 78 % Nitrogen, 21% Oxygen, perfect to accommodate life. Anymore or less of either would affect our biological systems by one degree or another. Tectonic plates under the oceans, land masses and volcanic activity dramatically affect our oceans, weather and climate, and have helped to shape our planet and ecosystems, causing birth of some species and extinction of others.
Although Earth is teaming with life, 99.9% of every species that ever lived is extinct. Before the second mass extinction, there were more species than ever, but they lived in the oceans. A celestial object, most likely a comet slammed into the Earth, wiping out almost all life on the planet. This has happened several times in its 4.5 billion history. Life began in the ocean 1 billion years ago, after a long formation from a hot, molten rock in space. It is believed that another planet at one time collided with ours, forming the Earth, and knocking a chunk of it off, forming our moon. Without our moon, there would be erratic tides, and life as we know it could not exist here. Comets also brought water here, necessary for life as well. Our magnetosphere and ozone layer also protect us from harmful radiation. All these conditions work together to help this planet survive and flourish. Today there are 10-14 million species in the world, and over 7.2 billion people.
Due to climatic change, however, this may soon change. We are heading towards a global catastrophe if we do not change. The Centarians know from other societies on other planets that species such as ours are susceptible to self extinction. Problems such as pollution, war, famine and the spread of disease all interact to speed up to the process. Only until the day we can work together as a race can we expand across our region of space. Monday, we will look at our history as a planet and our future as a race. We are extending our stay another day on this interesting and colorful world. Until tomorrow, here are today’s links:
THE HISTORY AND FUTURE OF THE PLANET EARTH
As we know, our Earth was at first at hot, molten rock floating through space. Once it cooled , about 3.5 billion years ago, a funny thing began to happen. Oceans formed from the constant bombardment of comets, and as they did , so did primitive one celled organisms during a period called the Proterozoic eon, about 3 to 2.5 billion years ago. These primitive animals evolved into the multi-celled organisms that we know today. In the Paleozoic era, about 42 million years ago, complex life began , in the form of sea animals and plants, and later amphibians and reptiles. During this time there was a mass extinction event that almost wiped out all life on Earth, but somehow, we prevailed.
We are all familiar with the dinosaurs that lived about 300 million years, during the Mesozoic period. They owned this planet for 150 million years, longer than any other life, except for insects and plants. The world was warmer then, and there was more oxygen, causing animals to grow to tremendous sizes. We are pale in comparison, only existing a mere 2 million years, and apes, our predecessors, a mere 6 million. It is estimated that all the people who ever lived is about 108 billion, and by next year we will have a record 12 billion people living all at the same time.
Which brings us to the future of our planet. We have built global civilizations , had great advances in the worlds of science ,medicine, and mathematics, but will any of this save us from extinction? The answer is no, unless we can get off this big blue ball in the middle of nowhere. Space exploration is our only hope for our survival. Even if we survive war, famine, disease, and our own overpopulation, we will still become extinct-it’s inevitable. There are too many factors, such as celestial collisions, gamma ray bursts, climate changes, the colliding of galaxies, and the death of our sun. We will have to be resourceful, intelligent and innovative to survive as a species. But after all, isn’t that what makes us different than the dinosaurs? Tomorrow, we will skip Mars because I’ve already covered the world in my Martian History series. We will be heading to one of the most mysterious and interesting worlds in our system-Jupiter. Until tomorrow, here are the links:
JUPITER-THE GENTLE GIANT?
As we leave Earth and Mars behind us and journey farther into the solar system, we realize things begin to become more weird and turbulent. The Centarians have guided us past the asteroid belt, the area between Mars and Jupiter, where the gravitational pull of the sun and the gas giant hold most of these objects in a locked orbit, until they collide, and are hurled either towards us or out into space. We pass through it with relative ease because the objects are actually farther apart than you might expect.
Jupiter was named after a Roman God and, and is the biggest of the Jovian worlds as well as the biggest in our solar system. It has 2 1/2 times the mass of all the other planets combined, and is the third brightest object in the night sky, next to the moon and Venus. The atmosphere is made of mostly Hydrogen and Helium gas, swirling in a soup of noxious gases, high velocity winds and lightning. It is protected from radiation from a strong magnetosphere, extending 2 million miles and sheltering its 67 moons. It is 484 million miles from the sun, orbits every 12 years, and has 10 hour days. Its core is made of metal, Methane, and ice, and reaches a temperature of 70 degrees. The atmosphere is much colder, reaching -234 degrees. The red spot is a storm that has raged for at least400 years.
Jupiter has four major moons-Ganymede, Europa, Callisto, and Io. The first three are ice moons, with possible oceans underneath. Io is the closest and volcanically active. Ganymede is the biggest. It is believed that Europa may support life. A mission is in planning to send a probe under its icy surface. It is also believed that the icy moons all have possible geyser activity on a scale that would dwarf Old Faithful by miles. The Voyager and Pioneer missions flew by Jupiter, obtaining essential information from the planet, including the discovery of a small ring system similar to Saturn, which is our next stop.
Jupiter has been a subject of many science fiction movies, including the classic 2001 Space Odyssey. In that movie, Jupiter became a sun. This is not possible by physics, due to the coldness of the planet and the fact that the planet is made of leftover gases from the sun itself. It was an interesting idea, and there is a small correlation, because Jupiter and its moons are like a small solar system. Europa is a possible place for life, but it would be much different than we are accustomed to. The Centarians know that if intelligent life is to flourish on a planet, it would have to be under conditions that were compatible to that form of life. We just don’t know if life under extreme atmospheric conditions is even possible yet. Maybe one day we may even find life in our own back yard. Tomorrow, we will move on to our next planet-the one with all those rings-Saturn. Until tomorrow, here are the links:
As we continue our tour of our solar system, we come to a world that has perplexed astronomers for hundreds of years. Only until recently have we discovered the answer of what Saturn’s beautiful rings are made of. We used to believe that there were maybe about 100 of them. We now know that it has nine main rings, and three minor rings, which are really just millions of tiny ice particles in a locked orbit around the world. Looking further, we can see that these twelve rings have thousand of sub-rings within them.
Saturn is named after the Roman god of agriculture, the sixth planet from the sun and is also one of the gas giants. Its radius is nine times that of Earth, and it is 1/12th the size of Jupiter. Its magnetic field is weaker than Earth’s, a mere 722,000 miles in space, but due to the liquid metallic properties within its lower atmosphere and large size, its magnetic moment is 580 times more than Earth. It orbits the sun every 29 1/2 years, and its day is 10.7 hours. The core of the planet is surrounded by a deep layer of metallic hydrogen, a layer of liquid hydrogen and Helium, with ammonia crystals in the upper atmosphere. The winds spiraling through the atmosphere reach 550 mph at the Southern polar vortex, faster than Jupiter, but not as fast as Neptune.
Earth compared to Saturn in size & rings seen by Casini flyby.
Saturn has 62 moons, with some of them like Enceladus, which are geyser-like worlds, and others that are volcanic in origin. Titan, the largest moon, slightly bigger than Mercury, has also fascinated astronomers due to the recent Cassini mission, launched in 2004. NASA has discovered Titan consisted of frozen H2O with methane lakes on its surface. Titan is the only moon in the solar system to retain a substantial atmosphere, where methane raindrops blanket the surface. The -290 degree atmosphere allows methane to exist as a liquid, forming streams and lakes on its surface. The Cassini mission has allowed us to reexamine our whole idea of what life may consist of. Small microscopic living organisms have been known to exist on Earth in a totally methane environment, and amino acids, the building blocks of life, are believed to exist there as well. One day we may be able to physically land on these worlds and terraform them. The Centarians believe that this may be our only hope for survival as a race. Tomorrow, we will be heading to another Jovian planet and ice giant, Uranus. Until then, here is our today’s links:
Before I get into today’s topic, I would like to note that the Kepler probe has reported that it has found the galaxy’s oldest solar system. I felt because I am covering the solar system this week, this would be an appropriate time to mention it. It has five planets orbiting it, it is 117 light years away, and is 11.2 billion years old. The star is Kepler 444. and is a little bit smaller than our own sun. The planets are too close to the sun to sustain life, but the fact that the system is similar to our own is in itself a promise that life could exist elsewhere in the galaxy sometime in the past or present.
Uranus is the only planet to be named after a Greek god, the third largest and is the 7th planet from the sun. It is a gas giant, but is considered an ice giant, due to its lower temperature and abundance of water ice, frozen ammonia and methane lower to the core. It is the coldest planet in the solar system at -357 degrees, and has a most complex ring and layered cloud system, with methane in the upper atmosphere, and water in the lower atmosphere. It has a magnetosphere and ring system similar to the gas giants. Wind speeds at the lower atmosphere reach 560 mph.
Uranus is unique from the other planets because its north and south poles are at their equator, causing the planet to rotate vertically. It also travels in retrograde, like Venus, in the opposite direction as Earth. It has 27 moons, which are small but close together, baffling scientists as to why they do not collide into one another. It is also believed there are many more moons that are too small to be seen. All of these moons are similar to our own, and other than different ages and physical features, are uneventful, cold lifeless places. The planet is 1.8 billion miles away, not an easy place to reach by today’s rocket propulsion systems. One day here is 17 hours, and it orbits the sun every 84 years. Voyager 2 is the only spacecraft to ever visit the world, and very little is known about its properties or its moons. The Centarians, our guides, have determined that other than harnessing the hydrogen and helium of the planet, there is limited use for this world. Life is impossible here. Tomorrow we will reach our last planet which is even farther away, Neptune, Roman god of the sea. Until tomorrow, here are today’s links:
It is named after the Roman god of the sea, and is the eighth planet from the sun. It is similar in composition as Uranus and is also an ice giant, with frozen gases such as hydrogen, helium, ammonia, methane, and nitrogen. The atmosphere consists of clouds of ammonia sulfate, and has winds up to 1300 mph in its large dark spot. It is 2.8 billion miles from the sun, orbits every 164.79 years, and has a day of 16 hrs. Its surface reaches a blistering cold temperature of -353 degrees. Neptune’s gravity creates gaps in the Kuiper belt, causing Pluto and itself to sometimes cross paths. Their 2:3 resonance ensures that they don’t collide. It has 14 known moons, with Triton being its largest. Triton is the only moon in the solar system to spin in retrograde with its host planet. The temperature here is even colder, -391 degrees, making it one of the coldest places in the solar system. Geysers spew 5 miles into space, suggesting that the moon may harbor an ocean underneath.
PLUTO, THE KUIPER BELT & OORT CLOUD
Once considered a planet, Pluto is a small dwarf planet with four moons, and is 3.7 billion miles from the sun. It has a thin methane atmosphere that expands and contracts according to its distance from the sun. It orbits every 284 years, has a day that lasts 153 hours, and for the most part is a very cold -369 degrees. It is 1400 miles wide.
The Kuiper belt is the region beyond Neptune that has more than 200 dwarf planets, and 1000 asteroids and comets. Shorter range comets are in this area.
The Oort cloud is a spherical gas cloud that surrounds our solar system. Beyond that is interstellar space. A probe called New Horizons is going to be launched this year to examine this region of space. This is the region where longer term comets are from. Both the kuiper belt and the Oort cloud are too cold a region to sustain habitable life.
Well, it’s been entertaining with our friends, the Centarians. From what evidence they could gather from our system, Earth is the only habitable planet for colonization. Other planets would take massive terraforming. It’s not that it isn’t possible, it would just be a lot of work, even for an advanced race. It would make more sense to do what we do first-send out machines to investigate the cosmos. Perhaps one day, the Voyagers will be found by someone like the Centarians, and it may answer their question as well-are we alone? I’ll see you all on Monday with a brand new series. Until then, here are today’s links: