By Julie Hammel

Astronomy is one of the most exciting sciences due to numerous celestial phenomena that are simply awesome and beautiful to see. Not only that, the universe as a whole is a mysterious fact that may never be fully explained by science. There are new discoveries such as the existence of distant galaxies and black holes that are constantly revealed by space exploration programs. The reason why we are so fascinated by these celestial objects is because many of them pose as threats to our human existence. Whatever cataclysm that occurs far away can cause destruction to our planet.

Most of these strange occurrences happen in extremely long distances from Earth and are too far away to cause a catastrophe. However, there are some that are relatively near to us. Among these are the asteroids which are large rocks, having a diameter that can reach miles. These celestial objects have become the talk of the town by astronomers, soothsayers, and the public due to fears that if just one of them strikes us, the human race will be wiped out. Scientists are still looking for evidence that support the theory about the extinction of dinosaurs caused by huge asteroid impacts.

It is very important to separate the facts from fiction regarding asteroids. By virtue of popular culture as represented by science fiction books and movies, one of the wildest ideas is that these space objects are allegedly used by aliens to dominate our world. Certain forms of extraterrestrial life are suspected to be found in impact zones, spawning a strange epidemic and causing havoc to humans. However, the most popular concept is asteroids hitting Earth and using our latest technological advances to avert the said disaster.

In order to allay our fears, the scientific community is always conducting research on the nature and composition of these celestial bodies. Their studies have helped us understand the truth about asteroids. These are actually debris that can range from a golf ball up to gigantic rocks as large as continents. Since they have no particular orbits unlike planets and moons, they can and have many times actually struck our planet. Nevertheless, the ones that have penetrated our Earth’s atmosphere are called meteorites and these are typically small. Some are known as meteors because they have been thoroughly burned and have totally turned to dust. The chances of a direct hit from a giant asteroid are relatively small, but astronomers are not taking this fact for granted. By using giant telescopes that are strategically placed in different sites around the world, they constantly observe the heavens for tell-tale signs of asteroids that may stray into a dangerous collision path with our planet.

Another fact is that an asteroid belt exists between Mars and Jupiter. This is where most asteroids come from. Astronomers have separated these into classes based on their material composition and proximity to the said planets. Those that are the nearest to Mars belong to the Class S, while the ones that are closest to Jupiter are known as Classes C, D, and V. The latter classes are called Centaur asteroids and they have particular material compositions and are known to drift the vast space from Jupiter to Uranus. To gain a first-hand look at these celestial behemoths, scientists have sent space probes to fly near them. The asteroid called Ida was observed by the probe Galileo from a distance of approximately 1,000 miles and was found to have its own moon. Some probes have actually landed on asteroids and have sent amazing photographs for us to enjoy.

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By: Rachael Stone

If you want to measure our solar system, how would you do it? This simplest way is to measure it in light years. For those not familiar with the term, a light-year is the distance that light travels in a vacuum in one year. This is because the distances between stars is so huge that it is otherwise very challenging to imagine them. A light year is exactly 9,460,730,472,580.8 kilometers. Putting this into real world distances, the Milky Way is approximately 100,000 light-years across.

The Earth is one of nine planets that form the Solar System, so called because the sun, the source of solar energy, is the central point around which all the planets revolve. So far, scientists have not been able to establish or prove the existence of life forms on any other planet within the solar system. Often, the search for other life forms has focused on looking at the climatic conditions of the celestial body in question. Scientists assume that life forms on a different planet would need similar conditions as life on earth, such as oxygen, light and water, to grow. This may or may not be true.

Other than the sun, no other celestial body significantly affects the earth as the moon does. It is well known that the moon affects the rise and fall of the ocean tide. Such is the effect of the gravitational pull between the earth and the moon. Jupiter is easily the largest planet in our solar system. To put its size in context, Jupiter is more than 300 times the mass of Earth. Here is the interesting part; Jupiter has 63 moons that orbit it and yet it is not the planet in the Solar System with the most moons. That honor belongs to the ringed-planet Saturn, which has 66 moons identified so far. Pluto, the farthest flung among the nine planets, has been the subject of heated debate on whether it really qualifies to be considered a planet. Nowadays, it is classified as a dwarf planet. Its orbit around the Sun is somewhat heavily elliptical. In fact, there are instances where Pluto is actually closer to the Sun than Neptune, the planet that precedes it.

Now speaking of size within the Solar System, well, let us just say that the Sun is unmatched. Did you know that the Sun comprises more than 99% of the total mass of the entire solar system? Jupiter actually takes up much of the remaining proportion. Surface temperatures on the Sun stand at 5000 Kelvins (4727 degrees Celsius). With temperatures at its core reaching a 15.6 million Kelvins (15.6 million Celsius), the Sun is truly a celestial spectacle. It gets even better when one realizes that the Sun is classified as a class G star. Stars are classified in six major categories that tie in to the surface temperature and brightness. The categories are M, K, G, F, A, B and O listed in ascending order brightness and surface temperature. You can see that the Sun falls on the lower end of this classification. Category B and O are rare in the universe while most stars are in the category M and emit less heat and light energy. That said, the Sun is within the 90th percentile by mass among all stars. We have found other stars that are larger than our sun: one is estimated to be approximately 60,000 times bigger.

The Solar System forms a tiny part of the Milky Way Galaxy, a vast conglomeration of stars and planets. What makes astronomy so thrilling is that despite its size, the Milky Way is not the only galaxy in the universe. There are hundreds of billions of galaxies out there, probably more. The closest galaxy to our own Milky Way is Andromeda. Now, brace yourself for the distance: it is 2.3 million light years away. One of the most exciting phenomena for astronomers is the black hole. It is an area of the universe where the concentration of mass is so massive (no pun intended) that the gravitational pull it generates sucks in everything around it. Everything includes light. Remember that the escape velocity for any object in the universe is the speed required to escape the objects gravitational pull. The escape velocity for the Earth is slightly over 11 kilometers per hour while for the Moon is 2.5 kilometers per second. Well for a black hole, the escape velocity exceeds the speed of light. That is how strong the pull is.

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The Nereids were outraged by this proclamation and demanded revenge. Poseidon, to appease his vengeful daughters, sent flood waters along with the sea monster Cetus, to destroy King Cepheus’ kingdom. Cetus wreaked havoc along the coastline; death and destruction followed in his wake. Desperate to protect his land and people, Cepheus sought the help of Ammon, the Oracle of Zeus.

Ammon told Cepheus that the only way to stop the brutal devastation of his kingdom was to sacrifice his virgin daughter Andromeda to the sea monster Cetus. Andromeda was then chained to a rock on the coast of Jaffa (modern day Tel Aviv) to atone for the boastful sins of her mother Cassiopeia.

Andromeda, shackled, alone and terrified, saw Cetus approaching through roiling sea waters and began to scream. The sea monster had its maws opened to consume the sacrificial virgin when Perseus arrived riding the winged horse Pegasus, after beheading the Gorgon Medusa. Perseus swooped down from the sky holding the head of Medusa with the face toward Cetus. The sea monster was turned to stone upon seeing the head and perished, sinking forever to the depths of the sea.

Andromeda had been previously promised to Phineus but due to the heroic rescue by Perseus, Cepheus and Cassiopeia readily agreed to a marriage of Perseus and Andromeda. Their marriage produced seven sons and one daughter.

Andromeda was placed in the constellations of the Northern sky by Athena. She is surrounded by her father Cepheus, her mother Cassiopeia, her husband Perseus and the winged horse that made the marriage possible – Pegasus. The sea monster Cetus is always close by but Pisces, the constellation of fishes, now keeps Andromeda out of harms way.

The constellation Andromeda boasts, as befitting her mother, the Andromeda Galaxy, a spectacular galaxy close enough to be seen by the naked eye. Close is a relative term here, being that the galaxy is 2.5 million light years away, giving it the distinction of being the most distant object visible without the need for a telescope. The Andromeda galaxy is larger than the Milky Way, while the Milky Way contains more dark matter and is most likely more massive. Being so incredibly far away, the galaxy is difficult to spot without a telescope.

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For more on the world of astronomy, visit Starr’s site at Space for the Earthbound

The Pleiades star cluster consists of over 400 mostly faint stars, along with the 6 to 15 brighter stars seen well with the naked eye during good viewing conditions. There are also several nebulae within the star cluster. These nebulae are blue in color indicating reflection nebulae, which reflect the light of bright stars near or within the nebulae. The reflection nebula seen at right is most likely part of the dust in a molecular cloud and is not actually related to the Pleiades; these two bodies are simply crossing each other in the sky, like two ships in the night. It is estimated that the Pleiades star cluster will survive for roughly another 250 million years. Gravitational interactions with the spiral arms of the galaxy and giant molecular clouds will cause the demise of this most impressive star cluster.

The Seven Sisters are the daughters of the titan Atlas, who held up the sky, and the sea-nymph Pleione, the protectress of sailing. The daughters were Maia (the eldest), Electra, Taygete, Alcyone, Celaeno, Sterope (which is a double star) and Merope (the youngest). Their half-sisters include the Hyades, Calypso, Hyas and the Hesperides.

The only one of the seven sisters to marry a mortal was Merope, who wed Sisyphus and bore him several sons. The other six sisters all consorted with gods. Zeus sired four children with three of the sisters. Poseidon was father to three children from two of the sisters and Ares fathered a child with one sister.

Atlas joined one of his brothers and several other Titans in a war against the Olympic gods. Two of Atlas’ brothers, after weighing the odds, betrayed the battling Titans by siding with the Olympians. The Titans were defeated and Zeus condemned Atlas to stand at the edge of the Earth and hold up the heavens with his shoulders.

One day while strolling the Boeotian countryside, the Pleiades were spotted by Orion, the great hunter. Orion was immediately taken by the incredible beauty of the seven sisters and pursued them across the earth for seven years. Zeus took pity on the sisters on behalf of Orion’s relentless pursuit of them and changed them into doves, giving them a place in the heavens and putting them again under their father’s watchful eye. When Orion was later placed in the heavens, he was set in a position to be behind the Pleiades, forever chasing the lovely ladies he couldn’t catch while mortal.

For more on the world of astronomy, visit Starr’s site at Space for the Earthbound