Friday, 27 March 2009
Thursday, 26 March 2009
Anyone indulging in a scientific enquiry should approach a problem with an open mind (as far as that is humanly possible), observe things objectively, and then draw the most reasonable conclusions possible in terms of explaining their observations. At this point a person’s explanation is called a hypothesis (not, as in everyday speech, a theory). In science, this ‘best guess’ hypothesis only becomes a theory after withstanding repeated and extensive testing.
‘Science’ is a human construct, and like all human intellectual activity is grounded in the surrounding milieu of those carrying out the enquiry at any given time, in any given place. At a philosophical level therefore scientific knowledge can never be wholly objective, and any scientific fact has to be open to reinterpretation in the light of new evidence. That being said, it is highly unlikely that the fact of the Earth orbiting the sun (rather than vice versa) will ever be reinterpreted (although only officially accepted by the Vatican in 1822), because scientific theories are based on the best and most objective evidence possible, without having to fit into an a priori belief system.
Wednesday, 25 March 2009
Tuesday, 24 March 2009
Monday, 23 March 2009
The chewed cud goes directly to the other chambers of the stomach (the reticulum, omasum, and abomasum, in that order). Additional digestion, with the aid of various microorganisms, continues in these other chambers. For example, in the omasum, some fatty acids and 60-70 percent of the water are absorbed. In the abomasum gastric juice (containing hydrochloric acid) is secreted, as in an ordinary mammalian stomach, further digesting the food. Also, those micro-organisms that used the ammonia and other nitrogen substances from protein in the rumen, actually get digested by the ruminant in the abomasum and small intestine, thereby providing the cow with protein. Thus can cattle can get a balanced diet from just eating grass or other foliage.
Saturday, 21 March 2009
Containing the world’s largest spiders, the tarantula family is split into one hundred and thirteen genera and eight hundred and ninety seven species. They are generally very large and hairy, and in recent years have become popular pets. They are found in most tropical and desert climates around the world. The name tarantula originally comes from the town of Taranto in Italy, where it was originally used for the wolf spider, an unrelated species. They are also called, in various places around the world, baboon spiders, earth tigers, bird-eating spiders, barking spiders and whistling spiders. Like all spiders, the tarantula is an invertebrate and has an exoskeleton which it relies on for support. It has eight legs and eight semi-functional eyes. It has three main parts, the head, the cephalothorax and the abdomen. Click here to download the full article (.pdf format 351KB).
Thursday, 19 March 2009
Wednesday, 18 March 2009
Tuesday, 17 March 2009
Snakes first evolved from their lizard ancestors about 100 million years ago during the late Cretaceous Period, about the same time that Tyrannosaurus rex first appeared. Early snakes were small and wormy, resembling modern blind snakes. Ancient snake fossils are found only on southern continents, suggesting that snakes first radiated from Gondwanaland — a former super-continent comprising modern-day Antarctica, South America, Africa, India, and Australia. Migrating to Ireland wasn't an option at this time, as the area was completely underwater. Now snakes are found in deserts, grasslands, forests, mountains, and even oceans virtually everywhere around the world. Everywhere that is except Ireland, New Zealand, Iceland, Greenland, and Antarctica. One thing all of the few snake-less parts of the world have in common is that they are surrounded by water. New Zealand, for instance, split off from Australia and Asia before snakes ever evolved.
Another plausible reason for the lack of snakes in Ireland is the weather. It's quite cold here but just 12,000 years ago we were in the midst of the Nahanagan Stadial - with full blown 'ice age' conditions. The ice age began about 2.5 million years ago and, technically, continues into the present. During this time there have been alternating cold and warm periods (stadials and interstadials), and glaciers have advanced and retreated more than 20 times, often completely blanketing Ireland with ice. Snakes, being cold-blooded animals, simply aren't able to survive in areas where the ground is frozen year-round. Ireland thawed out for the last time only 11,500 years ago. Since then, 12 miles (19 km) of icy-cold water in the Northern Channel have separated Ireland from northern Britain (Scotland) which has adders and, in warm spells, grass snakes. In southern Britain, a third native species, the smooth snake is also found. So, there are no snakes in Ireland for the simple reason that they can't get here, and probably never did - as no fossil snakes have been found here either.
Saturday, 14 March 2009
Friday, 13 March 2009
The planet Pluto has yet to be visited by a spacecraft. However, NASA is hoping that the New Horizons craft will reach the planet on July 14th, 2015. We do know that Pluto is a dwarf planet made up mostly of ice. Like its atmosphere, this icy surface is composed of Nitrogen, Methane and Carbon Monoxide. Pluto is 4.34 billion km from earth and has a diameter of 2,301 km, making it roughly 400 times smaller than Earth and only 70% the mass of the Moon. Pluto itself has one moon, Charon. Pluto's unusual 90,613 day orbit causes an anti-greenhouse effect through freezing and sublimation. Unusually, it's orbit sometimes brings it closer to the sun than Neptune. This occured in 1989 and it then remained ahead of Neptune for 10 years. It won't happen again until 2226.
Thursday, 12 March 2009
Wednesday, 11 March 2009
Tuesday, 10 March 2009
Monday, 9 March 2009
A galaxy is a system made up of billions of stars, like our Sun, and there are probably more than one hundred billion galaxies in the observable universe. Earth is found in The Milky Way galaxy which consists of at least 200 and maybe as many as 400 billion stars. It is spread out as a thin disk, and from the outside it would look like a spiral galaxy (as shown above in an artist’s depiction). The Milky Way is about 100 000 light years across. The fact that it divides the night sky into two roughly equal hemispheres suggests that our Solar System lies close to the galactic plane. Our galaxy is visible from Earth as a band of light in the night sky, but the low surface brightness makes it difficult to see due to light pollution. Andromeda is the nearest spiral galaxy to us and it is about twice as big as the Milky Way. The Milky Way and Andromeda galaxy are on a collision course, and in a few billion years the two galaxies will make their first close encounter. The oldest star in the Milky Way is estimated to have an age of 13.2 billion years, nearly as old as the Universe itself. The Universe is estimated to be 13.7 billion years old, with an uncertainty of about 200 million years. There should be hundreds of dwarfs, small galaxies, gravitationally bound to the Milky Way, but only about 20 dwarfs have been observed. Scientists have been puzzled about the missing galaxies, and now it has been suggested that the galaxies are there, but we simply cannot see them because they owe their existence to cold dark matter. This matter does not emit any light, so you cannot observe it directly.
Sunday, 8 March 2009
Saturday, 7 March 2009
His talents in natural sciences emerged at a very early age too. At the age of ten he read a Latin copy of Euclid, his introduction to Geometry. Hamilton started studying Mathematics at 13 when he studied Clairaut's Algebra, through French. In 1822 at the age of 17, he found a mistake in Laplace's Mechanique C'eleste, a five volume work of mathematical astronomy. This brought him to the attention of Dr. John Brinkley, Astronomer Royal of Ireland. Hamilton entered Trinity College at the age of 18, studying classics and science. While a student in Trinity he received an "optime" (a distinction that was very rarely awarded) in Greek in his first year. Two years later, he received another optime, this time in mathematical physics. In 1827, at the age of only 22, he was nominated as Professor of Astronomy at Trinity College. Hamilton's home thereafter was at the observatory at Dunsink, which lies about five miles from the centre of Dublin.
His most famous discovery is of Quaternions (a non-commutative extension of complex numbers) was made. On Monday Oct 16th, 1943, when he was walking along the Royal Canal with his wife, the idea of Quaternions came to him, in a dramatic flash of inspiration. In his excitement he carved the formula in the stone of Brougham Bridge. This can still be seen today.
Quaternions opened up a vast new field of mathematics. However many mathematicians at the time found them too difficult to use. Today they are the basis of computer graphics. In 1834, he published "General Methods in Dynamics " which was to be the most important of all his mathematical discoveries. This mathematical method, which allows light to be treated as waves or particles equally, virtually predicted modern wave mechanics. Atomic fission and laser beams are just some of the modern developments that are grounded in this same maths. Hamilton also predicted the unexpected phenomenon of Conical Refraction in bi-axial crystals, which served to immediately highlight his name, and won him the Royal Medal of the Royal Society, in 1835.
Hamilton's later life was unhappy. The death of his sister and friend William Wordsworth (the acclaimed English romantic poet) and an unhappy marriage resulted in troubled times for Hamilton. After two years of abstaining, he became addicted to alcohol. In 1865, he died from a severe attack of gout.
Hamilton is still regarded as Ireland's finest mathematician and one of our great scientists. Today there is a Crater named after William Hamilton on the moon, in memory of this great mathematician. In addition, the Hamilton Mathematics Institute in Trinity College Dublin is an institute dedicated to fostering mathematics and related disciplines. The Institute also aims to improve the public understanding of mathematics.
Friday, 6 March 2009
Thursday, 5 March 2009
Wednesday, 4 March 2009
Tuesday, 3 March 2009
Monday, 2 March 2009
The Great Barrier Reef (GBR) is the largest coral reef in the world, running roughly parallel to the coast of Queensland, Australia, for almost 2,000 km. It consists of 900 islands stretching over an area of approximately 344,400 square km. Australia has almost 1/5th of the world's reef area and most is located in the GBR. Washed by the warm waters of the South-West Pacific Ocean the perfect environment is created for the world's largest collection of corals. The GBR is has been listed by the World Heritage Trust as a protected site and is therefore managed by the Great Barrier Reef Marine Authority to ensure that its beauty is maintained for many generations to come. Thousands of visitors come to marvel at the spectacular sight every year.
The waters of the Great Barrier Reef provide the world's richest marine habitats - teeming with exotically coloured fish and diverse marine life. Amongst other things there are approximately 1,500 fish species, 400 coral species, 4,000 mollusc species, 500 species of seaweed, 215 bird species, 16 species of sea snake and 6 species of sea turtle. The corals, which form the framework of the reef, are colonial cnidarians that secrete an exoskeleton of calcium carbonate.