Saturn:Planet with the rings

Saturn is the sixth planet from the sun and the second largest planet in the solar system. Although the other gas giants in the solar system — Jupiter, Uranus and Neptune — also have rings, those of Saturn are without a doubt the most extraordinary.

Saturn was the Roman name for Cronus, the lord of the Titans in Greek mythology. Saturn is the root of the English word “Saturday.”

Physical characteristics of Saturn

Saturn is a gas giant made up mostly of hydrogen and helium. Saturn is big enough to hold more than 760 Earths, and is more massive than any other planet except Jupiter, roughly 95 times Earth’s mass. However, Saturn has the lowest density of all the planets, and is the only one less dense than water — if there were a bathtub big enough to hold it, Saturn would float.

Saturn is the farthest planet from Earth visible to the naked human eye. The yellow and gold bands seen in Saturn’s atmosphere are the result of super-fast winds in the upper atmosphere, which can reach up to 1,100 mph (1,800 kph) around its equator, combined with heat rising from the planet’s interior.

Saturn spins faster than any other planet except Jupiter, completing a rotation roughly every 10-and-a-half hours. This rapid spinning causes Saturn to bulge at its equator and flatten at its poles — the planet is 8,000 miles (13,000 km) wider at its equator than between the poles.

Saturn’s most recent curiosity may be the giant hexagon circling its north pole, with each of its sides nearly 7,500 miles (12,500 km) across — big enough to fit nearly four Earths inside. Thermal images show it reaches some 60 miles (100 km) down into the planet’s atmosphere. It remains uncertain what causes it.

Composition & structure

Atmospheric composition (by volume)

96.3 percent molecular hydrogen, 3.25 percent helium, minor amounts of methane, ammonia, hydrogen deuteride, ethane, ammonia ice aerosols, water ice aerosols, ammonia hydrosulfide aerosols

Magnetic field

Saturn has a magnetic field about 578 times more powerful than Earth’s.

Chemical composition

Saturn seems to have a hot solid inner core of iron and rocky material surrounded by an outer core probably composed of ammonia, methane, and water. Next is a layer of highly compressed, liquid metallic hydrogen, followed by a region of viscous hydrogen and helium. This hydrogen and helium becomes gaseous near the planet’s surface and merges with its atmosphere.

Internal structure

Saturn seems to have a core between about 10 to 20 times as massive as the Earth.

Orbit & rotation

Average distance from the sun: 885,904,700 miles (1,426,725,400 km)
By Comparison: 9.53707 times that of Earth

Perihelion (closest approach to sun): 838,519,000 miles (1,349,467,000 km)
By Comparison: 9.177 times that of Earth

Aphelion (farthest distance from sun): 934,530,000 miles (1,503,983,000 km)
By Comparison: 9.886 times that of Earth

Image

Saturn’s moons

Saturn has at least 62 moons. Since the planet was named after Cronus, lord of the Titans in Greek mythology, most of Saturn’s moons are named after other Titans, their descendants, as well as after giants from Gallic, Inuit and Norse myths.

Saturn’s largest moon, Titan, is slightly larger than Mercury, and is the second-largest moon in the solar system behind Jupiter’s moon Ganymede. Titan is veiled under a very thick, nitrogen-rich atmosphere that might be like what Earth’s was long ago, before life. While the Earth’s atmosphere extends only about 37 miles (60 km) into space, Titan’s reaches nearly 10 times as far.

These moons can possess bizarre features. Pan and Atlas are shaped like flying saucers, Iapetus has one side as bright as snow and one side as dark as coal, and Enceladus shows evidence of “ice volcanism,” spewing out water and other chemicals. A number of these satellites, such as Prometheus and Pandora, are shepherd moons, interacting with ring material to keep rings in their orbits.

Saturn’s rings

Galileo Galilei was the first to see Saturn’s rings in 1610, although from his telescope they resembled handles or arms. It took Dutch astronomer Christiaan Huygens, who had a more powerful telescope, to propose that Saturn had a thin, flat ring.

Saturn actually has many rings made of billions of particles of ice and rock, ranging in size from a grain of sugar to the size of a house. The largest ring spans up to 200 times the diameter of the planet. The rings are believe to be debris left over from comets, asteroids or shattered moons. Although they extend thousands of miles from the planet, the main rings are typically only about 30 feet thick. The Cassini-Huygens spacecraft revealed vertical formations in some of the rings, with particles piling up in bumps and ridges more than 2 miles (3 km) high.

The rings are generally named alphabetically in the order they were discovered. They are usually relatively close to each other, with one key exception caused by the Cassini Division, a gap some 2,920 miles (4,700 km) wide. The main rings, working out from the planet, are known as C, B and A, with the Cassini Division separating B and A. The innermost is the extremely faint D ring, while the outermost to date, revealed in 2009, could fit a billion Earths within it.

Mysterious spokes have been seen in Saturn’s rings, which might form and disperse over a few hours. Scientists have conjectured these spokes might be composed of electrically charged sheets of dust-sized particles created by small meteors impacting the rings or electron beams from the planet’s lightning. Saturn’s F Ring also has a curious braided appearance — it is composed of several narrow rings, and bends, kinks, and bright clumps in them can give the illusion that these strands are braided.

For more such posts like our page : Like us on facebook

Unknown History of Brain Science

         Brain Science is older than you might expect. Of course, many of the first brain theories were wrong, but you might be surprised by the fact that the first known writings about the brain date fback to 4000 BC. Let’s have a quick overview of some of the main historical milestones regarding the Unknown History of Brain Science:

  • Around 4000 BC, the Sumerians wrote a text describing the effects of the ingestion of the ‘poppy’ plant. This is often considered the first known writing on the brain.
  • Back in 2500 BC, the Egyptians believe that the heart is the most important organ of the body and the source of good and evil. During the embalming process, the heart is preserved for mummification while the brain is discarded, since it is considered a minor organ.
  • Around 400 BC, Hippocrates, the father of medicine, discusses epilepsy as a disturbance of the brain. He also considers the brain to be related with sensation and to be the seat of intelligence. Some few years later, Plato teaches that the brain is the seat of mental processes. His disciple Aristoteles on the other hand, believes that the heart is the seat of mental processes. I guess not all geniuses are always right, or might it be that Aristoteles was fascinated by the Egyptian culture?
  • Around 47 AD, the first neurostimulation therapies are undertaken by Scribonius Largus, the court Physician to Roman emperor Claudius. This fact struck me the most, since electricity was not even discovered yet! How the heck did Scribonius manage to apply electrical currents? Well, the solution he found is simple and elegant: using electrical torpedo fish (eels), which he applied on the body of patients to release pain. Cool!!
  • Until around 1500 AD, not much more happens in brain science, since human dissection and anatomy is banned by the Church. In any case, primitive brain surgery is performed by barbers who offer they services to extract the ‘stone of madness’ from the skull of mentally ill patients. I would not go for that surgery…Aren’t barbers meant to shave?
  • During the Renaissance (1400-1600), human dissection starts againand many advances in neuroscience (mostly from an anatomical point of view) are made. A hidden fact from this time is that vivisections are also carried out on death-penalty criminals. Ouch! That must have hurt…
  • In 1791, Luis Galvany publishes a work describing his experiments on electrical stimulation of frog’s nerves. A few years later (1819) Mary Shelley publishes her famous novel ‘Frankenstein‘, which can also be considered a milestone in brain science…fiction.
  • In 1808, Franz Joseph Gall publishes work on phrenology, a pseudoscience stating that different brain functions are located in different places or modules, such as friendship, courage, ambition, etcetera …. He also states that measuring the skull of a subject provides a lot of information about his/her personality. This theory, which was soon abandoned because of lack of scientific rigour, happened to be very influential in neuropsychology. Actually, in modern times it has been discovered that the brain actually does have specialised areas such as the visual cortex and the motor cortex…we can conclude that Mr. Gall had a lucky fluke.
    • In 1848, Phineas Gage, a railroad worker, survives and actually recoveres from an accident in which an iron rod (3.2 diameter and 110 cm long) was driven completely through his head, destroying much of his left frontal lobe. Although little is known about Gage’s life, it seems that his personality changed radically after the accident. Being hard-working, responsible, and “a great favourite” with the men in his charge, after the accident he was fitful, irreverent, indulging at times in the grossest profanity, at times pertinaciously obstinate, yet capricious and vacillating, … This incident showed that behaviour and personality traits are indeed localised in certain areas of the brain.
    • In 1929, Hans Berger records the first human electroencephalogram (EEG). Nowadays EEG is a widely used technique in psychiatric diagnosis and in brain research. What it is less known is that Hans Berger had a great interest in the scientific study of telepathy. It seems that he had a near-death-experience and that his sister, many kilometres away, had a feeling that Hans was in danger. This fact struck Mr. Berger so much that he decided to switch his mathematical/astronomy studies for medicine, with the goal of discovering the physiological basis of “psychic energy”.

    Much more interesting things happened in the 20th century and for sure many important discoveries will be made in the 21st century. Soon I will write about modern discoveries in Brain Science, which are also quite fascinating. As a preview, the discovery of Quantum Physics allowed many important discoveries in Neuroscience…how can this be? I am sure many readers know the answer. For those who don’t, please stay tuned!

  • For more such posts like us on facebook: Like us on facebook