The Earliest Record of a Solar Eclipse :

The earliest record of a solar eclipse comes from ancient China. The date of this eclipse, usually given as October 22, 2134 B.C., is not certain. Historians know the account was written sometime within a period of about two hundred years. During that time there were several total eclipses visible in China. The 2134 B.C. eclipse is simply the best guess. The ancient Chinese document Shu Ching records that "the Sun and Moon did not meet harmoniously." The story goes that the two royal astronomers, Hsi and Ho, had neglected their duties and failed to predict the event. Widespread Oriental belief held that an eclipse was caused by an invisible dragon devouring the Sun. Great noise and commotion (drummers drumming, archers shooting arrows into the sky, and the like) were customarily produced to frighten away the dragon and restore daylight.

The date of an eclipse referred to in the Bible is known for certain: "`And on that day,' says the Lord God, `I will make the Sun go down at noon, and darken the Earth in broad daylight'." (Amos 8:9) "That day" was June 15, 763 B.C. The date of this eclipse is confirmed by an Assyrian historical record known as the Eponym Canon. In Assyria, each year was named after a different ruling official and the year's events were recorded under that name in the Canon. Under the year corresponding to 763 B. C., a scribe at Nineveh recorded this eclipse and emphasized the importance of the event by drawing a line across the tablet. These ancient records have allowed historians to use eclipse data to improve the chronology of early Biblical times.

Many ancient civilizations believed the occurrence of an eclipse was a demon eating the sun. They thought that the best way to get rid of the “demon” that was consuming their sun was to unite and make as much noise as possible to scare it away. At the first sight of an eclipse, everyone would immediately gather to bang drums and shout or scream as loudly as possible. The ancient Greeks believed that an eclipse was a sign of angry gods, therefore it was thought of as a bad omen.

Solar eclipses have even altered the course of human history. In 585 BCE the Lydians and Medes were engaged in battle in what is present-day Turkey. The Greek historian Herodotus recorded that at the height of a particularly fierce battle, darkness fell upon the land. Apparently the two armies waged a war close to the path of a solar eclipse. The armies took this as a sign and stopped fighting instantly, making peace with each other.

The ancient Greek astronomer Hipparchus tried to understand eclipses by using them to make scientific observations. Around 130 BCE, from observations of a solar eclipse seen from Hellespont and Alexandria, Hipparchus determined that the moon was about 429,000 kilometers (268,000 miles) away – only about 11 percent more than today’s accepted distance.

Although early eclipse pioneers, including Chinese astronomer Liu Hsiang, showed initiative and advanced thinking in their conclusions, it was not until 1605 when astronomer Johannes Kepler recorded a scientific observation of a total solar eclipse. More than a century later Edmund Halley published his account of a total solar eclipse that occurred in 1715 in the Philosophical Transactions of the Royal Society in London. He described the sight although he misinterpreted much of what he saw.

During the eclipse of August 16, 1868, Sir Joseph Lockyer of England and Monsieur Pierre Janssen of France independently discovered the telltale signs of helium in the sun's corona. Helium became the first chemical element to be discovered outside the earth. It takes its name from the Greek word for the sun − Helios. On May 29, 1919, a total solar eclipse was used to prove Albert Einstein's theory of general relativity by showing that gravity can bend light. These days, astronomers also use total solar eclipses to photograph and study the composition of the sun's corona. They time the eclipse accurately to calculate the exact dimensions of the sun.

The Great Pyramid

The shape of Egyptian pyramids is thought to repfrom which the Egyptians believed the earth was created. The shape of a pyramid is thought to be representative of the descending rays of the sun, and most pyramids were faced with polished, highly reflective white limestone, in order to give them a brilliant appearance when viewed from a distance. Pyramids were often also named in ways that referred to solar luminescence. For example, the formal name of the Bent Pyramid at Dahsur.

The Egyptians believed the dark area of the night sky around which the stars appear to revolve was the physical gateway into the heavens. One of the narrow shafts that extends from the main burial chamber through the entire body of the Great Pyramid points directly towards the center of this part of the sky. This suggests the pyramid may have been designed to serve as a means to magically launch the deceased pharaoh's soul directly into the abode of the gods.
 "The pyramids at Giza—descendants of primitive 'stepped' prototypes built in superimposed layers—are gigantic prisms unique in world architecture, mathematics at an ultimate scale. It is quite possible that Cheop's Great Pyramid consumed more dressed stone blocks than any structure ever built, an estimated 2,300,000 of them, averaging 2.5 tons each. It is generally thought that the blocks were moved on log rollers and sledges and then ramped into place." Khufu or Cheop's Great Pyramid is 756 feet (241 meters) square in plan, and 481 feet (153 meters) high. The angle of inclination of the triangular faces is about 51.5 degrees. The square of its height equals the area of each triangular face, as determined by Herodotus in 450 B. C. The base of the pyramid covers about 13 acres.
The other two pyramids in the famous trio are Khafre, 704 feet (214.5 meters) square, 471 feet (143.5 meters) high, with a face inclination of 53.2 degrees, and Menkaure, 345.5 feet (110 meters) square, 216 feet (68.8 meters) high, with a face inclination of 51.3 degrees (or possibly 330ft wide and 206 ft high (105m x 65.5m)).
For ease of modeling the pyramids, it may be useful to also know the triangular face height for each as measured along the surface instead of vertically. According to trigonometry, these surface face heights are: Khufu, 612 feet (195 meters); Khafre, 588 feet (179 meters); Menkaure, 276.6 feet (88 meters) (or possibly 263.6 feet (84m)).

For ancient Egyptians, it was of key importance that when someone died their physical body should continue to exist on earth, so they could progress properly through the afterlife. Consequently, providing proper eternal accommodation for their body after they had died was very important to them. The afterlife they wanted to attain was thought of as a bigger and better version of the earthly Egypt - and in it they were to live close to their family and friends.

There was one exception to this rather homely vision of the next world. This was for the king, already a divine being on earth, who would complete his apotheosis on death. According to the earliest set of texts dealing with the next world, the Pyramid Texts, which were inscribed inside the royal tombs of 2500-2300 BC, the king would dwell with his fellow gods in the entourage of the sun-god, Re. He would spend eternity traversing the sky and underworld: one might be tempted to regard the fate of his subjects as more desirable.

The Great Sphinx

is a large human-headed lion that was carved from a mound of natural rock. It is located in Giza where it guards the front of Khafra's pyramid.

Legends have been told for many years about the Great Sphinx. These stories tell about the powers and mysteries of this sphinx. Some people even believe that there are hidden passageways or rooms underneath the Great Sphinx, but nothing has been found yet.

The beginning of one story about the Great Sphinx is written on a stele between the sphinx's paws.

The story reads that one day, a young prince fell asleep next to the Great Sphinx. He had been hunting all day, and was very tired. He dreamt that the Great Sphinx promised that he would become the ruler of Upper and Lower Egypt if he cleared away the sand covering its body (the Great Sphinx was covered up to its neck).

The rest of the story is gone, so you will have to use your imagination to work out the ending. This stele was put up by the pharaoh Thutmosis IV who lived around 1400 B.C.

Thunderstorms create beams of antimatter

A space-based telescope has detected beams of antimatter shooting out the top of thunderstorms, in what has been described as an “amazing curiousity of nature”.
The data was collected from NASA's Fermi Gamma Ray SpaceTelescope. In some cases the thunderstorms were thousands of kilometres away, and the beams were detected only after they had travelled along the Earth’s magnetic field and collided with the spacecraft.
“These signals are the first direct evidence that thunderstorms make antimatter particle beams,” said lead author astrophysicist Michael Briggs from University of Alabama in Huntsville.
Fermi launched in 2008 to study similar high-energy bursts from space. In space, gamma ray bursts stem from high energy events such as the death of a star.
These beams, though, stem from terrestrial gamma-ray flashes, high energy bursts of gamma rays that occur in Earth's atmosphere and are most likely associated with lightning.
Fermi has detected 130 terrestrial gamma-ray flashes, which last about a millisecond, but scientists estimate 500 such flashes occur daily worldwide.
The antimatter, which has the same properties of their matter 'twin' except with the opposite electric charge, is thought to be created when an avalanche of electrons are thrown up by a thunderstorm’s strong electromagnetic field. When these electrons strike other atoms in the atmosphere they release a burst of gamma rays.
Travelling near the nuclei of other atoms causes the gamma rays to transform into an electron/positron pair (a positron is an electron’s antimatter counterpart, with positive instead of negative charge).
Beams of high-energy positrons and electrons then travelled thousands of kilometres, guided by the Earth’s magnetic field. When the positrons struck Fermi, it detected a high-energy gamma ray signal, indicating the matter in the spacecraft and antimatter in the beams had annihilated each other.
Antimatter particles can be created by particle accelerators like the Large Hadron Collider and in high energy environments in space around black holes and supernovae. Just what it means that antimatter is also associated with lightning during thunderstorms is currently unclear.
“This result is so new and right at the cutting edge that we don’t fully understand the significance in terms of what we know about the atmosphere and space weather,” said Australian space weather scientist Murray Parkinson from the IPS Radio and Propagating Service at the Bureau of Meteorology, who wasn’t involved in the research. “It’s a stunning result,” he said.
“At the very least it is an amazing curiousity of nature. It makes me wonder how much we know about the Earth’s atmosphere and space environment.”

Cosmic ‘hall of mirrors’ distorts galaxy counts

Nearby bright galaxies have been distorting the view of the earliest galaxies, which are important in understanding what happened to the universe just after the Big Bang, researchers report.

Nearby bright galaxies have been distorting the view of the earliest galaxies, which are important in understanding what happened to the universe just after the Big Bang, researchers report.

"Our finding shows images from the earliest galaxies reach us more often via a gravitationally bent path. What you see is not exactly what is really there," astrophysicist Stuart Wyithe from the University of Melbourne, lead author of the study, said in a statement.

"Our finding shows images from the earliest galaxies reach us more often via a gravitationally bent path. What you see is not exactly what is really there," astrophysicist Stuart Wyithe from the University of Melbourne, lead author of the study, said in a statement.

Using images from the Hubble Space Telescope, Wyithe and colleagues measured the separation between older, more distant galaxies and brighter foreground galaxies. They compared what they saw to a mathematical model that takes in account gravitational lensing, and concluded that the ancient galaxies were seen to be larger, brighter and more distorted than they actually are.

This effect has likely resulted in inaccurate counts for number density of ancient galaxies as seen by the recent near-IR surveys with the Hubble Space Telescope Wide Field Camera 3, according to the researchers.

But, in a twist, this effect may help astronomers find these distant, hard-to-see galaxies. "The lensing acts as a natural telescope too, so it can also help us find these distant galaxies,” said Wyithe.

 Astronomers such as Wyithe study the earliest galaxies - called 'high redshift galaxies' because the light they emit gets shifted to longer wavelengths over time - to understand the source of energy that re-ionised the universe a mere 100, 000 years after the Big Bang.

Most scientists believe that the energy needed to heat the universe's early hydrogen gases to their ionised form came from high-energy photons from stars. However, the numbers of observed early galaxies do not provide enough starlight to account for the injected energy, so scientists continue to search for other fainter, unobservable galaxies.

Astrophysicist Andrew Hopkins from the Australian Astronomical Observatory in New South Wales, who was not involved in the research, said this study is "very exciting" because it ensures astronomers have the most accurate data possible for their search.

"It identifies a clear bias that future surveys of high redshift galaxies will be subject to, and shows what the effect of that bias is. We will actually have a very clear understanding of the true numbers of the highest redshift systems that are out there," he said.

Satellites criss-cross northern lights

Two satellites have simultaneously flown through a natural particle accelerator just above Earth's atmosphere for the first time to discover how the dramatic light displays of auroras are generated.

The European Space Agency’s (ESA) C3 Cluster satellite first crossed the region at an altitude of 6,400 km, followed five minutes later by C1 at 9,000 km, and the readings have allowed the electrical landscape of the acceleration region to be mapped.

“Cluster has now shown us the very heart of the acceleration process responsible for most bright auroras. It has given us our first look at the electrical structure and stability of such an accelerator,” said Göran Marklund from the Royal Institute of Technology in Stockholm, Sweden.

Mapping the creation of auroras

“This is like geography,” said Marklund, “Only instead of the contours being the height of a landscape, they are the electrical potentials that span the region.” These electrical potentials act in both uphill and downhill directions, accelerating particles towards and away from Earth, according to their charges.

When particles strike the atmosphere, they create the shimmering curtains of light known as the aurora, or more commonly the northern and southern lights. About two-thirds of the bright auroras are estimated to be produced in this way.

Since 2006, the Cluster satellites have been drifting away from their initial orbits because they are being constantly nudged by the gravity of the Moon and the Sun. Fortuitously, the current orbit occasionally passes through the Auroral Acceleration Region, which spans 4000 km to 12000 km above our planet.

Insight into the secrets of space plasma

The satellites do not encounter a natural particle accelerator on every orbit. Those responsible for the bright auroras are temporary alignments of the electrical fields around Earth. They are highly variable in altitude and so not always present.

This first encounter with a natural particle accelerator associated with a large-scale aurora has proved that they may be stable for at least five minutes. A few more encounters are expected in the near future before Cluster’s orbit drifts back out of the region.

Such natural particle accelerators pop up ubiquitously throughout the Solar System, especially in the strong magnetic fields of the gas giants Jupiter and Saturn.

A fizzy ocean found on saturn’s moon

New evidence has shown that Enceladus, a tiny moon floating just outside Saturn's rings, is home to a vast underground ocean, which is probably fizzy like a soft drink and could be friendly to microbial life.

For years researchers have been debating whether Enceladus, is wet or not, and a close encounter with the moon by NASA's Cassini probe in 2005 kicked off an investigation into its unusual conditions.

"Geophysicists expected this little world to be a lump of ice, cold, dead, and uninteresting," said Dennis Matson of NASA's Jet Propulsion Laboratory. "Boy, were we surprised!"

A precociously active moon

Cassini found the little moon busily puffing plumes of water vapor, icy particles, and organic compounds out through fissures (now known as ‘tiger stripes’) in its frozen carapace. Mimas, a nearby moon about the same size, was as dead as researchers expected, but Enceladus was precociously active.

Many researchers viewed the icy jets as proof of a large subterranean body of water. Near-surface pockets of liquid water with temperatures near 32o F could explain the watery plumes. But there were problems with this theory. For one thing, where was the salt?

In initial flybys, Cassini's instruments detected carbon, hydrogen, oxygen, nitrogen, and various hydrocarbons in the plume gasses. But there were none of the elements of salt that ocean water should contain.

Resetting the clocks

In 2009 Cassini's cosmic dust analyser located the missing salt – in a surprising place.

"It wasn't in the plume gasses where we'd been looking for it," said Matson. "Instead, sodium and potassium salts and carbonates were locked up in the plumes' icy particles.* And the source of these substances has to be an ocean. Stuff dissolved in an ocean is similar to the contents of these grains."

The latest Cassini observations presented another intriguing discovery: thermal measurements revealed fissures with temperatures as high as -120o Fahrenheit (190 Kelvin). "This discovery resets our clocks!" said Matson. "Temperatures this high have to be volcanic in origin. Heat must be flowing from the interior, enough to melt some of the underground ice, creating an underground waterworks."

Are physicists wasting their time hunting for a theory that unites the forces of nature?

In Ancient Greece, Pythagoras and his followers believed nature was a mathematical puzzle, constructed through ratios and patterns that combine integers, and that geometry was the key to deciphering it. The idea re-emerged in the late Renaissance, although Galileo Galilei, Johannes Kepler and Isaac Newton believed the mathematical description of nature could be found through the painstaking application of the scientific method, where hypotheses are tested by experiments and observations, and then accepted or rejected.
But that’s really only half the story. According to Newton, God was the supreme mathematician and the mathematical laws of nature were Creation’s blueprint.
And while the notion that God interfered with natural phenomena faded with the march of science, the idea that nature’s hidden code lay in wait to be discovered did not.
Modern Incarnations of unified field theories come in two flavours. The more traditional version, the so-called Grand Unified Theory, seeks to describe electromagnetism and the weak and strong nuclear forces as a single force, and the first of these theories was proposed in 1974 by Howard Georgi and Sheldon Glashow.
The more ambitious version seeks to include gravity in the unification framework. Superstring theory tries to do this by abandoning the age-old paradigm that matter is made of small, indivisible blocks, substituting them with vibrating strings that live in higher-dimensional spaces.
Like all good theories in physics, grand unified theories make predictions. One is that the proton, the particle that inhabits all atomic nuclei, is unstable. But for decades, experiments of increasing sensitivity have looked for decaying protons and failed to find them.
As a consequence, the models have been tweaked so that protons decay so rarely as to be outside the current reach of detection. Another prediction fared no better: bundled-up interacting fields called magnetic monopoles have never been found.