Friday, 17 August 2012

Coming back home yesterday from work, i decided to switch my phone on (which has been off  throughout the day). I was surprised as messages flooded my phone and i actually thought River Niger is now close to my house.

The messages read '' Cosmos rays are entering earth tonight from mars.pls switch off your mobile at night, don't keep your phone with you. The rays are dangerous. NASA BBC NEWS''. For God sake this is not possible, as i will educate you on what cosmic rays really is.

Cosmic rays are energetic charged subatomic particles, originating in outer space.[1] They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation. Most primary cosmic rays (those that enter the atmosphere from deep space) are composed of familiar stable subatomic particles that normally occur on Earth, such as protons, atomic nuclei, or electrons. However, a very small fraction are stable particles of antimatter, such as positrons or antiprotons, and the precise nature of this remaining fraction is an area of active research.

All the light and the heat which we receive on the Earth comes from the sun, so it might seem a reasonable guess to suspect that cosmic rays may also come from the sun. This however is not the case. There are two bits of experimental evidence which backs up this statement.

Firstly it is well known that during the day it is light and at night it is dark, in other words a variation of light intensity seen on Earth occurs during a day (24 hour cycle). Similarly the hottest part of the day occurs between 11am and 3pm, the coolest part occurring in the early hours of the morning. In other words there is a heat variation during the day. Based on these facts, it is reasonable to assume that if cosmic rays came from the sun, they too would have some daily variation in intensity. For example the intensity of cosmic rays received by the Earth would be large around lunchtime, and much less in the middle of the night. However no such variation is observed. Indeed the cosmic rays received by the Earth is rather constant at all times during the day.

The second reason why cosmic rays cannot come from the sun, is that the sun is not able to give out particles with the high levels of energy which cosmic rays are known to have.

Evidence also exists to suggest that cosmic rays cannot exist outside of our galaxy. In order to understand why this is so it is first necessary to consider what exactly our galaxy looks like.

The galaxy can be modelled as a 'fried egg'

The galaxy has a large number of stars at it's centre and fewer further out. In all our galaxy contains of the order 100,000 million stars. The Earth is found towards the edge of the galaxy. The galaxy is of a spiral shape and is rotating at 290km/s which is equivalent to 640,000mph. This means that all the stars and planets within the galaxy are also rotating. Therefore the Earth is rotating and moving through space, relative to neighbouring galaxies, with a speed of 640,000mph.

Let us briefly stop for a moment and consider how fast 640,000mph is. To get a rough idea, the maximum speed a car can legally travel in Britain is 70mph, 9143 times slower than the speed with which the Earth is moving through space. When Linford Christie broke the 100m world record a few years ago, he ran at a speed of 0.01km/s. Concorde moves a bit faster and can travel at 0.63km/s. Faster still is the speed at which chemicals from a chemical explosion are ejected. This happens at the order of 7.5km/s. Even so this speed is still almost 40 times slower than the Earth is moving through space.

Returning to the issue of cosmic rays coming from outside the galaxy, then the fact that the Earth is moving through space implies that the intensity of the cosmic rays coming from outside of space will be greater on the side of the Earth facing the direction from which the cosmic rays came.

To make this clearer, If cosmic rays come from outside of the galaxy, say travelling (as shown) from right to left, then the number of cosmic rays received on face A must be greater than the number received on face B, (as the purple cosmic ray intensity shadow shows)

Furthermore if cosmic rays come from outside of the galaxy the spatial position of cosmic ray intensity would change at different times during the day, due to the fact that the Earth is spinning on it's own axis. No such variation is observed. Indeed the cosmic ray intensity on all points on the Earth's surface are roughly the same, at all times during the day. Therefore it is thought cosmic rays have no spatial or time variation.

We conclude from these observations that the majority of cosmic rays must originate within our galaxy. The next question which inevitable follows is: where from within our galaxy do cosmic rays come from?

Some cosmic rays are formed from stars, but most come from Supernova explosions. As keen astronomers will know, a star evolves over about 1010 years. At the end of their lives some stars explode. These are called Supernova explosions. About 100 supernova explosions occur during one year, they are observed mostly by professional astronomers, although during February this year the 5th ever supernova explosion seen by an amateur was recorded.

When these supernova explosions occur they release atomic nuclei. These atomic nuclei are the source cosmic rays and are mostly hydrogen and helium nuclei. These source cosmic rays are known as Primary cosmic rays.

Wednesday, 18 July 2012

Grenade Attack in Jos..

Hundreds of pupils escape death as RPG misses target
...Fresh bloodbath averted as STF stops youths’ protest over boy’s killing
Another possible bloodbath was averted on the Plateau yesterday as a Rocket Propelled Grenade (RPG) fired at an Islamic school missed the target, killing a seven-year-old boy in a nearby house. The attack took place at Kerana community in Bukuru metropolis.

 Angry youths from the place and Dadin Kowa also in Jos were prevented from going on rampage by the Special Task Force soldiers. Two weekends ago, scores were killed when gunmen suspected to be Fulani hersdsmen attacked residents of four Plateau councils.

A serving Senator, Dr. Gyang Dantong and the Majority Leader of the state’s Assembly, Gyang Fulani, died of exhaustion while trying to escape during an attempt to give mass burial to the victims. A member of the House of Representatives, Simon Mwadkon, escaped death by the whiskers.

The state government promptly declared curfew in the four local governments. There is fragile peace in the state since then. Yesterday’s failed mattack on the Islamic school led to tension in neighbouring Nasarawa as the news filtered into the state.

An eyewitness said someone riding in an ash coloured Jetta car which was being escorted by a Vetra car, had shot the RPG into Nuhu Islamic School at Kerana community in Bukuru. The RPG overshot its target and penetrated the wall of a house behind the school where the seven-year-old boy was killed instantly.

He said the attacker seemed not to be a professional because apart from overshooting the target, the device shattered the car’s windscreen. STF’s spokeman, Captain Salisu Mustapha, who confirmed the incident, explaned that the RPG was able to destroy the windscreen because the impact could affect anything behind it within a certain range.

As news of the attack spreads into Bukuru town and Dadin Kowa settlements, some youths took to the street in protest; a move which would have snowballed into another crisis.   The sound of the gunshots also caused pandemonium in some areas like Rayfield where people started closing shops and hurrying back home.

The appearance of the aggrieved youths in Bukuru and Dadin Kowa also made traders to lock up their shops. Banks were immediately closed even in both Jos and Bukuru metropolis while parents also rushed to schools to withdraw their children and wards.

At press time, the situation was normal, but most shop-owners refused to open for the rest of the day because of the fear that the aggrieved youths may regroup.  Men of the task force were still on the streets of both Bukuru and Jos to prevent any breakdown of law and order. In neighbouring Nasarawa, there was panic among residents of Lafia, the state capital over the Jos attack.

People gathered in groups discussing the latest development in Plateau State which had been calm lately after the initial violence. Some drivers who left early in the day to catch up with their businesses in Jos were disappointed and returned immediately to avoid being attacked by hoodlums.

Narrating his experience to Daily Sun in Lafia, one of the passengers, Abubakar Abdullahi, said they were forced to return to Lafia from Riyom by some irate youths who vowed to kill anybody that does not belong to their religion.

Abubakar said that he and his co-travellers escaped death by the whiskers as the angry youths at Riyom Railway crossing were pursuing them with dangerous weapons such as knives, cutlasses, machetes and dane guns.  “We asked our driver to turn back immediately in order to escape”, he said.