Cosmic Ray

Discovery and Early Research: Cosmic rays were discovered in 1912 by Victor Hess, when he found that an electroscope discharged more rapidly as he ascended in a balloon. He attributed this to a source of radiation entering the atmosphere from above, and in 1936 was awarded the Nobel prize for his discovery. For some time it was believed that the radiation was electromagnetic in nature (hence the name cosmic “rays”), and some textbooks still incorrectly include cosmic rays as part of the electromagnetic spectrum. However, during the 1930′s it was found that cosmic rays must be electrically charged because they are affected by the Earth’s magnetic field.

From the 1930s to the 1950s, before man-made particle accelerators reached very high energies, cosmic rays served as a source of particles for high energy physics investigations, and led to the discovery of subatomic particles that included the positron and muon. Although these applications continue, since the dawn of the space age the main focus of cosmic ray research has been directed towards astrophysical investigations of where cosmic rays originate, how they get accelerated to such high velocities, what role they play in the dynamics of the Galaxy, and what their composition tells us about matter from outside the solar system. To measure cosmic rays directly, before they have been slowed down and broken up by the atmosphere, research is carried out by instruments carried on spacecraft and high altitude balloons, using particle detectors similar to those used in nuclear and high energy physics experiments.

Cosmic Ray Energies and Acceleration: The energy of cosmic rays is usually measured in units of MeV, for mega-electron volts, or GeV, for giga-electron volts. (One electron volt is the energy gained when an electron is accelerated through a potential difference of 1 volt). Most galactic cosmic rays have energies between 100 MeV (corresponding to a velocity for protons of 43% of the speed of light) and 10 GeV (corresponding to 99.6% of the speed of light). The number of cosmic rays with energies beyond 1 GeV decreases by about a factor of 50 for every factor of 10 increase in energy. Over a wide energy range the number of particles per m2 per steradian per second with energy greater than E (measured in GeV) is given approximately by N(>E) = k(E + 1)-a, where k ~ 5000 per m2 per steradian per second and a ~1.6. The highest energy cosmic rays measured to date have had more than 1020 eV, equivalent to the kinetic energy of a baseball traveling at approximately 100 mph!

It is believed that most galactic cosmic rays derive their energy from supernova explosions, which occur approximately once every 50 years in our Galaxy. To maintain the observed intensity of cosmic rays over millions of years requires that a few percent of the more than 1051 ergs released in a typical supernova explosion be converted to cosmic rays. There is considerable evidence that cosmic rays are accelerated as the shock waves from these explosions travel through the surrounding interstellar gas. The energy contributed to the Galaxy by cosmic rays (about 1 eV per cm3) is about equal to that contained in galactic magnetic fields, and in the thermal energy of the gas that pervades the space between the stars.

Cosmic Ray Composition: Cosmic rays include essentially all of the elements in the periodic table; about 89% of the nuclei are hydrogen (protons), 10% helium, and about 1% heavier elements. The common heavier elements (such as carbon, oxygen, magnesium, silicon, and iron) are present in about the same relative abundances as in the solar system, but there are important differences in elemental and isotopic composition that provide information on the origin and history of galactic cosmic rays. For example there is a significant overabundance of the rare elements Li, Be, and B produced when heavier cosmic rays such as carbon, nitrogen, and oxygen fragment into lighter nuclei during collisions with the interstellar gas. The isotope 22Ne is also overabundant, showing that the nucleosynthesis of cosmic rays and solar system material have differed. Electrons constitute about 1% of galactic cosmic rays. It is not known why electrons are apparently less efficiently accelerated than nuclei.

Cosmic Rays in the Galaxy: Because cosmic rays are electrically charged they are deflected by magnetic fields, and their directions have been randomized, making it impossible to tell where they originated. However, cosmic rays in other regions of the Galaxy can be traced by the electromagnetic radiation they produce. Supernova remnants such as the Crab Nebula are known to be a source of cosmic rays from the radio synchrotron radiation emitted by cosmic ray electrons spiraling in the magnetic fields of the remnant. In addition, observations of high energy (10 MeV – 1000 MeV) gamma rays resulting from cosmic ray collisions with interstellar gas show that most cosmic rays are confined to the disk of the Galaxy, presumably by its magnetic field. Similar collisions of cosmic ray nuclei produce lighter nuclear fragments, including radioactive isotopes such as 10Be, which has a half-life of 1.6 million years. The measured amount of 10Be in cosmic rays implies that, on average, cosmic rays spend about 10 million years in the Galaxy before escaping into inter-galactic space.

Very High Energy Cosmic Rays: When high energy cosmic rays undergo collisions with atoms of the upper atmosphere, they produce a cascade of “secondary” particles that shower down through the atmosphere to the Earth’s surface. Secondary cosmic rays include pions (which quickly decay to produce muons, neutrinos and gamma rays), as well as electrons and positrons produced by muon decay and gamma ray interactions with atmospheric atoms. The number of particles reaching the Earth’s surface is related to the energy of the cosmic ray that struck the upper atmosphere. Cosmic rays with energies beyond 1014 eV are studied with large “air shower” arrays of detectors distributed over many square kilometers that sample the particles produced. The frequency of air showers ranges from about 100 per m2 per year for energies >1015 eV to only about 1 per km2 per century for energies beyond 1020 eV. Cosmic ray interaction products such as neutrinos are also studied by large detectors placed deep in underground mines or under water.

Most secondary cosmic rays reaching the Earth’s surface are muons, with an average intensity of about 100 per m2 per second. Although thousands of cosmic rays pass through our bodies every minute, the resulting radiation levels are relatively low, corresponding, at sea level, to only a few percent of the natural background radiation. However, the greater intensity of cosmic rays in outer space is a potential radiation hazard for astronauts, especially when the Sun is active, and interplanetary space may suddenly be filled with solar energetic particles. Cosmic rays are also a hazard to electronic instrumentation in space; impacts of heavily-ionizing cosmic ray nuclei can cause computer memory bits to “flip” or small microcircuits to fail.

Cosmic Rays in the Solar System: Just as cosmic rays are deflected by the magnetic fields in interstellar space, they are also affected by the interplanetary magnetic field embedded in the solar wind (the plasma of ions and electrons blowing from the solar corona at about 400 km/sec), and therefore have difficulty reaching the inner solar system. Spacecraft venturing out towards the boundary of the solar system they have found that the intensity of galactic comic rays increases with distance from the Sun. As solar activity varies over the 11 year solar cycle the intensity of cosmic rays at Earth also varies, in anti-correlation with the sunspot number.

The Sun is also a sporadic source of cosmic ray nuclei and electrons that are accelerated by shock waves traveling through the corona, and by magnetic energy released in solar flares. During such occurrences the intensity of energetic particles in space can increase by a factor of 102to 106 for hours to days. Such solar particle events are much more frequent during the active phase of the solar cycle. The maximum energy reached in solar particle events is typically 10 to 100 MeV, occasionally reaching 1 GeV (roughly once a year) to 10 GeV (roughly once a decade). Solar energetic particles can be used to measure the elemental and isotopic composition of the Sun, thereby complementing spectroscopic studies of solar material.

A third component of cosmic rays, comprised of only those elements that are difficult to ionize, including He, N, O, Ne, and Ar, was given the name “anomalous cosmic rays” because of its unusual composition. Anomalous cosmic rays originate from electrically-neutral interstellar particles that have entered the solar system unaffected by the magnetic field of the solar wind, been ionized, and then accelerated at the shock wave formed when the solar wind slows as a result of plowing into the interstellar gas, presently thought to occur somewhere between 75 and 100 AU from the Sun (one AU is the distance from the Sun to the Earth). Thus, it is possible that the Voyager 1 spacecraft, which should reach 100 AU by 2007, will have the opportunity to observe an example of cosmic ray acceleration directly.

http://www.srl.caltech.edu/personnel/dick/cos_encyc.html
References:

Longair, Malcolm S. 1992 Particles, Photons, and Their Detection, Vol. 1 of High Energy Astrophysics, 2nd ed. , Cambridge, Cambridge University Press.

Gaisser. Thomas K., 1990, Cosmic Rays and Particle Physics, Cambridge, Cambridge University Press.

Simpson, J. A., 1983, “Elemental and Isotopic Composition of the Galactic Cosmic Rays, Annual Reviews of Nuclear and Particle Science, Vol. 33, 323-381.

Jokipii, J. R., and F. B. McDonald, 1994 “Quest for the Limits of the Heliosphere”, Scientific American 272, 58-63.

Sun dogs on 22o halo flank South Pole sun (photo courtesy of NOAA/US Dept of Commerce).

Sun dogs, or mock suns, are technically called solar parhelia (parhelia meaning “with the sun”) and appear as bright bursts of light formed when sunlight passes through ice crystals at the proper angle. Usually, cirrus clouds in front of the sun produce sun dogs, but other ice clouds, such as ice fog and diamond dust, may also generate them. Sun dogs are sometimes so brilliant that dazzled observers mistake them for the sun. They are often bright white but may show a partial spectrum of color with the red wavelengths on the edge nearest the sun. Sun dogs often have comet-like appearance with a bluish-white tail facing away from the sun.

Sun dogs are the second most frequent halo phenomena behind the 22o halo and often accompany that halo. The difference between sun dog and halo formation is the orientation of the ice crystals through which sunlight passes before reaching our eyes. Halo formation requires a mixture of random ice crystal orientations in the sky. But if the sky has only horizontally oriented, flat ice crystals, we just see a sun dog.

Ice crystals in the atmosphere are hexagonally shaped. Crystals forming most optical phenomena in the air are typically hexagonal rods, shaped like pencils, or flat, hexagonal plate patterns, like microscopic stop signs or dinner plates. When plate-shaped ice crystals fall unimpaired, drag forces automatically orient them horizontally so that their larger, flat surface parallels the earth like a large maple leaf drifting down from a tree.

Sun dogs emerge when sunlight passing through the ice plate’s thin sidefaces is refracted. The more perfectly aligned the falling crystals are to the horizontal, the more compact the resulting sun dog. Crystal misalignment from true horizontal will spread the sun dog vertically — its angular height being approximately four times the maximum crystal angular tilt.

Sun dogs frequently display a reddish tint on the side facing the sun and may sport bluish-white tails which stretch horizontally away from it. The degree to which colours are visible depends on the amount of wobble in the ice crystal’s fall: the more wobble, the more colour. The sun dog’s tail is formed by light passing through the crystal at angles other than the optimal deviation angle.

Sun dogs typically appear when the sun is low to the horizon, usually just prior to sunset or after sunrise, or during winter months at mid-latitudes. If the sun is low (horizon to about 15o above it), each sun dog is separated from the sun by 22o (or about two handsbreadth on extended arms), and both will lie on the circle of the 22o halo if one is present.

Sun dogs form tightest to the sun at lowest solar altitudes, but they are never less than 22o from it. As the Sun climbs in the sky, the sun dogs slowly move away from the 22o separation, although they remain on the line through the sun parallel with the horizon. When the sun has climbed to more than 45o altitude, sun dogs are fainter and noticeably off the 22o circle, and they vanish altogether above 61o solar altitude.

Over two millennia ago, the Greeks recognized that haloes and sun dogs foretold rain. Today we known this is often a valid prediction, because haloes and sun dogs are produced by ice crystals that form the cirroform clouds which make up the typical cloud sequence preceding a precipitating warm front.

One last word. There are also moon dogs that appear alongside the moon and are formed by lunar light passing through ice crystals. Moon dogs (or paraselenae) are less commonly seen because the moon can only produce them when bright and because they appear during the night when most of us are asleep.

The Signs are listed in roughly chronological order, although the order is not necessarily precise, especially for those in the future.

This is a brief summary of the signs; there are many books, articles, cassettes etc. which discuss these in greater detail. May Allah enable us to recognise and heed the Signs, and strengthen us in the times of tribulation.

“Are they waiting for anything except the Hour, to come to them suddenly? But its Signs have already come!” (Al-Qur’an, Surah Muhammad)

Past
1. Splitting of the Moon.
2. Death of the Prophet Muhammad, may Allah bless him and grant him peace.
3. A form of death which will kill thousands of Muslims. (Understood to refer to the plague of Amwas during the caliphate of ‘Umar ibn al-Khattab.)
4. A major fighting in Madinah (understood to refer to the battle of al-Harrah during the caliphate of Yazid, 63 AH).
5. The Muslim conquest of Jerusalem.
6. The Muslim conquest of Constantinople.
7. Two large groups of Muslims will fight in war.
8. A war between the Muslims and a reddish people with small eyes, wearing sandals made of hair (understood to refer to the Mongol Tatar invasion of the Islamic lands.)
9. A peace agreement between the Muslims and non-Muslims from the yellow race (Chinese, Mongols, etc.)
10. Thirty impostors (dajjal) will appear, each thinking he is a prophet.

Present?
11. Naked, destitute, barefoot shepherds will compete in building tall buildings.
12. The slave-woman will give birth to her master or mistress.
13. A trial (fitnah) which will enter every Arab household.
14. Knowledge will be taken away (by the death of people of knowledge), and ignorance will prevail.
15. Wine (intoxicants, alcohol) will be drunk in great quantities.
16. Illegal sexual intercourse will become widespread.
17. Earthquakes will increase.
18. Time will pass more quickly.
19. Tribulations (fitan) will prevail.
20. Bloodshed will increase.
21. A man will pass by the grave of another and wish he was in the latter’s place.
22. Trustworthiness will be lost, i.e. when authority is given to those who do not deserve it.
23. People will gather for prayer, but will be unable to find an imam to lead them.

Future
24. The number of men will decrease, whilst the number of women will increase, until for every man there are 50 women.
25. The Euphrates will reveal a treasure of gold, and many will die fighting over it, each one hoping to be the one who gains the treasure.
26. The Romans (Europeans) will come to a place called A’maq or Wabiq, and an army of the best people will go forth from Madinah to face them.
27. The Muslim conquest of Rome.
28. The Mahdi (guided one) will appear, and be the Imam of the Muslims.
29. Jesus Christ will descend in Damascus, and pray behind the Mahdi.
30. Jesus will break the cross and kill the swine, i.e. destroy the false christianity.
31. The Antichrist (al-masih al-dajjal, the false christ) will appear, with all his tools of deception, and be an immense trial. He will be followed by 70,000 Jews from Isfahan (present-day Iran).
32. The appearance of Ya’juj and Ma’juj (Gog and Magog), and the associated tribulations.
33. The emergence of the Beast from the Earth, carrying the Staff of Moses and the Seal of Solomon, who will speak to the people, telling them they did not believe with certainty in the Divine Signs.
34. A major war between the Muslims (including Jews and Christians who truly believe in Jesus after his return) led by the Imam Mahdi, and the Jews plus other non-Muslims led by the Antichrist.
35. Jesus will kill the Antichrist at the gate of Ludd (Lod in present-day Israel, site of an airport and a major Israeli military base).
36. A time of great peace and serenity during and after the remaining lifetime of Jesus.
37. Wealth will come so abundant that it will become difficult to find someone to accept charity.
38. Arabia will become a land of gardens and rivers.
39. Society will then decay.
40. The buttocks of the women of the tribe of Daws will again sway in circumambulation (tawaf) around the idol Dhul-Khulsah.
41. A great fire in the Hijaz, seen by the inhabitants of Busra.
42. Three major armies will sink into the earth: one in the east, one in the west, one in Arabia.
43. An Abyssinian leader with thin shins will destroy the Ka’bah.
44. The huge cloud of smoke.
45. The sun will rise from the west (its place of setting).
46. A gentle wind which will take the souls of the believers.
47. There is no-one left on the earth saying, “Allah, Allah” or “There is no god except Allah.”
48. Eventually the Day of Judgment is established upon the worst of the people, who copulate like donkeys in public.
49. The blowing in the Trumpet by the Angel Israfil, upon which everyone will faint except as Allah wills.
50. The second blowing in the Trumpet, upon which everyone will be resurrected.

teflon molecule

Teflon was discovered by Roy Plunkett in 1938 while he was attempting to develop a new kind of refrigerant (remember CFC’s). One of the compounds polymerized while in a storage container and its non-stick properties were soon recognized as unlike any other chemical. The official patent was acquired by DuPont in 1941.

Structurally, Teflon consists of a chain of carbon atoms which, if they are not sticking to eachother, are stuck to fluorine atoms. The flourine atoms are stuck so tightly to the carbon chain that virtually nothing can detach them. As a result, nothing can attach itself to the molecule — nothing.

One of the initial problems manufacturers of non-stick cookware had was how to make the Teflon stick to the pan. The early process called for the metal pans to be sand blasted, creating microscopic pits and grooves for the Teflon to grip. Later a “glue” was made from the Teflon and three layers were applied, then baked on the metal. This newer process goes by the name Silverstone. Both processes require PFOA and no substitute has yet been announced.

Teflon is used in thousands of different products, from your car to your grandfather’s hip joint replacement. It coats pizza boxes, it’s on paper and it is now approved for food packaging.

The Teflon molecule can degrade with heat and other environmental or biological conditions, but the product of this degradation is toxic PFOS and PFOA which never breaks down further. It is accumulating in our environment — always more and more of this man made, toxic molecule in our food, clothes, lungs and blood. And it seems as if no one is listening.