A surprisingly large number of massive stars have been spotted in regions across the universe, shedding new light on how galaxies near and far evolve, a new study shows. By Samantha Mathewson | SPACE.com In the study, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile investigated intense bouts of star formation in four […]
L’événement de la Toungouska est une explosion survenue le 30 juin 1908 vers 7 h 13 en Sibérie centrale, dans l’empire russe. L’onde de choc, équivalant à plusieurs centaines de fois celles qu’engendreront les explosions des bombes nucléaires d’Hiroshima et de Nagasaki 37 ansplus tard, a détruit la forêt sur un rayon de 20 kilomètres et fait des dégâts jusqu’à une centaine de kilomètres.
Plusieurs hypothèses scientifiques ont été émises sur l’origine du phénomène : météorite, foudre, méthane échappé de conduits volcaniques… L’hypothèse la plus plausible, et retenue au début du xxie siècle, est celle de l’impact d’un objet céleste (un petit corps du Système solaire de caractéristiques encore inconnues), ayant explosé à une altitude comprise entre 5 et 10 kilomètres. Cela fait de l’événement de la Toungouska la plus grosse explosion connue de l’histoire humaine due à la rencontre d’un tel corps avec la Terre.
Dans la matinée du 30 juin 1908 (correspondant au 17 juin du calendrier julien, alors en usage dans l’Empire russe), quelques témoins voient passer une boule de feu dans le ciel sans nuage de la Sibérie centrale. Celle-ci explose à une altitude comprise entre 5 et 10 kilomètres, au-dessus de la rivière Toungouska pierreuse, à 63 km nord-nord-ouest du village de Vanavara1 (60° 20′ 24″ N, 102° 16′ 48″ E) à 7 h 14 locale (0 h 14 TU ou 7 h 2 heure locale solaire). Cette explosion est enregistrée, sous forme de séisme de magnitude 4,5 à 5, à 7 h 17 min 11 s, à l’observatoire magnétique d’Irkoutsk, à 1 000 km de là.
L’explosion détruit intégralement la forêt dans un rayon de plus de 20 km, abattant 60 millions d’arbres ; le souffle fait des dégâts sur plus de100 km et la déflagration est audible dans un rayon de 1 500 km. De nombreux incendies se déclenchent, brûlant des zones forestières pendant plusieurs semaines.
Un vortex de poussières et de cendres se forme et est entraîné jusqu’en Espagne par la circulation atmosphérique, créant des halos dans la haute atmosphère, qui s’étendent sur tout le continent. On peut observer des couchers de soleil très colorés et une luminosité exceptionnelle en pleine nuit est constatée pendant plusieurs jours en Europe occidentale, à tel point que l’on peut lire un journal de nuit. Les scientifiques pensent alors à l’éruption d’un volcan, comme le Krakatoa en 1883, qui avait injecté d’énormes quantités de poussières dans l’atmosphère et, de ce fait, avait engendré des phénomènes lumineux semblables.
L’onde de choc fut enregistrée en Europe occidentale et aux États-Unis.
L’éloignement de la région et les troubles en Russie ne permirent une étude sur place qu’en 1927 par une équipe russe menée par Leonid Kulik. Sur les lieux, les scientifiques découvrirent stupéfaits qu’il n’y avait ni cratère, ni trace d’impact, ni débris. Avec l’arrivée de la Seconde Guerre mondiale, puis de laGuerre froide, seules deux expéditions purent retourner enquêter en 1958 et 1961. On découvrit une multitude de petites sphères de métal et de silicatesdispersées dans le sol de la région, ce qui permit d’émettre quelques hypothèses. Une étude américaine en 1993 avança qu’il s’agissait d’un petit noyau cométaire, essentiellement composés de gaz gelés ayant fondu et explosé entre 6 et 9 km d’altitude, le reste de la matière étant dispersé en une pluie de sphérules.
Le lac Cheko (en) est un lac d’eau douce, près de la rivière Toungouska pierreuse. Il a la forme d’un rectangle aux coins arrondis, d’une longueur de 708 mètres, d’une largeur de 364 mètres et d’une profondeur d’environ 50 mètres. Il est situé à environ sept kilomètres au nord-ouest de l’hypocentre et son grand-axe est orienté vers ce point. Il semble inconnu avant 1908 et sa première référence cartographique date de 1928.
Luca Gasperini, géologue italien, entreprend des études sur les sédiments de ce lac en juillet 1999 et sa première publication de 2001 affirme que le lac est antérieur à l’événement de 1908.
Toutefois, en 2007, le même Gasperini, cité par National Geographic, émet une hypothèse opposée : « La forme en entonnoir du bassin et des échantillons de sédiment suggèrent que le lac s’est formé dans un cratère d’impact ». L’impact serait dû à un fragment de l’objet et la forme inhabituelle pour un impact à une puissante émission de gaz carbonique, de vapeur d’eau et de méthane contenus dans le pergélisol.
La question de la nature de cet objet se pose toujours : petit astéroïde, comète ou autre ? Cet objet est dénommé souvent TCB (Tunguska Cosmic Body ou Corps cosmique de Toungouska), et surnommé parfois Ogdy, nom du dieu du feu des Évenks.
Ses caractéristiques furent d’abord estimées aux alentours de 50 mètres de diamètre et 10 millions de tonnes avant qu’une nouvelle simulation présentée en 2007 par les laboratoires Sandia ne réduisent l’estimation à 62 000 tonnes.
Des études ont été menées en 2007 pour rechercher le parent de cet objet : des similitudes ont été trouvées avec la comète 97P/Metcalf-Brewington et avec l’astéroïde (106538) 2000 WK63 (découvert le 26 novembre 2000 par LINEAR).
En 2010, l’expédition menée par Vladimir Alexeev pour l’institut TRINITY (en) lève le voile sur la nature ambiguë de l’objet à l’origine du choc. Les résultats découlant de l’expédition indiquent qu’une comète à noyau de glace s’est fragmentée et dispersée sur quelques kilomètres en formant plusieurs cratères d’impact. La découverte, dans la résine d’arbres, de restes de poussière cosmique formant la queue de la comète pourrait confirmer cette hypothèse.
Pour certains commentateurs, l’absence de cratère d’impact ne semble pas compatible avec la chute d’un astéroïde ou d’une comète. Il existe des cratères d’impact qui correspondent à des chutes d’objets à la surface de la terre. La liste de cratères d’impact sur Terre en recense un bon nombre, mais l’événement de la Toungouska ne correspond pas à ce modèle.
Une étude9 menée et publiée en 2013 par le chercheur Victor Kvasnytsya met en avant l’hypothèse de la météorite. Il avance cette hypothèse grâce à des fragments de roche microscopiques piégés dans la tourbe.
Autre objet cosmique
D’autres hypothèses de chute d’objets cosmiques sont parfois évoquées :
- Un micro trou noir (1021 grammes, soit 1015 tonnes dans un volume correspondant à quelques atomes) aurait pénétré la Terre à la Toungouska et serait ressorti, 12 minutes plus tard dans l’AtlantiqueNord (Al Jackson, Mike Ryan, 1973), sans qu’il n’y ait consensus scientifique ;
- Une météorite d’un kilogramme d’antimatière se serait annihilée lors de son entrée dans l’atmosphère(Clyde Cowan, Chandra R. Atluri et Willard Frank Libby, 1965) ; cette hypothèse a les faveurs de Jean-Pierre Ader. Ce qui a été vu à Mourmansk, le 19 avril 2014 pourrait être de même nature bien que d’une plus faible ampleur.
- Un astéroïde de matière noire (invisible) aurait explosé en altitude (Robert Foot, 2002) ;
De nombreuses hypothèses de toutes sortes, parfois relevant de la science-fiction, ont été émises sur ce phénomène mystérieux :
- ce serait une boule de foudre d’un kilomètre de diamètre (Anthony Lawton, 1977) ;
- une dernière expérience désespérée de la Tour de Tesla
- une explosion nucléaire d’origine extraterrestre ;
- dix millions de tonnes de méthane se seraient échappés de conduits volcaniques et se seraient embrasés, (Wolfgang Kundt, 2001).
- un OVNI (à propulsion nucléaire) se serait écrasé
La théorie récente de l’astronef extraterrestre qui explose
Cette théorie a été mise au rebut scientifiquement presque depuis qu’elle a été formulée parce que l’impact d’un navire assez grand pour provoquer une telle explosion et destruction environnementale aurait nécessairement dû éjecter des milliers de restes épars.Ce n’est pas ce qui est arrivé dans l’événement de Tunguska.Aucun fragment de métaux,de polymères ou d’alliages particuliers n’ont été trouvés à l’époque de l’impact…ce qui aurait prouvé l’origine extraterrestre de manière certaine.
Par contre,en 2009,une expédition mieux outillée et organisé que dans le passé a mis la main sur des éléments fantastiques pouvant servir à avancer un début de preuve sur l’origine extraterrestre de l’événement.
Dirigée par un scientifique de renom,le professeur Labvin,l’expédition exhuma une pierre très rare de 50 kilos qui fut transportée à Krasnoïasrsk pour analyse plus précise.
Déjà en 1998,lors du 90 ième anniversaire de l’événement,Labvin avait exposé 2 barres de métal d’origine inconnue.Ces barres auraient été retrouvé près de la ville de Vanavara à 65 kilomètres du lieu de l’explosion.La pierre a été surnommée « pierre-reno ».
La zone couverte par l’explosion se prépare à recevoir de nombreuses expéditions scientifiques et surtout des ufologues qui sont encouragés par les récentes découvertes dont celle d’une expédition italienne dans la région en 1999 qui avait annoncé dès 2007, avoir trouvé un cratère (le lac Cheko,notre photo) associé à l’événement.Ce serait un cratère de 50 mètres de profondeur et de 450 mètres de diamètre situé à 5 kilomètres seulement de l’épicentre de l’explosion.Des scientifiques affirment avoir étudié les anomaliers gravitationnelles et des échantillons du lac qui révèlent cette origine.En outre,il n’existe aucune preuve,aucun témoignage,ni carte à l’appui de l’existence de ce lac ,avant 1908.
La grande vérité dans cette affaire est que l’événement de Tunguska,en dépit de diverses théories et croyances largement répandues dans la communauté scientifique qui mise sur une explosion de comète,nous laisse encore une masse d’inconnues que la science actuelle n’a pas encore fini d’expliquer en totalité.
LE LIEN VIDÉO:
Scientists find potential evidence of methanogenesis, a biological process, on Saturn’s moon Enceladus. By Becky Ferreira | MOTHERBOARD The ocean interior of Saturn’s moon Enceladus may have the “temperatures and chemical energy sources necessary for habitable conditions,” according to new research published in Science on Thursday. This major finding is the result of an extremely […]
« They look at us. » That is the impression that we could have two bright spots side by side on Ceres appeared on the photo taken at 46,000 miles away, on 19 February. The dwarf planet in only had in previous vigils. The tweet says it is a « variable » stain.
An « unexpected and mysterious » event
Chriss Russell, the charge of the Dawn mission, the spacecraft that took the photo, provided the following explanation: « The bright spot now has a companion of a lesser brightness, but apparently in the same crater. This may indicate a similar origin to volcanism, but it will be a better resolution before making such geological interpretations « >> Read:. A mysterious radio signal came from ailleursLe responsible for the shooting, Andreas Nathues adds that » the bright spot is too small for the camera, but despite its size, it is brighter than anything else on Ceres. This is really unexpected and it remains a mystery to us. « Dawn should take new pictures in March which may help to find answers to this.
The surface of the sun was surprisingly quiet – with fewer spots than at any time in the last century – encouraging curious scientists to wonder exactly what this might mean here on Earth.
Sunspots were observed for thousands of years – first by Chinese astronomers and then, for the first time with a telescope by Galileo in 1610.
Sunspots appear in cycles of about 11 years – more in a daily avalanche and then decreasing drastically, before amplification again .
But this cycle – nicknamed « the cycle of 24 – has surprised scientists with its slowness .
The number of points scored because it began in December 2008 is well below the average over the last 250 years . In fact , this is less than half .
« This is the weakest solar cycle that was all from the space age , 50 years , » said the National Oceanic and Atmospheric Association , the physicist Doug Biesecker .
Young people play football at sunset on the artificial beach located in the Ponta Negra …
The intense electromagnetic energy sunspot has a significant impact on emissions of ultraviolet rays and X rays of the sun as well as solar storms .
Solar storms can disrupt telecommunications and electronic networks Terre.L Activity sunspots can also have an impact on the climate of the Earth.
Cycle 23 peaked in April 2000 with an average of 120 solar day points. Then the cycle wound down, hit bottom around December 2008, the time for scientists, began the beginning of the current cycle.
The minimum solar activity at the end of cycle 23 has led astronomers to predict a slow 24 cycle. But the reality is even fell below expectations .
In the first year of the cycle, during which solar activity have increased , astronomers have 266 days without a single stain sun.
Hindu Devotees return after taking a holy dip at Sangam while the sun sets in Allahabad …
« The peak forecast was 90 sunspots, » said Biesecker, noting that even if the activity has increased over the last year, « it is very clear that he will not be close to 90. »
« The number of sunspots peaked last year to 67, almost half of a typical cycle, » he added.
The last time the sunspot cycle was this slow was in February 1906, the peak of cycle 14, with only 64 points per day.
The « long minimum: three years, three times more than the previous three rounds of the Space Age » was a surprise, said University of Montana physicist Andres Munoz-Jamillio.
A magnet switch
A photo taken from an airplane shows the sun rising behind the clouds at dawn over the outskirts of Bankok
Cycle 24 also deviated from the standard of another surprising way.
In general, towards the end of each solar cycle of 11 years, the magnetic fields of the sun changes direction . The northern and southern hemispheres change their polarity , often simultaneously.
In exchange, the magnetic field strength drops to near zero and reappears when the polarity is reversed, the scientists explain .
But this time, something different seems to happen . The north pole already reversed polarity, several months ago – and now the same polarity as the south pole .
The most recent satellite measurements , » the southern hemisphere should return to the near future , » said Todd Hoeksema , Director of the Solar Observatory Wilcox at Stanford University .
It does not seem concerned about the phenomenon .
But scientists are watching closely to see the sun if the cycle 24 will be an aberration – or if it will calm the next solar cycle stretch through.
« We will not know for another good three or four years , » said Biesecker .
Some researchers believe this could be the beginning of a long period of low solar activity.
The last time it happened, during the so-called » Maunder Minimum » between 1650 and 1715 almost no sunspots were observed. During the same period , temperatures plummeted to Earth , causing the so-called » Little Ice Age » in Europe and North America.
As the number of sunspots continue to remain low , it is possible the Earth’s climate is affected again .
But thanks to global warming, we are unlikely to see another ice age. « Things did not start to cool , they just do not grow as quickly , » said Biesecker .
Other articles on the same subject:
ONLY 500 YEARS TO LIVE … THE MAXIMUM !
The European Space Agency Friday launched three satellites, Ellel hopes to help understand why the magnetic field that makes human life possible on Earth, appears to be weakening . Satellites, including ESA Swarm project were launched from the Plesetsk Cosmodrome in Russia on a Rockot at 7:02 EST and were placed in near-polar orbit at an altitude of 490 kilometers ( 304 miles ) about 91 minutes later. Swarm data that is due to be collected for the next four years will improve the relatively vague understanding of scientific magnetic field that protects life on Earth from deadly solar radiation and helps the migration of certain animals. Scientists say that the magnetosphere is weakening and could completely disappear within 500 years as a precursor pole reversal and inversion of the magnetic field . All this has happened – the geological history suggests the magnetic field is reversed there 250,000 years , which means that , with the last event, there 800,000 years , the current situation , a reversal of fields magnetic . seems to be late. While the effects are difficult to predict , the consequences can be enormous. Satellites, among other essential communications, may be more exposed to the solar wind , and the oil industry uses readings from the magnetic field to guide exercises. » Swarm is an essential task , not only for Europe but also for the world , » said the Director General of ESA Jean- Jacques Dordain Reuters after launch. « We can not live on planet Earth without the (magnetic) shield. » The Swarm mission was developed and built by Astrium unit , European aerospace group EADS .
IN 2007 , I predicted :
In 2007, I wrote an article in my forum ( http://lesporteursdufutur.forumpro.fr ) on the fragility of life and the inversion of pôles.Je then describing the discoveries of Themis -1 satellite reception gaps in the magnetic field of the Earth.
Breaches discovered by Themis-1 in 2007.The danger is growing.
Magnetic anomaly observed in the South Atlantic: a magnetic reversal taking place?
Article » British Geological Survey »
The Earth’s magnetic field, generated deep within the planet, is a shield against particle radiation from space. In the South Atlantic this shield is much lower than anywhere else in the world and therefore the space radiation penetrates deeper into the atmosphere. This region is known as the » South Atlantic Anomaly (SAA) » and the influence of the SAA is a known hazard to satellites, spacecraft and aircraft at high altitude.
Monitoring changes in the magnetic field
The entrance to the radiation in the atmosphere depends on the magnetic activity of the sun and geometry (or shape ) of the magnetic field of the Earth . Thus, to understand the space environment , particularly during magnetic storms , is important. Equally important is the understanding of changes in the magnetic field over time , the surface of the Earth.
See also » the long-term monitoring of the magnetic field of the Earth » : http://www.bgs.ac.uk/research/longTermMonitoringGeomag.html
During a magnetic reversal ?
The South Atlantic anomaly is known to be more extended and oriented to the west of South Africa, where the internal magnetic field rapidly weakens in this region. This may be the first signs of a change of direction coming into the internal magnetic field . We do not know in detail what exactly happens during inversions between the observed changes in the magnetic field and when the reversal is completed . However, these factors are important in knowing where the radiation risk may be increased and how the atmosphere might respond .
Earth’s magnetic field has had many ups , downs and reversals in the past. The last reversal back to 800,000 years. Therefore , the earth is known to be able to regenerate its magnetic field. Understand the development of the SAA may therefore be significant in understanding the reversal process and its impact on life and the natural environment.
An observatory on terrestrial magnetism , located in South Georgia , keeps track of the anomaly in the South Atlantic and notes the changes that occur in the center of the Earth.
New data will be used to build better mathematical models for the magnetic field. These models can be used to deduct the evolution of the liquid flow in the outer iron core of the Earth . This fluid flow supports the magnetic field of the Earth and allows us to make predictions about future changes .
Alarming NOAA data : acceleration of the pole shift
NOAA National Geophysical Data Center maintains a set of annual magnetic north pole coordinates going back to the year 1590 , based on measurements at the beginning of logs to modern techniques.
Noting that there have been many recent reports of pole shift , to the point where the phenomenon because of real problems people such as the temporary closure of airports, further investigation was required.
After transferring 420 years of data from different positions of the north pole of the Geo Data Center , NOAA , the configuration to fit in an Excel spreadsheet , adding a complicated formula to determine the exact distance between 2 calculations of latitude- longitude, apply the formula to each point of the data series, and then finally traced all in a visual graph, it is alarming to discover the great distance traveled only poles in the last 10-20 years .
Here is a very interesting fact …
Since 1860, the movement of the magnetic pole has more than doubled every 50 years. It’s pretty important.
Here is another very interesting fact …
Over the past 150 years, the pole shift has been in the same direction.
The following fact is even more amazing …
Over the past 10 years, the magnetic north pole has shifted nearly half of the total distance of the past 50 years ! In other words, the pole shift has apparently accelerated significantly .
The pole shift has more than doubled over the past 50 years.
The current rate of switching the magnetic north pole is about 55 kilometers per year. According to the data set, in 2000, the North Magnetic Pole has moved more than 70 km.
Now the problem is that since the pole shift amounted to a record high over the last 10-20 years in almost 400 years of data, the cumulative effect starts now be felt worldwide .
Does the effects affect us little or going to the wrong way ? I guess time will tell, but at current rates , there will probably direct effects on many systems in the coming years , many of them will be nuisance issues such as documentation changes while others are likely to be severe.
It is not known if the change will accelerate or slow down in the coming years . Some say that a pole shift is already late, and this phenomenon may be indicators of the beginning of this process.
Note that the Earth’s magnetic field is what protects us from radiation. Without him, we would not have survived. Is a reverse polarity cause between the two » flip- flop » a period of time without any magnetic fields so that we would be exposed to deadly radiation?
At the direction of the current , the magnetic north pole is heading directly towards Russia. The following image shows the dramatic acceleration while pointing out the last 50 years compared to the last 10 years of the movement .
The magnetic field variations and climate : the interweaving between the magnetic field of the Sun and the Earth: http://albert-nodon.e-monsite.com/rubrique , the magnetic – field – , 118504.html
Magnetic and geographic north magnetic declination : http://f1rzv.free.fr/astrinfo/decl_magn.php
Very good site on the magnetic field : http://poseidonia.forumpro.fr/t231-le-soleil-le-champ-magnetique
The inclination Earth will cool us http://www.laterredufutur.com/html/modules.php?name=News&file=article&sid=556
Compasses do not end up losing the north :
North magnetic pole and earthquakes today
The increase in the number of strong earthquakes today can be linked to the phenomenon of polar change and are both byproducts of the Earth core turbulent liquid iron and outdoor hot, raging around a solid iron inner core as hot as the Sun and rotate faster than the rotation of the planet itself .
The Earth mantle and crust are floating above an electrically conductive stormy sea which produces molten iron magnetic field of the planet called the dynamo effect . The magnetic north pole was located in 1831 and has been regularly followed up to the most recent measurement taken some time ago in 2001. Meanwhile , the division has proposed an amazing 1.100 kilometers . In fact, since 1970, the division was much faster , from 10 km to 40 km per year , an incredible four-fold increase .
We do not know why there was no mission to physically locate the magnetic North Pole since the last observed position in 2001 . There are only estimates of its current location.
As the speed of its movement has accelerated up by a factor of four in such a short time , it might be reasonable to ask whether his speed has continued to increase since 2001. Apparently the incentive is there to check .
Polar change is caused by substantial changes in the movement of the molten iron outer core .
Dr. Tony Phillips Science News – NASA has identified the following information … About 400 times polar shift took place during the last 330 million years, while the average interval between reversals in recent geological time was about 200,000 years . Reversal of the last field Earth occurred 780,000 years ago and we are apparently very late.
Most of the evidence gathered from the analysis of certain types of rocks indicates that a polar shift inversion process can take up to 1,000 or 8,000 years . However there have also been reports of the process itself completed much faster than that, the most famous story are measures of lava rock at Steens Mountain , Oregon , which indicate that the magnetic field has been moving up to 6 degrees per day for a particular position polar nearly 16 million years.
The process of polar change itself is of concern not only for its effects on the earth such as volcanoes and earthquakes , but if the behavior is such that the first field reduces to zero before reconstruct, Earth will be exposed without sufficient defense to solar radiation, which would be disastrous . In fact , the magnetic field is now rapidly weakening according to some scientists . There are several theories on how a reversal would take place , some still maintain protection against the sun while others do not.
We know that the current magnetic pole shift occurs quickly, and we know that this is the result of an outer core tumultuous evolution . We could conclude that this cause – effect could contribute to other changes observed on the surface of the planet such as the movement of tectonic plates resulting in more earthquakes today. So far in 2010 , we observed a significant increase in earthquakes, especially in the range of magnitude higher . Everything we see here on recent magnetic pole shift and today earthquakes can all be linked and can be reflections of changes occurring deep beneath our feet.
Drift velocity of the position of the magnetic north pole since 1840, based on field measurements (blue curve) and three different geomagnetic models for three different time intervals.
This phenomenon of sudden acceleration is not yet fully explained. It could be related to an increase in the magnetic field flux in the polar region north of the Earth’s core. This would be caused by the expulsion of the magnetic field lines of the core, in a close to the origin of the appearance of sunspots mechanism.
Other article on the same subject:
What created this unusual hole in Mars? The hole was discovered by chance on images of the dusty slopes of Mars’ Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. The hole appears to be an opening to an underground cavern, partly illuminated on the image right. Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep. Why there is a circular crater surrounding this hole remains a topic of speculation, as is the full extent of the underlying cavern. Holes such as this are of particular interest because their interior caves are relatively protected from the harsh surface of Mars, making them relatively good candidates to contain Martian life. These pits are therefore prime targets for possible future spacecraft, robots, and even human interplanetary explorers.
Today February 15, 2013, an asteroid weighing 135,000 tonnes and measuring 45 meters in diameter pass close to our planet to the incredible speed of 28,000 km / h. However, we can breathe. NASA ensures that it will not collide with the Earth.
Note that the meteor that hit the Urals region, north-western Russia this morning, has more than 1,000 wounded (including 200 children) according to the Russian authorities, but this natural phenomenon is not bound to the asteroid that will pass close to Earth tonight.
After the meteor that hit Russia in Friday morning another celestial body came to visit us in the vicinity of our planet. Asteroid 2012 DA14 passed very close to Earth at 14 h 24 (EDT), only 27 700 miles from sol.plus near the geostationary satellites. This celestial body not yet represent any danger.
There would be no link between the two events, according to scientists.
2012 DA14 is about 50 m long and has a mass estimated at 130 000 tonnes (equivalent to 3 carriers). The asteroid was found upright in Indonesia and 8,000 km below the ring formed by the artificial satellite orbit above the equator. Some of them are at 36 000 km, but the risk of collision remained almost nonexistent.
The object reaches the speed of 28 000 km / hour.
Observation impossible with the naked eye
Even if passed very close to Earth, 2012 DA14 was not visible because of its – relative – small. In fact, it is moved to a distance of 14 times closer than the Moon as our planet. In addition, it does not reflect much sunlight. Thus, its brightness has remained lower than any star discernible without instruments.
Amateur astronomers equipped with binoculars, goggles or telescopes have been able to see him in a favorable environment, away from city lights. He appeared as a moving dot as an artificial satellite.
Did you know? 2012 DA14 is known for less than a year. Its discovery, La Sagra Observatory in Andalusia, Spain, dates back to February 22, 2012, during his visit to 2.6 million kilometers away.
In the event that an asteroid struck the Earth size, it would create a crater of a kilometer in diameter and destroy all life in a radius of 20 kilometers.
2012 DA14 loop current its revolution around the sun with a period of 366 days. It belongs to the group of near-Earth asteroids that cross Apollos regular trajectory of the Earth and may thus represent a potential threat of collision.
In June 2004, Apophis, an asteroid of about 325 m (± 15 m) in diameter and a mass of more than 45 million tons has been discovered by astronomers. In its race around the sun, asteroid directly threatens our planet a cataclysmic collision.
For the first time, a NEO , so named in 2004 MNA was ranked second degree on the Torino Scale  explained Donald Yeomans, a scientist at the Jet Propulsion Laboratory of NASA in 2004.
The NEO threat was discovered by R. A. Tucker, D. J. Tholen and F. Bernardi via Observatory Kitt Peak, Arizona, southwest of the United States. NASA immediately alerted its network of ground detection.
Initial estimates indicated when the asteroid that crosses Earth’s orbit twice during its revolution, could meet the Earth’s orbit in April 2029, with a collision unlikely, but not impossible.
Other calculations, dated 31 October 2005, extended the maturity of a cross with the Earth in April 2036 with an assessed risk then one of 5560! This corresponds to level 1 (10) of the Torino Scale. 2004 MNA was then renamed 99942 Apophis , the name of an Egyptian deity of evil and darkness (Apep).
New calculations dated May 6, 2008 dismissed a little more risk of collision. The NEO then had a « chance » to 45000 to collide with Earth April 13, 2036: the level of risk on the Torino Scale pondered 0.
Finally, the latest calculations by NASA October 7, 2009 indicated that the risk of Apophis collision with Earth is no more than 1 in 233,000 for Sunday, April 13, 2036. If we consider all the dates where Apophis would cross the Earth’s orbit, the probability of impact is 1 in 135,000, ie, there is 99.99926% chance that the asteroid not touch the Earth …
Apophis is expected to come close to Earth April 13, 2029
Russian astronomers have confirmed this likelihood, Ria Novosti reported. According to Leonid Sokolov, professor at the Faculty of celestial mechanics at the University of St. Petersburg, « April 13, 2029, Apophis will approach Earth at a distance of about 37,000 or 38,000 miles. There may be a collision with the Earth April 13, 2036. »
In fact, in April 2029 seems more worrisome because Apophis should pass only 30,000 km from the Earth! For comparison, the Moon is distant about 385,000 km from Earth. The NEO frôlerait so the Earth at a distance less than our communication satellites which are in geostationary orbit 36,000 km above the Earth. The object should be visible in the sky is cause a few scares.
Fortunately, for the moment, other researchers, including experts from the Institute of Applied Astronomy of Russian Academy of Sciences, view this as unlikely collision.
These estimates are bound to be refined in the coming years because the trajectory of the asteroid is subject to uncertainty  which may well prove or disprove the likelihood of impact.
Indeed, « the precise determination of the orbit of Apophis is particularly difficult due to the ignorance of the » Yarkovsky effect « , named after the Russian engineer who discovered in the early twentieth century phenomenon: when a celestial body by rotation approaches the sun, it is heated on one side before cooling when turned on itself. This cooling occurs by emitting infrared radiation which creates a thrust infinitesimal but Continuing on the asteroid and thus alters the path « specifies the CNES.
The Apophis asteroid came close to Earth Jan. 9, 2013 about 14,460,000 miles. An opportunity for astronomers to study its orbit and to better assess the risk of collision with the Earth.
Apophis will remain observable with telescopes until February-March 2013 and will again be out of reach until 2021.
Consequences of a collision still unlikely
Scientists, however, indicate that « in the unlikely event where it would crash well, » the meteor that is heated to over 1600 ° C entering the atmosphere, with consequential cataclysmic tsunami (tidal- tide) if he plunges into the ocean,  or massive damage on land and populated areas.
Impact with Earth would release more energy of 506 megatons. It is about 34 000 times the power of the bomb dropped on Hiroshima on August 6 1945 which had then reached a power of about 15 kilotons.
Fear that such an event is raised Apophis is already nicknamed the « destroyer of worlds. »
How to avoid the worst?
If the risk of collision with the Earth fell sharply after the new details about the trajectory of 99942 Apophis, he susbiste doubt about its precise trajectory when it passes near Earth. Thus, Patrick Michel, an astrophysicist at the Observatory of Côte d’Azur showed  that only 600 meters, Apophis could crash into Earth or continue its course in space during its passage 32000 km from the Earth in 2036. This gap will depend on the Earth gravitational perturbations it is, for the moment, not possible to determine.
This is why scientists have insisted that discussions be engaged on ways to avoid disaster or regional warming. Thus, a working group of experts from several countries prepared a draft international treaty to be submitted to the UN in 2009.
Already, examines CNES space mission designed to determine the internal structure of the asteroid and allow to change the trajectory of the NEO, if it should become really threatening.
Several more or less risky ways to deflect Apophis is already considered: explosion, deviation, gravity tractor, satellite parasol …
Some asteroids like Apophis, regularly pass near the Earth. And so the chances of one of them hitting our planet are almost nil, scientists think actively ways to neutralize these cars space and avoid disaster.
Consider ways to deflect the trajectory of the NEO is not in vain because odds are that others will be discovered asteroids threatening the meantime.
Asteroid moving close to Earth
The Torino Scale which comprises 10 degrees assesses the impact probability of asteroid or comet with Earth
Also known as Apep the Destroyer, Apophis is the Egyptian god of evil and destruction who lived in eternal darkness.
Apophis can see its trajectory altered by gravitational perturbations caused by other solar system bodies.
Oceans cover 77% of the surface of the Earth
The Earth-Moon distance is about 384 403 km on average.
Astronomers have long known that many surveys of distant galaxies miss 90% of their targets, but they didn’t know why. Now, astronomers have determined that a large fraction of galaxies whose light took 10 billion years to reach us have gone undiscovered. This was found with an extremely deep survey using two of the four giant 8.2-meter telescopes that make up ESO’s Very Large Telescope (VLT) and a unique custom-built filter. The survey also helped uncover some of the faintest galaxies ever found at this early stage of the Universe.
Astronomers frequently use the strong, characteristic “fingerprint” of light emitted by hydrogen known as the Lyman-alpha line, to probe the amount of stars formed in the very distant Universe Yet there have long been suspicions that many distant galaxies go unnoticed in these surveys. A new VLT survey demonstrates for the first time that this is exactly what is happening. Most of the Lyman-alpha light is trapped within the galaxy that emits it, and 90% of galaxies do not show up in Lyman-alpha surveys.
“Astronomers always knew they were missing some fraction of the galaxies in Lyman-alpha surveys,” explains Matthew Hayes, the lead author of the paper, published this week in Nature, “but for the first time we now have a measurement. The number of missed galaxies is substantial.”
To figure out how much of the total luminosity was missed, Hayes and his team used the FORS camera at the VLT and a custom-built narrowband filter to measure this Lyman-alpha light, following the methodology of standard Lyman-alpha surveys. Then, using the new HAWK-I camera, attached to another VLT Unit Telescope, they surveyed the same area of space for light emitted at a different wavelength, also by glowing hydrogen, and known as the H-alpha line. They specifically looked at galaxies whose light has been traveling for 10 billion years (redshift 2.2), in a well-studied area of the sky, known as the GOODS-South field.
“This is the first time we have observed a patch of the sky so deeply in light coming from hydrogen at these two very specific wavelengths, and this proved crucial,” said team member Goran Ostlin. The survey was extremely deep, and uncovered some of the faintest galaxies known at this early epoch in the life of the Universe. The astronomers could thereby conclude that traditional surveys done using Lyman-alpha only see a tiny part of the total light that is produced, since most of the Lyman-alpha photons are destroyed by interaction with the interstellar clouds of gas and dust. This effect is dramatically more significant for Lyman-alpha than for H-alpha light. As a result, many galaxies, a proportion as high as 90%, go unseen by these surveys. “If there are ten galaxies seen, there could be a hundred there,” Hayes said.
Different observational methods, targeting the light emitted at different wavelengths, will always lead to a view of the Universe that is only partially complete. The results of this survey issue a stark warning for cosmologists, as the strong Lyman-alpha signature becomes increasingly relied upon in examining the very first galaxies to form in the history of the Universe. “Now that we know how much light we’ve been missing, we can start to create far more accurate representations of the cosmos, understanding better how quickly stars have formed at different times in the life of the Universe,” said co-author Miguel Mas-Hesse.
The breakthrough was made possible thanks to the unique camera used. HAWK-I, which saw first light in 2007, is a state-of-the-art instrument. “There are only a few other cameras with a wider field of view than HAWK-I, and they are on telescopes less than half the size of the VLT. So only VLT/HAWK-I, really, is capable of efficiently finding galaxies this faint at these distances,” said team member Daniel Schaerer.