The end of the world is in doubt faster than one thinks
In summer nights, people spare the sky to discover shooting stars and want to wish something. But if rough chunks hit on the earth, then it becomes danger to a global climate catastrophe could be the result at worst. Now scientists have proven that the way from asteroids to earth can be short than previously thought.
Between Mars and Jupiter circles a whole lot of smaller and coarse boulders, which are called asteroids or planetoids. They are too small to apply as planets, but there is probably more than a million of them with a diameter of several kilometers. The biggest among them, Ceres always has an eup of 960 times 932 km.
Schematic model view of a (simple) irradiation history of a meteoroid
The potential meteoroid (green) is shielded deep in its mother corper before cosmic radiation (red) A violent collision destroyed the mother corper and the meteoroid (grun) starts his journey through all During his journey, the meteoroid of cosmic radiation is exposed. There are new atoms (so-called. COSMOGEN NUCLIDE = CALLATION PRODUCTS). The travel time corresponds to the irradiation age. After his case on the earth’s surface (here Antarctic), the Earth’s atmosphere protects the meteorite against primary cosmic radiation
Pictures: Philipp Heck
Again and again they crash against each other, these static collisions they also owe their strange shapes that are the nickname "Stone potatoes" brood. Through the combiner also causes trumbler stucco, which can be drawn as a meteoride (definition: extraterrestrial body in centimeter and meter grooves prior to passing through the atmosphere) towards earth. He then glows in the ATMSphare glory, he becomes a meteor, he hits on the ground, is called him meteorites. But the way to then is long.
However, they have been severely understood in their journey speed, like Phillipp R. Heck, Heinrich Baur and Alex Halliday and Rainer Wieler from the Swedish University of Technology Zurich and Birger Schmitz from the Swedish University of Lund in the current ie of the Science Journal Nature.
AsteroidsTrummer on a quick collision course
The meteoride noise in Expresspo. 480 million years ago, it crumbled in the asteroid streets and then a meteor showers rained down on the earth. But how long traveled the breakpoints until they reached our world? Having much had been speculated in recent times, because calculations were the broad amption, they had used several million years for their trip, to whale. What was missing was a handful proof. The team has now provided the team.
Computer simulations show that most fragments of asteroids, which crash, sturle directly into the sun. Some breakpoints also fly through all and are really after millions of years in our atmosphere. But this does not apply to the chunks and punching, which in the places in the asteroid streets, where the circulation time of an object around the sun is a multiple of the circulation time of the giant planet Jupiter. Your train is by resonances. The episode is an express journey time of only a few hundred thousand years to the earth.
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If asteroids sail through the interplanetary space, they are exposed to a bombardment of cosmic radiation. This bombardment of lost reactions (spallation), which are the creation of noble gases such as helium and neon, which no chemical reaction. If the meteorite hit the earth, this process is stopped. The concentration of the noble gases thus lies to direct jerks on the journey time: the high the concentration, the longer the meteorite was traveling (irradiation age of meteorites).
The group around Heck examined meteorites, so-called chondrites, from sediments in Sud-Sweden, which are 480 million years old. The Auberrish stucco were found in a quarry in the middle of ancient sea deposits.
The ETH Zurich has a highly sensitive mass spectrometer with the lousy name "Tom Dooley", which allows the Meng smallest gas quantities themselves from dustcorners. It realized that the chondrites had traveled by express. In your press release, the researchers draw the conclusion:
The short irradiation age is an indication that the collision occurred in the near a rail resonance in the Asteroid Turtle. In addition, it is possible for the fossil meteorites from Sudschweden to come from the same event. The newly developed method of the institute for isotopen geology makes it possible to confirm theories about the behavior of donations in space. This facilitates the researchers essential to predict future collisions with our planet.
Danger and defense
Daily paws about one hundred tons of interplanetary material on the earth, most of them glad far over our power. Whether for the extinction of the dinosaurs 66 million years ago really a meteor impact is mainly responsible, is currently being discussed at the time"The dinosaurs are getting sad .."To). It is clear that a correspondingly huge asteroid destroys our world or at least could destroy all life on her. How often such an event is likely is still debated, but the science community takes the risk very seriously (pancakes against fragments).
Internationally, Near Earth Objects (NEO) are intensively observed, NASA operates its own program for this purpose. But the ESA also rusts (ESA Considers The Next Step in Assessing The Risk from Near-Earth Objects). The Europeans want to be the first one with the mission "Don Quichotte "A asteroid with collision course on the earth can throw the course (Sancho observed Hidalgo).