An impact winter is a hypothesized period of prolonged cold weather due to the impact of a large asteroid or comet on the Earth's surface. If an asteroid were to strike land or a shallow body of water, it would eject an enormous amount of dust, ash, and other material into the atmosphere, blocking the radiation from the Sun. This would cause the global temperature to decrease drastically. If an asteroid or comet with the diameter of about or more were to hit in a large deep body of water or explode before hitting the surface, there would still be an enormous amount of debris ejected into the atmosphere. It has been proposed that an impact winter could lead to mass extinction, wiping out many of the world's existing species. The Cretaceous–Paleogene extinction event probably involved an impact winter, and led to mass extinction of most tetrapods weighing more than 25 kilograms (55 pounds).
Each year, the Earth is hit by diameter meteoroids that deliver an explosion above the surface with the power equivalent of one kiloton of TNT. The Earth is hit every day by a meteor less than in diameter that disintegrates before reaching the surface. The meteors that do make it to the surface tend to strike unpopulated areas and cause no harm. A human is more likely to die in a fire, flood, or other natural disaster than to die because of an asteroid or comet impact. Another study in 1994 found a 1-in-10,000 chance that the Earth will be hit by a large asteroid or comet with a diameter of about during the next century. This object would be capable of disrupting the ecosphere and would kill a large fraction of the world's population. One such object, Asteroid 1950 DA, currently has a 0.005% chance of colliding with Earth in the year 2880, though when first discovered the probability was 0.3%. The probability goes down as orbits are refined with additional measurements.
Over 300 short-period comets pass near larger planets, such as Saturn and Jupiter, which can change the comets' trajectories and could potentially put them into an Earth-crossing orbit.
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Introduction à la physique des plasmas destinée à donner une vue globale des propriétés essentielles et uniques d'un plasma et à présenter les approches couramment utilisées pour modéliser son comport
Nuclear winter is a severe and prolonged global climatic cooling effect that is hypothesized to occur after widespread firestorms following a large-scale nuclear war. The hypothesis is based on the fact that such fires can inject soot into the stratosphere, where it can block some direct sunlight from reaching the surface of the Earth. It is speculated that the resulting cooling would lead to widespread crop failure and famine.
An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, though atmospheres mitigate many surface impacts through atmospheric entry.
Explores polymer collapse, protein folding, and interactions, emphasizing the role of hydrophobicity and attractive forces.
Underground storage of radioactive waste is consensually recognised as the safest storage solution by European and worldwide countries relying mainly or partially on nuclear energy production. Over twenty years of research led by the French national agency ...
EPFL2024
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The objective of this study is to address the difficulty of simplifying the geometric model in which a differential problem is formulated, also called defeaturing, while simultaneously ensuring that the accuracy of the solution is maintained under control. ...
In this study, we present results from continuous field monitoring and a flume ex-periment of a sediment augmentation measure in a residual flow reach of the Swiss midlands. A straight morphological channel with fixed bed material was constructed to repres ...