Comets and asteroids have created great impacts on the earth systems throughout history. For instance, astrologists have identified close to 170 impact craters on earth, with diameters of not less than 250km and age of up to two billion years. Upon impact, these extraterrestrial objects transfer energy through ultra-high-pressure shockwave to the intended rock, thus creating shocking metamorphic effects in rocks.
Markedly, during the formation of planets, close to one trillion asteroid bodies collided to form 30 young planets; they had individual masses of about 10% that of the Earth. The embryos went through giant collisions to form a few planet-sized bodies. At one point, a giant impact led to the formation of the moon and immense re-melting of the Earth that made the original atmosphere to disappear.
On the moon, successive collisions led to the formation of 6,000 craters with a radius greater than 6 miles. Additionally, impact collisions formed the South Pole Aitken basin, which has a radius range of 150km to 1250km and Procellarum basin of 1750km in radius.
Recently, subsequent collisions formed large craters such as Manicouagan in Quebec, which has a diameter of 100km and over 212 million years old. Such impacts released energies that can form destructive surface blast-waves that can cover over a million square kilometers. According to NASA, a giant asteroid of 6 miles in diameter killed the dinosaurs. About 1.8 to 2.5 billion years ago, four asteroids impacted the moon while seventy asteroids hit the Earth.
The extraterrestrial impact that killed the dinosaurs formed a spherule layer that had a depth comparable to those of the Archean times. At the seas, muds remain deposited at the beds beyond the reach of waves. Notably, 65 million years ago, a key collision at the Cretaceous-Tertiary (K/T) boundary led to mass extinction in the terrestrial biosphere.
Chemical anomalies, shocked, and melted materials show further evidence of the massive impact. Also, the K/T occurrence formed the 180-kilometer Chicxulub crater in Mexico. Extraterrestrial impacts have also ejected a lot of dust into the atmosphere; the effect has resulted in the termination of photosynthesis and reduction in land temperatures below the freezing point.
Continuous bombardments of the extraterrestrials within the solar system have led to the formation of beds. Spherule beds came into being during the Archean period due to twelve mighty-impacts. Planets such as Saturn, Neptune, Uranus, and Jupiter moved to their present orbits due to the bombardment of asteroids. The young planet Earth, moon, and comets underwent bombardments with space rocks, thus making them move towards the inner solar system.
As an asteroid moves into the upper atmosphere, it penetrates deeper layers, thus increasing the density of the atmosphere. The air begins to form blasts and shockwaves in front of the asteroid. When the asteroid strikes the Earth, the potential energy transforms to kinetic energy, thus propelling the hot air into the atmosphere.
Strikingly, the sudden impact generates heat that vaporizes the object. The rapid transformation of state forms a hot air blast that travels upward at high speed. The high speed and temperature of the air blast can destroy objects within a 1600km radius.
When asteroids and comets strike any place in the earth system, they cause devastating effects. For instance, a 10-kilometer asteroid can terminate all forms of life in the earth systems. When the hot air moves into the upper atmosphere, high-speed winds disperse it around the globe hence resulting in thermal radiation.
On the other hand, when the material radiates downwards, it heats the earth’s surface to close 1000o centigrade. Consequently, spontaneous fires set in covering large portions of the earth. Besides, asteroids that impact in the ocean causes shockwaves that generate into a tsunami.