Impact craters is the excavation of the surface of a celestial body when he is hit by a meteor or comet. Impacts are instantaneous events. They leave very striking features

What are craters?

Craters are dug holes, approximately circular, made by impact events. The circular shape is due to the material flying out in all directions as a result of the explosion on impact. Craters are one of the most common surface features in many solid planets and moons. Mercury and our moon is covered with craters. A large number of craters in a region indicates that this part is quite old because geological processes have failed to erase craters over time.

What happens when one hits bolide?

When an impact hits the solid surface of a planet or moon, a shock wave spreads out from the impact site. The shock wave to fracture the rock and dig a large cavity (much higher than the fireball). The impact material is ejected in all directions. The bolide is broken into small pieces and can melt or vaporize. Sometimes the force of the impact is great enough to melt some of the local rock. If a pendulum is big enough to push some material towards the edges of the crater and then drop back to the center, the rock beneath the crater is about to hit jumping up and creating a central peak in the crater. The edges of these larger craters can also fall, creating terraces into the crater.

What are the main parts of a crater?

Floor - The bottom of a crater has a basin shape is flat or generally lies below the level of the surrounding soil.

Central peaks - peaks formed in the central area of ​​the floor of a large crater.

Walls - are the interior sides of a crater, usually steep. They can have ladder-terraces that are created by the fall of the walls due to gravity.

Rim - The rim of the crater. It is raised above the surrounding ground material compound as it is pushed up during the excavation at the end.

Ejecta - material formed by stones thrown out of the crater area during the impact event. It is distributed off the edge of the crater on the surface of coirpo impacted as debris. Can be loose materials or debris mantle around the crater, diluting the outermost regions.

Rays - bright rays extending from the crater, sometimes over long distances, composed of material ejected.

What are the different types of craters?

Simple craters: are small cup-shaped usually has smooth wall. As an example in the picture we have Cyrillus G and Beaumont L.

Complex craters: large craters are with complicated features the largest craters may have terraces, central peaks, several rings, rilles, pyroclasticos deposits, etc. As an example in the picture we Theophilus, Madler and Kant.

Impact basins: are very large impact structures typically more than 300 kilometers of diâmetro.Na Moon large impact basins formed seas with such Crisium, Serenitatis, Nectaris, etc. Large impact basins are also found on other planets, including Mars and Mercury.

Multi-touch basins - A very large impact basin surrounded by up to five or six circular rings of mountain ranges, beyond the edge of the main basin.

Irregular Craters - irregularly shaped craters or more impact craters formed at the same time. Oblong craters can be created by impacts that reach the surface with a very low angle. Ex. Schiller

Degraded craters - Craters more or less worn due to weathering, lava flows, other impacts or downward movement of material. Ex: Cyrillus and Daguerre

What influences the size and shape of a crater?

The size and shape of the crater and the amount of excavated material depends on such factors as the speed and the mass of the impact body and the geology of the site. The faster the input bolide, the greater the crater. Typically, the materials reach the space moon about 10 to 20 kilometers per second. Such high velocity impact produces a crater that is approximately 10 to 20 times larger in diameter than the impacting object. The greater the mass of Bolido, the greater the size of the crater.

Craters are most often circular. But elongated craters can be produced by an impact that reaches the surface in a very low angle less than 20 degrees.

Finally, each crater tells a unique story and reveals a little more of the body's secrets she is.

Source: Lunar and Planetary Institute

Adaptation and text: Avani Soares