On the occasion of the anti-aircraft causing the fall of the NASA satellite, the landing of aliens… the fall of the meteor Kyiv on April 19, 2023, let’s remember the previous “visits” of extraterrestrial guests to Earth, which, fortunately, did not kill us.

The probability that you will be killed by a meteorite is extremely small, especially now, when there are many more reasons to fear for your own life and the lives of your loved ones. But several cases of space rocks hitting buildings, cars and people have been officially recorded. On the other hand, the probability that humanity will ever be destroyed by a random asteroid is heading toward one. Not only that, there have already been cases in the history of the Earth when space guests became the cause of catastrophic mass extinctions, which significantly thinned out the “population” of the planet. Where on Earth can you find scars from these cosmic catastrophes, and what were the consequences of falling meteorites in the past?

At the beginning of the article, there is a photo of the most famous meteorite crater on Earth – Arizona. It is young, it is only 50 thousand years old.

Why are there fewer craters on Earth than on the Moon?

Earth’s cosmic scars: meteorites that didn’t kill us

The huge Herschel Crater makes Mimas, one of Saturn’s moons, very popular with Star Wars fans.

There are far fewer visible meteorite craters on Earth than on the Moon, Mars, moons of the giant planets, and large asteroids. Much less. However, the Earth is bombarded by meteorites no less often than other celestial bodies. Astronomers estimate that hundreds of meteorites with a total weight of 5-6 tons fall to Earth every day, which gives an impressive figure of 2 million kg of celestial stones every year.

But only a small part of these space guests reaches the Earth’s surface. Most of the small and medium-sized meteorites burn up in the atmosphere, leaving an alarm and a beautiful fiery streak in the night sky, as it was on April 19, 2023, over Kyiv. Bigger stones lose speed and fall to the ground leaving craters or without causing significant damage. But disasters happen in the history of the Earth that are remembered for a long time, such as the well-known fall of a meteorite on the Podkamennaya Tunguska River in June 1908.

Earth’s cosmic scars: meteorites that didn’t kill us

Here, for example, is a map of the fall of meteorites from 2300 BC. to 2013. The size of the point corresponds to the mass of the object. It should be understood that the absence of identified traces of meteorites in the Amazon jungle, Central Africa, Siberia, and Canada is due only to the difficulty of searching in these areas.

According to scientists’ calculations, a meteorite with a diameter of about 10 m falls to Earth approximately once every 4 years. Once every millennium, a larger “gift” arrives – an asteroid up to 100 m in size.”Pebbles” 1 km in size fall once every 250 thousand years, and once every 70 million years our planet is “lucky” to catch a celestial body with a diameter of 10 km. It would seem that only these huge meteorites during the long history of the Earth should have completely covered the surface of the planet with craters of considerable size. So where are the tracks?

Earth’s cosmic scars: meteorites that didn’t kill us

Unlike our celestial neighbors, the Earth has an atmosphere, which means that winds, rains, snows, and other hurricanes are the free beauticians of the planet. Over a millennium, let alone a million years, erosion phenomena are capable not only of “hiding” a meteorite crater of any size but also of erasing whole mountain massifs into the sand. Do not forget about sedimentary rocks either – many impact craters are buried under a hundred or more meter layer of organic sediments. Meteorites that fell into the water, which covers 71% of the Earth’s surface, were even less lucky – their traces can no longer be found, and they perished in the abyss. Plus other masking factors: movement of tectonic plates, volcanic eruptions, mountain formation processes, etc.

In a word, meteorite craters on Earth are well disguised. Traces of small meteorites that fell more recently on a geological scale can still be found, such as this relatively young impact crater Pingahualuit in Canada, which is 3.44 km in diameter and about 1.4 million years old. But the scars left by large celestial bodies millions of years ago are still the subject of controversy among scientists. Let’s get acquainted with the most famous and largest meteorite craters of Earth.

Old scars of the Earth

The beautiful word astrobleme, which is a combination of two Greek words – άστρον (star) and βλήμα (wound) is used to denote large impact craters with a diameter of more than 2 km on the Earth’s surface. That is, these are star wounds. The Planetary and Space Science Centre (PASSC) deals with the classification and accounting of impact craters on Earth in Canada and maintains an Earth Impact Database (EID) of such objects. Until scientists reach a consensus on the origin of the crater or geological structure, it will not be listed in the EID. The largest officially confirmed astrobleme according to PASSC is the Vredefort crater in South Africa, with a diameter of 160 km. At the same time, if you count all the geological structures “affected” by the impact, you can take the diameter of Vredefort as 300 km.

The largest crater in the solar system is on Mars. This is the North Polar Basin, which occupies about 40% of the planet’s surface. Scientists believe that this crater was left by a huge asteroid with a diameter of 1,600-2,700 km, which moved at a relatively low speed in cosmic terms – 6-10 km/s. That is, in essence, it was a collision of two planets.

But let’s return to Earth. Below we will consider the most interesting of the large impact craters.

Warburton Basin (Australia, diameter 400 km)

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The latest discovery by scientists, which has not yet been entered into the Earth Impact Database. At the end of March 2015, Australian researchers reported that, based on the analysis of the results of deep drilling in the Warburton basin, which lies on the border of the regions of South Australia, the Northern Territory, and Queensland, it can be concluded that it has an impact origin. The reason for the appearance of this astrobleme is the fall of an asteroid, which split into two fragments of approximately 10 km each before impact. That is, they are actually two craters with a diameter of about 200 km each, which intersect with each other. Traces of craters on the surface have already been erased by time because their age is approximately 300-600 million years.

Interestingly, not far from this place, there is another potential astrobleme – the Australian impact structure, 600 km in diameter, located between two popular attractions of the Northern Territory – the red rocks of Uluru and Mount Conner. The age of this structure, which has not yet been confirmed as an astrobleme, is about 545 million years.

Vredefort Crater (South Africa, diameter 160 km)

Earth’s cosmic scars: meteorites that didn’t kill us

The largest officially confirmed astrobleme and one of several multi-ring (which is clearly visible in the photo) impact craters on Earth. Plus one of the oldest. It appeared about 2 billion (2023 ± 4 million) years ago as a result of the impact of an asteroid with a diameter of about 10 km. The outer diameter of the structure is 300 km, and the inner diameter is 160 km. Inside the crater are four cities (the largest is Parys with a population of almost 50,000), one of which gave the astrobleme its name. In 2005, Vredefort Crater was included in the list of UNESCO World Heritage Sites.

Chicxulub Crater (Mexico, diameter 150 km)

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The celestial body “responsible” for the appearance of the Chicxulub crater is also accused of mass murder. A 10-kilometer meteorite that fell 66 million years ago on the Yucatan Peninsula caused a 100-meter-high tsunami that went far inland, as well as massive forest fires throughout the Earth. Soot particles raised into the air blocked the sun and caused something like a nuclear winter. It was this event, according to scientists (far from all), that caused the mass Cretaceous extinction, the victims of which were, in particular, dinosaurs.

The initial depth of the crater was 20 km with a diameter of 180 km, and the impact energy reached 100 teratons in TNT equivalent. The largest hydrogen bomb created by the USSR had a power of only 0.00005 teratons. Unfortunately, the time has erased all visible traces of the Chicxulub Crater.

Some researchers support the multiple impact theory, according to which several meteorites hit the Earth almost simultaneously, which caused the Cretaceous extinction. One of the components may have fallen on the territory of modern Ukraine, creating the 24 km diameter Boltysh crater in the Kirovohrad region. The term “at the same time” should be understood on a geological scale, which means “with a difference of only thousands or tens of thousands of years.”

Sudbury Crater (Canada, diameter 130 km)

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Over the past 1849 million years since Sudbury Crater was formed, tectonic processes have distorted its original shape, turning the once round crater into an elliptical one. The culprit of the appearance of the second largest crater on Earth is an asteroid measuring 10–15 km. The impact was so powerful that debris covered an area of 1,600,000 km², and individual fragments flew 800 km away, they are even found in Minnesota.

The meteorite literally split the earth’s crust, the crater was filled with hot magma, rich in metals – copper, nickel, platinum, gold, and palladium. Therefore, today Sudbury is one of the world’s largest mining regions and a well-populated place. The mineral-rich soil made the crater some of the best farmland in Northern Ontario. On the edge of the crater is the city of Greater Sudbury with a population of 160,000.

Popigai Crater (Russia, diameter 90 km)

Earth’s cosmic scars: meteorites that didn’t kill us

The crater is located in northern Siberia, partly in the Krasnoyarsk krai, partly in Yakutia. The nearest settlement, the village of Khatanga, is 400 km away. The crater was formed 35 million years ago almost simultaneously with the Chesapeake crater (diameter 40 km) on the east coast of the USA in the state of Virginia. Scientists link both of these events to the Eocene-Oligocene extinction, which was second in magnitude to the five most severe mass extinctions in Earth’s history, but killed 3.2% of marine animals (15% at the genus level). The Popigai Crater is filled with small impact diamonds, but due to its remote location, no one is mining them.

Acraman crater (Australia, diameter 90 km)

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This crater, which became the “base” for the drying Lake Acraman in South Australia, was created by a fast (25 km/s) meteorite with a diameter of 4 km about 580 million years ago. Debris was scattered over a distance of up to 450 km. The characteristic shape of Lake Acraman reminds us of the reason for its emergence.

Manicouagan Crater (Canada, diameter 85 km)

Earth’s cosmic scars: meteorites that didn’t kill us

One of the most visible large craters on Earth ( a view of the crater from aboard the Columbia space shuttle in the picture). Today it is a ring lake of the same name. It arose 215 million years ago as a result of an asteroid impact with a diameter of about 5 km. For a long time, the meteorite that created the crater was believed to be the culprit of the mass extinction in the late Triassic, but recent studies have debunked these accusations.

There is a theory that at the same time or almost simultaneously (on a geological scale) with the asteroid that “created” Manicouagan, four more celestial bodies fell to Earth, including the meteorite responsible for the Ukrainian Obolon crater near the village of Obolon, Poltava region.

Impact craters very often become lakes. The largest include Lake Karakul in Tajikistan – 25 million years old, crater diameter 52 km or Lake Taihu in China – 360-415 million years old, 65 km.

Meteorite craters of Ukraine

Thanks to the stability of the Ukrainian crystal shield, several large astroblemes have been preserved on the territory of our country, moreover, their density is the highest in the world. All craters on the territory of Ukraine are under a layer of organic deposits with a thickness of 100 to 500 m, that is, no signs of astroblemes are visible on the surface.

The largest of the potential Ukrainian astroblemes – Manevychna in the Volyn region, near the village of Krymne, has a diameter of 45 km and appeared probably 65 million years ago. The origin of this structure is still a matter of dispute.

Earth’s cosmic scars: meteorites that didn’t kill us

The Boltysh depression in the Kirovohrad region near the village of Bovtyshka has a diameter of 25 km and was formed 65 million years ago, just 2-5 thousand years earlier than the Chicxulub crater, which confirms the multiple impact theory as the cause of the Cretaceous extinction.

The Obolon crater in the Poltava region appeared 170 million years ago and has a diameter of 20 km. According to some researchers, it arose at the same time as Manicouagan (Canada), Rochechouart (France), Saint Martins (Canada), and Red Wing (USA).

The Ternivka crater in Kryvyi Rih is 280 million years old and 12 km in diameter. The Terniv district of the city and several mining quarries are located right in the crater.

The Bilylivka crater (6.2 km) in the Zhytomyr region appeared 165 million years ago, the Ilyinetscrater in the Vinnytsia region with a diameter of 4.5 km – 400 million years ago. The Rotmistrivka crater in the Cherkasy region and the Zeleny Gai crater in the Kirovohrad region are 120 million years old and have diameters of 2.7 and 2.5 km, respectively.

False astroblemes

Earth’s cosmic scars: meteorites that didn’t kill us

It would seem that with the current level of technology, and the presence of a huge number of satellites that capture the Earth from all conceivable angles and optical ranges, the search for astroblemes should be simplified, but it is not. Moreover, many cyclic structures clearly visible from space, which, at first glance, cannot be anything other than impact craters, are actually not such.

So, for example, the perfect Nastapoka arc in Hudson Bay has long been considered the outer shaft of a huge, 450-kilometer crater hidden underwater. Research in 1976 showed a complete absence of minerals and debris characteristic of impact structures. Currently, it is believed that the arc arose naturally in the process of mountain formation.

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Another good example of a false astrobleme is the Eye of the Sahara, the Richat ring structure, 50 km in diameter in Mauritania. At first, it was believed that Richat is a typical impact crater, but the flat shape of the floor and the absence of impact rocks disprove this idea. According to the current version, the structure owes its shape to the erosion of sedimentary rocks.

The biggest sky stone

The largest meteorite found on Earth came to us 80,000 years ago and was found in 1920, near the Hoba West farm in Namibia. It was given the name Hoba after the name of the area. The heavenly stone was found by accident, during the plowing of the field, no crater remained around it, it is believed that the fall occurred at a low speed and was not accompanied by a significant release of energy.

Earth’s cosmic scars: meteorites that didn’t kill us

The Hoba iron meteorite, which most resembles an ancient altar, measures 2.7 x 2.7 x 0.9 meters and is 84% iron plus 16% nickel. The mass of the “bar”, which was never weighed, was estimated in 1920 at 66 tons. As a result of oxidation, the taking of scientific samples, and vandalism, the meteorite lost weight to 60 tons. However, it still remains the largest piece of non-man-made iron on the planet.

Nuclear crater

The crater on the site of Elugelab Island, which was once part of Eniwetok Atoll, which in turn belongs to the Marshall Islands, is not related to astroblemes, but it best illustrates the consequences of human activity.

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A hole with a diameter of 1.9 km and a depth of 50 m remained after the world’s first test of a hydrogen bomb on November 1, 1952. The Ivy Mike device, which had no practical military value due to its size, was intended exclusively for testing a two-stage design in which a nuclear bomb was used as “ignition” for a hydrogen bomb. The power of the explosion is estimated at 10-12 megatons in TNT equivalent.

Victim #1

The only documented case of a meteorite hitting a person occurred on November 30, 1954, in the United States. The 3.86 kg meteorite, later named Sylacauga, pierced the roof of the Hodges family home, bounced off a radio set on a table, and struck 31-year-old Ann Elizabeth Hodges, who was dozing on a couch. The sky stone was slowed down by the Earth’s atmosphere and roof covering so that it did not cause Ann Hodges serious injury, the woman got only bruises. The next day, a second fragment of the same meteorite, weighing 1.68 kg, was found by Julius C. McKinney, a neighbor of the Hodges family. Ann Hodges didn’t make money on her popularity, but her neighbor sold a meteorite and repaired his farm.

Planetary Defense

In the press, especially the yellow press, there are often reports about the approach of another asteroid approaching the Earth capable of destroying all living things. Indeed, modern detection means, space and ground telescopes are capable of spotting even a relatively small celestial body. But the detection happens, as a rule, only a few days before the passage of the space object at the minimum distance from the Earth. And most often already after the maximum convergence.

Asteroids ranging in size from 10 to 150 m fly past our planet, including at a distance of only 14 thousand km (slightly larger than the diameter of the Earth), almost every year. Such objects were discovered in 2005, 2006, 2008, 2009, 2010, 2011, and 2014, but none of them received a significant danger rating.

For example, asteroid 2009 VA, 7 m in size, flew by on November 6, 2009, just 14,000 km from Earth. It was discovered 15 hours before the approach.

Earth’s cosmic scars: meteorites that didn’t kill us

But humanity already has the tools to defend against unwanted visitors from outer space, at least against some of them detected in advance. September 26, 2022, NASA’s Double Asteroid Redirection Test (DART) probe hit asteroid 65803 Didymos I (or Dimorphos) measuring 177 × 174 × 116 m and weighing 1.33–4.3 million tons at a speed of 6.6 km/s. A head-on collision between the 500-kilogram DART and the asteroid released approximately 11 GJ of energy, equivalent to detonating 3 tons of explosives.

Earth’s cosmic scars: meteorites that didn’t kill us

The last picture that DART transmitted to Earth before the collision with the asteroid.

Such a collision was expected to reduce Dimorphos’ orbital velocity by 1.75–2.54 cm/s. It’s not much, but it proves the concept. At the same time, with the early detection of a threat due to large distances, such a correction is enough to divert a potentially dangerous asteroid from the Earth.

The DART impact shortened Dimorphos’ orbital period around Didymos, and Dimorphos acts as a companion to a larger asteroid, for 33 minutes and ejected more than 1 million kilograms of debris into space, creating a dust plume more than 10,000 kilometers long. This dust tail persisted for several months. According to scientists, the DART impact caused significant deformation of the Dimorph surface and left a crater several tens of meters in size.

The European Space Agency’s Hera mission, due to launch in October 2024, is going to investigate in detail the effects of the collision between DART and Dimorphos and measure the exact difference in velocities after the impact in 2026.

Planetary protection of the Earth has already been tested, and if astronomers detect potential threats in advance (a few years beforehand), and politicians don’t cosplay Don’t Look Up, let’s hope that the meteorites that will kill us never appear.

For independent study

Earth Impact Database – officially recognized impact craters sorted by age, diameter, and regions.

Meteor Impact Viewer – a Google map with meteor craters built on the basis of the Earth Impact Database.

The original of this article in Russian was published on the website gagadget.com. Before you is the supplemented and corrected version of the material.

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