In the cold autumn of 2182, humanity must rally together to survive the impending collision with asteroid Bennu.
The asteroid Bennu is considered one of the most dangerous among those already detected. A collision with it is quite probable.
Let's Feed on Plankton
The scale of the impending disaster that the asteroid Bennu seems poised to cause in 157 years has been assessed by South Korean scientists at the Center for Climate Physics at Pusan National University. They modeled the catastrophe and provided some reassurance: a 500-meter rocky mass will not bring about an apocalyptic end of the world, leaving no survivors on Earth. It's too small for that. However, it will cause significant damage, especially if it lands in a densely populated area. The Earth as a whole will also suffer substantial harm.
According to the simulation results, the explosion from an asteroid striking land could launch between 100 to 400 million tons of dust into the atmosphere. This release would alter the chemical composition of the atmosphere and disrupt the climate. The Earth would darken and cool down. The average global temperature at the surface could drop by 4 degrees—not a severe "nuclear winter," but close to it. Additionally, global precipitation would decrease by 15 percent.
Even more concerning is the conclusion from the Korean researchers that the ozone layer would be harmed—thinning by about a third. This would severely impact plant and animal life. The situation would be worsened by sudden, cold "twilight," leading to decreased photosynthesis. "This," the researchers cautiously state, "will likely lead to widespread disruptions in global food security." In essence, they are predicting a decline in agriculture and famine for humanity.
On a somewhat positive note, iron from the dust ejected by the asteroid and the dust itself will "nourish" marine diatoms, which are food for zooplankton. Both will increase in volume.
According to the Koreans, if plankton is used as food, hunger won't be as dire.
Bennu is taller than an American skyscraper but shorter than the Ostankino Tower. The tower is 525 meters tall.
Who Will Suffer the Most
British scientist Nick Bailey from the University of Southampton developed mathematical software for the NEOimpactor program back in 2007, which estimates the potential damage from the impact of relatively small celestial bodies, like Bennu and similar objects.
Nick created a sort of "damage ranking," identifying the ten most vulnerable countries where destruction and casualties would be most horrific. Some may even be unable to recover.
Western Europe, North America, and the Far East will be hit hardest. Specifically (according to the ranking) China, Indonesia, India, Japan, the USA, the Philippines, Italy, the UK, Brazil, and Nigeria.
Areas (in red) where impacts would result in the highest human losses (above). Below are areas with the most significant damage to human infrastructure.
Russia did not make it into the "deadly ten." This is likely due to the fact that large swathes of our territory are uninhabited—just nature. Little has changed there since the Tunguska meteorite fell in 1908. It fell, and what happened? Not a single house was destroyed. No one was killed. Yet it became a globally significant event.
What If It Hits Water? Nothing Good Either
One can hope that Bennu will crash into the ocean, which covers over 70 percent of the Earth's surface. There would likely be no casualties or destruction—this is certainly a good thing. However, the asteroid would create a water "fountain" with a diameter of a thousand kilometers, shooting up to over 100 kilometers high.
Modeling conducted by Elisabetta Pierazzo from the Planetary Science Institute in Tucson, Arizona, showed that splashes and vapor would release 42 billion tons of water into the atmosphere.
Chlorine and bromine compounds found in seawater would destroy the planet's ozone layer. An ozone hole formed above the impact site would rapidly expand to cover about 70 percent of the Earth's surface, primarily affecting the Northern Hemisphere. As a result, harsh ultraviolet radiation would bombard the ecosystem through this hole.
People will surely come up with ways to protect themselves—hiding or applying something to their skin. However, animals, plants, and especially the zooplankton, on which the Koreans are relying, will undoubtedly suffer.
An image from the study on modeling an asteroid impact in the ocean.
Who knows, perhaps it was precisely ultraviolet radiation that doomed the dinosaurs 66 million years ago—"burning" them after a massive asteroid—10 to 15 kilometers in diameter—struck what is now the (for now) Gulf of Mexico. It’s reasonable to assume it "splashed" into the atmosphere with far greater force.
If Bennu were to plunge into the ocean, it would certainly generate monstrous waves—tsunamis hundreds of meters high. However, they would rise close to the impact site and quickly "subside." Already 30 kilometers from the epicenter, the waves would travel as 60-meter walls. A thousand kilometers away, their height would not exceed 10 meters. This was determined by Norwegian scientists led by Galen Gisler from the University of Oslo.
Galen is more concerned about the splashes. He warns that they would not only shoot upwards but also sideways—at speeds of 300 meters per second. Such forces would sweep away everything in their path if the asteroid fell near the shore.
It’s logical to assume that the water lifted into the atmosphere would return as rain. Yet scientists tend to overlook this aspect of the catastrophe. What if it rains for 40 days and 40 nights? Just like when old Noah was saved in his ark?
BY THE WAY
How Do We Know Bennu Will Hit Earth?
The asteroid Bennu, also known as 101955, was discovered in 2013. Astronomers classified it as an Apollo group asteroid—those rocky bodies whose orbits cross that of our planet from the outside.
Scientists from NASA have confirmed that Bennu indeed poses a threat to us. Data from the OSIRIS-REx spacecraft (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) helped. It was in close proximity to the asteroid and even landed on it to collect soil samples. These measurements allowed for a more precise orbit calculation and an estimation of the chances of its collision with Earth. Unfortunately, the results confirmed: there is a possibility. Although not as soon as previously thought.
From earlier approximate calculations, it was suggested that a collision could occur on September 25, 2135. No, scientists assured: on that day the asteroid will pass by, albeit very close in cosmic terms—at a distance roughly equal to half the distance from Earth to the Moon.
In refining Bennu's orbital parameters, NASA took into account all possible "force" influences on the asteroid's movement—the gravitational pull of the Sun, Moon, neighboring planets, 300 other asteroids, and even the push the rock experienced when OSIRIS-REx touched it to collect soil samples. Scientists guarantee that a catastrophe is ruled out in 2135. However, the next dangerous close approach expected on September 24, 2182, unfortunately, poses serious troubles.
The odds of a collision in 157 years are estimated by NASA to be 1 in 2700, or 0.037 percent. This means it is possible. Scientists, however, optimistically emphasize that the probability of avoiding a catastrophe exceeds 99.9 percent. That's much higher than the likelihood of encountering it.
Doubts arise from the Yarkovsky effect and Earth's gravity. Both could alter Bennu's orbit: our planet might slightly attract the asteroid, or the effect could push it slightly towards us.
The Yarkovsky effect occurs due to the Sun's thermal influence on the surface of a rotating body. The surface heats up under direct sunlight and cools down when it turns away—showing another side to the Sun. The asteroid emits photons in the process; the cold side is smaller than the heated side. As a result, a thrust is created—a reactive force. This force is minuscule—only a few grams—but it acts constantly. And as NASA has confirmed, it exists.
Final adjustments will be made by scientists in 2135—after the asteroid passes between the Moon and Earth. For now, the odds that a catastrophe will occur before 2300 stand at 1 in 1750—0.057 percent. Again, not a zero probability.