2021-10-17

Physicists have proposed a new way to protect the earth from cosmic rocks

By yqqlm yqqlm

When they prepared for this once-in-a-decade event, they did not realize that another celestial fragment was flying towards the earth in a more direct direction. On February 15, 2013, Chelyabinsk meteor, an asteroid with a diameter of about 62 feet (19 meters), exploded over Chelyabinsk City, Russia. It entered the earth’s atmosphere at a shallow angle. The explosion shattered windows, damaged buildings and injured nearly 2000 people, but fortunately no one died

Philip Lubin, Professor of physics at the University of California, Santa Barbara, said: “it has been proved that there are two completely independent asteroids to pass that day. One of them we know will miss the earth. The other, we don’t even know its arrival.” it is reported that Lubin is one of many scientists looking forward to the 2012 da14 near earth rendezvous

for Lubin and scientists like him, events like this emphasize the importance of strong Planetary Defense – detection, tracking, characterization and ultimately defense against potentially dangerous asteroids and comets. Events that threaten cities like Chelyabinsk are rare and occur about every 50 to 100 years, but they can be devastating. The most recent of these events was the Tunguska incident. An air explosion over eastern Siberia in 1908 destroyed hundreds of square miles of forest. More rare, but still possible, are objects threatening mass extinction, such as the Chicxulub meteorite impact that wiped out dinosaurs about 66 million years ago, or the more recent (12800 years ago) air explosion caused extensive combustion and the beginning of the “impact winter” known as the young dry period

however, we cannot rule out the possibility that larger objects will approach the earth uncomfortably in the near future. Apophis, with a diameter of 1214 feet (370 meters), will pass close on Friday, April 13, 2029, while Bennu, with a diameter of 1608 feet (490 meters), is expected to make a similar pass in 2036. Although they are not expected to hit the earth, even relatively small changes in their orbits may cause them to enter a gravitational bag called a “keyhole”, placing them in a more direct orbit towards the earth

Physicists have proposed a new way to protect the earth from cosmic rocks

Lubin said: “if it passes through the gravitational keyhole, it will generally hit the earth in the next round.”

the strategy of Planetary Defense has evolved from studying better ways to understand threats to trying to deflect potential dangers and change their orbits

in two papers on terminal Planetary Defense submitted to advances in space research and a review article published in Scientific American, Lubin and co researcher Alexander Cohen proposed a more proactive approach to deal with dangerous extraterrestrial space debris. The project is called pulverize it, or PI for short

prepare for the inevitable — do it or not

“although we often say that nothing in life is certain except death and taxes, we can certainly add the extinction of mankind to this list,” Lubin said. “There is a large asteroid or comet lurking in our solar system, which says’ earth’. We just don’t know where it is or when it will hit.”

in the past 113 years, the earth has been hit by two large asteroids. If they collide over big cities, they may threaten the lives of millions of people. However, human beings are lucky. The researchers said that in view of this very real threat, it is time to seriously plan and implement the planetary defense program. PI allows a reasonable and cost-effective method to achieve the final environmental protection plan

The key to the

PI strategy is to deploy a penetration rod array, which may be filled with explosives and then laid on the path of the asteroid, and then pass through “slicing and cutting” threatening objects. Penetrating rods – about 4-12 inches (10-30 cm) in diameter and 6-10 feet long – break asteroid or comet nuclei when they hit them at great speed

crucially, the researchers said that the strategy is not to deflect the object, but to make the earth bear the impact, but first decompose the asteroid into smaller debris – usually the size of a house – and let these debris enter the earth’s atmosphere. The atmosphere can then absorb energy and further vaporize house sized debris into small pieces that will not hit the ground

since the original asteroids now entered the atmosphere as a large and distributed small debris cloud, they distributed the impact energy in space and time, which made the explosion waves generated by each debris lose relevance. This greatly reduces threats, from catastrophic to more “fireworks shows” with lights and sound

Cohen indicates: “If you can reduce a dangerous big event to a pile of harmless small events, you will eventually reduce the threat. The uniqueness of this method is that you can have an incredibly short response time. One problem with other technologies such as the asteroid deflection method is that their response time is severely limited. In other words, they rely on asteroids Long before approaching the earth, let the assets deflect all the threats. ”

on the contrary, PI’s” slicing and slicing “method intercepts asteroids or comets when they approach the earth and can be deployed by today’s existing launch vehicles, such as SpaceX Falcon 9 and NASA SLS (the latter is used for larger targets) According to physicists’ calculations, smaller targets such as the Chelyabinsk meteor can be intercepted with smaller launchers similar to the intercontinental ballistic missile interceptor a few minutes before the impact, while targets that pose a more serious threat such as Apophis can be intercepted 10 days before the impact. The researchers say that such a short mitigation time is completely unprecedented

Good attack is the best defense

researchers point out that another part of the plan is to consider taking a proactive approach to protect our planet.

Lubin said: “Just as we vaccinate against future diseases, as we are painfully aware now, we can prevent catastrophic loss of life in the future by vaccinating the earth with a penetrator array like a vaccine needle.”

in this method, the same system can be used to actively eliminate threatening celestial bodies such as Apophis and bennus to protect future generations.

“It is not well recognized that large threatening objects such as sapophis and bennus asteroids are extremely serious. If they hit, the energy of each of them at the time of impact is equivalent to the sum of all nuclear weapons on earth. Imagine that all nuclear arsenals on earth are detonated in a few seconds. With PI, we can prevent this from happening “Lubin continued.

according to Lubin and Cohen, this new method can make Planetary Defense quite feasible and will allow a reasonable road map for a powerful planetary defense system.

Lubin said: “An unusually fast response is possible. We don’t see any technical obstacles. It has synergy with the current generation of launch vehicles and other upcoming launch vehicles. In addition, Lubin added that this method will have a great synergy with future lunar operations. The moon may serve as a forward base for operations. Humans can finally control themselves And prevent mass extinction in the future, just like dinosaurs, a resident on earth who disdained Planetary Defense. “