Science

Physicists propose new ways to protect the Earth from the effects of space

Credit: Alexander Cohen

In February 2013, Sky-Watchers around the world focused on the asteroid 2012 DA14. This is a space rock about 150 feet (50 meters) in diameter that flies closer to Earth than the spacecraft that brings satellite TV.


They were barely aware that a few more celestial debris was rushing towards Earth in a more direct direction in preparation for the once-in-a-decade event. On February 15, 2013, the Chelyabinsk meteor, an asteroid about 62 feet (19 meters) in diameter, exploded in the city of Chelyabinsk, Russia, when it invaded the Earth’s atmosphere at a shallow angle. The blast shattered windows, damaged buildings and injured nearly 2,000 people, but thankfully no one died.

“By that day, we knew that two completely independent asteroids were coming,” said a professor of physics at the University of California, Santa Barbara, and one of many scientists anticipating the 2012 DA14 Earth orbit rendezvous. Physics Rubin said. “One of the things we knew would miss the Earth. The other didn’t even know that the Earth was coming.”

For Rubin and scientists like him, incidents like these underscore the importance of powerful planet defense — detection, tracking, characterization, and ultimately potentially dangerous asteroids and comets. Defense against. Cities-threatening events like Chelyabinsk are rare, occur about once every 50 to 100 years, but can be catastrophic. The latest of these outbreaks was the Tunguska event in eastern Siberia in 1908, which flattened hundreds of square miles of forest. Even more rarely, but still possible, the Chicxulub Impactor, which wiped out dinosaurs about 66 million years ago, and the widespread burning and “influential winter” called Younger Dryas.

However, we cannot ignore the possibility that larger objects will become uncomfortable with the Earth in the near future. Apophis, 1,214 feet (370 meters) in diameter, will be approaching on Friday, April 13, 2029. With a diameter of 1,608 feet (490 m), a similar path will be performed in 2036. It is not expected to hit the Earth, but even relatively small changes in orbit can enter a gravity pocket called a “keyhole.” Place them in a more direct orbit towards Earth.

“If it goes through the gravitational keyhole, it will generally hit Earth in the next round,” Rubin said.

Planet defense strategies are moving from researching better ways to understand threats to divert potential dangers and change orbits. This includes a strategy developed by Rubin’s group that proposed using lasers to keep threatening objects out of the way of the Earth.

In two papers on the topic of terminal planet defense submitted to the journal Advances in space researchAccompanied by an opinion piece published in Scientific American, Rubin and co-worker Alexander Cohen present a more proactive way to deal with dangerous extraterrestrial space debris. This project is called PI and is lovingly an abbreviation for Pulverize It.

Preparing for the inevitable: Do or not?

“It’s often said that life is uncertain except for death and taxes, but we can add the extinction of humanity to this list,” Rubin said. “Our solar system is lurking with large asteroids and comets labeled” Earth. ” I don’t know where it is or when it will hit. “

Over the last 113 years, the Earth has been hit by two large asteroids that could threaten the lives of millions of people if they hit a big city. But humanity was lucky. In the light of this very real threat, it’s time to seriously plan and implement a planetary defense program, researchers say. PI enables a logical and cost-effective approach to the ultimate environmental protection program.

Divide and rule

The key to the PI strategy is probably to place a series of explosive-filled penetrator rods in the path of the asteroid to “slice and diced” the threatening object. Penetrator rods, approximately 4-12 inches (10-30 cm) in diameter and 6-10 feet long, fragment asteroid or comet nuclei when they collide at extreme velocities.

The important thing is not to distract the object, but to hit the Earth, but first break the asteroid into smaller pieces (usually the size of a house) and put the pieces into the Earth’s atmosphere. The atmosphere then absorbs energy and can further vaporize house-sized debris into smaller debris that does not hit the ground.

Since the original asteroids now enter the atmosphere as large dispersed clouds of small fragments, they disperse the energy of the impact spatially and temporally, discorrelating the blast generated by each fragment. This greatly reduces the threat from a catastrophic threat to a “fireworks display” with light and sound.

“If we could reduce the big dangerous events into a bunch of small harmless events, we could ultimately mitigate the threat,” Cohen said.

“The unique thing about this method is that the response time can be very short,” Rubin added. “The problem with other technologies like asteroid deflection is that response times are severely limited, in other words, relying on acquiring assets to completely divert the threat. asteroid Long before approaching the earth “

Instead, PI’s “slice and dice” scheme can intercept asteroids and comets as they approach Earth and deploy them with existing rockets such as SpaceX’s Falcon 9 and NASA’s SLS. Physicists have calculated that small targets such as the Chelyabinsk meteorite can be intercepted just minutes before a collision using a much smaller launcher similar to an ICBM interceptor, but more serious like Apofis. Targets that pose a threat can be intercepted just 10 days before the collision. .. According to researchers, this short relaxation time is completely unprecedented.

The best defense is a good attack

Another part of the program is to consider aggressive approaches to protecting our planet, the researchers said.

“Like we are vaccinated to prevent future illness, we are so painful now that it is like a vaccination needle to prevent future catastrophic loss of life. You can vaccinate the planet with a simple penetrator array, “Rubin said.

With this approach, the same system can be used to proactively eliminate threatening objects such as Apophis and Benne to protect future generations.

“It is not well understood that large and threatening objects such as Apophis and Bennu asteroids are very serious,” he continued. “If they attack, each has an impact energy equal to the sum of all the nuclear weapons on Earth. Imagine that all the nuclear weapons on Earth explode in seconds. With PI, You can prevent this scenario. “

According to Rubin and Cohen, this new approach will make planet defense very feasible and “as easy as PI” and will allow a logical roadmap to a robust planet defense system. ..

“We can respond very quickly,” Rubin said. “I don’t see any technical shortpers. It has a synergistic effect with current generation rockets and other rockets.” In addition, Rubin said the method “has a great synergistic effect with future lunar operations.” Yes, he added, adding that the moon could act as a “forward operating base.”

“Humanity was finally able to control its fate and prevent future mass extinctions that it doesn’t care about like its former occupants of the planet. Planet defense,dinosaur. ”


Slight chance of the asteroid Bennu colliding with Earth: NASA


For more information:
Project website: www.deepspace.ucsb.edu/project… al-planetary-defense

paper: www.deepspace.ucsb.edu/project… al-planetary-defense

Quote: Physicists, the influence of the universe obtained on October 13, 2021 from https: //phys.org/news/2021-10-physicists-method-defending-earth-cosmic.html (October 13, 2021) We propose a new way to protect the earth from the sun)

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https://phys.org/news/2021-10-physicists-method-defending-earth-cosmic.html Physicists propose new ways to protect the Earth from the effects of space

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