December 5, 2023

Planetary Defense: Physicists Propose New Way To Defend Earth Against Cosmic Impacts

On February 15, 2013, the Chelyabinsk meteor, a roughly 62-foot (19 meter)- diameter asteroid exploded over the city of Chelyabinsk, Russia, as it entered Earths environment at a shallow angle. “There is a big asteroid or comet lurking in our solar system with Earth written on it. In the last 113 years, the Earth has actually been struck by two large asteroids that could have threatened the lives of millions, had they struck over a major city. In other words, they rely on getting a property to deflect the risk all the method out to the asteroid long prior to it comes close to the Earth.”.
Rather, the PI “piece and dice” technique intercepts asteroids or comets as they approach the Earth and might be released by launch cars that currently exist today, such as SpaceXs Falcon 9 and NASAs SLS for bigger targets.

” It ended up that 2 entirely independent asteroids were coming over that day,” said Philip Lubin, UC Santa Barbara professor of physics, and one of the many researchers anticipating 2012 DA14s near-Earth rendezvous. “One of them we understood was going to miss the Earth. The other one, we didnt even understand it was coming.”
For Lubin and scientists like him, occurrences like these highlight the value of robust planetary defense– the detection, tracking, characterization and eventually defense versus possibly harmful asteroids and comets. Rarer still, however nevertheless possible, are things that threaten mass-extinction, such as the Chicxulub impactor, which cleaned out the dinosaurs some 66 million years ago, or the more recent (12,800 years ago) airburst that triggered prevalent burning and the start of an “effect winter season” called the Younger Dryas.
Credit: Alexander Cohen
One can not mark down the possibility of bigger objects coming annoyingly close to Earth in the near future: Apophis, with its 1,214-foot (370 meter) size, is due to make a close pass on Friday the 13th in April 2029, while Bennu, at 1,608 feet (490 m) in size, is anticipated to carry out a comparable pass in 2036. They are not prepared for to strike Earth, even relatively little changes in their orbit might trigger them to enter gravitational pockets called “keyholes” that can place them on a more direct trajectory toward Earth.
” If it goes through the gravitational keyhole, it will usually strike Earth on the next round,” Lubin said.
Techniques for planetary defense have actually progressed from research into better techniques for comprehending the risks, to efforts to deflect possible risks and change their orbits, consisting of a strategy developed by Lubins group, which proposed making use of lasers to push threatening things out of Earths method. (See their site to find out more on laser-based planetary defense:
In two papers on the topic of terminal planetary defense submitted to the journal Advances in Space Research, accompanied by an opinion piece published in Scientific American, Lubin and co-researcher Alexander Cohen set out a more proactive technique for handling harmful extraterrestrial space debris. The job is called PI, which affectionately represents Pulverize It.
Getting ready for the Inevitable– Do or Do Not?
” While we frequently state that nothing in life is particular however death and taxes, we can definitely also add human termination to this list,” Lubin stated. “There is a large asteroid or comet lurking in our planetary system with Earth composed on it. We just do not understand where it is or when it will strike.”.
In the last 113 years, the Earth has been hit by 2 big asteroids that could have threatened the lives of millions, had they struck over a major city. However, humanity was lucky. Due to this really real hazard, it is time to seriously plan for and execute a planetary defense program, the researchers say. PI permits for a economical and logical method to the ultimate environmental security program.
Conquer and divide.
Secret to the PI method is the implementation of an array of penetrator rods, potentially filled with explosives, laid in the path of the asteroid to “slice and dice” the threatening item. The penetrator rods– about 4-12 inches (10-30 cm) in diameter and six to 10 feet long– piece the asteroid or comet nucleus as it crashes into them at extreme speed.
Most importantly, instead of deflecting the item, the technique is to let the Earth take the hit, the researchers stated, but first to disassemble the asteroid into smaller pieces– generally the size of a home– and let the fragments get in the Earths atmosphere. The environment can then absorb the energy and additional vaporize the house-sized pieces into small debris that do not hit the ground.
Since the original asteroid now enters the atmosphere as a big, dispersed cloud of little pieces, they spatially and temporally disperse the energy of the impact, which de-correlates the blast waves developed by each fragment. This significantly minimizes the hazard from catastrophic to more of a “fireworks show,” complete with light and sound.
” If you can lower the big occasions, which are hazardous, into a lot of little occasions that are harmless, youve eventually mitigated the risk,” Cohen stated.
” Whats unique about this technique is that you can have extremely brief response times,” Lubin included. “A problem that other strategies like asteroid-deflecting methods have is that they are severely limited in their reaction times. In other words, they rely on getting an asset to deflect the danger all the method out to the asteroid long before it comes close to the Earth.”.
Instead, the PI “piece and dice” method intercepts asteroids or comets as they approach the Earth and could be released by launch vehicles that already exist today, such as SpaceXs Falcon 9 and NASAs SLS for bigger targets. According to the physicists estimations, smaller targets like the Chelyabinsk meteor might be intercepted just minutes prior to impact utilizing much smaller launchers comparable to ICBM interceptors, while targets that position a more major threat, like Apophis, could be intercepted just 10 days prior to impact. Mitigation times this brief are completely extraordinary, according to the scientists.
The Best Defense is a Good Offense.
Another part of the program is to think about a proactive technique to safeguarding our world, the scientists stated.
” Much as we get immunized to prevent future illness, as we are now so painfully mindful, we might immunize the planet by utilizing the penetrator selections like the needles of a vaccine shot to prevent a devastating death in the future,” Lubin stated.
In this technique, the same system can be utilized to proactively get rid of threatening objects like Apophis and Bennu to protect future generations.
“Should they strike, each of them has an energy at effect equivalent to all of the nuclear weapons on Earth combined. Picture all of the Earths nuclear arsenal being detonated in a couple of seconds.
This new technique, according to Lubin and Cohen, might make planetary defense quite practical and “easy as PI,” and would enable a logical roadmap to a robust planetary defense system.
” Extraordinarily quick action is possible,” Lubin stated. In addition, Lubin included, the method “would be in terrific synergy with future lunar operations,” with the moon potentially acting as a “forward base of operations.”.
” Humanity might lastly manage its fate and prevent a future mass termination like that of the previous occupants of the Earth who did not bother with planetary defense, the dinosaurs.”.
To see how this system works, go to the UCSB Experimental Cosmology groups PI-Terminal Planetary Defense job page.
Research in this task was conducted likewise by Jeeya Khetia, Tegan Costa, Hannah Shabtian, Dharv Patel, Alok Thakrar, Alex Korn and Kellan Colburn.

Is Planetary Defense PI in the Sky?
In February of 2013, skywatchers around the globe turned their attention toward asteroid 2012 DA14, a cosmic rock about 150 feet (50 meters) in diameter that was going to fly closer to Earth than the spacecraft that bring us satellite TV.
Little did they recognize as they prepared for the once-in-several-decades event that another little celestial particles was hurtling towards Earth, with a more direct heading. On February 15, 2013, the Chelyabinsk meteor, a roughly 62-foot (19 meter)- size asteroid took off over the city of Chelyabinsk, Russia, as it got in Earths atmosphere at a shallow angle. The blast shattered windows and damaged structures, and nearly two thousand individuals were harmed, though fortunately no one passed away.