For those who want to delay the apocalypse as long as possible, there is good news: A new study shows that Earth's last line of defense against an asteroids hitting Earth is an effective strategy.
This line of defense is known as a late time small-body disruption. It sounds exactly like it. It is designed to destroy relatively small asteroids when there has been little warning that they are on a collision course.
The latest calculations show that this defense is very effective in protecting against asteroid strikes when the impact time is less then a year away. This means we can all rest a little better in our beds.
Spheral simulation used in the analysis. (Lawrence Livermore National Laboratory).
Patrick King, a physicist at Johns Hopkins University in Maryland, says that one of the difficulties in assessing disruption is modeling all of the fragment orbits. This is usually far more difficult than modeling a simple deflection.
"Nevertheless, we must try to address these challenges if disruption is to be considered as a strategy."
Researchers created models to simulate the impact of a nuclear bomb of 1-megaton yield hitting an asteroid 100 meters (328 feet) in diameter (roughly a fifth of Bennu's size).
Five different orbits of asteroid were examined. Detonations occurred anywhere from one week to six months prior to impact. It is possible to reduce the amount of destruction by 0.1 percent in cases where the asteroid arrives two months ahead of its anticipated arrival.
If the asteroid has a larger pile of rocks, we still have a chance to reduce its impact mass to 1% if it is hit six months before its due date.
This is a fantastic result but scientists don't want this to be their last resort option. The preferred option is to deflect an asteroid away even earlier than that, which has been thoroughly researched and tested.
King says, "We concentrated on studying 'late disruptions," which means that the impacting bodies are broken down shortly before they impact." It is preferred to use kinetic impactors to deflect the impacting bodies when you have a lot of time, which can often be a decade long.
It is not easy to determine where many fragments of an asteroid will end up after it has been broken apart. The team used Spheral, a piece of software that specializes in figuring out how gravity and other forces would transport these pieces of rock.
If you make mistakes in your calculations to destroy an incoming object, a single impact of an asteroid could quickly become multiple impacts in many different locations on Earth.
NASA and other agencies continue investing in planetary defense systems, especially when it comes to spotting potentially hazardous asteroids as soon as possible. For the best chances of preventing an asteroid from traveling off course, we need to be able to wait longer periods.
Megan Bruck Syal, physicist at the Lawrence Livermore National Laboratory, (LLNL), says that "our group continues to refine its modeling approaches for nuclear disruption and deflection, including ongoing improvements in X-ray Energy Deposition modeling which sets the initial shock and blowoff conditions for a problem with nuclear disruption."
"This paper is an important step in showing how modern multiphysics tools can help simulate this problem across multiple relevant physics regimes.
Acta Astronautica published the research.
