"A plume erupts from Dimorphos as the DART mission impacts the asteroid moonlet in this artist’s concept. Such kinetic impacts are one way an asteroid might be deflected — but a new study suggests nuclear bombs could also be effective. Credit: ESA" (Astronomy.com /Nuclear bombs really could deflect asteroids, lab tests suggest)
Sometimes people say that nuclear explosions will break the large asteroid into pieces. The fact is that the 500-meter asteroid causes less damage if it is in smaller pieces than in one large piece. But a large group of small asteroids can cause terrible damage in another way than some large asteroids, which can make large impact craters and megatsunamis. Asteroid debris can destroy large numbers of satellites. Large groups of small asteroids can raise the temperature in the planet's atmosphere.
In the worst scenarios, those asteroids or their impact energy turn the atmosphere glowing hot. That can be an extremely dangerous situation. The asteroid swarms are the thing that researchers can turn away using nuclear explosives. The nuke is detonated on another side of the asteroid group, and that detonation can vaporize material from the other side of those asteroids. And then that can turn their direction.
The effect of the nuclear explosion depends on where that nuke detonates. If the researchers can drill holes in the asteroid core or center of the asteroid, and detonate high-yield nuke in there. That thing can vaporize the entire asteroid. Another way is to detonate the nuke at another side of the steroid. And that detonation makes the asteroid shell vaporize, and that vaporized material pushes the asteroid away from its course.
If the asteroid is water ice the nuclear explosion can easily vaporize it. If we think about big asteroids like Ceres, there could be water ocean under its ice. If a nuclear detonator detonates in that ocean it opens a hole in the ice, and that can turn water into a rocket engine. The biggest problems are not large-size asteroids whose trajectory is well-known.
The biggest problems are the small irregular-shaped silicone, metal, or carbon asteroids. If the last one's carbon is in crystal form. They can travel through the atmosphere. Those asteroids are hard to detect. And sometimes the sensor sees them in the last moments. If less than 100 meters asteroid hits to city area, it causes extreme large-scale destruction.
The DART mission was a successful attempt to turn an asteroid using kinetic penetrators. That was a primitive system, and we need more powerful and effective systems. If we want to avoid cosmic stone hitting our heads. That kind of hit is dangerous and we know cases from other solar systems like the Formalhault B case where cosmic impact may destroy a planet in a mature solar system. That thing should warn us that also mature solar systems are dangerous and there is always a possibility that cosmic impact will destroy entire planets.
Nuclear explosives allow to turn large groups of objects away from their course. They are effective tools for planetary defense. Normally researchers could use things. Like rocket engines to turn small asteroids out from their course.
There is the possibility to use small space shuttles that close asteroids into the net made of mylar or some other hard material. Those space systems can push those asteroids out from the course.
But the problem is that those systems must detect asteroids soon enough. In worst cases. There are only a couple of hours for us, to react to the asteroid impact. And that causes the need to use something more radical than gently push. The fact is this: also drilling holes in the asteroid center for nuke takes time. In the worst case, deep space surveillance detects an asteroid when it already passed Earth. And that is too late.
https://www.astronomy.com/science/nuclear-bombs-really-could-deflect-asteroids-lab-tests-suggest/
https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Test
https://en.wikipedia.org/wiki/Fomalhaut_b
