Asteroids Across Earth’s Orbit

Earth is a beautiful planet, a wondrous blue and green sphere orbiting a bright yellow star. Life abounds in the deepest oceans and on the highest mountains, in the rain forest and in the arid deserts; from the equator to the poles. It is unique in our solar system and in the known universe. But it is no picnic.
It is alive in more ways than just the organisms that call it home. We have weather patterns that can be unpredictable to say the least. Thunderstorms, blizzards, hurricanes, tornadoes, drought and dust storms wreck havoc worldwide.
Earthquakes, volcanoes and tsunamis are testament to the fact the land that we live upon is in constant motion. Tectonic plates pull apart and collide together creating oceans and mountain ranges.
Despite all these things and probably because of them, life on Earth thrives. Yet, in our past there have been times when life came close to being extinct, and sometimes it wasn’t because of anything terrestrial.
Along with our fellow planets revolving in their orbital paths, we have to share the solar system with asteroids, comets and planetesimals sailing along toward their own destinies.
Left over from the formation of the solar system billions of years ago, the majority of these objects are just harmless masses of rock, ice or ” sand ” ; ranging from pea size to floating mountains. But, now and then one of the larger ones, with the diameter of 500 feet or more, crosses the orbit of the Earth, becoming what is known as a PHO or potentially hazardous object.
One of these is enough to cause regional destruction if it impacts land, or major tsunamis if it strikes the ocean. In fact, the Earth is impacted by one of these objects approximately every 10,000 years. Scientists believe that the extinction of the dinosaurs was caused by a PHO 6 miles in diameter that impacted the Earth in what is now the northern Yucatan Peninsula and the Gulf of Mexico 65 million years ago creating an enormous crater known as Chicxulub, with the diameter of 112 miles. Asteroids of this size are known as planet killers and our solar system is full of them.
NASA and independent astronomers have been busy in the last 20 years or so, watching the skies and identifying as many of these objects as they can find. It can be tricky though, as many factors can change these objects from benign to threatening and vice-versa. Gravity plays a big part in their trajectories and even passing another asteroid can be enough to slightly alter their course. Consequently, an object that was considered to be on a path that would take it close to the Earth, can change course away from that meeting because of an unknown object passing in close proximity.
Because of the vigilance of a dedicated few, there is currently 1,223 PHOs identified, and the number will continue to grow as we have barely scratched the surface, there are millions more out there roaming our solar system.
Scientist know that it is only a matter of time before we experience a major impact. It is just a question of when. Many are working on ways to avert such an occurrence, but so far nothing practical has emerged. Despite movie portrayals, detonating the object could just create multiple smaller objects that could cause damage over a wider area.
Our home sails through a cosmic shooting gallery. We are daily bombarded by small meteorites that burn up in our atmosphere, but now and then we encounter one that has the capability to wipe out life on our planet. Let us hope that when the next one comes, we will have the technology to avert it. Only time will tell.