This article was originally published at The Conversation. The publication contributed the post to Space.coms Expert Voices: Op-Ed & & Insights.Gail Iles, Senior Lecturer in Physics, RMIT UniversityA NASA spacecraft the size of a golf cart has been directed to smash into an asteroid, with the intent of knocking it slightly off course. The test intends to show our technological preparedness in case an actual asteroid danger is spotted in the future.The Double Asteroid Redirection Test (DART) lifted off aboard a SpaceX rocket from California on Nov. 23 and will reach the target asteroid system in September, next year.The mission will travel to the asteroid Didymos, a member of the Amor group of asteroids. Every 12 hours Didymos is orbited by a mini-moon, or “moonlet,” Dimorphos. This smaller half of the set will be DARTs target.Related: If an asteroid actually threatened the Earth, what would a planetary defense mission appearance like?Are we dealing with an extinction hazard from asteroids?Weve all seen catastrophe films in which an asteroid strikes Earth, creating an extinction event comparable to the one that exterminated the dinosaurs millions of years ago. Could that take place now?Well, Earth is really bombarded frequently by little asteroids, ranging from 1-20 meters in size. Practically all asteroids of this size break down in the environment and are usually harmless.There is an inverted relationship between the size of these item and the frequency of impact occasions. This means we get hit far more often by small items than larger ones– merely since there are a lot more smaller things in space.Small asteroid impacts revealing day-time effects (in yellow) and night-time effects (in blue). The size of each dot is proportional to the optical radiated energy of the impact. (Image credit: NASA JPL)Asteroids with a 1km diameter strike Earth every 500,000 years, on average. The most “current” effect of this size is thought to have formed the Tenoumer impact crater in Mauritania, 20,000 years ago. Asteroids with an approximate 5km diameter impact Earth about once every 20 million years.The 2013 Chelyabinsk meteoroid, which harmed structures in 6 Russian cities and injured around 1,500 individuals, was estimated to be about 20m in diameter.Assessing the riskNASAs DART objective has actually been stimulated by the threat and worry of a significant asteroid hitting Earth in the future.The Torino scale is a technique for categorizing the effect threat associated with a near-Earth things (NEO). It utilizes a scale from 0 to 10, where 0 implies there is negligibly little opportunity of accident, and 10 methods imminent accident, with the affecting object being large enough to precipitate a worldwide disaster.The Chicxulub effect (which is attributed to the extinction of non-avian dinosaurs) was a Torino scale 10. The effects that developed the Barringer Crater, and the 1908 Tunguska event, both correspond to Torino Scale 8. With the increase of online news and people ability to film occasions, asteroid “near-misses” tend to generate fear in the public. Presently, NASA is keeping a close eye on asteroid Bennu, which is the item with the biggest “cumulative danger rating” today. (You can keep as much as date too). With a 500m diameter, Bennu can developing a 5km crater on Earth. NASA has also stated there is a 99.943% possibility the asteroid will miss out on us.Brace for impactAt one point in their orbit around the sun, Didymos and Dimorphos come within about 5.9 million km of Earth. This is still even more away than our moon, however its extremely close in astronomical terms, so this is when DART will strike Dimorphos.DART will invest about ten months travelling towards Didymos and, when its nearby, will change instructions a little to crash into Dimorphos at a speed of about 6.6 km per second.This animation shows DARTs trajectory around the Sun. Pink = DART
This smaller half of the pair will be DARTs target.Related: If an asteroid truly threatened the Earth, what would a planetary defense mission look like?Are we facing an extinction threat from asteroids?Weve all seen catastrophe films in which an asteroid hits Earth, creating a termination event comparable to the one that killed off the dinosaurs millions of years earlier. Could that happen now?Well, Earth is really bombarded often by small asteroids, ranging from 1-20 meters in size. (Image credit: NASA JPL)Asteroids with a 1km diameter strike Earth every 500,000 years, on average. NASA has likewise said there is a 99.943% chance the asteroid will miss out on us.Brace for impactAt one point in their orbit around the sun, Didymos and Dimorphos come within about 5.9 million km of Earth. The trains integrate to end up being a brand-new system with different speeds than before.So we will not experience any impact, ripples or debris from the DART mission.Typical asteroid orbits remain between Mars and Jupiter, however some with elliptical orbits can pass close to Earth.
