Standing on planet Earth, it’s easy to forget that we’re sitting on a rock hurtling through the solar system on a path that could potentially collide with other (smaller) space rocks, largely because we can’t feel that motion.
If you ever have the urge to feel completely at the mercy of random space rocks, we highly recommend heading over to NASA’s Eyes on Asteroids website and selecting their closest approximation.
NASA and other observatories track the orbits of objects discovered in the solar system, especially keeping an eye on “near Earth objects” (NEOs) of 140 meters (460 feet) and larger that could cause destruction if they hit Earth touch. By observing their orbits, astrophysicists can estimate the objects’ future orbits and predict whether they might place them in our part of the solar system.
These objects are given a score on the Palmero scale.
“The scale compares the probability of the detected potential impact to the average risk of objects of the same size or larger over the years to the date of the potential impact,” explains NASA’s Center for Near Earth Object Studies. “This average risk from random impacts is known as the background risk. For convenience, the scale is logarithmic, so for example a Palermo scale value of -2 indicates that the detected potential impact event is only 1 percent as likely as a random background event. occurs in the intervening years, a value of zero indicates that the single event is as threatening as the background hazard, and a value of +2 indicates an event that is 100 times more likely than a background impact by an object that is at least as threatening is considered large before the date of the potential impact in question.”
The objects are also given a friendlier ‘Torino’ score of 0-10, where a score of 0 means the probability of an impact is zero or thereabouts, and 10 means ‘a collision is certain, which could cause a global climate catastrophe that would can threaten the entire world. future of civilization as we know it, be it land or ocean.” These are helpfully color-coded in green, yellow and red, to clarify the situation for the public.
Over the years of monitoring space objects, astronomers have discovered objects that have strayed outside the green zone. However, there are a few that have reached level 4; the highest level of the yellow zone.
“A close encounter that deserves the attention of astronomers,” NASA explains about the level. “Current calculations indicate a 1 percent or more chance of a collision that could lead to regional destruction. Most likely, new telescopic observations will lead to a reassignment to level 0. Attention from the public and government officials is deserved if the encounter lasts less than ten years. away.”
One of these objects was 99942 Apophis. After it was first discovered in 2004, observations placed it at level 2 on the Turin scale. However, further observations in December that year placed it at level 4 due to a 1.6 percent chance of the asteroid hitting us in 2029. Further observations ruled out a collision in 2029, as well as in 2036 and 2068, although it will happen. are still close encounters.
Currently there are no known objects with a Torino score higher than 0. However, there are objects that require further observation, with a score of -0.93 and -1.59 on the Palmero scale, which have not been assigned a Torino score because the possible collisions take place further. than 100 years in the future.
(29075) 1950 DA, an object 1.3 kilometers (0.81 mi) across, scores -0.93 due to a “potentially very close” approach to Earth on March 16, 2880. This is likely to occur in the coming years change as more observations are made. made.
101955 Bennu (1999 RQ36) – known more simply as “Bennu” – currently stands at -1.59 on the Palmero scale. As far as we can tell, it will make several close approaches to the moon and Earth. In September 2135, it is expected to pass within 0.00143 Astronomical Units (AU) of Earth, where 1 AU is the distance between Earth and the Sun. That’s 213,925 kilometers (132,927 miles)which is quite close in terms of space.
As these asteroids orbit Earth, more observations are made and trajectories are refined, meaning these scores can go up or down. The further back in time, the greater the chance that objects’ orbits will be disrupted by close encounters with other objects (such as Earth).
So far, astronomers have been able to predict the orbits of known objects up to about 100 years into the future. The good news is that “no known asteroid larger than 450 feet has a significant chance of hitting Earth in the next 100 years,” said Dr. Kelly Fast, manager of NASA’s NEO Observations Program at NASA Headquarters in 2018.
The better news was that a team led by Oscar Fuentes-Muñoz of the University of Colorado Boulder was able to go even further and predict the orbits of larger asteroids 1,000 years into the future.
“Assessing impact risk over longer timescales is challenging as orbital uncertainties increase. To overcome this limitation, we analyze the evolution of the Minimum Orbit Intersection Distance (MOID), which represents the closest possible encounters between the asteroid and Earth limits,” the researchers said. team explains in their paper. “The evolution of the MOID highlights NEOs that are near Earth for extended periods of time, and we propose a method to estimate the probability of an encounter at Earth depth during these periods.”
Using this method, the team was able to rule out that the majority of NEOs would hit our planet within the next thousand years, and estimate the likelihood that others would hit us like a bunch of dinosaurs. The chance of being hit before the year 3000 seems quite low, according to the team, with the most likely object to hit us – 7482 (1994 PC1) – having only a 0.00151 percent chance of a close encounter, with the earth comes closer than the earth. the orbit of the moon.