By European Space Company (ESA).
February 26, 2022.
Its a funny thing about homing in on an asteroid and determining its path, future position, and possibility of affecting Earth– it will typically appear dangerous during initial observations, get riskier, and after that all of a sudden ended up being totally safe.
In the case of an asteroid on a definite collision course, the threat would keep growing till it reaches 100%. Can we actually be sure asteroids eliminated from ESAs threat list are safe?
In the case of an asteroid on a certain crash course, the risk would keep growing up until it reaches 100%. Can we actually be sure asteroids gotten rid of from ESAs risk list are safe?
The extremely first observation of an asteroid is simply a single dot of light in the sky. At this moment, its not clear what it is or where its going. A second observation is required to expose an object in motion, and it is normally agreed that a minimum of 3 are needed to determine an orbit– how quickly our asteroid is going and where it is headed. Further observations fine-tune the orbit a bit more, minimizing uncertainties till we can be sure of where it wont go: to Earth.
In the beginning, the future position of an asteroid doubts therefore the “threat passage” is a large tunnel through which the asteroid could fly at any point. When any part of the corridor overlaps with Earth, the asteroid is considered a danger.
As is typically the case, the overlap with Earth stays even while the possible corridor gets smaller sized due to more observations and a more accurate understanding of the asteroids course– therefore the danger appears to increase.
Typically, as the danger zone narrows with more observations, the passage moves off Earth and the risk suddenly drops. Even if some unpredictability remains about the course of an asteroid, we can understand for sure it does not position a danger.
A second observation is needed to reveal a things in movement, and it is normally concurred that at least three are required to determine an orbit– how quickly our asteroid is going and where it is headed.