An asteroid, 2020 HQ, grazed the Earth this Sunday, August 16, 2020. The simulations of its passage show that it followed a curved trajectory. How to explain this phenomenon ?
2,900 kilometers: this is the distance that separated 2020 HQ from Earth this Sunday, August 16, when the object passed as close as possible to our planet. This 3-meter-wide asteroid approached without posing a danger. Its trajectory in the vicinity of our planet has been illustrated in several simulations, from Center of minor planets and of amateur astronomer Tony Dunn.
These representations show that the trajectory of 2020 HQ appears curved when the object grazes the Earth. One might have imagined, for example, that the asteroid would follow a straight line. As the scientific mediator explains Pierre Henriquet at Numerama, it is ” gravity which distorts the trajectory of the object. These trajectories are called ‘conical’. »
Its orbit has changed
This situation is not only valid when an asteroid approaches a little too close to our planet: any body (planet, moon, star) ” exerting gravity distorts the trajectory of bodies passing by, more or less according to their mass », Adds the scientific mediator. The deformation of the trajectory of the body is different depending on the mass of the object which exerts its gravity: ” at the same initial speed and at equal distance, the more massive the star next to which the asteroid passes, the more its trajectory is curved », Adds the specialist.
In the case of 2020 HQ, this event clearly resulted in a distortion of its orbit. According to the indications of Jet Propulsion Laboratory, the object normally has an orbital period of about 990 days (the time it takes for it to circle the Sun). Its approach to Earth could have reduced this orbital period to 964 days.
The deformation of trajectories under the effect of the gravity of a body is a well-known phenomenon, very useful in the field of space exploration. It is ” used by space probes to propel themselves through the solar system without spending fuel, using the gravity of the planets as a ‘slingshot’ to accelerate or decelerate », Summarizes Pierre Henriquet. Acceleration makes it easier to explore the outer solar system while deceleration makes it easier to explore the inner solar system, such as this is the case with the Bepi Colombo probe tasked with exploring Mercury.
