September 13 () –
An unpredictable impact of a space rock against Apophis would place this large asteroid, which will approach Earth in 2029, on an impact trajectory in 5 percent of cases examined.
That’s the conclusion of new research by University of Western Ontario astrophysicist Paul Wiegert on the 335-metre asteroid, whose unlikely impact could cause widespread devastation.
Near-Earth asteroid 99942 Apophis will pass close to our planet in April 2029. Numerous observations and calculations reveal that it is on track to pass within tens of thousands of kilometres of our planet.
However, calculations of Apophis’ trajectory to date have not considered the possibility that Apophis could be hit by a small asteroid or meteoroidsuch as those that occasionally and unpredictably strike the Earth and are observed as meteors or shooting stars.
The likelihood of a small asteroid being significantly deflected is extremely low. “It is only the unusual nature of Apophis that leads to considering it in detail here, so that we can understand its future motion as best as possible,” warns Weigert.
This new paper accepted by the peer-reviewed Planetary Science Journal estimates the odds of Apophis being significantly deflected by such an impact at less than 1 in a million, and only 1 in a billion that the deflection would be dangerous to Earth.
The analysis also looks at how and when a deviation from Apophis would become apparent to observers on Earth, and how telescopic observations can be used to assess whether or not Apophis has strayed.
To determine the likelihood of Apophis being diverted onto a trajectory that would collide with Earth, thousands of hypothetical scenarios were examined in which a small velocity change or “boost” was applied to Apophis from a random direction and at a random time. The effect of this boost on Apophis’ distance from Earth near the time of its approach to Earth in April 2029 was then examined.
THE PROBABILITY OF PREVIOUS IMPACT IS LESS THAN ONE IN ONE BILLION
It has been found that sufficiently large impulses (with a change in velocity of more than 5 centimeters per second, in the form of a “delta-vee”), corresponding to the impact of an asteroid 3 meters in diameter or more on Apophis, could deflect Apophis towards Earth in 2029, But the chances of such an impact occurring are less than one in a billion.well below the one-in-a-million risk threshold typically adopted for assessing asteroid impact risk.
The study shows the effect of the impact of a 3-meter-diameter asteroid, creating an impulse of 10 centimeters per second on Apophis, sometime between 2021 and 2029.
In an animation Hundreds of hypothetical scenarios are shown, where the impact occurs at a random time and from a random direction. The 5% of cases that could result in an impact with Earth are identified with an orange grid. The nominal Apophis is identified in green.
“Although an asteroid impact that could deflect Apophis enough to be dangerous is a theoretical possibility, Large enough impacts on Apophis are extremely rare.“and it is estimated that there is only a one in a billion chance of such an outcome occurring,” Wiegert sums up.
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