NASA confirms for the first time that an asteroid 500 meters in diameter will come dangerously close to Earth in 114 years, in the year 2135, and that it will pass our planet at a distance less than that which separates us from the Moon.
It also confirms that, although at that time there will be no catastrophic impact, it is very possible that this fatality will occur in later years.
They consider that possibility because, as it passes so close to Earth in 2135, the gravitational pull of our planet can alter its trajectory and later make it coincide with that of our planetary habitat.
Scientists have calculated that, due to this possible alteration of its current orbit, the probability of impact in the year 2300 is approximately 1 in 1,750 (or 0.057%). That means there is a 99.94% chance that its trajectory will have no impact that year, according to the scientists.
The researchers were also able to identify September 24, 2182 as the most significant date in terms of a potential impact, with an impact probability of 1 in 2,700 (or about 0.037%), NASA notes .
Although the chances of it hitting Earth are very low, Bennu remains one of the two most dangerous known asteroids in our solar system.
REGULAR VISITOR
Regular visitor Bennu has been an old acquaintance since its discovery in 1999. It orbits the Sun with a period of 1.1955 years. The Earth approaches about 480,000 km of its orbit between September 23 and 25.
On September 22, 1999, Bennu passed at 0.0147 au on Earth, and six years later, on September 20, 2005, it passed at 0.033 au on Earth.
The next close approaches have been recalculated using observations made by NASA’s OSIRIS-REx spacecraft, which was in close proximity to the asteroid for more than two years.
In addition to collecting a sample from Bennu’s surface, the spacecraft provided precision data to better predict its orbit around the Sun.
Before leaving Bennu’s orbit on May 10, 2021, OSIRIS-REx collected information on its size, shape, mass, and composition, and also collected a sample of rock and dust from the asteroid’s surface, which it will deliver to the Earth on September 24, 2023, for further scientific investigation.
GRAVITATIONAL KEYHOLE
Gravitational Keyhole Precision measurements at Bennu obtained by OSIRIS-Rex have helped better determine how the asteroid’s orbit will evolve over time and whether it will pass through a “gravitational keyhole” during its approach to 2135.
Researchers have identified 26 of the so-called “gravitational keyholes” around Earth – areas of space where, if the asteroid passes through them that year, Earth’s gravity could deflect Bennu onto a collision course with our planet after 2135.
To calculate exactly where the asteroid will be during its 2135 close approach, and whether it could pass through one of 26 gravitational keyholes, the scientists evaluated several types of small forces that can affect the asteroid as it orbits the Sun.
Even the smallest force can significantly deviate its orbital path over time, causing it to either pass through a keyhole or rule it out altogether.
Among those forces, the Sun’s heat plays a crucial role. When an asteroid travels around the Sun, sunlight warms its daytime side. Because the asteroid rotates, the heated surface will rotate and cool as it enters the night side.
DISTURBING FORCES
Disturbing forces As it cools, the surface releases infrared energy, which generates a small amount of thrust on the asteroid, a phenomenon called the Yarkovsky effect.
In short periods of time, this thrust is miniscule, but over long periods, the effect on the position of the asteroid accumulates and can play an important role in changing the trajectory of an asteroid.
The team also considered many other disturbing forces, including the gravity of the Sun, planets, their moons, and more than 300 other asteroids, drag caused by interplanetary dust, solar wind pressure, and Bennu’s particle ejection events.
The researchers even evaluated the force that OSIRIS-Rex exerted when conducting its Touch-And-Go (TAG) sample collection event on October 20, 2020, to see if it could have slightly altered Bennu’s orbit – they confirmed that it had produced negligible effect on the asteroid’s orbit.
RELATIVE CONCERN
Relative concern Scientists’ concern about the probability of an impact of these characteristics is relative, highlights the journal Science.
Should it finally prove unavoidable, there is the technical possibility of diverting Bennu from his fateful trajectory through “multiple kinetic impacts,” a technology that will be available to us 50 years from now.
There are also other options, such as gravity tractors or ion beams, since within 100 years we will have much more powerful technologies than the current ones.
Lo que es indudable es que, si el impacto se produjera finalmente, sería catastrófico.
It is estimated that Bennu would leave a crater between 5 and 10 kilometers in diameter and that the destroyed geographical area could be up to 100 times larger than the size of the crater.
IN 700 YEARS WE WILL KNOW
In 700 years we will know. Nothing to do with the meteorite that 66 million years ago killed 75% of species, including dinosaurs, since its diameter was 10 kilometers.
However, it is estimated that an asteroid with a diameter of 500 meters, such as Bennu, hits the Earth approximately every 130,000 years.
In addition to Bennu, there is another dangerous asteroid for Earth: (29075) 1950 DA, just over 1 km in diameter. It stands out for having the highest known probability of impacting the Earth.
It is traveling at a speed of 59,000 km per hour, bringing with it a force of 44,800 megatons of TNT that could impact our planet.
Astronomers have calculated that the date of possible impact with Earth would be March 16, 2880, almost 700 years after the possible impact with Bennu. Scientists hope to have enough technology by that date to divert it from its fatal path.
