A team of astronomers believe that our planet’s gravitational pull could alter the surface of Apophis, a near-Earth asteroid (NEA) set to make a close approach to Earth in five years’ time.
Apophis is currently 1.97 astronomical units from Earth—or about twice as far from Earth as our planet is from the Sun.
Space scientists are paying close attention to Apophis’ April 13, 2029 flyby (and yes—April 13, 2029 is a Friday).
If it were to hit Earth—which it won’t—Apophis’ footprint would fit neatly inside Manhattan’s Battery Park (as shown above).
Though by the recent team’s measure, Earth will cause much more havoc on Apophis than the asteroid will on our planet.
According to a group of astronomers, the gravitational pull of our planet may change the surface of Apophis, a near-Earth asteroid (NEA) that will approach Earth closely in five years.
The current distance between Apophis and Earth is 1.97 astronomical units, or roughly twice as far apart as Earth is from the Sun. However, a team of researchers predicts that the asteroid will pass directly by our planet in April 2029, causing landslides and earthquakes on the smaller rock. The team’s results are now available on the preprint server arXiv and are scheduled to appear in The Planetary Science Journal.
The researchers stated in the paper that “the 2029 encounter will induce short-term tidally-driven discrete seismic events that lead to high-frequency surface accelerations that achieve magnitudes similar to Apophis’ gravity and that may be detectable by modern seismometers.”.
Apophis’ flyby on April 13, 2029, is attracting the attention of space scientists (yes, that is a Friday). The asteroid, which is 1,100 feet (335 meters) wide, will be within 24,000 miles (38,625 kilometers) of the surface of our planet when it makes its closest pass. This is about ten times closer than the Moon typically is during its orbit around our cosmic neighborhood.
Given its closeness to Earth, Apophis will be influenced by our planet’s gravitational pull, which also maintains the Moon’s orbit around us. However, because Apophis is smaller than the Moon and will be nearer Earth, the asteroid will be more severely affected by Earth’s gravity. This is the same force that stresses and fractures the surface of moons like Miranda on Uranus, and it makes us wonder if our own Moon is stable enough for NASA to safely land astronauts on it during the next Artemis 3 mission.
According to the team, “we also find that there will be a significant change in Apophis’ tumbling spin state that could lead to longer-term surface refreshing in response to tumbling-induced surface slope changes.” They also noted that other asteroids like Apophis might have their surfaces refreshed by such a mechanism.
Because scientists can learn a lot from asteroids’ interiors, this part of the team’s discovery is compelling. These obscure asteroid fragments can provide insight into the history of our solar system and beyond, as well as the origins of the space rocks. Asteroids’ organic molecules may provide clues about the origins of the elements necessary for life, while the metals in the rocks may reveal the intense cosmic interactions that gave rise to the asteroid. The interior of an asteroid can reveal layers of older information about the composition of a space rock and how it interacts with its local environment in space. It can also explain why some objects, such as the odd interstellar intruder ‘Oumuamua,’ accelerate like spaceships.
Apophis is anticipated to swing by Earth, just like ‘Oumuamua. Apophis is unlikely to pose a threat to life as we know it. To put the asteroid on a collision course with our planet, a lot would need to go wrong with its trajectory.
However, once every 80,000 years or so, objects the size of Apophis strike our planet, causing severe damage in the immediate area and potentially causing climate change. Apophis’ trajectory won’t endanger our planet—that is, there won’t be any threat of harm—for at least a century, according to a 2021 NASA analysis.
Earlier this year, Blue Origin and other space companies suggested missions to take advantage of the asteroid’s close encounter with Earth. Space agencies are basically cosmic doctors who visit patients at their homes; it is extremely uncommon—and far less expensive—for the patient to come to you.
For a moment, however, forget about mission concepts—one mission is already en route to meet up with Apophis. A NASA mission called OSIRIS-APEX is en route to the asteroid to learn more about how the rock might change as a result of coming in close proximity to Earth.
Even if it were to strike Earth, which it won’t, Apophis’ footprint would fit neatly inside Battery Park in Manhattan (see above). A rock roughly the size of a small building, the Chelyabinsk fireball exploded over Russia in 2013 and was the last major asteroid to reach Earth. A bright flash and a strong shockwave were produced by the explosion, which released energy equal to about 500 kilotons of TNT. The Chelyabinsk asteroid was roughly 17 times smaller than Apophis, measuring only 66 feet (20 meters) across.
Nevertheless, that comparison highlights the possible threat posed by near-Earth asteroids and the reason why organizations like NASA keep such a close eye on them. According to the latest team’s calculations, however, Earth will harm Apophis far more than the asteroid will our planet.
