On April 13, 2029, the asteroid 99942 Apophis will make an incredible approach to Earth. Over 2 billion people in Africa and Western Europe will have the chance to see it. Under clear skies, Apophis will look like a faint star, visible to the naked eye and gliding through the night sky.
This event is historic. According to Richard Binzel, a planetary sciences professor at MIT, it’s the first time a potentially hazardous asteroid can be seen without a telescope. This flyby is rare; astronomers say a close encounter with an asteroid of this size, which is about 1,100 feet wide—similar to the Eiffel Tower—happens once every 7,500 years.
For many, this will be a dazzling experience. For scientists, it offers a rare chance to study how Earth’s gravity affects an asteroid. Binzel emphasized, “We won’t know until we look.” This underscores the quest for knowledge in planetary science.
Initially, when Apophis was discovered in 2004, uncertainty surrounded its path. Early estimates suggested a 2.7% chance of impact, putting it at a Level 4 on the Torino Scale, the highest risk classification available. Named after the Egyptian god of chaos, Apophis seemed dangerous at first.
Over the years, extensive tracking and observations have refined its orbit, reducing uncertainties significantly. By 2021, it was deemed safe for at least the next century. While a recent study highlighted a minute chance of an unknown asteroid nudging it off course, the odds are more than one in a billion, providing reassurance to scientists and the public alike.
As Apophis approaches, it won’t just glide by unnoticed. It will undergo significant changes. It will fly just 18,600 miles above Earth, which is closer than many satellites. Binzel explained that while Earth “won’t care,” the asteroid’s orbit and rotation will change, leading to what scientists call “encounter physics.”
NASA is preparing for this extraordinary event by reassigning its OSIRIS-REx spacecraft to a new mission named OSIRIS-APEX. This spacecraft will study Apophis before its flyby, mapping its surface and monitoring seismic activity. Binzel noted that this could be a groundbreaking opportunity since we’ve only measured seismic activity on the Moon and Mars so far.
In addition, the European Space Agency is considering a mission called RAMSES to gather further data about Apophis just before and after the flyby. This mission could explore the asteroid up close, potentially launching a small satellite to analyze its surface and collect seismic data.
Experts agree that Apophis serves as a valuable learning opportunity for planetary defense. Although the asteroid itself poses no threat, understanding how Earth’s gravity interacts with it can help us prepare for potential future threats. As NASA’s Tom Statler stated, “Apophis is not a planetary defense emergency; it is an opportunity.” By studying it, we can enhance our knowledge and response strategies for future asteroid threats.
Asteroids aren’t something to fear; they are celestial bodies presenting chances to deepen our understanding of the universe. As we await the Apophis flyby, the astronomical community looks forward to the discoveries that await us. For more on this topic, check out further insights from NASA’s planetary defense strategies here.
