On April 13, 2029, the asteroid 99942 Apophis, measuring 340 meters in diameter, will make a close flyby of Earth at a distance of 5.9 Earth radii, providing a rare observational opportunity that will be visible to over 2 billion people across Africa and Western Europe.

This event is expected to be the most widely observed astronomical event in human history, with Apophis appearing as a faint star in the night sky, an occurrence that happens roughly once every 7,500 years for an object of its size.

Despite initial fears, scientists including MIT's Richard Binzel confirm that Apophis will safely pass Earth and pose no threat during this encounter, which is characterized as a significant scientific event rather than a danger.

Studying Apophis during this flyby will help refine models for planetary defense, as it serves as a natural laboratory for understanding how Earth's gravity can influence asteroid behavior, crucial for future impact mitigation strategies.

Several planned missions, such as Europe's RAMSES, Japan's DESTINY+, and NASA's OSIRIS-APEX, aim to observe and analyze Apophis before and after the encounter, although some like OSIRIS-APEX face potential cancellation due to budget constraints.

NASA's OSIRIS-REx spacecraft will be repositioned as OSIRIS-APEX to map Apophis's surface, monitor its spin, and measure seismic vibrations, providing valuable insights into its internal structure during the flyby.

Recent studies have refined Apophis's orbit, showing an extremely low probability (over one in a billion) of collision before the 2029 flyby, and scientists are confident it poses no threat for the next century.

While Apophis is classified as potentially hazardous, its close approach offers a rare scientific opportunity to better understand asteroid behavior, seismic activity, and planetary defense techniques.

Earth's gravity will alter Apophis's orbit during the flyby, potentially changing its trajectory and rotation, which could cause it to tumble or shift from its current orbital class.

This event provides a unique natural experiment for spacecraft and ground-based observations to study the asteroid's physical properties and the effects of Earth's gravitational and magnetic influences, advancing planetary defense and asteroid science.

Scientists consider this a groundbreaking opportunity to significantly improve understanding of asteroid physics and develop better planetary defense strategies.

The orbit of Apophis has been carefully refined, and current data suggest an extremely low probability of impact, reinforcing that it poses no threat during this flyby.

If approved, the European Space Agency's RAMSES mission, planned for launch in 2028, will observe Apophis before, during, and after its flyby, including deploying a cubesat to study seismic and tidal effects.