Asteroid 99942 Apophis is going to give an unprecedented close encounter with Earth on April 13, 2029. Even though it once was one of the few asteroids to be worried about, NASA has assured that as present knowledge, Apophis will not impact the Earth during the next 100 years and Because of this is of no concern. Instead, astronomers are hoping to gain the most data for one the most close encounters by an asteroid.
Apophis is a large near-Earth object with a diameter of about 340 m. The fly-by during 2029 will see Apophis crossing the north of Earth’s surface at an altitude of around 32,000 km, closer than the orbits of many geostationary satellites. NASA have suggested this is a ”historic chance” to learn more about it as it is not thought to have come so close before.
This was the first time the asteroid received global publicity. Calculations carried out soon after its discovery in 2004 indicated that despite its resonance with the Earth’s orbit there was only a very slim chance of an impact during a future pass. As more observations were made using optical and radar telescopes Though, astronomers were able to Much refine data for Apophis’s orbit and NASA finally discounted the potential impact scenarios from their impact-risk list.
The most recent orbital predictions suggests that Apophis cannot hit the Earth for at least 100 years, meaning that the 2029 encounter is not a planetary crisis but a rather unique natural experiment whereby scientists will be able to keep an eye out for the way in which a reasonably large asteroid reacts to Earth’s gravity at a remarkably proximity. Another major scientific question is “how will Earth’s gravity affect the asteroid?”.
When Apophis is in close proximity to Earth, the huge gravity field will pull and cause strain on the asteroid. It is believed this changes could occur: a small change to the asteroid’s rotation, small changes to the asteroid’s orbit and possibly some alteration to the asteroid’s surface. Scientists would like to know if the encounter could produce minor landslides or move debris on the surface of the asteroid.
These movements could tell scientists something about the composition of the central body of the asteroid and how the surface clumps together. Studying the asteroid over time could be valuable information about the physical properties of near-Earth objects. To the respective organizations, the scientific campaign will be using telescopes and spacecraft around the world.
Ground-based telescopes will be used to observe Apophis around the Earth before and during the flyby. Rader observations may deliver information about Apophis shape and surface. NASA planetary defense community will facilitate the organization for observations using the International Asteroid Warning Network, including researchers from various countries.
NASA is also planning to survey Apophis up close. The spacecraft known previously as OSIRIS-Rex (as it sampled asteroid Bennu) has been refocused onto Apophis and been renamed OSIRIS-APEX. It will arrive at Apophis shortly after the asteroid’s flyby and will study the physical changes in the asteroid.