The National Aeronautics and Space Administration (NASA) has recently allayed fears about the potentially catastrophic asteroid Apophis. The organization has confirmed that there is no risk of this menacing asteroid causing harm to our planet for the next century.
About Asteroid Apophis
Apophis is a near-Earth asteroid notable for its larger size, spanning approximately 335 meters in width. It was named after the ancient Egyptian god of chaos and darkness when it was discovered in 2004. Post-discovery, NASA identified it as one of the most dangerous asteroids for Earth. The agency initially anticipated that Apophis might get troublingly close to Earth in 2029 and 2036, but later dismissed these predictions. Despite this, concerns about a potential collision in 2068 continued to loom. On March 5th, 2021, the asteroid passed Earth, getting as close as 17 million km. During this flyby, scientists captured radar observations to study the asteroid’s orbit around the sun in detail.
The Nature and Impact of Asteroids
Asteroids, sometimes referred to as minor planets, are rocky objects that orbit the Sun. They are significantly smaller than actual planets. Currently, we are aware of 994,383 known asteroids, believed to be remnants from the formation of the solar system over 4.6 billion years ago.
Classification of Asteroids
Asteroids are typically divided into three categories:
- Main Belt Asteroids: These are located within the primary asteroid belt situated between Mars and Jupiter. It is estimated to contain anywhere from 1.1 to 1.9 million asteroids.
- Trojans: These are asteroids that share an orbit with a bigger planet. NASA has reported Jupiter, Neptune, and Mars trojans to date, and in 2011, noted the presence of an Earth trojan as well.
- Near-Earth Asteroids (NEA): This group consists of asteroids with orbits that pass close to the Earth. The ones that intersect with Earth’s orbit are dubbed Earth-crossers. More than 10,000 such asteroids are known, over 1,400 of which are classified as Potentially Hazardous Asteroids (PHAs), by NASA’s Center for Near-Earth Object Study (CNEOS).
The CNEOS calculates the times and distances of these objects via the Asteroid Watch Widget when their approach to the Earth is close.
About Potentially Hazardous Asteroids (PHAs)
PHAs are asteroids with orbits that could potentially collide with Earth. Specific criteria define a PHA: it should have a Minimum Orbit Intersection Distance (MOID) of 0.05 AU (roughly 7,480,000 Km) or less and an Absolute Magnitude (H) of 22.0 (around 150 mt in diameter) or less. The MOID calculates the smallest distance between two almost overlapping elliptical orbits, while the Astronomical Unit (AU) measures the distance between the Earth and the Sun, estimated at about 150 million km. Asteroid Apophis falls under this category of PHAs.