News: NASA has announced that a giant asteroid called as 163348 (2002 NN4) is expected to pass Earth.The asteroid is a Near-Earth Object(NEO) and is classified as Potentially Hazardous Asteroid(PHA).
- Near Earth Object(NEO): These are comets and asteroids pushed by the gravitational attraction of nearby planets into orbits which allow them to enter the Earth’s neighbourhood.They are composed mostly of water ice with embedded dust particles.
- Potentially Hazardous Asteroid (PHA):It means that an asteroid has the potential to make threatening close approaches to the Earth.
- Asteroid: They are small, rocky objects that orbit the Sun.Although asteroids orbit the Sun like planets, they are much smaller than planets.
- Comets: They are cosmic snowballs of frozen gases, rock and dust that orbit the Sun.