What is 199145 (2005 YY128)?

About 199145 (2005 YY128):

• 199145 (2005 YY128) is an asteroid whose orbit crosses the orbit of Earth. 
• It orbits the sun every 774 days (2.12 years) in an elliptical orbit.
• 2005 YY128 is probably between 0.566 to 1.265 kilometers in diameter.
• Its orbit is 0.03 astronomical unit from Earth’s orbit at its closest point. 

What is an Asteroid?

• Asteroids are small, rocky objects that orbit the sun.
• Although asteroids orbit the sun like planets, they are much smaller than planets.
• Most of them live in the main asteroid belt—a region between the orbits of Mars and Jupiter.

What is an astronomical unit (AU)?

• An Astronomical Unit (AU) is the average distance between Earth and the Sun, which is about 93 million miles or 150 million kilometers.
• Astronomical units are usually used to measure distances within our Solar System.

Q1) What happens if an asteroid hits earth?

If the asteroid impacts a land mass, in addition to a huge shock wave, massive amounts of particles would be released into the atmosphere, causing serious environmental damage on a global scale and mass extinctions.

Source: Giant Asteroid to hit Earth’s Atmosphere; Find out when will It happen