3. There is no risk to the earth
When Dart reaches Didimos in 11 months, the spacecraft will be 6.8 million miles (11 million km) from Earth, According to NASA. Didymos, which is Greek for “twins”, measures 2,560 feet (780 m) in diameter, while Dimorphos, which is Greek for “two forms”, measures 525 feet (160 m) in diameter, which is two football fields. Just shy in between. The long moonlet, also known as Didimon, is in orbit around Didimos, orbiting it once every 11.9 hours.
To be crystal clear, neither Didymos nor Dimorphos is a threat to Earth. They do not present a risk now, nor do they after a redirection test. NASA chose this special system because it was considered ideal for testing purposes. The smash-up will “change the speed of the Moon in its orbit around the main body to a fraction of a percent, but it will change the time of the Moon’s orbit in a matter of minutes – enough to observe and measure on Earth using a telescope.” Explained.
As it stands, DeMarphos or any known asteroid larger than that is not likely to hit Earth in the next 100 years. The concern, however, relates to a potentially dangerous object that suddenly emerges from the blue. This time the picture was the same Asteroid effect simulation, Where participants were told about an imaginary 460-foot-wide (140-meter-wide) asteroid that has a 100% chance of hitting the Earth in just six months. This left them with very little time for response and preparation. If asteroids of this size hit the Earth, it would cause serious damage across a 120-mile-wide (200-kilometer-wide) radius.