Astronomers have been calculating the likelihood of the asteroid hitting Earth with greater precision as they gather more data. It is estimated as being anywhere from 131 feet to 295 feet wide, with the potential of releasing the energy equivalent to almost 8 megatons of TNT, or 500 times the power of the atomic bomb the United States dropped on Hiroshima, Japan, during World War II, if it and the Earth collide.
The European Space Agency's odds of YR4 hitting Earth are a little lower than NASA's, at about 2.4%.
The increasing odds don't really mean that the asteroid has become more likely to hit Earth, as they may come down, Hugh Lewis at the University of Southampton, UK, told New Scientist.