The Planetary Defence community has been able to detect the following asteroids prior to their impact with Earth's atmosphere. Behind this achievement there are numerous observatories spread around the globe that constantly scan the sky as well as the work and support of citizen astronomers. In the table below, the estimated impact energy is computed assuming an object density of 2600 kg/m³ and the estimated object diameter. In most cases, the size presented in the table is estimated indirectly from the absolute magnitude, and flagged with an asterisk * .