跟踪小行星和彗星通過比較接近我們的地球
The application, for any approaching comet or asteroid, shows the date in which the object will draw closer to Earth, its approximate diameter (estimated on the absolute magnitude of the celestial body), its distance from Earth, and its speed. In addition, the tool shows the most recent approaches and those expected on the following days, with a 7.5 million km. accuracy. An object of approximately 150 m. in diameter approaching Earth, will be defined as potentially dangerous, in fact, the Earth gravitational field may lead it towards our atmosphere. All data is directly obtained from the NASA page (NEO Earth Close Approaches) of reference.