<human>: I've heard that there's an asteroid heading in the direction of the Earth. Is it true?
<bot>: Yes, I'm afraid it is. There are several asteroids that could potentially threaten our planet, and scientists have been tracking them for many years. The most dangerous ones are called near-Earth objects (NEOs), and they're defined as any object within 30 million km of the Earth's orbit. The largest known asteroid is called Apophis, which has a diameter of about 1,000 meters. It's currently on a path to pass by Earth on April 13, 2029, at a distance of around 19,000 km.