Image Credit: NASA / Reuters
According to NASA there are no asteroids or comets detected that stance a threat of impact in the predictable future and approximations the chance of a PHO crash in the next century at less than 0.01 percent.
But impacts with PHOs have taken place in the past. Although small meteorites attack our planet’s atmosphere every day, the last truly big impact was about 65 million years ago.
Researchers consider that a comet hit the Yucatan peninsula in Mexico at that time, triggering such terrible damage to the atmosphere that all the dinosaurs died out.