really good test of technology to see whether the theory is that the scientists and engineers have come up scientists and engineers have come up with will actually nudge a potentially hazardous asteroids off—course from hitting the earth. yes, it is very exciting. the off-course from hitting the earth. yes, it is very exciting.— yes, it is very exciting. the most famous one _ yes, it is very exciting. the most famous one that _ yes, it is very exciting. the most famous one that hit _ yes, it is very exciting. the most famous one that hit the - yes, it is very exciting. the most famous one that hit the earth i yes, it is very exciting. the most | famous one that hit the earth was how many millions of years ago? 66 how many millions of years ago? 55 million how many millions of years ago? 1515 million years ago. a large asteroid about ten kilometres wide impacted the earth in the region that is now the earth in the region that is now the yucatan peninsula, and that caused mass devastation. the crater was 200 kilometres wide and it killed about 75% of all species that were on earth at the time. we know it has happened in the past. another one i talk to people about was 49,000 years ago, so much more recently, and an asteroid that was about 50 metres wide, about the size of an olympic —sized swimming pool, smacked into the arizona desert and calculations have been done and that really enough energy to the