Earth has suffered many tragedies in its 4.5 billion year history. Fossil records have shown that mass extinction have occurred on a number of occasion. Some scientists now believe that a number of these mass extinctions were as a result of extra terrestrial events. In this unit we have discussed the Ordovician extinction believed to have been caused by a supernova.

Research the topic of mass extinctions and identify the scientific evidence that point to extra terrestrial activity. Explain the events that occured to cause the mass extinction. Investigate two other mass extinctions apart from the Ordovician and the Triassic mass extinctions mentioned in this text. You may use a Power Point presentation, animations or any other visual media. In your presentation answer the following questions?

What is a supernova?
What is a carbon star?
How do scientists use the element iridium to identify an asteroid impact?