There are two ways supernovae are useful. First, supernovae recycle elements. After a supernova explosion, the supernova sends elements into space. These elements become parts of other planets and stars.

The other way is rather interesting. Scientists use a method called "standard candles" to measure distances. They look at a supernova or other bright occurrence and calculate how bright it is locally and how bright it appears to us here on earth. They then use the difference in brightness to calculate the distance from earth. While other deep space phenomena, such as red giants and globular clusters, can be used to measure distances by the "standard candles" method, supernovae can measure the greatest distances from earth. Supernovae can be used to calculate a distance of up to approximately 500 million light years away.