The death of
a massive star.

A massive star ended its life in a supernova. The expanding remnant now has a radius of \( 1.89 \times 10^{17}\ \mathrm{m} \) and grows at a steady \( 6.0 \times 10^6\ \mathrm{m/s} \). How many years ago did the star explode?

• Remnant radius\( 1.89 \times 10^{17}\ \mathrm{m} \)
• Expansion speed\( 6.0 \times 10^6\ \mathrm{m/s} \)
• One year\( 3.15 \times 10^7\ \mathrm{s} \)
• Answer inyears