Stronomers estimate the internal temperature of the sun is 15,000,000  K. What is 15,000,000 written in scientific notation? 1.5 x 10^8 1.5 x 10^8 1.5 x 1^7 1.5 x 1^7 1.5 x 1^6 1.5 x 1^6 1.5 x 1^ 5