Question

A group of astronomers observed light coming from a star located a distance of 331,000,000,000,000,000,000,000,000 light-years from Earth. What is this distance expressed in scientific notation?
3.31 × 1026 light-years

3.31 × 10-26 light-years

3.31 × 1024 light-years

3.31 × 10-24 light-years

3.31 × 1025 light-years

Answer 1

To show this number using scientific notation, you will look at where the decimal point is and imagine that in the original number.  Then count the number of place values to the right of this.  That will be the exponent that belongs with the 10 because that is how many place values (groups of 10s) the number has past the decimal point.

The answer is 3.31 x 10^26 light years.  ^ means to the power of.

Answer 2

3.31 × 1026 light-years