Because it reduces very large or very small numbers into less digits but retaining their original values as for example 1,000,000,000,000 = 1.0*10^12 in scientific notation
You have it in reverse. Scientific notation is useful for measuring stars.
Scientific notation is useful in economics to compute very large or very small numbers.
Scientific notation is useful in mathematics because it makes very large or very small numbers easier to compute.
1.9 X 1027 kilograms ------------------------ This is the mass of Jupiter. Try writing that out in longhand and you will see why scientific notation is useful to astronomers. Very large numbers in astronomy need a way to write them in a useful and compact form.
Scientific notation gives a compact notation, which is especially useful for writing down - and doing calculations with - very large, and very small, numbers.
When you have a number with a large amount of digits.
You use scientific notation when it comes to "too large" or "too small" numbers. The reasons why using scientific notation is useful are that it saves time to do the computation and also that it makes people's life easier to compute values instead of writing them out completely!
When numbers are tremendously large or small.
Scientific notation
Scientific notation tends to be useful any time you have to deal with either very large numbers or very small numbers.
It is used for recording very large or very small numbers. This is particularly true for sciences.
Scientific notation is useful for very large or very small numbers. If you use such numbers in your "real world", then scientific notation will be very useful. This may be the case, for example, when you work in science or engineering. Otherwise, if you don't work in an area that uses such large or small numbers, you probably won't find much use for them.