I don't get this. What does it mean when http://www.nineplanets.org/neptune.... said Neptune's mass is: "1.02

Question

So "1.0247e26 kg." is really " 1024700000000000000000000000000 kg." OR did you mean "1.024700000000000000000000000000 kg." ?

Answer 1

I assume that continues ...1.02 × 10^26 kg.  The 10ª means 10 multiplied by itself "a" times (I'm putting the *a* in asterisks so you know I'm talking about the variable *a*, and not the word "a").  Thus, for instance,

10² = 10 × 10 = 100

10³ = 10 × 10 × 10 = 1000

and so on.  Notice that 10ª is 1 followed by *a* zeros, so 10^26 is 1 followed by 26 zeros.  So the mass of Neptune, in kilograms, is roughly 1 followed by 26 zeros.  Or, written out, it's

102,000,000,000,000,000,000,000,000 kg

In words, that's about "one hundred thousand million, million, million tons" (where a ton is about 1,000 kg).  Very massive indeed.

Answer 2

Brian has it correct, Matt has it slightly wrong (as do you in your clarification question).

102470000000000000000000000 kg = 1.0247e26 kg

To write 1.0247e26 as a normal number you need to move the decimal point 26 places to the right, adding zeros as you go.  You use up 4 of those 26 getting to the end of the "mantissa", the numbers after the decimal point, and have to add another 22 zeros after that.  This exponential notation is the preferred way of writing such large numbers, as also very small numbers like 1.602e-19 and so on.

Answer 3

1.0247E26 means that its mass is...

1024700000000000000000000000000 kg

1.0247e26 represents an exponent, or the 26th power, just basically a shorter way of saying it. try doing something  your calculator cant handle as far as digits (i.e 89345789 * 352646) it will probably come back with an error if its a cheap calculator, but other ones will come back with something similar to the 1.0247e26.