i think it has been 100048554766587658 seconds
31,536,000 seconds
One.
They have been on Earth since Earth has existed.
86,400
About 500 seconds
The average distance from the Earth to the Moon is about 1.28 light-seconds. This means it takes light about 1.28 seconds to travel from the Earth to the Moon.
Electricity is a natural feature of Earth, and has existed almost as long as Earth had existed.
Pick any date before tomorrow, and Earth existed on that date.
8 minutes and 31 seconds
According to the International Astronomical Units, a Julian year is 31,557,600 seconds long.
Many environments are not suitable for fossil formation.
If the age of the universe is equivalent to 1 day, which is 86,400 seconds, then the proportion of mankind's age to the age of the universe is 106 years to 1010 years. Therefore, multiplying 86,400 seconds by 106/1010 will give you the number of seconds mankind would have existed, which is approximately 9,072 seconds.