what has a four second lifespan?
470977
Certain radioactive isotopes have such short half-lives that they almost completely decay into daughter isotopes in less than 10 seconds or even less than 1 second. Look it up on Wikipedia.
517634
It lasts for\n1/24 from second
41504
Usually, seconds.\n\nSometimes, days.\n\nOccasionally, never.
215459
I dont think they live too long, I found an article that say the life cycle is about 14 days and as little as 4 days.
721714
put it this way: every 6 seconds someone dies\nand every 4 seconds someone is born.
176116
A halflife is a form of time constant for characterizing exponential trends with a decay rate of 1/2. Another common time constant decay rate is 1/e.
133226
One millionth of a second looks like this .000001. That is not a lot of time. A millionth of a second is so useless that if you took a picture every millionth of a second that you wouldn't be able to tell the difference between most of the pictures. Plus you would need 1,000,000 pictures to have a second.
829311
Do you mean life expectancy? I understand it was about three weeks.\n\nJust for comparison, the life expectancy of a bomb disposal officer in London in WWII was around six weeks.
667027
Press power button and hold for MORE THAN 4 seconds.
616855
The sun is approx 98 million miles away, light travels 186,282.397 miles per second. So we would know ( and die) about 8.768 minutes later
62696
http://www.wonderquest.com/LifeSpan-MaxMin.htm
516804
We don't know. People used to think it was 4 seconds, but now studies are showing it's longer. They probably run tests. But who cares for one, and two how do they know for certain.
966423
24 hours *(3600sec /1 hr) = 86,400 sec
1036967
Good question!  I would have to say between 5-10 seconds.
133260
.68181818181818 etc. \n(a little more than 1/2 a foot per second)
401360
Depends really on how long it lives.
760649
10,000\n\nHalf life means that after 5,000 years, half the radiation is present. In another five thousand years years, only a quarter is left. In another 5,000 only an eighth is left, etc.