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4.2.4 Fraction of the above that actually go on to develop life, f l 4.2.5 Fraction of the above that develops intelligent life, f i 4.2.6 Fraction of the above revealing their existence via signal release into space, f c
4.8 Ma Mammoths appear in the fossil record. 4.5 Ma Marine iguanas diverge from land iguanas. 4 Ma Australopithecus evolves. Stupendemys appears in the fossil record as the largest freshwater turtle, first modern elephants, giraffes, zebras, lions, rhinoceros and gazelles appear in the fossil record 3.6 Ma Blue whales grow to modern size. 3 Ma
The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. [2] The earliest evidence of life found in a stratigraphic unit, not just a single mineral grain, is the 3.7 Ga metasedimentary rocks containing ...
The timeline of the early universe outlines the formation and subsequent evolution of the Universe from the Big Bang (13.799 ± 0.021 billion years ago) [1] to the present day. An epoch is a moment in time from which nature or situations change to such a degree that it marks the beginning of a new era or age. Times on this list are measured ...
Half-life (symbol t½) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential (or, rarely ...
In statistics, the 68–95–99.7 rule, also known as the empirical rule, and sometimes abbreviated 3sr, is a shorthand used to remember the percentage of values that lie within an interval estimate in a normal distribution: approximately 68%, 95%, and 99.7% of the values lie within one, two, and three standard deviations of the mean, respectively.
Outside the circle, the continued fraction represents the analytic continuation of the function to the complex plane with the positive real axis, from +1 to the point at infinity removed. In most cases +1 is a branch point and the line from +1 to positive infinity is a branch cut for this function.
It is unknown whether these constants are transcendental in general, but Γ( 1 / 3 ) and Γ( 1 / 4 ) were shown to be transcendental by G. V. Chudnovsky. Γ( 1 / 4 ) / 4 √ π has also long been known to be transcendental, and Yuri Nesterenko proved in 1996 that Γ( 1 / 4 ), π, and e π are algebraically independent.