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From today's featured article
The Fibonacci sequence is a sequence of numbers in which each number is the sum of the two preceding ones. Beginning with 0 and 1, its first terms are 0, 1, 1, 2, 3, 5, 8, 13, and 21.
The sequence is named after the Italian mathematician Leonardo of Pisa, also known as Fibonacci, who introduced it to Western European mathematics in his 1202 book Liber Abaci. Related sequences had been described earlier in Indian mathematics.
Fibonacci numbers appear in the study of algorithms, number theory, and some patterns in nature. The ratio of consecutive terms approaches the golden ratio as the terms grow larger. Full article...
Recently featured: Cartography · Light · The ocean
Did you know ...
- ... that the word cartography refers to both the study and the practice of making maps?
- ... that the ocean covers about 71% of Earth's surface?
- ... that a prime number has exactly two positive divisors?
- ... that light from the Sun takes about eight minutes to reach Earth?
In focus
Ideas that changed the way we understand the world:
- Scientific inquiry connects observation, explanation, and testing.
- Historical sources help us interpret the lives of people who came before us.
- Mathematics describes patterns through numbers, structures, and logical relationships.
- Natural history begins with a close look at the living world.
Selected moments in history
Selected milestones
- 1202 – Fibonacci's Liber Abaci helps introduce Hindu–Arabic numerals to a wider European readership.
- 1687 – Isaac Newton publishes the Principia, describing his laws of motion and universal gravitation.
- 1859 – Charles Darwin publishes On the Origin of Species.
- 1969 – Apollo 11 astronauts make the first human landing on the Moon.
A question worth asking
How can a simple rule produce a complex pattern?
From spirals and branching trees to the numbers in a sequence, small steps can create surprisingly rich structures. Start with mathematics.
Today's featured illustration
The phases of the Moon describe the changing portion of its sunlit half visible from Earth. A cycle from one new moon to the next takes approximately 29.5 days.
These changes result from the relative positions of the Sun, Earth, and Moon. The Moon itself does not change shape.
Schematic illustration · Not to scale