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A May 2016 study based on scaling laws estimated that 1 trillion species (overwhelmingly microbes) are on Earth currently with only one-thousandth of one percent described, [28] [29] though this has been controversial and a 2019 study of varied environmental samples of 16S ribosomal RNA estimated that there exist 0.8-1.6 million species of ...
(1 000 000 000 000 000; 1000 5; short scale: one quadrillion; long scale: one thousand billion, or one billiard) ISO: peta- (P) Biology – Insects : 1,000,000,000,000,000 to 10,000,000,000,000,000 (10 15 to 10 16 ) – The estimated total number of ants on Earth alive at any one time (their biomass is approximately equal to the total biomass ...
One billion years may be called an eon in astronomy or geology. Previously in British English (but not in American English), the word "billion" referred exclusively to a million millions (1,000,000,000,000). However, this is not common anymore, and the word has been used to mean one thousand million (1,000,000,000) for several decades. [5]
In many early attempts, such as in Ancient Egypt and the Persian Empire, the focus was on counting merely a subset of the population for purposes of taxation or military service. [2] Published estimates for the 1st century (" AD 1 ") suggest uncertainty of the order of 50% (estimates range between 150 and 330 million).
[9] [15] This future visibility limit is calculated at a comoving distance of 19 billion parsecs (62 billion light-years), assuming the universe will keep expanding forever, which implies the number of galaxies that can ever be theoretically observed in the infinite future is only larger than the number currently observable by a factor of 2.36 ...
So to understand how we came to exist on planet Earth, we'll need to know how Earth managed to stay fit for life for billions of years. Earth has been habitable for billions of years ...
The mass of the oceans is approximately 1.35 × 10 18 metric tons or about 1/4400 of Earth's total mass. The oceans cover an area of 361.8 million km 2 (139.7 million sq mi) with a mean depth of 3,682 m (12,080 ft), resulting in an estimated volume of 1.332 billion km 3 (320 million cu mi). [195]
The Day of Five Billion, 11 July 1987, was designated by the United Nations Population Fund as the approximate day on which the world population reached five billion. Matej Gašpar from Zagreb , Croatia (then SR Croatia , SFR Yugoslavia ), was chosen as the symbolic 5-billionth person alive on Earth .