Search results
Results From The WOW.Com Content Network
In Larry Niven's 1980 short story "The Green Marauder", [6] an alien over 700 million years old (due to relativistic travel) tells a human about the last time it visited Earth, and the hopeless plea from Earth's anaerobic civilization for help against the growing environmental threat of chlorophyll.
The ice age was probably not as long-lasting as once thought; study of oxygen isotopes in fossil brachiopods shows that it was probably no longer than 0.5 to 1.5 million years. [41] The event was preceded by a fall in atmospheric carbon dioxide (from 7000ppm to 4400ppm) which selectively affected the shallow seas where most organisms lived.
Earth formed in this manner about 4.54 billion years ago (with an uncertainty of 1%) [25] [26] [4] and was largely completed within 10–20 million years. [27] In June 2023, scientists reported evidence that the planet Earth may have formed in just three million years, much faster than the 10−100 million years thought earlier.
Short story – A circular paradox in which a man discovers that he is his own mother and father. 1959–1989 The Time Machine series "Donald Keith" alias of Donald & Keith Monroe: Series of 23 short stories published in Boys' Life magazine centered around a patrol of Boy Scouts who acquire an abandoned time machine. 1961 Danny Dunn, Time Traveler
1808 short stories (1 P) Pages in category "1800s short stories" This category contains only the following page. This list may not reflect recent changes. F.
Ancient giant stromatolites used to be widespread in Earth’s Precambrian era, which encompasses the early time span of around 4.6 billion to 541 million years ago, but now they are sparsely ...
A megaannus (Ma) represents one million (10 6) years. The geologic time scale or geological time scale ( GTS ) is a representation of time based on the rock record of Earth . It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...