Search results
Results From The WOW.Com Content Network
The United States Naval Observatory states "the Equation of Time is the difference apparent solar time minus mean solar time ", i.e. if the sun is ahead of the clock the sign is positive, and if the clock is ahead of the sun the sign is negative. [6] [7] The equation of time is shown in the upper graph above for a period of slightly more than a ...
Artist's concept of the Earth5–7.5 billion years from now, when the Sunhas become a red giant. While the future cannot be predicted with certainty, present understanding in various scientific fields allows for the prediction of some far-future events, if only in the broadest outline. [1][2][3][4]These fields include astrophysics, which ...
This is a list of the largest known epidemics and pandemics caused by an infectious disease in humans. Widespread non-communicable diseases such as cardiovascular disease and cancer are not included. An epidemic is the rapid spread of disease to a large number of people in a given population within a short period of time; in meningococcal infections, an attack rate in excess of 15 cases per ...
Geological history of oxygen. O 2 build-up in the Earth's atmosphere. Red and green lines represent the range of the estimates while time is measured in billions of years ago ( Ga ). Stage 1 (3.85–2.45 Ga): Practically no O 2 in the atmosphere. Stage 2 (2.45–1.85 Ga): O 2 produced, but absorbed in oceans and seabed rock.
Earth's polar circumference is very near to 21,600 nautical miles because the nautical mile was intended to express one minute of latitude (see meridian arc ), which is 21,600 partitions of the polar circumference (that is 60 minutes × 360 degrees).
Radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at ...
The Phanerozoic [4] is the current and the latest of the four geologic eons in the Earth 's geologic time scale, covering the time period from 538.8 million years ago to the present. [5] It is the eon during which abundant animal and plant life has proliferated, diversified and colonized various niches on the Earth's surface, beginning with the Cambrian period when animals first developed hard ...
The Last Glacial Maximum ( LGM ), also referred to as the Last Glacial Coldest Period, [1] was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent 26,000 and 20,000 years ago. [2] Ice sheets covered much of Northern North America, Northern Europe, and Asia and profoundly affected Earth 's climate ...