PhysicsWiki featured article
The geological history of Earth
began 4.57 billion years ago when the planets of the Solar System
were formed out of the solar nebula
, a disk-shaped mass of dust and gas left over from the formation of the Sun. Initially molten
, the outer layer of the planet Earth
cooled to form a solid crust
when water began accumulating in the atmosphere. The Moon
formed soon afterwards, possibly as the result of a Mars
-sized object with about 10% of the Earth's mass, known as Theia
, impacting the Earth in a glancing blow. Some of this object's mass merged with the Earth and a portion was ejected into space, but enough material survived to form an orbiting moon. Outgassing and volcanic
activity produced the primordial atmosphere. Condensing water vapor
, augmented by ice delivered by comets
, produced the oceans
. As the surface continually reshaped itself, over hundreds of millions of years, continents formed and broke up. The continents migrated across the surface, occasionally combining to form a supercontinent
. Roughly 750 Ma
(million years ago) (ICS
2004), the earliest known supercontinent Rodinia
, began to break apart. The continents later recombined to form Pannotia
, 600–540 Ma (ICS 2004), then finally Pangaea
, which broke apart 180 Ma (ICS 2004). The present pattern of ice ages
began about 40 Ma (ICS 2004), then intensified during the Pleistocene
about 3 Ma (ICS 2004). The polar regions have since undergone repeated cycles of glaciation and thaw, repeating every 40,000–100,000 years. The last glacial period
of the current ice age
ended about 10,000 years ago.
Did you know...
Mock mirage of the setting sun
- ...that your watch would run slower when orbiting a black hole than it would on Earth?
- ...that Aristotle's ideas of physics held that because an object could not move without an immediate source of energy, arrows created a vacuum behind them that pushed them through the air.
- ...that nuclear fusion reactions are probably occurring at or above the sun's photosphere; it is a process called solar surface fusion.
Artist's depiction of the WMAP
satellite measuring the Cosmic Microwave Background Radiation
to help scientists understand the Big Bang
- ...that neutron stars are so dense that a teaspoonful (5 mL) would have ten times the mass of all human world population?
- ...that every year, the Moon moves 3.82 cm away from Earth?
- ...that Neptune was discovered by its gravitational pull on Uranus?
Suggest a fact
In the news this month
This Month's Aniversarys...
- May 1, 1960 - U-2 spy plane shot down
- May 6, 1937 - Hindenburg fire
- May 9, 1012 BC – Solar Eclipse seen at Ugarit, 6:09–6:39 PM.
- May 9, 1904 – City of Truro, a steam locomotive exceeds 100 mph (160 km/h).
- May 10, 1946 – V-2 rocket's first successful launch at White Sands Proving Ground
- May 10, 1960 – The nuclear submarine USS Triton completes Operation Sandblast, the first underwater circumnavigation of the earth.
- May 11, 1862 – American Civil War: The ironclad CSS Virginia is scuttled in Virginia.
- May 11, 1995 – In New York City, over 170 countries extend Nuclear Nonproliferation Treaty indefinitely, without conditions.
- May 11, 1998 – India conducts three underground nuclear tests, including a thermonuclear device.
- May 16, 1960 - Theodore Maiman operates the first optical laser, at Hughes Research Laboratories in Malibu, California.
- May 16, 1969 – Venera 5, a Soviet spaceprobe, lands on Venus.
- May 17, 1865 – The International Telegraph Union is established.
- May 18, 1998 - Microsoft sued by US Government
- May 19, 1943 - RAF uses bouncing bombs in combat
- May 20, 1932 - Amelia Earhart crosses Atlantic Ocean
- May 26, 1972 - President Nixon and Leonid Brezhnev sign nuclear weapon non-polifertion pact.
- May 24, 1844 - First official telegraph message is sent by Samuel Morse.
- May 27, 1937 - Grand opening, Golden Gate Bridge
- May 28, 1998 – Pakistan conducts five underground nuclear tests, named Chagai-I.
- May 6, 1872 - Willem de Sitter physicist, mathematician, astronomer
- May 9, 1931 – Vance Brand, astronaut
- May 10, 1746 – Gaspard Monge, mathematician
- May 10, 1788 – Augustin-Jean Fresnel physicist
- May 10, 1963 – Lisa Nowak, astronaut
- May 11, 1918 – Richard Feynman, physicist
- May 14, 1686 - Gabriel Fahrenheit, physicist and engineer
- May 21, 1921 - Andrei Sakharov, nuclear physicist
- May 7,1861 - Rabindranath Tagore,poet, patriotist,philosopher