Tuesday, 6 December 2016
Tuesday, 16 August 2016
Time-resolved 2-million-year-old supernova activity discovered in Earth’s microfossil record
Massive stars, which terminate their evolution in a cataclysmic explosion called a type-II supernova, are the nuclear engines of galactic nucleosynthesis. Among the elemental species known to be produced in these stars, the radioisotope 60Fe stands out: This radioisotope has no natural, terrestrial production mechanisms; thus, a detection of 60Fe atoms within terrestrial reservoirs is proof for the direct deposition of supernova material within our solar system. We report, in this work, the direct detection of live 60Fe atoms in biologically produced nanocrystals of magnetite, which we selectively extracted from two Pacific Ocean sediment cores. We find that the arrival of supernova material on Earth coincides with the lower Pleistocene boundary (2.7 Ma) and that it terminates around 1.7 Ma (details).
Sunday, 14 February 2016
Gravitational waves and The Theory of Relativity
AN IDIOT'S GUIDE TO...
The Theory of Relativity
Albert Einstein
Albert Einstein explained that what we perceive as the force of gravity in fact arises from the curvature of space and time.
He found that space and time were actually interwoven into a single continuum known as space-time.
As he worked out the equations for this general theory of relativity, Einstein realised that massive objects caused a distortion within this continuum.
Imagine a large body in the centre of a trampoline. The body would press down into the fabric, causing it to dimple. If a marble was then rolled around the edge, it would spiral inward toward the body, pulled in much the same way that the gravity of a planet pulls at rocks in space.
He proposed that objects such as the sun and the Earth work in a similar way. In the presence of matter and energy they can evolve, stretch and warp, forming ridges, mountains and valleys that cause things moving through to zigzag and curve.
Einstein determined that massive objects (like the Earth) cause a distortion in space-time which is felt as gravity.
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Article of the Day
  The Mystery of Skeleton LakeAn uninhabited area located high in the Indian Himalayas, Roopkund is best known as the home of Skeleton Lake, where in 1942 a park ranger made a startling discovery—a mass grave containing the remains of some 300 to 600 people. Using radiocarbon dating, scientists traced the skeletons to the 9th century. Though people initially believed the dead were victims of landslides, an epidemic, or a blizzard, further examination of the skulls revealed that the people died in what unusual way? More... Discuss |
Article of the Day
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This Day in History
 Sidney Poitier Becomes the First African American to Win Best Actor Oscar (1964)The first African American to achieve leading man status in Hollywood, Poitier began acting with the American Negro Theatre in New York City and made his film debut soon after. He won acclaim on Broadway for his role in 1959's A Raisin in the Sun and, in 1964, became the first African American to win the Academy Award for Best Actor, for his role in Lilies of the Field. Many of his films address issues of race, yet some have criticized his choice of film roles for what reason? More... Discuss |
This Day in History
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Today's Birthday
 Lanford Wilson (1937)One of the founders of the "off-off-Broadway" theater movement, Wilson began writing plays in 1962 and helped found the Circle Repertory Company in 1969. His plays frequently address themes of decay, solitude, and loss, and are known for their realistic dialogue in which monologue, conversation, and direct audience address overlap. His Pulitzer Prize-winning Talley's Folly depicts the post-Vietnam War world of a Southern family. What Russian work did he translate for the stage? More... Discuss |
Today's Birthday
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In the News
habit-forming discuss | |
| Definition: | (adjective) Capable of leading to physiological or psychological dependence. |
| Synonyms: | addictive |
| Usage: | Cocaine is a habit-forming drug. |
In the News
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Quote of the Day
Quote of the Day
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