#GS1 #Universe 

Explosion of a nearby star — occurred at between Devonian and Carboniferous periods — could have caused a mass extinction event that took place 359 million years ago. 

  • The Earth suffered an intense loss of species diversity that lasted for at least 300,000 years. The event is thought to have been caused by long-lasting ozone depletion, which would have allowed much more of the Sun’s ultraviolet (UV) radiation to reach and harm life on Earth. It was called the Hangenberg crisis. 
  • The research, published in the Proceedings of the National Academy of Sciences on August 18, 2020, was supported by the Science and Technology Facilities Council and the Estonian Research Council. 

About Supernova 

  • Supernova is a transient astronomical event that occurs during the last stellar evolutionary stages of a massive star’s life, whose destruction is marked by one final titanic explosion of a star. 
  • This causes the sudden appearance of a “new” bright star, before slowly fading from sight over several weeks or months. 
  • Supernovae are more energetic than new bright star. 
  • It is the largest explosion that takes place in space. 
  • The word supernova was coined by Walter Baade and Fritz Zwicky in 1931. 
  • A supernova happens where there is a change in the core, or centre, of a star. 
  • A change can occur in two different ways, with both resulting in a supernova. 
  • The explosion may expel much, if not all, of the material away from a star at velocities up to 30,000 km/s or 10% of the speed of light. 
  • This drives an expanding and fast-moving shock wave into the surrounding interstellar medium, and in turn, sweeping up an expanding shell of gas and dust, which is observed as a supernova remnant. 
  • The expanding shock waves from supernovae can trigger the formation of new stars. 
  • A supernova burns for only a short period of time, but it can tell a lot about the universe. 
  • One kind of supernova has shown scientists that we live in an expanding universe, one that is growing at an ever-increasing rate. 
  • Scientists also have determined that supernovas play a key role in distributing elements throughout the universe. 
  • When the star explodes, it shoots elements and debris into space. 
  • They are also potentially strong galactic sources of gravitational waves. 
  • Many of the elements we find on Earth are made in the core of stars. 
  • These elements travel on to form new stars, planets and everything else in the universe. 

Types of supernova 

  • The first type of supernova happens in binary star systems. 
  • Binary stars are two stars that orbit the same point. One of the stars, a carbon-oxygen white dwarf, steals matter from its companion star. Eventually, the white dwarf accumulates too much matter. Having too much matter causes the star to explode, resulting in a supernova. 
  • The second type of supernova occurs at the end of a single star‘s lifetime. 
  • As the star runs out of nuclear fuel, some of its mass flows into its core. Eventually, the core is so heavy that it cannot withstand its own gravitational force. The core collapses, which results in the giant explosion of a supernova. 
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