Positron Excess Phenomenon – UPSC Prelims

What is Antimatter?
  • Antimatter is the opposite of normal matter. More specifically, the sub-atomic particles of antimatter have properties opposite those of normal matter. For example, the electrical charge of antimatter particles is reversed.
  • Antimatter was created along with matter after the Big Bang. But in today’s universe, antimatter is rare.
  • Positron is an example of Antimatter.
What is Positron or anti-electron?
  • A Positron is an antimatter counterpart to an electron.
  • A positron has the equal or same mass as an electron.
  • But the electron has a Negative Electric Charge whereas Positron has a Positive electric Charge.
What is Positron Excess?
  • Over the years scientists observed excess of positron having the energy of more than 10 GeV
  • But Positrons having an energy of more than 300 GeV are lower in comparison to astronomers’ expectations.
  • This behaviour of positrons between 10 and 300 GeV is called as the ‘positron excess’.
  • Why in News? Researchers from the Raman Research Institute(RRI) have solved mystery behind this.
Reason for Positron Excess:
  • The Milky Way consists of giant clouds of molecular hydrogen. They are the seats of the formation of new stars. These clouds can be as massive as 10 million times of the Sun’s mass. Further, these clouds can extend up to 600 light-years.
  • The Milky Way is a huge collection of stars, dust, and gas. It is called a spiral galaxy because if viewed from the top or bottom, it will look like a spinning pinwheel.
  • Cosmic rays are produced in supernovae explosions. These waves propagate through these giant clouds before they reach the Earth.
  • Cosmic rays interact with molecular hydrogen and can give rise to other cosmic rays primarily electrons and positrons.
  • Further, cosmic rays propagate through these clouds and decay from their original forms and lose their wave energy by energising the clouds. Some may also get re-energised.
  • Researchers from the Raman Research Institute(RRI) found out that Cosmic rays interaction with giant clouds is a viable contributor to the origin of positron excess phenomenon.
What are Cosmic Rays?
  • Cosmic rays are one of the very few direct samples of matter from outside the solar system. They are high energy particles that move through space at nearly the speed of light.
  • They originate from the sun, from outside the solar system in our own galaxy, and from distant galaxies.
  • They have been blamed for electronics problems in satellites and other machinery.
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