LONDON: The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, NASA scientists have discovered.
New data from the Ulysses deep-space probe show that the heliosphere, the protective shield of energy that surrounds our solar system, has weakened by 25 per cent over the past decade and is now at it lowest level since the space race began 50 years ago.
Scientists, baffled at what could be causing the barrier to shrink in this way, were set to launch a mission overnight to study the heliosphere.
The Interstellar Boundary Explorer, or Ibex, will orbit 240,000 kilometres above the Earth and “listen” for the shock wave that forms as our solar system meets interstellar radiation.
Dr Nathan Schwadron, a co-investigator on the Ibex mission at Boston University, said: “There is a very high-energy galactic radiation that is dangerous to living things.
“Around 90 per cent of [it] is deflected by our heliosphere, so the boundary protects us from this harsh galactic environment.”
The heliosphere is created by the solar wind meeting the intergalactic gas that fills the gaps in space between solar systems. Where they meet, a shock wave is formed that deflects interstellar radiation away from the solar system as it travels through the galaxy. The scientists hope Ibex will enable them to better understand what happens at this boundary.
If the heliosphere continues to weaken, it is feared intergalactic cosmic radiation reaching Earth will increase, disrupting electrical equipment, damaging satellites and potentially harming life.