Sun's protective 'bubble' is shrinking

The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, Nasa scientists have warned.

Dr Nathan Schwadron, co-investigator on the IBEX mission at Boston University, said: "The interstellar medium, which is part of the galaxy as a whole, is actually quite a harsh environment. There is a very high energy galactic radiation that is dangerous to living things.

"Around 90 per cent of the galactic cosmic radiation is deflected by our heliosphere, so the boundary protects us from this harsh galactic environment."

The heliosphere is created by the solar wind, a combination of electrically charged particles and magnetic fields that emanate a more than a million miles an hour from the sun, meet the intergalactic gas that fills the gaps in space between solar systems.

At the boundary where they meet a shock wave is formed that deflects interstellar radiation around the solar system as it travels through the galaxy.

Without the heliosphere the harmful intergalactic cosmic radiation would make life on Earth almost impossible by destroying DNA and making the climate uninhabitable.

If the heliosphere continues to weaken, scientists fear that the amount of cosmic radiation reaching the inner parts of our solar system, including Earth, will increase.

This could result in growing levels of disruption to electrical equipment, damage satellites and potentially even harm life on Earth.

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