The sun's winds are less blustery than they used to be, NASA said on Tuesday, revealing data from a solar probe that promises new insights about Earth's local star but poses few if any consequences for humans -- unless you're an astronaut.

The data show the solar wind, a steady stream of charged sub-atomic particles emitted by the sun and blowing at 1 million mph (1.6 million kph), has dwindled to its lowest level in at least 50 years, reducing its strength as a shield against potentially harmful galactic cosmic radiation.

The solar wind inflates a massive protective bubble, called the heliosphere, around the solar system. But measurements from the spacecraft Ulysses show the wind's pressure has dropped 20 percent since the mid-1990s. At the same time, the electron temperature of the solar wind has declined 13 percent.

As the solar wind weakens, the heliosphere is expected to dwindle in size and strength as well, allowing more cosmic radiation -- super high-energy electrons and protons zipping through interstellar space -- to reach the inner solar system.

Scientists studying the phenomenon insist Earth's inhabitants have nothing to fear. Humans remain protected from cosmic rays by virtue of the magnetic field that surrounds Earth, acting as an inner barrier to our exposure.

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