How does the solar wind affect Earth?

James Marshall
December 6, 2019

The first major results from NASA's Parker Solar Probe are in, a little over a year after the spacecraft set the record for the closest approach to the sun by an artificial object.

Launched in 2018, Parker has come within 15 million miles (25 million kilometres ) of the sun and will get increasingly closer - within 4 million miles (6 million kilometres ) - over the next six years.

The U-M findings, part of the first wave of results from the spacecraft that launched in August 2018, provide important insights into two fundamental questions the mission was created to answer: Why does the sun's corona get hotter as your move further away from the surface?

In four papers published December 4 in Nature, researchers describe odd space phenomena and a flood of new data that will help us understand everything from the nature of stars to improving our forecasting of solar storms that can affect electronics on Earth.

This ionised gas, called plasma, carries with it the Sun's magnetic field, stretching it out through the solar system in a giant bubble that spans more than 10 billion miles. Scientists still don't understand how that weather is produced - which is risky given that it could destroy large parts of our infrastructure.

Just the other day, NASA revealed the probe's most important discoveries that it made so far. Even though the sun is located in the centre of the solar system, and the light from the star has nurtured life on the earth, it still remains the most unexplored space body in the solar system due to the intense heat and dreaded radiation.

Parker Solar Probe flew through several "switchbacks" - tubes of fast solar wind emerging from coronal holes in the Sun's upper atmosphere.

They observed bursts of energetic particles never seen before on such a small scale as well as switchback-like reversals in the out-flowing solar magnetic field that seem to whip up the solar wind.

Professor Tim Horbury from Imperial's Department of Physics is a co-investigator on Parker Solar Probe's FIELDS instrument, which is led by the University of California, Berkeley.

Here on Earth's surface, we're protected from the solar wind by our blanket of atmosphere.

Through these flybys, the mission also has examined the dust of the coronal environment, and spotted particle acceleration events so small that they are undetectable from Earth, which is almost 93 million miles from the Sun.

It is trusted it will permit a superior comprehension of the sun oriented breeze and electromagnetic tempests which can cause disorder on Earth by taking out the power network.

As Parker Solar Probe continues on its journey, it will make 21 more approaches to the Sun at progressively closer distances, culminating in three orbits which are merely 3.83 million miles from the solar surface.

They found that the magnetic field suddenly reversed itself by 180 degrees and then, seconds to hours later, flipped back.

Another surprise was the dust that peppered the spacecraft repeatedly during each fly-by at perihelion - the point in the orbit where the spacecraft was closest to the sun.

Smaller than a micron, which is a thousandth of a millimetre, the dust particles are likely debris from asteroids or comets that melted near the Sun and left behind their trapped dust, the researchers said.

How strong is the solar wind? "We've already seen evidence for some very surprising phenomena-which you should always expect when you travel into regions where spacecraft have never been before".

This discovery by NASA's Parker probe was totally unexpected, and scientists are still unable to provide a convincing explanation to describe these phenomena.

"We can now go look at the surface of the sun and figure out what is launching these waves", he said. "It is a big case of delayed gratification, but it is terrific stuff". The first results from NASA's Parker Solar Probe, which aims to "touch the sun" have been announced by scientists.

Other reports by Click Lancashire

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