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Solar wind protects us from cosmic rays

Startling discoveries from the Voyager 2 space probe


Published: 3 March 2020 (GMT+10)
An artist’s concept of NASA’s Voyager spacecraft.

In 1977, NASA launched its two Voyager space probes. Thanks to them, we know so much more about the outer planets, including Jupiter and Saturn (Voyager 1 and 2), and Uranus and Neptune (Voyager 2). Recently, they have reached interstellar space—some reports say they have left the solar system. In particular, Voyager 2 reached interstellar space on 5 Nov 2018, over six years after Voyager 1. They have also taught us much about the sun itself.

Solar wind

The sun’s super-hot atmosphere, the corona, emits the solar wind, a stream of extremely fast (250 to 750 km/s) charged particles. This wind pushes against the particles in comet tails, causing them to point away from the sun. Fortunately we are protected from the particles in the solar wind by earth’s strong (albeit decaying) magnetic field, which traps them. We see the results as the aurorae, which are most prevalent near the poles in the wintertime.

Some might ask, why would God make such a dangerous sun? But in reality, our sun is ideal for life here on earth. First of all, it is remarkably stable. It is very quiescent compared to most stars of its type. And the latest Voyager 2 findings show that the powerful solar wind produced by our sun is an important design feature.

Solar system boundary?

The Voyager probes discovered that the solar wind was still blowing at enormous distances, many times further than any planets. We knew the solar wind would be slowed down by the gases of the interstellar medium. We knew this would happen, but we did not know how far out the solar wind would go.


The boundary is called the heliopause, and the Voyager probes have told us that it is over 121 astronomical units (AU) from the sun (1 AU is the earth-sun distance, 150 million km or 93 million miles). They also found that the distance is not constant. Rather, according to Voyager project scientist Ed Stone, of the California Institute of Technology in Pasadena, “The heliosphere itself is breathing in and out.”1

This encloses an immense ‘bubble’ around the sun called the heliosphere. Some call the heliopause the boundary of the solar system. However, there are some solar system objects that travel past this boundary and back, so it is not really the ‘edge’.

The sun’s gravity is still dominating at distances far larger than the heliopause. E.g. the planetoid Sedna is about the size of Pluto and is thought to travel to over 900 AU away from the sun at the maximum extent of its highly elliptical orbit, and the hypothetical Oort comet cloud (the supposed source of long-period comets) is claimed to be 2,000 to 200,000 AU.

The extent where a body’s gravitational field dominates all others is called the Hill sphere or Roche sphere (not to be confused with the Roche limit). The sun’s Hill sphere can be considered the real boundary of the solar system, and could even be a light year or more in radius.

Importance of the solar wind

The sun

A year after Voyager 2 crossed the heliopause, scientists had a chance to analyse its findings.2 They found that, as expected, the plasma density was higher outside this boundary. There are many more high-energy cosmic rays here, which make up a significant proportion of the ‘plasma’ in interstellar space. These are extremely energetic particles, therefore dangerous to us, and many come from supernova explosions of massive stars. Also as expected, the number of solar wind particles plummeted.

National Geographic summarizes these amazing findings:

Based on Voyager data, this bubble extends about 11 billion miles from the sun at its leading edge, surrounding the sun, all eight planets, and much of the outer objects orbiting our star. Good thing, too: The protective heliosphere shields everything inside it, including our fragile DNA, from most of the galaxy’s highest-energy radiation.3

That is, from our perspective inside the heliosphere, there are far fewer extremely energetic particles because the lower-energy particles jetting outward from the sun are creating a ‘shield wall’ for the solar system. So it turns out that the heliopause is actually very important.

References and notes

  1. Cited in Wall, M., Voyager 2’s Trip to Interstellar Space Deepens Some Mysteries Beyond Our Solar System, 4 Nov 2019. Return to text.
  2. Voyager 2 Illuminates Boundary of Interstellar Space, jpl.nasa.gov, 4 Nov 2019. Return to text.
  3. Greshko, M., Interstellar space even weirder than expected, NASA probe reveals, nationalgeographic.com, 4 Nov 2019 [Emphasis added]. Return to text.

Helpful Resources

Readers’ comments

John P.
Is this wind going to blow away all of the toxic chemicals that are being deliberately put into our airspace on a daily basis via Chemtrails.

Are there people /organisations/governments really trying to manipulate and control our weather by chemical means?

Have you looked up at the sky in Perth recently / There are very weird looking clouds that look more man made than natural
Jonathan Sarfati
In sequence:



They are man-made, but they are contrails (condensation trails), since water vapour is a major combustion product of burning hydrocarbons.

See for example Contrails, Not Chemtrails, Say Scientists in New Study, but more importantly, Why CMI rejects ‘conspiracy’ theorizing.
Lyn W.
To think that the Creator of the universe took such care to ensure our survival and wellbeing.
The same Creator suffered and died for us in the most horrific way. I watched a documentary on Roman crucifixion last night. It was described as the most barbaric method of torture known.
Murk P.
Great article! Thank you.
Like an air bag expanding toward the driver in a crash, the heliosphere grew on day 4 as the energy from the created stars rushed towards it.
The plants were already standing.
Amazing coincidence lol
Ira E.
There is nothing that God has not thought of.
Kathy K.
Very interesting article. I am just fascinated at what we have discovered about our sun, moon and planets, stars and the fact we can send people, probes, satellites into space. But then this whole universe is absolutely a wonderful creation. What an awesome God who lets us discover these interesting facts about it from the tiniest atom to the objects in space millions of miles away! The discoveries are endless it seems. Thank you, Lord, for a most suited universe for life!

CMI scientists take the information and break it down so it can be better understood by folks like me. I do so enjoy reading the many articles on topics that I am curious about and from those articles, there’s even more topics. Thank you Lord for such dedicated servants who have worked so hard to bring all this information to the public over all these years. Thanks, CMI! God bless.
Pete B.
Thanks, this is a lot to think about. One question though that I've had for a while is whether the decay of Earth's magnetic field (and its relationship to solar wind) has any influence on our climate. Is this something that has ever been investigated?
Martin J.
And God has already revealed that in His Word. Especially Ps. 19:4.

Ps 19:1  To the chief Musician, A Psalm of David. The heavens declare the glory of God; and the firmament sheweth his handywork. 
Ps 19:4  Their line is gone out through all the earth, and their words to the end of the world. In them hath he set a tabernacle for the sun, 
Ps 19:5  Which is as a bridegroom coming out of his chamber, and rejoiceth as a strong man to run a race. 
Ps 19:6  His going forth is from the end of the heaven, and his circuit unto the ends of it: and there is nothing hid from the heat thereof. 

Not just an ancient culture's worldview then.
Antonio F.
Wow! This makes me weep. To think that Jesus, our Creator and Saviour, made all this and yet lowered himself by taking up the form of a man, denied His omnipotence when tested in the garden of Gethsemane, allowed Himself to be tortured for our sins, died and rose again so we can share in His glory, with the Father and the Holy Spirit. I don't care what any atheist says (or anyone else for that matter says), you deny how beautiful and kind our Creator is and take fallen gods like Buddha or materialism as your meaning in life, your really asking for it. I can only hope their hearts soften enough to be saved and pray for those that are lost. Praise the Holy Father, Jesus Christ, and the Holy Spirit.

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