The Interstellar Medium

Another informative gem from the greatest science reporter living today.

Steve Smith: The Interstellar Medium.

A diffuse cloud of gas surrounds the Solar System. What is holding it together?

It is often stated that space is a vacuum. It is true that the material in space is at a far lower density than any vacuum that can be created on Earth, but matter does exist in the regions between stars and galaxies. The best pumped vacuums on Earth typically reach a 0.1 millimeter spacing between individual atoms.

Between stars, there is one atom per cubic centimeter, while in the Milky Way's galactic halo they are estimated to be ten centimeters apart. The regions of least density are in the intergalactic voids, where it is theorized that there is only one atom for every ten cubic meters.

The Interstellar Medium (ISM), through which the Solar System and all other star systems are moving, consists of a mass of gas and dust primarily composed of hydrogen and helium, with an admixture of dust grains that are less than one-tenth of a micron in size. One micron is equal to one-millionth of a meter, so the dust is almost as small as the frequency of blue light (0.450 microns).

The size of the dust particles means that blue light is scattered when it passed through the ISM, so more red light reaches Earth than it would without the dust. This phenomenon is called "interstellar reddening", and is the same effect that causes reddening of the sunrise and sunset. Dust clouds lit from the side by starlight appear blue, on the other hand, for the same reason that Earth's sky is blue: blue light is scattered by Earth's atmosphere.

What the dust is and where it came from is not known, but astrophysicists speculate that it is ejected from stars. Supergiant stars are often seen with immense clouds of dust surrounding them. However, deep space images also reveal dust lanes thousands of light-years in circumference looping around many galaxies.

One important characteristic of the ISM is that it contains ionized particles, as well as neutral molecules. It is those electrons and positive ions that are critical to understanding the behavior of the ISM and how the Solar System interacts with it.

Although the ISM is extremely diffuse, if charge separation takes place in different regions, a weak electric field will develop. An electric field, no matter how weak, will initiate an electric current.

According to a recent press release, there is an unexpected cloud of gas and dust that is encompassing the Sun's heliosheath. Prior to the discovery, conventional understanding did not predict that it would be there because high pressure supernova shockwaves should have blown it away.

However, according to Merav Opher of George Mason University: "Using data from Voyager, we have discovered a strong magnetic field just outside the Solar System. This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all."

On August 20, 1977, NASA launched the Voyager 2 mission on a multiyear journey to the outer Solar System. Voyager 1 was launched on a faster, shorter trajectory on September 5, 1977. Voyager 1 passed through the Sun's termination shock in December 2004. Voyager 2, traveling a different path, did the same in August 2007. It was data from those "old-timers" that provided the information for Opher's assessment of the ISM.

What is the heliosheath? When Voyager 1 experienced "unusual events" as it approached the boundary between the Sun and interstellar space, Electric Universe advocate Wal Thornhill explained that the spacecraft was entering a "double layer", or Langmuir plasma sheath between the solar plasma and the plasma of the ISM.

It is a well-known principle that electric currents generate magnetic fields. Since Opher's research team has found magnetic fields strong enough to hold tenuous clouds of gas and dust together against the influence of hypothetical supernova explosions, then electric currents must be flowing through the ISM in order to create those fields.

Whenever an electric discharge takes place in plasma, the current flow is compressed inward by induced magnetic fields. This effect is known as a "z-pinch", and is a foundational principle of Electric Universe theory. The compression can be so intense that plasma is squeezed down into solid particles. Indeed, stars and galaxies are thought to owe their existence to massive electric currents forming cosmic z-pinches in the vast clouds of plasma that make up 99% of the Universe.

In conclusion, the ultra-fine dust, magnetic fields, influences on spacecraft, and the heliosheath, itself, are all manifestations of the electric force. Electricity will eventually supplant gravitational theory as the primum mobile of existence. Meanwhile, patient observations continue to support Electric Universe concepts.