Wednesday, July 18, 2012

Star Trek: The Physics of Solar Flares

Star Trek the Next Generation (1987-1994) (Picture)
Season 1, Episode 21

When the Enterprise comes the the aid of a small freighter, the crew discovers two cultures that have come to be dependent on one another for survival. Solar flares from the nearby sun make it difficult to rescue these people from their freighter, because the flares are interfering with the electronic equipment on the Enterprise. What are solar flares, and can they really be powerful enough to interfere with the Enterprise's electronics?

Solar flares

A solar flare is a sudden large release of energy near a star's surface. With each flare electrons, ions, atoms, and a large amount of electromagnetic radiation are ejected.

The ions, electrons, and atoms are not very penetrating. Most of them, even the energetic ones, can be stopped by a small amount of shielding - the Enterprise's armor, for example. These forms of radiation are pretty easy to stop because they have fairly strong interactions with other matter.

The more worrisome radiation is the electromagnetic radiation. This includes a wide range of possible energies, and therefore wavelengths of electromagnetic radiation.

A diagram of the  electromagnetic spectrum (Source)

The entire spectrum of electromagnetic radiation above is represented in a solar flare, though the bulk of the radiation is high energy, meaning x-rays and gamma rays. This radiation is much more penetrating, because it does not interact with matter as frequently, or as strongly as electrons, ions, and atoms.

During the episode Lt. Worf says that a burst of x-rays is disrupting their electrical systems. The fact that a large amount of x-rays have bombarded the Enterprise is unsurprising, given the fact that it has gone close to the source of the solar flares. There should also be a large amount of gamma radiation produced. However, I am not convinced that the x-rays (or gamma rays) should be the primary source of concern when it comes to the electronics. I think there is another much more legitimate mechanism for the solar flares to interfere with the electronics aboard the Enterprise.

How do solar flares interfere with electronics?

Solar flares are produced in the sun, which is chock full of high-temperature plasma. Plasma is the fourth state of matter, an ionized gas. In stars, the ionized gas is often comprised primarily of hydrogen and helium ions. For all of the ions there are also the electrons that have been pulled away from the nuclei. When a great number of charged particles, both positive (ions) and negative (electrons), move very fast, they produce strong and turbulent magnetic fields. Magnetic fields, in turn, induce current to flow in conducting materials. 

Electronics rely heavily on electrical currents and are therefore confused or broken by strong magnetic fields.

Have you ever held a magnet up to an old tv? If you have, you will know that it distorts the colors on the screen, sometimes permanently. This is because old tvs render images on their screens by shooting electrons at bits of phosphor. When a magnet is brought close to a tv, it deflects electrons away from their intended targets, causing the wrong colors to be presented on the screen.

 The effect of a magnet on an old tv screen. (Source)

In the same way, magnetic fields can disrupt other electronics, by sending electrons to the wrong place, or at the wrong speed.

Thus the extra-turbulent magnetic fields produced by the solar flares in the Star Trek episode could very reasonably be responsible for interference with electronics. One thing I do not want to overlook, though, is that magnetic fields can often be shielded against by surrounding electronics with conductive or magnetic materials. I do not know whether the Enterprise would have sufficient magnetic shielding to not feel the effects of the magnetic field from the solar flares on the electronics.

I do not believe, however, that bursts of x-rays or gamma rays would affect electronics much. X-rays and gamma rays are uncharged radiation, meaning they do not produce magnetic fields. They are more dangerous to living things, because they can damage DNA, than they are to electronics. In fact, many electronic devices are used to collect information about x-rays and gamma rays.

Despite what I just said, large amounts of any kind of radiation can permanently damage or destroy electronics, as well as anything else. In believe, however, that in this case the signal interference would most likely come from the strong and turbulent magnetic fields generated by the solar flares.


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