The Mysteries of Dark Lightning

The pursuit for the understanding of the world around us is one of man’s greatest obsessions. Entire fields of study have been formed to explain everything from the inner workings of tiny particles to the awesome power of phenomena such as storms and lightning. There are those among us that build their careers on finding the reason ‘why’ things behave the way they do. These are the fearless, the bold, and maybe just a little bit crazy research scientists.

XKCD's Depiction of Scientific Curiosity

 

One such group of scientists from the Florida Institute of Technology, led by Joseph Dwyer, is studying a newly observed type of lightning called ‘dark lightning’ or terrestrial gamma-ray flashes (TGFs). Currently there are conflicting opinions about the specific properties of dark lightning. What is not disputed is that this type of wave exists and it is one of the most powerful energy forms composed of light that scientists have observed here on Earth. 

First a brief explanation of visible lightning

Lightning is nature’s way of equalizing the polarization between two clouds, within a single cloud, or between a cloud and the surface of the Earth. As the electric field within a cloud increases, the air around the cloud begins to ionize. That is, electrons are pulled away from the surrounding air molecules. These fragments of molecules form a conductive plasma pathway between two objects. The positive ions travel upward through this path and the negative ions (electrons) travel downward. When they meet, a complete pathway is formed. Lightning is the result of the charge transfer between cloud and cloud or cloud and ground through that pathway.

Basic Principles of Visible Lightning

So exactly what is dark lightning and how is it related to regular lightning?

Periodically energy outbursts are observed in high energy thunderstorms. The theory is that certain conditions cause the electric field built up by the storm to discharge in a different way. Storms can discharge energy by converting it into a flash of intense ionizing (x-rays and gamma rays) radiation that travels upward rather than channeling that energy downward in the form of heat and light. These waves are radiated upward in all directions instead of formed into a directed bolt. As such, this cloud of energy dissipates quickly.

(From left to right) Start of energy transferal, energy discharged up as 'dark lightning', energy discharged down as visible lightning (Credit: Studio Gohde)

Gamma rays? Those are only man-made or found around black holes and supernovas right? 

Scientists previously assumed that this was the case.  After some extensive research, Professor Dwyer and his team have a theory that the thunderstorm acts as a giant particle accelerator. Electrons are accelerated almost to the speed of light by the strong electrical fields in the storm.  More study is needed to define the method of generation and properties of this phenomenon. The advantage to further research in this field is that there are many devices already designed that detect and analyze gamma radiation.

Is dark lightning dangerous to humans?

Any kind of ionizing radiation is harmful to humans on some level. However, the likelihood of being close enough to absorb enough rays to be harmed is pretty slim. Dark lightning occurs in the neighborhood of 16,000 feet. Commercial airplanes cruise at an altitude of about 30,000 to 40,000 feet so at most the plane would pass through the height in question twice during their flight. Also pilots try to avoid flying through the heart of a thunderstorm.  Even if the timing was just right, the amount of radiation emitted by a flash of dark lightning is maybe up to the equivalent of 10 chest X-rays around the edges and up to 1 full-body CT scan in the very center of the radiation burst according to research scientist, Joseph Dwyer. Dwyer also indicated that dark lightning seems to be fairly rare; he and his team have figured that dark lightning occurs maybe once for every thousand visible lightning flashes.

So next time a storm rolls in, think about all of the amazing properties that come along with that storm. This discovery shows just how much exploring we have to do even in our own backyards. Imagine what future generations of research scientists will find.

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D-tect Systems is a supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

References:

Thunderstorms Generate Mysterious 'Dark Lightning', Rick Pantaleo, voanews.com

http://www.voanews.com/content/thunderstorms-generate-mysterious-dark-lightning/1652547.html

Dark Lightning Linked to its Luminous Twin, Becky Oskin, Live Science

http://www.livescience.com/29019-dark-lightning-linked-visible-lightning.html

Scientists detect dark lightning linked to visible lightning, Nikolai Østgaard, AGU

http://www.agu.org/news/press/pr_archives/2013/2013-15.shtml

Florida Institute of Technology

http://gpl.fit.edu/Overview.htm

Wikipedia (Overview of Lightning)

http://en.wikipedia.org/wiki/Lightning

The Case of the Leaking Microwave

One of my hobbies is online gaming. The enjoyment derived from going with a group of friends to accomplish some difficult task in the game is gratifying. There can be some interesting frustrating situations that pop up in this scenario though. One of these is having a party member disconnect at a critical juncture. I had one particular friend, whom we call Tim, who often disconnected for no apparent reason. After a few weeks of observation, Tim realized that he would lose his signal every time one of his roommates would nuke anything in the microwave. This led to a lively discussion about whether or not a microwave should leak enough radiation to cause interference. After a little further research, I noted that this is a fairly common occurrence. Common enough that many related humorous articles and comics can be found including this XKCD comic.

A rather devious way to exploit a leaking microwave

Radiation? Is my microwave radioactive?

When radiation is mentioned, most often the first thought is of glowing green mutants and super heroes. Discounting the Hollywood influence, the next, more realistic, thought is of nuclear bombs and power plants. Radiation is a general term for energy that is emitted or ‘radiated’ from a given source. Microwaves fall into the category of non-ionizing radiation whereas radioactive materials such as uranium or plutonium emit waves that qualify as ionizing radiation. Non-ionizing indicates there is enough energy generated to jostle the electrons in the atoms around but not enough to remove them completely. Cells stay intact even though there is more activity going on internally. When enough energy is generated to push electrons out of stable atoms, this is categorized as ionizing radiation. Even more specifically, the radioactive materials used in power plants and bombs emit gamma rays. The chart from the EPA as pictured below lists several of the more common types of radiation and where they fall in the spectrum. Note that microwaves and gamma rays are a significant distance apart.

Types of radiation as illustrated by the EPA

Practically speaking, any microwaves that escape through the cracks and through the mesh display window won’t harm you any more than if you stood in front of your router. Even if you are concerned about these waves you can step back a few feet from the microwave. The few stray waves don’t travel very far before dissipating. Please note that these waves do transfer their energy to heat as they move through fats, oils, and water. If your microwave is damaged especially around the door, you will want to get it fixed.

Does my microwave leak? 

Most microwaves leak a little bit. If you are curious about whether or not your microwave leaks, one simple test you can perform is a ping test. The supplies you will need are as follows:

• Laptop or tablet with WiFi enabled 
• Microwave 
• Another PC, tablet, or laptop connected to the same network

Disconnect the power to your microwave. Make sure your portable computer is powered on and that the Wi-Fi is allowing proper communication. Place it in your microwave and close the door. Do not turn on the microwave. Proceed to your other device on the same network and run a ping for the laptop’s IP address. If you receive a response, your microwave leaks. If you receive a time-out response, your microwave is fairly well shielded.

Ok, so what do I do if my microwave is interfering with other electronics in my house? 

Most microwaves aside from a few industrial ones run at approximately 2.4 GHz. Because this is an unlicensed ISM (Industrial, Scientific, and Medical) frequency band, many other electronics utilize this band as well. Notably Wi-Fi and some cordless phones use this band as well. Unfortunately you cannot change the frequency your microwave runs at as it a very effective frequency for speeding up the activity of water molecules. However, you can look on the label inside of your microwave to figure out the center frequency that the device uses. (There is a range and microwaves do vary.) Once you have that information, you can adjust your router to operate on a frequency outside of the microwave’s operating range. You can also move your router or microwave even just a few feet. This can alter the paths of the RF waves throughout your environment and possibly reduce the interference.

Sources:
Jim Geier, Wi-Fi Planet, “Dueling with Microwave Ovens” http://www.wi-fiplanet.com/tutorials/article.php/3116531
EPA, Radiation, “Non-Ionizing and Ionizing” http://www.epa.gov/radiation/understand/index.html