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Searching for Habitable Planets

by Ron Blue ( and Woody Lakey
Lehigh County Community College
4525 Education Park Drive
Schnecksville PA 18078

Copyright ©1993, All right reserved
Permission to duplicate for non-profit educational purposes is granted


The usage of radio emissions from lightning storms in extraterrestrial oxygenated atmospheres or Jovian atmospheres are proposed to provide detectable radio signals suggesting Earth type planets and Jovian type planets. Significant technical problems and procedures are discussed.


The debate over whether or not there are earthlike planets outside our own solar system has raged for quite some time. Recently, in an effort to support that there are other planets capable of sustaining life as we know it, the necessary mathematical calculations, based on current knowledge about planet formation and stellar evolution, were made. The results supports that life on other planets is mathematically probable. Although, the calculations show that life should be on other planets, there is no strong empirical evidence to lend credence to this theoretical statement.

Many advances have been made in the "art" of predicting planets around other stars. Radio astronomy has detected evidence that planet formation may be common in the universe. For example, it has been noticed that a one hundred meter wobble occurs on a certain star. It was then theorized that a planet about ten times the size of Jupiter is causing this particular wobble due to it's gravitational pull. Analysis of pulsar radio signals strongly suggest a planet like object is interfering with the signal. Further analysis of other radio signals reveal circular spaces of material missing around many stars. This absence of a signal is believed to be due to planet forming forces that may have swept that area clean of any type of debris when planets were formed. The Hubble space telescope pictures of developing star systems provided more confirming evidence.

The theory that stars have planets is seductive. The theory that some of these planets may have life is provocative. Extreme caution must be exercised in the procedures used to discover planets, as the history of science clearly points to the fact that scientists often find what they are looking for, even if it does not exist.

Scientists will not know for a fact that other stars have planets until they or their equipment arrives at another star system. The empirical evidence needed to accurately assess whether or not a planet has the ability to sustain life as we know it will not be available until such time as man actually sets foot upon that planet. However, evidence has advanced enough to strongly suggest that stars have planets, and some of these planets may be able to sustain life. What is required are promising techniques to suggest where and how to look for other planets. One way that this mission could be accomplished, maybe using naturally occurring phenomenon to our advantage in discovering these planets. One type of phenomenon that may be used, is lightning.

All planets in our solar system are suspected of creating lightning or lightning like phenomenon. Lightning has been observed on Venus, Jupiter, Mars, Uranus, and possibly Neptune, Titan and Mercury. The type of lightning and type of atmosphere that lightning is created in, creates a unique radio signal. The easiest signal from another planet to detect is from Jupiter. This strong radio signal goes through our atmosphere easily. A way to further substantiate the theory that there are other planets around other stars would be to tune in for this signal by using a radio telescope. It is known that the lightning from Jupiter's atmosphere occurs at a frequency of 10 megahertz. Therefore, if another planet were to be discovered having a lightning radio signal frequency of 10 megahertz, it could be assumed that the planet's atmosphere would be similar to that of Jupiter. Whether the signal strength is strong enough will have to wait until further experimentation and improved technology. Current opinion is that it is unlikely the signal is strong enough based on current technology. In science you should never say never. The plasma (lightning like activity) on Jupiter is similar to signals from the sun from Type II and Type III bursts. Other stars will produce the same type of signal. We have already observed this from relatively nearby stars. There may no way to differentiate between a Jovian planet and a star. Using our planet as shield to protect us from the strong signals from strong local noise produced by the sun and Jupiter we may increase our chances for success. If your dream is big enough you will search for solutions to your problems. While doing this you will learn a lot about yourself and nature and sometimes accomplish your dream. Based on computer simulations of planet formation Earth type planets should be quiet common but Jovian type planet may be rare. This rareness will lower the probability of intelligent life because a Jovian type planet is necessary to sweep a solar system of comets. Collisions with comets once every million years do to the absence of a Jovian type planet would limit the chance of development of stable life systems. This means it will be important to also listen for radio signals from Jovian type planets.

Since the bigger goal is the discovery of empirical evidence of earth-like planets, some further discussion is in order. Life as we know it has created as a biological waste, our oxygenated atmosphere. No known planet in our solar system has an oxygenated atmosphere, except for Earth. There is no known way to have an oxygenated atmosphere, without the process of photosynthesis to create the oxygen. Currently, our national program for searching for extra terrestrial intelligence is searching the radio window (those signals that the atmosphere allows through) for patterned signals, similar to radio broadcasts, or television signals. Our own man made radio signals are now about 100 light years from Earth and could be detected by a SETI like program created by intelligent beings on another planet in another star system.

While the SETI program should continue, a radio search as we are proposing could locate planets in the future for the SETI program to monitor. In addition, a draw back of the SETI program is that life must have evolved in a manner similar to that of Earth, in order to be sending signals of this type. Another limitation, is the obtaining of useable information from any of these signals that are received. Again, in order for mankind to make any type of sense from these signals, the other planet would have to have evolved in such a way that information would need to be within these signals, and not carried on some type of carrier wave. It is likely that within two hundred years all our electronic information will probably be carried over optic fibers. There is still another limitation. That is that in the history of mankind, radio and television have existed for a "mere tick of the clock", a clock that has been running for about 4.5 billion years. If life has evolved upon other planets, SETI could be searching star systems that have not yet reached that level of development or have already gone past that level of technology. The oxygenated atmosphere on Earth has existed for at least 3.75 billion years. Lightning storms have been sending signals of our existence as a planet with life for the same amount of time. Even if the SETI program never hits "pay-dirt," it would be of a great importance to know where other earth-type planets exist.

One cannot be lulled into a false sense of expectancy. There are considerable difficulties associated with the proposal of using lightning storms as an indicator of earth- type planets. Some of the problems could be eliminated with the use of a lunar radio telescope observatory on the dark side of the moon, a earth orbit space radio telescope, or a solar orbit space telescope at 550 AU or 7.4 light hours using the sun as a gravitational lens to focus radio waves. Since at best this is problematic and hundreds of years in the future, other ways should be considered.

One possible solution would be the use of radio- telescopes placed at strategic locations on Earth. A major problem with this proposal is that the radio telescopes will experience strong local radio noise from our own lightning storms. The question then becomes, are the radio signals that we need from another earthlike planet strong enough to get through our atmosphere and be detected. Current opinion is that the answer to this question is no.

A star that is quite similar to the sun, is called Epsilon Eri., which is about 11 light years away from Earth. A planet in the Epsilon Eri system, with a radio transmitting at 1 megawatt of power, with a 600 foot antenna could easily be detected from Earth according to Frank Drake, professor of astronomy at University of California at Santa Cruz.

On Earth, a bolt of lightning produces from 10,000 to 200,000 amperes of electricity moving over a distance of about a mile. This superheats the air from 20,000 to 40,000 degrees Celsius. The average frequency rate for lightning on Earth is from 60 to 100 cycles per second. The average power of all these lightning strikes, is about 100 billion watts per second. A single bolt of lightning can easily be detected around the world as a radio "whistler," or "spike." "Whistlers" are due to an interaction effect from lightning and ions trapped in the earth's magnetic field in outer space. The millions of volts in a cloud being simultaneously released in a lightning storm acts like a capacitor and causes the ions in outer space to oscillate, which causes radio waves. It could therefore be logical, from the technical aspects, to use "whistlers" in the search for planets with oxygenated atmospheres from a lunar radio telescope. It would be best, if the original sources, or lightning could be used instead. The moving electrical current in lightning creates radio waves. The electromagnetic waves from Earth lightning are all over the spectrum, but seem to be at a maximum output for radio waves at 5 to 7 kilocycles per second. The good news is that this very low frequency is rarely used by people because of the expensive antenna systems required for this frequency. The bad news is that the lower the frequency the more the noise you will hear. This frequency is very close to the noise of electrons moving randomly in circuits. This frequency is a ground wave which means the wave travels around the world for longer distances than higher frequency. This means the noise from earth lightning storms will be severe. The current in lightning flow in micron size plasma. This will raise the power of the radio signal. The speed of release of the discharge is in tens of a second. This will increase the power of the radio signal. The signal is polarized which increases the power of the signal.

It must be made clear that this radio signal only occurs in an oxygenated atmosphere. While it is true that there are other types of phenomena that could emit the same frequency radio emissions, it should be remembered that lightning occurs in sets.

A single bolt of lightning can be detected and tracked anywhere on the planet Earth. Therefore, it is not illogical to assume that lightning from other oxygenated atmospheres could be tracked from Earth, the moon, or outer space. This is not to say that the process would be easy. To begin with, there is always the possibility of human error. Then there is the problem of insuring that the radio frequencies that are discovered are indeed originating from deep space.

Of human error, there is not much that can be done, except for validation of findings. However, using the technology available today, it is possible to assure that the emanations that are being tracked are indeed from space.

One way of accomplishing this task, would be through the use of computers and discriminators tied into the "listening stations." It would be necessary to use the computer-discriminator system placed at a constant distance and in constant contact with the monitoring radio telescopes. At least two monitoring stations should be used. In this way, any transmission that was received by the monitoring station could be instantly checked against what the other station had received. If the signals matched, it could be investigated further. If they did not, the signals could be discarded as being "spurious radio emissions."

The antennae themselves would have to be a minimum of thirty-five feet high, and seventeen and one half feet long using the 10th harmonic. It would also be necessary for the antennae to be at least four thousand meters apart from each other. It must be understood that the receiving radio antennae must have the ability to track objects. Because the signal we are interested in will be weak a new procedure is suggested to solve that problem. By focusing the reflected radio waves onto a liquid helium cool superconductor the signal strength maybe increase millions of times. The first pair above would be strengthened by adding more pairs in a circular configuration with all data being correlated by a computer to eliminate spurious data. Using these configurations, it may be possible to monitor various star systems that may appear to be promising.

Another problem that must be overcome, is that of spurious emissions. In order to facilitate the most surreptitious response curves, it is suggested that the antennae be surrounded by a "super antenna." This would be constructed from the most conductive materials. In this way, these super antennae would be able to attract the spurious signals, and either send them to ground, or to provide a chart with which the signals from space could be differentiated. The use of the "super antenna" and the discriminator may allow a reasonable chance of success. What the super antenna could not filter out, could be compared to the emissions that are received by the discriminator. Any signals that do not match would be automatically discarded. Using these procedures, it may be possible to recognize an extraterrestrial Earth-type planet, Jupiter-type planet, a Venus-type planet or even a Mars-type planet.

Success will not end with these discoveries; instead, it will only begin. The wealth of information that may be available is staggering. Radio signals are capable of providing more information, if mankind has an idea of what to look for and the future technology to allow him to look. Science has a habit of catching up to our dreams. Lightning storms on Jupiter occur frequently at noon. A signal that peaks every ten hours would show that the Jupiter like planet, around another star system, has a "day" of this time period. On Earth, at Denver, Colorado, lightning storms distribute themselves in a skewed curve with the most frequent starting time being noon, and the highest frequency time being 3:00 PM. Lightning storms are infrequent over the oceans on Earth, therefore, it would be logical to assume that the frequency and location of lightning storms on planets with an oxygenated atmosphere, could show where water-land distributions may be located. This could provide an invaluable aid for mapping Earth type planets. A statistical plot of reception from another Earth type planet may reveal it's water to land mass ratio and the length of it's day.

Intelligent life in the universe could be actively listening to the radio frequencies associated with their type of lightning storms to discover early which planets they would attempt to colonize, explore, or possibly contact. These special frequencies may be the natural frequency to communicate with other species instead of the proposed 21 centimeters. The reason is because the admission price to the galactic civilization is quiet high. It is extremely difficult to have the technological advances necessary to monitor these frequencies. The question then becomes, "Is anybody really listening?"

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