As of this writing, the tiny man-made space probe New Horizons is gathering data on one of the last unexplored major bodies of our solar system – Pluto. Depending who you agree with, Pluto is the last of the classical planets that human probes have reached, yet, still, no smoking gun for the presence of alien life. Those hoping for such a discovery need not be too downhearted, there is always hope for what may lie in the icy depths of Europa, but for now scientists are casting their empirical net farther than our own backyard. They are looking to our galaxy and finding that, not only are there habitable planets in other solar systems, but that they might be common.
But what does this mean for humanity? When we look at those distant worlds, is someone looking back?
Brave New Worlds
Kepler has discovered a staggering 1,000 confirmed “exoplanets” orbiting stars, with another 3,601 unconfirmed possibilities. While many of these are similar to the gas giants of our solar system, Jupiter, Saturn, Neptune, and Uranus, and therefore inhospitable to earth-like life, we can see by looking at the Habitable Exoplanets Catalog that there are 30 planets which could potentially harbor microbial, and perhaps even multi-cellular life. These can be split into two categories. Twenty of the discovered habitable planets are Superterran, which suggests that a planet has between 2 and 10 times the mass of our planet. That means that gravity could be much stronger, but since those planets are rocky like ours and reside in the “habitable zone”, where they are not too close or far away from a star for liquid water to form, they could still foster life. The second category is simply labeled Terran. These are far closer in size to our own planet. Only 10 of these Terran, earth-sized planets have been confirmed.
With so few habitable planets found, readers would be forgiven for believing that life similar to us is probably very rare. But, when you take into consideration the number of stars in our own galaxy, and the proportion of those observed which have earth-like planets orbiting them, there could be a mind-blowing 40 billion Terran and Superterran planets on our galaxy alone.
The universe is an incredible place, and if there is such an abundance of habitable planets out there, we have to ask the question, why haven’t we heard from anyone yet?
What if E.T. Has Already Called Us?
Perhaps an alien intelligence would use a more reliable form of communication, one which could be understood by any other intelligence with a telescope. After all, in a few decades human beings will stop using radio waves, instead using digital signals exclusively which will not be transmitted out into the cosmos; why shouldn’t another species do the same? If so, then we’d have the tiniest of windows, a century or so, to pick up radio waves before they were gone.
It doesn’t seem that an intelligent species would use radio signals to contact us, which could leave SETI scientists disappointed. Instead, an intelligence with advanced technology would perhaps use another means, one which is easy to detect and recognizable. While this might sound like the realm of science fiction, it’s possible, and even plausible that we may already have found such a signal.
It has been suggested by famous astronomers such as Carl Sagan, that if an intelligent civilization were to attempt to contact us, they would use a universal language shared by all species – mathematics. No matter where you go in the observable universe 2+2 always equals 4. Mathematics is constant, and indeed some would argue that it is a primary part of reality.
Step in John Linder of The College of Wooster, Ohio. His team of researchers have made a fascinating discovery. They have found four stars of type RR Lyrae which behave in a peculiarly ordered way. As variable stars, their brightness is intermittent, increasing and lowering based on atmospheric changes. This type of variance is often random, but in these four stars it appears to be unusually ordered. Not only that, but the stars seem to pulse in relation to something called the golden ratio.
The golden ratio is a well known mathematical number which, much like pi, is nearly, if not in actual fact, infinite. You can calculate it by taking a line, splitting it into two pieces, one longer than the other. The golden ratio is in effect when the measurement of the longer piece divided by the shorter piece is the same value as the entire combined length divided by the longer piece. Readers needn’t be mathematicians, but to simply understand that mathematicians see this ratio as significant whenever it is present.
The golden ratio appears throughout man-made architecture such as the pyramids at Giza andthe Parthenon. It has been closely associated in experimentation with beauty, with participants in psychological experiments identifying those with features closer to the golden ratio as more attractive than others. It is said to appear in book design, painting, and even in music.
In the four stars studied by John Linder’s team, there seems to be a close relationship to the golden ratio, with the stars pulsing within 2% of this important number. This is significant, as they also exhibit something called nonchaotic dynamics, which involves fractal patterns which are ordered. In nature, chaotic fractal patterns are common, but to see something with regularity like this is highly unusual.
If there are so many habitable worlds out there, could an advanced species from one of them have altered a star to pulse at this rate? A calling card signaling through the grandeur of the cosmos to let us know the most important lesson we can learn as a species: We are not alone.