Whether extraterrestrial civilizations and other intelligent beings exist remains unknown, though scientists have long speculated on this topic. In the mid-20th century, astrophysicist Frank Drake formulated an equation to estimate the number of extraterrestrial civilizations in the galaxy based on variables such as the number of sun-like stars, planets with suitable conditions, or the time during which intelligent life might make contact. A recent study has added two more variables to Drake’s formula.
Planets of different masses possess varying parabolic velocities. Earth’s is 11.2 km/s, or over 40,000 km/h, calculated for a ballistic object without propulsion. This parameter is useful for comparing conditions on various planets regardless of the type of rocket and its engine. Super-Earth class planets have much greater mass, posing significant challenges for their inhabitants to reach orbit.
Professor Eli Kiroga from the University of Atlantico Medio (Spain) proposed two new variables: the exoplanet’s escape factor (Fex) and escape velocity (Vex). Using these, he calculated the parabolic speed for a range of exoplanets whose mass we know, reports Universe Today.
The results showed that planets with an Fex of less than 0.4 struggle to retain an atmosphere, making life there unlikely. Meanwhile, values of Fex over 2.2 would prevent inhabitants from leaving their planet, as they would not be able to gather enough fuel or build a sufficiently robust rocket capable of withstanding the pressure upon takeoff.
“Thus, it may turn out that intelligent species on these planets can never travel in space because it is physically impossible for them,” said Professor Kiroga. Moreover, they are unlikely even to conceive of the idea.
The author also addressed what intelligent life on a planet with such a large mass might be like. Most likely, it would be an aquatic world. In a liquid ocean, communication without additional devices is simpler than in the atmosphere, so the need for developing communication means is not as acute. Hence, such a civilization might not communicate with other planets at all and is accounted for in the Drake equation.
There are other circumstances that hinder astronomical observations and the venture of intelligent beings into space: an impenetrable cloud cover, for example, a warm water world without land, or a thick ice crust. All these adjustments complement the Drake equation and suggest that entire civilizations could have emerged, flourished, and perished in obscurity right next to us.
The search for extraterrestrial civilizations has so far yielded no results, so scientists continue to theorize where other forms of intelligent life might be hiding and what they might be like. The famous Fermi paradox — where are they all? — remains unanswered. Recently, researchers from the Philippines suggested that due to a time constraint, intelligent life in the universe spreads in geometric progression, like an epidemic.
