Are we alone?
Scientists have studied the possibility of intelligent extra-terrestrial life for more than a century. But we’ve yet to uncover any credible evidence that such species exist.
Some scientists insist that the grand scope of the universe — hundreds of billions of stars in hundreds of billions of galaxies — suggests there must be other intelligent life.
While scientists have made progress in estimating the number of stars in the universe and the likelihood that those stars are surrounded by potentially habitable planets, it’s much harder to figure out if we’d be able to communicate with intelligent life, even if it exists.
The physicist Enrico Fermi presented a famous question to colleagues who thought the universe must be rife with intelligent life: “Where is everyone?” What Fermi meant was that if there is an abundance of intelligent life in the universe, it stands to reason that we should be able to pick up some form of communication from them.
But so far, we haven’t detected any signal from space that bears the mark of an intelligent origin.
Scientists who have grappled with the so-called “Fermi paradox” sometimes argue that because of the age of the universe, other intelligent civilizations may be much older than ours and therefore reliant on much more advanced communications technology that humans couldn’t possibly detect. Others argue that intelligent life might exist and be attempting to communicate, but that the distances involved are so large that signals have yet to reach us. Some scientists have speculated that advanced civilizations might build giant spheres around their home stars to capture solar energy, thus cutting off their solar system from outside communication.
A scarier prospect is that advanced civilizations — like ours — have the ability to destroy themselves. We also know the universe is a dangerous place. Asteroid strikes, diseases and even massive solar flares can wipe out entire planets.
Ironically, intelligent life on Earth may owe something to asteroids. Humans are descended from tiny mammals that survived the mass extinction event that wiped out the dinosaurs. The event was likely caused when an asteroid struck the planet, near present-day Mexico, 66 million years ago.
Regardless, we know life on Earth depended on many events, including the evolution of early microbes and DNA. It’s difficult to estimate how common the conditions are that led to intelligent life developing on Earth.
Interested in learning more about how life works? Dino-lite microscopes feature strobe lights and a USB connection, which lets users digitally, capture life unfolding at the molecular level.
This is a guest post from Hayley. Hayley is an amateur scientist, author and blogger residing in Portland Oregon. Interested in fun and interesting science projects you can perform at home? Visit chemistry.about.com