The Search for Extraterrestrial Life Is a Roller Coaster of Hope and Disappointment
This article highlights how humans have long suspected the existence of life beyond Earth, spanning the past two centuries. In the late 1800s, Italian astronomer Giovanni Schiaparelli used a telescope and thought he saw “canali” (channels) on Mars. When it was translated, people believed the word meant canals. People believed that artificially made waterways and canals were built by an intelligent species on Mars. Later, American astronomer Percival Lowell expanded on this idea. In 1906, he suspected that life on Mars was certain. He pictured civilization with different technologies, all suspected from a translation error. By 1909, French astronomer Eugene Antoniadi had used a better telescope and shown that the canals were just an illusion. The belief in Martians was prevalent for decades. In 1965, NASA's Mariner 4 spacecraft flew by Mars and sent back images proving the planet was dry and desolate. One reason why life can't arise on the surface of Mars is due to Mars’ lack of an atmosphere, which would mean that UV radiation would sterilize all genetic material. However, if life did arise in an environment with high UV radiation, DNA or RNA would be too unstable for that much radiation. This begs the question: Could some organisms develop alternative coding structures, such as PNA/Peptide Nucleic Acids? PNA is a more stable coding structure than DNA, maybe too stable for mutation and genetic diversity on Earth, but ideal for planets with intense UV radiation. Lower in Mars’ crust, life could thrive and be blocked from the solar radiation. This also means that in the future, when humans travel to Mars, we must be careful not to contaminate Mars’ possible biosphere and potentially contaminate the astronauts on Mars, as well as people on Earth. Mars’ life could utilize an entirely different coding system and be blind to our immune system, potentially infecting Earth when the astronauts return, or vice versa.
The early telescopes could not accurately depict Mars, and the perceived canals were illusions, believed to be real due to a translation error. This was mainly due to technological limitations, and many people believed Lowell. Later, in 1965, Mariner 4’s flyby proved that Mars was desolate and could not support life to the extent we had thought. Another time we thought we proved extraterrestrial life was in 1977 when Frank Drake scanned for radio signals from other stars. It is commonly known as the WOW Signal. It was a 72 second unexplained burst, thought to be sent by aliens, but was never repeated, so it was not definitive proof of life. Later in 1992, the NASA Kepler program revealed over 6,000 different exoplanets that could potentially host life. We can also determine if a planet may harbor life by identifying specific biosignatures that only life can produce. Multiple planets have these biosignatures, but it is not considered definite proof. Additionally, the discovery of extremophiles in the boiling waters of Yellowstone reinforced the idea that life can arise in extremely harsh conditions. Are we too focused on finding Earth-like life? Earth is just one condition and selection pressure; in different conditions, imagine what traits could be beneficial to live in that alien climate.
The main argument is that there is no definite answer to whether extraterrestrial life exists, and that the hope for evidence has been a rollercoaster of emotions and beliefs. It was popularly believed that the intelligent Martian species existed. Microbial life is most likely to exist, and extremophiles demonstrate that life thrives in what was once thought to be uninhabitable places. Exoplanets are abundant, and Kepler has shown that most stars have planets, potentially habitable for life. The hope of finding life continues, and each new technology and understanding brings us closer to the truth.
