The “search for extraterrestrial intelligence” is the collective name for a number of activities searching for intelligent extraterrestrial life. As early as 1896, Nikola Tesla theorized that radio could be used to contact alien life. In 1899 he observed signals thought to be from Mars and the U.S. declared a “National Radio Day” between August 21st and 23rd, 1924 to allow scientists to listen for transmissions from the red planet. Current studies involve ground and space-based telescopes, large radio telescope arrays and distributed computing. But some are wary of the efforts, and worry that we may alert hostile alien civilizations to our existence… like Stephen Hawking cites mankind’s own history of harsh treatment when encountering civilizations with a significant technology gap.
2. Starfish Prime
Earths atmosphere is an important layer of charged particles that protects the atmosphere from solar wind. So what would happen if a large nuclear bomb was detonated there? The United States decided to find out in 1962. Seeking to find ways to disrupt Soviet missile systems, a thermonuclear warhead was detonated 250 miles above Johnstone Island in the Pacific Ocean. The 1.4 megaton explosion could be seen 900 miles (1450 km) away in Hawaii where the electromagnetic pulse damaged streetlights and phone lines. An artificial radiation belt was created around the Earth which lasted for five years and crippled one third of all satellites in low Earth orbit.
3. Large Hadron Collider
When it went live on September 10, 2008, some thought the Large Hadron Collider would end the world. The $6 billion particle accelerator was designed to accelerate proton beams around a 17 mile loop before crashing them together, to simulate the microscopic black holes that were formed during the Big Bang. Some thought that these black holes would grow to consume the Earth, but scientists dismissed the idea, calculating that any black holes formed would evaporate due to a phenomenon known as Hawking Radiation.
4. Trinity Test
Conducted as part of the Manhattan project by the U.S. Army on July 16th, 1945, the Trinity Test was the first ever detonation of a nuclear device. The bombs initial development was slowed by fears of project scientist Edward Teller, who speculated that a fission bomb might ignite the Earths atmosphere with a self-sustaining fusion reaction or Nitrogen nuclei. Further calculations showed that the odds of such a reaction were incredibly small, and development continued. The resulting bomb produced the explosive power of 21 kilotons of TNT, prompting project scientists J. Robert Oppenheimer to recall a line of Hindu scripture: “Now I become Death, the destroyer of worlds.”
5. Kola Superdeep Borehole
Located within the arctic circle in the far Northwest corner of Russia is the deepest hole ever drilled into the Earth. Soviet scientists began drilling the hole in 1970, eventually reaching a depth of 40,230 ft (12,262 m) in 1989. The soviets wanted to bore through the Earths crust and into the upper mantle, though no one knew what would happen. Fears of unleashing seismic disaster upon the world or even demons from hell proved to be unfounded… and the project was abandoned due to temperatures in excess of 177C (350F) which allowed rock to flow back into the borehole.