Scientists have identified several moons in our solar system that could harbour alien life, with Saturn's moon Enceladus emerging as a prime candidate. The moon emits huge water plumes that hint at hydrothermal vents on its ocean floor, similar to those found on Earth where life is believed to have originated.
Jupiter's moon Europa is thought to contain more liquid water than all of Earth's oceans combined, while other moons with potential for life include Jupiter's Callisto and Ganymede, and Saturn's Titan. Several major space missions are being planned over the next decade to search for hints of life in these alien oceans.
The discovery of extraterrestrial life would raise significant ethical questions, according to ethicists. Establishing the intelligence and sentience of any alien life form would be an important initial step, as would ascertaining its intent. If aliens possess the technology to land on Earth, we may need to hastily ask what rights they would be willing to afford us in return.
Meanwhile, astronomers continue to scan the heavens for signals, though not all turn out to be extraterrestrial. In 1998, scientists in Australia detected strange radio bursts that were later traced to the observatory's microwave oven, which emitted brief radio waves when opened before it had finished heating food.
