1. Why are scientists interested in the possibility of life beyond Earth?
The discovery of life of any kind beyond Earth would forever change our perspective on how we fit into the universe as a whole, and would teach us much more about life here on Earth.
2. People have long been interested in life beyond Earth. What is different today that makes this possibility seem scientifically reasonable?
Today, technology has flourished and is more advanced than it was in the past. We are able to have telescopic and spacecraft photos of planets and large moons, as well as launching missions to further investigate our curiosity. Because of these advances in technology, we know more about the ...view middle of the document...
e. basic laws of physics and same chemical elements). Because we haven’t yet observed biology anywhere else in the universe, we can’t yet know whether biology is universal. However, evidence from Earth gives us reason to
think that it might be. Laboratory experiments suggest that chemical constituents found on the early Earth would have combined readily into complex organic (carbon-based) molecules, including many of the building blocks of life. Scientists have found organic molecules in meteorites and through spectroscopy, in clouds of gas between stars.
7. Besides Earth, what worlds in our solar system seem most likely to have life? Why?
Planets orbiting around the Sun, moons orbiting planets, and huge numbers of smaller objects such as asteroids and comets are worlds in our solar system that are most likely to harbor life. Earth is the only planet in the universe to have such a vast amount of ocean water covering its’ surfaces, which provides us an instant clue about why Earth is home to so much life: Water is crucial to all life on Earth. On planets such as Mars, it seems reasonable to imagine life having arisen on Mars since it still has a significant amount of water ice. On such moons as Jupiter’s Europa, current evidence...