The Essence of Life

The 20th century was incredibly rich in scientific discoveries. Within that century more people worked in science and more money was spent on science than in all of the preceding human history. Among the great discoveries of the past century are the following (make your own list before reading on, and add the names associated with the discoveries):

Albert Einstein- His ideas changed the course of modern physics and astronomy. (From: Library of Congress)
In addition to such discoveries (many of which obviously bear on the likelihood of Life in the Universe; as you can easily verify, please) there are equally impressive feats of engineering accomplishments. Here are some of these: Two achievements stand out: Eventually, the ships that bacteria built over geologic time and that provide a sheltered environment and mobility, might seed other planets with bacteria to prepare them for more extensive occupation at a later stage. For example, it is possible that certain types of bacteria could survive right now on one of the moons of Jupiter (Europa). We could, in principle, decide that we wish to make sure there is Life on that body - or every body in the solar system that is able to support life of a kind evolved on Earth. This is a more likely scenario than moving some of the most complex organisms (ourselves) into rather inhospitable environments. Of course, we do not usually think of bacteria as "us." However, there are good reasons why we should. As far as we can tell, all living things on Earth are closely related, by common ancestry. This is the chief reason they have no problem feeding on one another - each can use the other's building materials.