The search for life on planets orbiting other stars will dominate astronomy for the remainder of this century (unless an incredible space phenomenon that was utterly unimagined pops up).
By the beginning of the next century scientists will be planning on how to travel to other worlds to see alien life forms up close. This will at last provide incontrovertible evidence for astrobiology on a muticellular level.
By 2110 we will have mapped the surfaces of the nearest exoplanets to see oceans, storms, continents, and volcanoes. There will be photometric and spectroscopic evidence for forests and savannahs. We will have also catalog numerous satellite companions.
Once convinced a planet is inhabited (which may not satisfy all scientific skeptics), there will be endless wonder and speculation about the type of creatures that are living there. Imagine beholding the interworking of an entire alien biosphere.
But it would take a telescope with the effective diameter of the sun to actually take photographs of something the size of an elephant strolling on an exoplanet only 4.3 light-years away. (In fact the sun could be used as a gravitational lens to amplify the image of a planet, but that would not come close to providing the needed magnification.)
In a recent paper Helmut Lammer of the Austrian Academy of Sciences, Space Research Institute, predicts that there will be a big hiatus in significant exoplanet research until we can send robotic probes to physically travel to these worlds and come face to face with whatever lives there.
Just surviving the encounter would be problematic. We'd be plopping artificially intelligent entities down in the middle of an extraterrestrial Serengeti - as dramatized in the Discovery Channel program "Alien Planet."
But surviving the flight to these worlds could be even more perilous. Lammer and Ian Crawford of the University of London recently debated the dangers in several Internet postings.
There isn't enough room here to discuss the various propulsion schemes for accelerating a craft to at least 1/10th the speed of light. Suffice to say that 22nd century technology is so unpredictable that the exercise is as pointless as asking Lewis and Clake to imagine how they might travel from St. Louis to the Pacific Coast in three hours.