In 1957, the USSR launched Sputnik 1, the first human object to leave Earth. In the 65 years since then the region of Earth orbit has become filled with satellites and space junk. The proliferation of debris has led to the prediction of Kessler Syndrome, a state where a never-ending cascade of collisions between orbital objects renders parts of space unusable for human purposes. However, there are many different ways to look at the space junk surrounding Earth. For example, it is also an archaeological record of humanity's first steps into outer space, a cultural landscape created by the combined effects of natural and cultural processes, and a technological signature of the same kind that SETI (Search for Extraterrestrial Intelligence) researchers are looking for around exoplanets in other solar systems. It's unclear when or whether the tipping point into Kessler Syndrome might be reached, but if humanity is confined to Earth in the future, what will this mean? (#37913)