The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high a priori likelihood of its existence. As a 2015 article put it, "If life is so easy, someone from somewhere must have come calling by now."
Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration is conducted both by uncrewed robotic space probes and human spaceflight. Space exploration, like its classical form astronomy, is one of the main sources for space science.
Space colonization is the use of outer space or celestial bodies other than Earth for permanent habitation or as extraterrestrial territory.
Spaceflight is an application of astronautics to fly spacecraft into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflight operates either by telerobotic or autonomous control. The more complex human spaceflight has been pursued soon after the first orbital satellites and has reached the Moon and permanent human presence in space around Earth, particularly with the use of space stations. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs, with currently the International Space Station as the main destination of human spaceflight missions while China's Tiangong Space Station is under construction.
Nick Bostrom is a Swedish philosopher at the University of Oxford known for his work on existential risk, the anthropic principle, human enhancement ethics, whole brain emulation, superintelligence risks, and the reversal test. In 2011, he founded the Oxford Martin Program on the Impacts of Future Technology, and is the founding director of the Future of Humanity Institute at Oxford University. In 2009 and 2015, he was included in Foreign Policy's Top 100 Global Thinkers list.
Pale Blue Dot is a photograph of planet Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers, as part of that day's Family Portrait series of images of the Solar System.
The Great Filter is one possible resolution of the Fermi paradox. It posits that in the development of life from the earliest stages of abiogenesis to reaching the highest levels of development on the Kardashev scale, there exists some particular barrier to development that makes detectable extraterrestrial life exceedingly rare.
Space advocacy is supporting or advocating for a human use of outer space. Purposes advocated can reach from space exploration, or commercial use of space to even space settlement. There are many different individuals and organizations dedicated to space advocacy. They are usually active in educating the public on space related subjects, lobbying governments for increased funding in space-related activities or supporting private space activities. They also recruit members, fund projects, and provide information for their membership and interested visitors. They are sub-divided into three categories depending on their primary work: practice, advocacy, and theory.
Human extinction is the hypothetical end of the human species due to either natural causes such as population decline from sub-replacement fertility, an asteroid impact, large-scale volcanism, or to anthropogenic (human) causes.
Our Final Hour is a 2003 book by the British Astronomer Royal Sir Martin Rees. The full title of the book is Our Final Hour: A Scientist's Warning: How Terror, Error, and Environmental Disaster Threaten Humankind's Future In This Century—On Earth and Beyond. It was published in the United Kingdom under the title Our Final Century: Will the Human Race Survive the Twenty-first Century?.
Asteroids, including those in the asteroid belt have been suggested as a possible site of human colonization. Some of the driving forces behind this effort to colonize asteroids include the survival of humanity, as well as economic incentives associated with asteroid mining. The process of colonizing asteroids does have many obstacles that must be overcome for human habitation, including transportation distance, lack of gravity, temperature, radiation, and psychological issues.
The following outline is provided as an overview of and topical guide to space exploration.
The Future of Humanity Institute (FHI) is an interdisciplinary research centre at the University of Oxford investigating big-picture questions about humanity and its prospects. It was founded in 2005 as part of the Faculty of Philosophy and the Oxford Martin School. Its director is philosopher Nick Bostrom, and its research staff include futurist Anders Sandberg and Giving What We Can founder Toby Ord.
Freeman Dyson proposed that trans-Neptunian objects, rather than planets, are the major potential habitat of life in space. Several hundred billion to trillion comet-like ice-rich bodies exist outside the orbit of Neptune, in the Kuiper belt and Inner and Outer Oort cloud. These may contain all the ingredients for life, including significant amounts of deuterium and helium-3. Since Dyson's proposal, the number of trans-Neptunian objects known has increased greatly.
Pale Blue Dot: A Vision of the Human Future in Space is a 1994 book by the astronomer Carl Sagan. It is the sequel to Sagan's 1980 book Cosmos and was inspired by the famous 1990 Pale Blue Dot photograph, for which Sagan provides a poignant description. In the book, Sagan mixes philosophy about the human place in the universe with a description of the current knowledge about the Solar System. He also details a human vision for the future.
A nuclear holocaust, also known as a nuclear apocalypse,nuclear Armageddon, or atomic holocaust, is a theoretical scenario where the mass detonation of nuclear weapons causes globally widespread destruction and radioactive fallout. Such a scenario envisages large parts of the Earth becoming uninhabitable due to the effects of nuclear warfare, potentially causing the collapse of civilization and, in the worst case, extinction of humanity and/or termination of all biological life on Earth.
A global catastrophic risk or a doomsday scenario is a hypothetical future event that could damage human well-being on a global scale, even endangering or destroying modern civilization. An event that could cause human extinction or permanently and drastically curtail humanity's potential is known as an "existential risk."
Human presence in space is about humanity in space, particularly about all anthropogenic presence in space and human activity in space, that is in outer space and in a broader sense also on any extraterrestrial astronomical body.
On the Future: Prospects for Humanity is a 2018 nonfiction book by British cosmologist and Astronomer Royal Martin Rees. It is a short, "big concept" book on the future of humanity and on potential dangers, such as nuclear warfare, climate change, biotech, and artificial intelligence, and the possibility of human extinction.
Scenarios in which a global catastrophic risk creates harm have been widely discussed. Some sources of catastrophic risk are anthropogenic, such as global warming, environmental degradation, engineered pandemics, and nuclear war. Others are non-anthropogenic or natural, such as meteor impacts or supervolcanoes. The impact of these scenarios can vary widely, depending on the cause and the severity of the event, ranging from temporary economic disruption to human extinction. Many societal collapses have already happened throughout human history.
