Space and survival

Some such catastrophes would ruin Earth's biosphere as well. Although many have speculated about life and intelligence existing in other parts of space, Earth is the only place in the universe known to harbor life. Eventually the Earth will become uninhabitable, at the latest when the Sun becomes a red giant in about 5 billion years. Humankind, or its intelligent descendants, if they still exist at that point, must leave the Solar System long before that to ensure survival of the human species.

Human

Expanding the living area of the human species increases the mean distance between humans and any known hazardous event. People closest to the event are most likely to be killed or injured; people farthest from the event are most likely to survive. Increasing the number of places where humans live also helps to prevent extinction. For example, if a massive impact event occurred on Earth without warning, the human species could possibly become extinct; its art, culture and technology would be lost. However, if humans had previously colonized locations outside Earth, the opportunities for the survival and recovery of the species would be greater.

Many challenges arise when travelling in outer space. One of the biggest issues that may affect the human body is interstellar radiation. While the Earth's magnetic field and atmosphere protects all living forms on the planet, this cannot be said for outer space. According to researchers from the University of Rochester Medical Center, a radiation equivalent to a mission to Mars can cause serious brain damage such as cognition problems and Alzheimer's disease.^[10]

The observation and study of space protects Earth, as space hazards can be seen in advance and, if discovered early enough, acted against.

Near-Earth objects (NEOs) are asteroids, comets and large meteoroids that come close to or collide with Earth. Spaceguard is the collective name for some of the efforts to discover and study NEOs, though these efforts are not sufficiently funded.

Some more contemporary reasons for space as a solution to survival have been identified as imperialist reasoning for space exploration, only relocating collective shortcomings and not solving them.^[11]

• Global catastrophic risks
   – Hypothetical global-scale disaster riskPages displaying short descriptions of redirect targets
• Human outpost – Human habitats located in environments inhospitable for humans
• List of microorganisms tested in outer space
• Planetary habitability – Known extent to which a planet is suitable for life
• Space colonization – Concept of permanent human habitation outside of Earth
• Space habitat
   – Type of space station, intended as a permanent settlementPages displaying short descriptions of redirect targets
• Terraforming – Hypothetical planetary engineering process