Jabarkan Asal-usul hirup dari Hirup dalam bahasa sunda

euweuh modél "baku" pikeun asal-usul hirup, tapi nu kiwari ditampa sacara umum diwangun dumasar papanggihan di handap ieu:

Kaayaan nu ngarojong prabiotik ngahasilkeun kaciptana molekul leutik dasar kahirupan. Ieu dipetakeun dina percobaan Urey-Miller.

Fosfolipid sacara spontan ngawangun lapis ganda lipid, struktur dasar mémbran sél.

Procedures for producing random RNA molecules can produce "ribozymes", which are able to produce more of themselves under very specific conditions.

There are many different hypotheses regarding the path that might have been taken from simple organic molecules to protocells and metabolism. Many of the possibilities have tended to fall into either "genes-first" or "metabolism-first", a recent trend is the emergence of hybrid modéls that combine aspects of both.

The possibility of extraterrestrial life

As of 2004, Earth is the only planet in the universe known by humans to support life. The question of whether life exists elsewhere in the universe remains open, but analyses such as the Drake equation have been used to estimate the probability of such life existing. There have been a number of false alarms of life elsewhere in the universe, but none of these apparent discoveries have so far survived scientific scrutiny.

Currently, the closest that scientists have come to finding extraterrestrial life is fossil evidence of possible bacterial life on Mars (via the ALH84001 metéorite). Séarches for extraterrestrial life are presently focusing on planets and moons believed to possess liquid water, presently or in the past. Recent evidence from the NASA rovers Spirit and Opportunity supports the théory that Mars once had surface water. See Life on Mars for further discussion.

Jupiter's moons are also considered good candidates for extraterrestrial life, especially Europa, which seems to possess océans of liquid water.