From: mk_thisisit
The question of whether there is life beyond Earth is considered “very important” in science [00:00:00]. This overarching question is at the forefront of modern scientific exploration and research [00:04:10].
The Search for Life in Our Solar System
Brian Cox notes that while many people believe life must exist elsewhere due to the universe’s immense size and age, finding such life could occur within the next “decade or two” [00:04:25].
Current Missions
There are numerous space missions dedicated to discovering extraterrestrial life [00:04:32]:
- Mars Sample Return: This mission aims to bring back samples collected by the Perseverance rover on Mars to Earth. Scientists will analyze these samples for any traces of past or present life [00:04:37].
- Jupiter’s Moons: Two missions are targeting a moon of Jupiter (likely Europa) to determine if it could support life. One mission is currently underway, and another is set to launch soon [00:04:51].
Potential future targets for exploration include:
- Mars [00:00:05] [00:07:53]
- Jupiter’s moon Europa [00:07:56]
- Saturn’s moon Enceladus [00:08:00]
- Other moons of Jupiter or Saturn [00:08:02]
Likely Forms of Life
If life is discovered within our solar system, Professor Cox anticipates it will be “microbes at most” [00:05:22]. He would not be surprised to find single-celled organisms, such as bacteria, on these moons or beneath the surface of Mars [00:06:19] [00:08:18]. However, he would be “extremely surprised” to find multicellular organisms [00:08:27]. This expectation is based on Earth’s history, where multicellular life did not appear until roughly 600-700 million to a billion years ago, implying that life remained simple for a very long time [00:08:34] [00:08:50].
Conditions for Life
The strategy for searching for life outside of Earth within the solar system is centered on finding places that offer suitable geological and chemical conditions [00:07:33] [00:08:07]:
- Liquid Water: Presence of liquid water, whether past or present [00:07:41].
- Geological Activity: Regions with geological activity [00:07:44].
- Right Chemistry: Environments with the appropriate chemical composition [00:07:46].
The presence of life on Earth 3.8 billion years ago, relatively close to Earth’s formation (4.5 billion years ago) and cooling, suggests that the origin of life might not be as unlikely given the right geological conditions [00:06:37] [00:07:18].
Intelligent Life in the Galaxy
When considering the number of civilizations in a typical galaxy, Professor Cox states that the answer is unknown [00:05:37] [00:05:40]. Based on his own assumptions, he concludes that there may be “very little intelligent life” in a typical galaxy [00:05:52]. He recalls a conversation with his friend and cosmologist, Carroll, who suggested “none” when asked about the average number of civilizations in a galaxy [00:06:01].