Presentation, Lecture
Life in the universe
- Current Exoplanet Discovery Status
- Prior to 1995, exoplanets were purely theoretical; thousands have since been identified.
- Data suggests there is roughly one planet for every star in the galaxy.
- Approximately one out of every five identified exoplanets could potentially harbor life.
- Recent findings indicate that billions of planets resembling Earth likely exist within the Milky Way.
- Key Astronomical Discoveries and Missions
- Kepler-452b: A planet discovered in July, located 14,000 light-years away, situated in the habitable zone with a size and orbital distance similar to Earth's.
- James Webb Telescope: Scheduled for launch in 2018 to study atmospheres of closer Earth-like planets for biosignatures.
- Search Scope: SETI scientists have currently examined only approximately one-millionth of the star systems in the galaxy.
- Breakthrough Listen: A recently funded project led by Stephen Hawking, Martin Rees, and Frank Drake, and funded by Yuri Milner, designed to significantly expand search capacity.
- Methods for Detecting Extraterrestrial Intelligence (SETI)
- Searches currently target detectable Earth-based technologies including radio signals, television broadcasts, and radar.
- SETI has recently expanded from radio searches to include optical (light) signal detection.
- A lack of detected signals to date is attributed to an insufficient sample size rather than the absence of civilizations.
- Life Within the Solar System
- Focus areas for life detection include Mars, and the subsurface oceans of Jupiter's moon Europa and Saturn's moon Enceladus.
- Research relies on the existence of extremophiles on Earth, organisms capable of surviving temperatures above boiling water or pH levels lower than battery acid.
- Jupiter's Moons: Several large moons are hypothesized to contain liquid water oceans hidden beneath ice or rock surfaces, potentially dating back 4 billion years.
- Mars Exploration: NASA's Curiosity rover is investigating Gale Crater for evidence of ancient riverbeds and water-related chemistry.
- Expectations are set for finding simple life forms rather than complex ones in these solar system locations.
- Origins of Life Research
- Objective: To determine if life's emergence is a rare cosmic fluke or a common chemical inevitability.
- Jack Szostak's Laboratory (Harvard): Conducting experiments to recreate early Earth conditions for abiogenesis.
- Key Experiments:
- Investigating how primitive lipid cell membranes can grow and divide.
- Developing RNA capable of spontaneous self-replication without modern enzymatic assistance.
- Current Progress: A "protocell" containing RNA and lipids has been created; the current challenge is achieving RNA self-replication without external help.
- Ultimate Goal: To observe Darwinian evolution in a synthetic system, proving the potential for life to emerge from basic chemicals.
- Implications: If life emerges easily in the lab, the probability of extraterrestrial life increases; if difficult, life may be unique to Earth.