write an account that considers what conditions would be required on an earth-like extrasolar planet for the carbon based life to evolve. In your answer you must keep in mind what is thought to have happened on earth, and you must:
according to this i have to write about how the occultation technique can indicate the presence of a large extrasolar planet.
can any1 tell me wat this means?
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Photometric Transit method
At:
http://www.novacelestia.com/space_art_extrasolar_planets/detect_extrasolar_planets.html
Also:
http://exoplanets.org/
To answer your question, I will explain two key parts: the conditions required for carbon-based life to evolve on an extrasolar planet, and how the occultation technique can indicate the presence of a large extrasolar planet.
Conditions for Carbon-Based Life on an Extrasolar Planet:
To consider what conditions would be required for carbon-based life to evolve on an extrasolar planet, we can base our understanding on what is thought to have happened on Earth. Carbon-based life, like humans, plants, and animals, requires a few fundamental conditions:
1. Suitable Temperature Range: Carbon-based life forms require temperatures that support liquid water, as it is essential for the biochemical reactions necessary for life. The planet should lie within the habitable zone, also known as the Goldilocks zone, where it is not too close or too far from its star to maintain liquid water.
2. Stable Atmosphere: An extrasolar planet needs to have a stable atmosphere to regulate its temperature, protect against harmful radiation, and provide the necessary gases for life. The atmosphere should contain elements like nitrogen, oxygen, carbon dioxide, and water vapor.
3. Suitable Chemical Composition: Carbon-based life forms require certain elements like carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. These elements are essential building blocks for organic molecules and the complex chemistry that supports life.
4. Presence of Liquid Water: Liquid water is critical for biochemical reactions and is considered a key ingredient for the evolution of life as we know it. The planet must have a sufficient amount of liquid water on its surface or in its subsurface oceans.
5. Energy Source: Life on Earth relies on energy from the Sun through photosynthesis (for plants) or alternative energy sources (for organisms that don't rely on sunlight). An extrasolar planet's star should provide a suitable energy source for life to thrive.
Occultation Technique for Planetary Detection:
Now, let's discuss the occultation technique for detecting large extrasolar planets. The occultation or transit method is one of the primary techniques used to detect exoplanets. It involves observing a star and looking for periodic dips in its brightness. Here's how it works:
1. Photometric Transit Method: The occultation technique relies on measuring the change in a star's brightness when an orbiting planet passes in front of it (transit). This causes a small decrease in the star's apparent brightness, like a mini-eclipse.
2. Detecting the Dip: Astronomers use sensitive instruments, such as telescopes equipped with photometers, to monitor the brightness of the star over time. By analyzing the light curve, which shows changes in brightness, they can identify regular, repetitive dips that indicate a planet is transiting across the star.
3. Planet Characteristics: From the light curve data, scientists can deduce important planetary characteristics, such as the period of the planet's orbit, size, and orbital distance. They can also estimate its mass and make rough approximations about its composition and atmosphere, depending on the specific observations and the precision of the instruments used.
By studying these light curves and applying various analytical techniques, astronomers can determine if an extrasolar planet exists and gather information about its properties.
To further explore the occultation technique and learn more about detecting and studying exoplanets, you can visit the provided links:
- http://www.novacelestia.com/space_art_extrasolar_planets/detect_extrasolar_planets.html
- http://exoplanets.org/