Space Exploration and Stellar Life

Space Exploration

• Geocentric Model: Earth is the center of the universe; proposed by Aristotle.

• Heliocentric Model: Sun is the center of the universe; developed by Nicholas Copernicus.

Life of a Star

• Nebula: Cloud of gas and dust where stars form.

• Main Sequence: Longest, stable phase of a star's life, where nuclear fusion occurs.

• Red Giant/Supergiant: Star expands as it runs out of fuel.

• Low-Mass Star Death: Planetary nebula, white dwarf, then black dwarf.

• High-Mass Star Death: Supernova, then either neutron star or black hole.

Other Bodies in the Solar System

• Asteroids: Rocky objects primarily found in the asteroid belt between Mars and Jupiter.

• Comets: Ice, dust, and gas; have tails when near the sun (e.g., Halley's Comet).

• Meteoroids/Meteors/Meteorites: Space rocks; meteors burn up in Earth's atmosphere (shooting stars); meteorites reach the surface.

• Dwarf Planets: Small planets that don't clear their orbit (e.g., Pluto, Ceres, Eris).

• Moons: Natural satellites orbiting planets (e.g., Earth's Moon, Jupiter's Europa).

Tracking Objects in the Night Sky

• Early Observations: Ancient civilizations used stars for timekeeping and seasonal tracking.

• Geocentric vs. Heliocentric Models: Geocentric (Earth-centered, Ptolemy); Heliocentric (Sun-centered, Copernicus, supported by Galileo).

• Telescopes: Improved observations (e.g., Galileo's discovery of Jupiter's moons).

• Planets' Motion: Retrograde motion: Planets appear to move backward due to Earth's movement.

• Modern Tracking: Today's astronomy uses telescopes, satellites, computers.

Triangulation

• Rocketry and Physics

• Newton's Third Law: For every action, there is an equal and opposite reaction (key to rocket propulsion).

• Rocket Components: Payload (cargo), propulsion system (fuel), structure (body).

• Forces on a Rocket: Thrust (upwards), weight (downwards), drag (opposing motion).

• Rocket Flight Stages: Launch, ascent, stage separation, orbit.

• Applications of Rocketry: Space exploration, satellite deployment, scientific research, military.

• Technological Advancements: Improved materials and fuel management for better safety and efficiency.

Hazards of Living in Space

• Microgravity Effects: Muscle loss, bone density reduction, fluid shift.

• Radiation Exposure: Increased cancer risk from cosmic radiation; spacecraft offer shielding.

• Psychological Challenges: Isolation, confinement, stress; support systems for mental health.

• Environmental Hazards: Extreme temperatures, micro-meteoroids, debris, need for insulated suits.

• Life Support Systems: Oxygen, water supply, recycling, waste management.

• Training: Astronauts receive extensive training.

Types of Telescopes

• Optical Telescopes: Use visible light; refracting (lenses, good for planets); reflecting (mirrors, good for deep-sky objects).

• Radio Telescopes: Detect radio waves; large dish antennas for studying objects like pulsars.

• Infrared Telescopes: Observe infrared radiation; study cool objects and dust clouds.

• Ultraviolet Telescopes: Detect ultraviolet light; study hot stars and galaxies.

• X-ray and Gamma-ray Telescopes: Observe high-energy radiation; placed in space due to atmospheric absorption.

Doppler Effect

• Definition: Change in frequency/wavelength of a wave due to relative motion.

• Types: Redshift (object moving away), blueshift (object moving closer).

• Applications: Studying celestial object motion; radar, Doppler ultrasound.

Space Travel Pros and Cons

• Pros: Scientific discovery, technology development, international collaboration, inspiration

• Cons: High cost, health risks for astronauts, environmental impact (pollution), risk of accidents.

Biological Diversity

Symbiotic Relationships

• Definition: Interactions between two species living closely together, often benefiting at least one species.

• Types: Mutualism (both benefit), commensalism (one benefits, other unaffected), parasitism (one benefits, other harmed).

• Importance: Symbiotic relationships are vital for ecosystem dynamics and community structure.

Heritable vs Non-Heritable Traits

• Heritable Traits: Passed from parents to offspring through genes (e.g., eye color).

• Non-Heritable Traits: Acquired during an individual's lifetime (e.g., skills, scars).

Variation Between/Within Species

• Variation Between Species: Differences in traits that distinguish species (e.g., dog vs. cat).

• Variation Within Species: Differences among individuals of the same species; influenced by genetics and environment.

Discrete vs. Continuous Variation

• Discrete Variation: Traits fall into distinct categories (e.g., blood type).

• Continuous Variation: Traits show a range of values (e.g., human height).

Asexual Reproduction

• Types: Binary fission, budding, fragmentation, vegetative propagation, spore formation.

• Advantages: Rapid reproduction, energy-efficient.

• Disadvantages: Lack of genetic diversity.

Sexual Reproduction

• Components: Gametes (sperm and egg), fertilization (external or internal), zygote development.

• Advantages: Genetic diversity.

• Disadvantages: Energy-intensive, slower population growth.

DNA, Genes, and Chromosomes

• DNA: Double helix, carries genetic information.

• Genes: DNA segments encoding protein instructions; different versions (alleles).

• Chromosomes: Coiled DNA and proteins; humans have 23 pairs.

Cell Division

• Mitosis: Creates identical cells for growth, repair; single cell division.

• Meiosis: Produces gametes for sexual reproduction; two cell divisions, creating genetic variation.

Patterns of Inheritance

• Mendelian Inheritance: Dominant and recessive traits.

• Incomplete Dominance: Traits blend (e.g., pink flowers).

• Codominance: Both alleles are expressed (e.g., AB blood type).

• Polygenic Inheritance: Multiple genes control a trait (e.g., height).

• Sex-Linked Inheritance: Traits linked to sex chromosomes.

Extinction vs. Extirpation

• Extinction: Species does not exist anywhere.

• Extirpation: Species is no longer present in a particular area but still exists elsewhere.

Biotechnology

• Definition: Using living organisms or products for technological applications.
• Applications: Medicine (vaccines, gene therapy), agriculture (GMOs), environment (bioremediation).
• Techniques: Recombinant DNA technology, CRISPR-Cas9.

Matter and Chemical Change

• WHMIS Symbols: Hazard communication system.

• States of Matter: Evaporation (liquid to gas), solidification (liquid to solid), sublimation (solid to gas), melting (solid to liquid).

• Pure Substances: Elements (e.g., oxygen), compounds (e.g., water); uniform composition.

• Mixtures: Combinations of substances; homogeneous (uniform), heterogeneous (different phases).

• Physical Properties: Observable without changing composition (e.g., color, boiling point).

• Chemical Properties: Describe a substance's ability to undergo chemical reactions (e.g., reactivity, flammability).

• Physical Changes: Changes in physical properties without altering composition (e.g., cutting, dissolving).

• Chemical Changes: Changes leading to new substances (e.g., burning).

Organizing the Elements

• Periodic Table: Organizes elements by atomic number and chemical properties.

• Periods: Horizontal rows; elements transition from metallic to nonmetallic.

• Groups: Vertical columns; similar properties due to valence electrons. (e.g., Alkali metals, Halogens, Noble gases).

• Types of Elements: Metals, nonmetals, metalloids.

Understanding the Periodic Table

• Atomic Number: Number of protons identifying the element.

• Element Symbols: Unique 1- or 2-letter symbols.

• Groups and Periods: Groups (vertical columns, similar properties), Periods (horizontal rows).

• Metal, Nonmetal, Metalloid Regions: Categorization on the table aiding identification of characteristics.

• Trends: Reactivity, atomic size, electronegativity.

Atomic Mass and Atomic Number

• Atomic Number: Number of protons.

• Atomic Mass: Average mass, measured in atomic mass units.

Protons, Neutrons, and Electrons

• Protons: Positively charged particles in the nucleus.

• Neutrons: Neutral particles in the nucleus.

• Electrons: Negatively charged particles orbiting the nucleus; usually equal to the number of protons.

Variables

• Manipulated Variable: Changed by the scientist.

• Responding Variable: Changes as a result of the manipulated variable.

• Control Variables: Remain constant throughout the experiment.