Astronomy and Galaxies

Astronomy

• Study of the physical nature of celestial objects and phenomena
• Branches:
  • Planetary science: study of planets, moons, and asteroids
  • Stellar astronomy: study of stars and their life cycles
  • Galactic astronomy: study of galaxies and galaxy evolution
  • Cosmology: study of the origin and evolution of the universe

Galaxies

• Massive, gravitationally bound systems consisting of:
  • Stars
  • Stellar remnants
  • Interstellar gas and dust
  • Dark matter
• Types:
  • Spiral galaxies (e.g., Milky Way)
  • Elliptical galaxies
  • Irregular galaxies
  • Active galaxies (e.g., quasars)

Space Travel

• Exploration of space beyond Earth's atmosphere
• Types:
  • Crewed spaceflight: human space travel
  • Uncrewed spaceflight: robotic spacecraft
• Methods:
  • Launch vehicles: rockets that carry spacecraft into orbit
  • Propulsion systems: engines that propel spacecraft through space
  • Life support systems: systems that sustain human life in space
• Challenges:
  • Radiation exposure
  • Microgravity effects on human health
  • Distance and communication delays
  • Extreme temperatures and environments

Space Exploration Timeline

• 1950s: Launch of Sputnik 1 (USSR) and Explorer 1 (USA)
• 1960s: First human spaceflight (Yuri Gagarin, USSR) and moon landing (Apollo 11, USA)
• 1970s: Launch of Voyager 1 and 2 (USA)
• 1980s: Launch of the Hubble Space Telescope (USA)
• 1990s: Launch of the International Space Station (USA, Russia, Japan, Europe, Canada)
• 2000s: Launch of the Mars Exploration Rovers (USA) and New Horizons (USA)
• 2010s: Launch of the Curiosity Rover (USA) and Voyager 1 enters interstellar space

Astronomy

• Study of celestial objects and phenomena, including their physical nature
• Divided into four main branches:
  • Planetary science: planets, moons, and asteroids
  • Stellar astronomy: stars and their life cycles
  • Galactic astronomy: galaxies and galaxy evolution
  • Cosmology: origin and evolution of the universe

Galaxies

• Massive, gravitationally bound systems consisting of:
  • Stars, stellar remnants, interstellar gas and dust, dark matter
• Types of galaxies:
  • Spiral galaxies (e.g., Milky Way)
  • Elliptical galaxies
  • Irregular galaxies
  • Active galaxies (e.g., quasars)

Space Travel

• Exploration of space beyond Earth's atmosphere
• Types of space travel:
  • Crewed spaceflight: human space travel
  • Uncrewed spaceflight: robotic spacecraft
• Methods of space travel:
  • Launch vehicles: rockets that carry spacecraft into orbit
  • Propulsion systems: engines that propel spacecraft through space
  • Life support systems: systems that sustain human life in space
• Challenges of space travel:
  • Radiation exposure
  • Microgravity effects on human health
  • Distance and communication delays
  • Extreme temperatures and environments

Space Exploration Timeline

• 1950s:
  • Launch of Sputnik 1 (USSR)
  • Launch of Explorer 1 (USA)
• 1960s:
  • First human spaceflight (Yuri Gagarin, USSR)
  • First moon landing (Apollo 11, USA)
• 1970s:
  • Launch of Voyager 1 and 2 (USA)
• 1980s:
  • Launch of the Hubble Space Telescope (USA)
• 1990s:
  • Launch of the International Space Station (USA, Russia, Japan, Europe, Canada)
• 2000s:
  • Launch of the Mars Exploration Rovers (USA)
  • Launch of New Horizons (USA)
• 2010s:
  • Launch of the Curiosity Rover (USA)
  • Voyager 1 enters interstellar space