Earth and space

• Planet conditions.

  • Orbits a star -sun.
  • Must be big enough to allow its own gravity to pull it inwards to make a sphere.
  • Must be big enough for its own gravity to move other objects around the same size out of its way in its orbit around the sun.
• Planetoids - dwarf planets - too big to be asterroirs and too small to be planets
• Large gas clouds in space - nebulae
• Life cycle of a star.

  1. Formation - large gas clouds - nebula - attractive forces of gravity of gas particles cause these gas to collapse and co-e together.
  2. Stable period - becomes a main sequence star /it creates heat and it expands.
  3. Red giant - When a star used all of its supplies of hydrogen in its core it begins burning helium on its outer parts.
  4. ‘White dwarf - Once the red giant has used exhausted his nuclear fuel/collapsed forming a tiny star that’s dense.
• Some stars explode during the process of dying dramatically releasing a dazzling amount of light that may be seen throughout the universe - supernova
• Jovian planets - Jupiter,Saturn,Uranus,Neptune
• Asteroids - small,rocky structures that have no air or atmosphere
• Small asteroids - 10m in diameter
• Moon - second brightest object in the sky after the sun
• The moon has no atmosphere
• Benefits of space Exploration

  • The development of long lasting food - as food in space must have a long shelf life - they’re are accessible in supermarket - powdered food e.g soup.
  • Heart monitor were developed to observe the heart rates of astronauts on missions; now used in hospitals.
  • Materials worn by astronauts wear fireproof,fighter fighters now wear protective suits made from these material.
  • Other benefits have included the development of satellites and associated technologies. With satellites we can communicate with anyone at almost any point on Earth
• Hazards of space exploration.

  • solar flares and radiation – danger from ionising radiations that could cause cancer
  • no atmosphere – we need air to breathe and atmospheric pressure to stop our bodies decompressing
  • temperature – space is extremely cold at -270.42 Celsius, far too cold for humans to survive without protection.
  • Lack of gravity can chase the muscles in the body to shrink
• Earth rotates at an axis/imaginary line that it’s titled at 23.5 degress
• Moon formation

  • When a large object about the size of Mars collided with the earth 4.6 billion years ago.
• Seasons - caused by the tilt of the Earth's axis. Because the Earth is not perfectly aligned with the plane of orbit (the ecliptic) the amount of sunlight reaching different parts of the planet changes throughout the year. In summer, the hemisphere facing the Sun receives more direct sunlight than the other half of the Earth. During winter, this position switches so the opposite side of the Earth gets most of the light. This causes seasonal variations in temperature and climate.