Space

Space Glossary Slide 3: Satellites Slide 4: Geo-stationary Satellites Slide 5: Re-entry Slide 6: Light Years Slide 7: Continuous Spectrum Slide 8: Line Spectrum

Satellites Satellites are something which orbits (goes around) a planet. They can be man-made or natural. Moons are natural satellites.

Geo-stationary Satellites Geo-stationary satellites remain in orbit above the same point above Earth’s equator. This occurs because the orbital time of the satellite is the exact same as the time for the Earth to rotate once. Therefore, a geo-stationary satellite has an orbital time of 24hours.

Re-entry When a space craft re-enters the Earth’s atmosphere it suddenly experiences air resistance. Air resistance is like friction caused by the air. All friction produces heat energy. This heat energy could cause the space craft to burn up so it is essential that it has a heat shield which will absorb the heat energy and evaporate rather than the space craft with astronauts inside.

Light Years A light year is the distance light travels in one year. As space is so large it is useful to describe distances in light years rather than km or miles. From the equation d=vt (with v being the speed of light in a vacuum and t being the number of seconds in one year), we can calculate the number of metres in one light year.

Continuous Spectrum A continuous spectrum shows all the colours of visible light. Visible light is part of the electromagnetic spectrum. Red light has the longest wavelength and violet light has the shortest wavelength.

Line Spectrum A line spectrum only shows particular colours of visible light. When a hot gas cools it can give out (emit) particular colours of light. A line spectrum shows the particular colours that are emitted for a particular element.