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Introducing the Solar System. The Solar System is made up of various celestial objects:. the Sun. the planets. moons. asteroids. comets. How do these objects interact?.
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Introducing the Solar System The Solar System is made up of various celestial objects: • the Sun • the planets • moons • asteroids • comets. How do these objects interact? The Sun is a star – a massive ball of hot glowing gas. It has the strongest gravitational field in the Solar System. All the other celestial bodies orbit around it.
What time is it? It is 4 am in London. Casablanca Philippines What is the time in the rest of the world? place GMT time Casablanca +1 hr 5 am Pretoria +2 hr 6 am Antananarivo +3 hr 7 am Pretoria Antananarivo Philippines +8 hr 12 pm
What are hemispheres? The Earth is divided into two hemispheres, separated by the equator. northern hemisphere equator southern hemisphere Why do the hemispheres have different seasons at different times of the year?
The Moon sunlight The Sun and the Moon look about the same size from Earth, but they are not. The Sun is about 400 times wider than the Moon but is 400 times further away! The Moon takes just over 27 days to orbit the Earth.
Eclipses A solar eclipsehappens when the Moon passes between the Sun and the Earth, casting a shadow over the Earth. The last solar eclipse over the UK was on 11th August 1999. They are rare in the UK. A lunar eclipsehappens when the Earth passes between the Sun and the Moon, casting a shadow over the Moon. Lunar eclipses happen in most years.
What happens during a solar eclipse? Where must the Moon be for a solar eclipse to take place? During a solar eclipse the Moon moves directly between the Sun and the Earth, blocking the Sun’s rays from reaching part of the Earth.
What happens during a lunar eclipse? Where must the Moon be for a lunar eclipse to take place? During a lunar eclipse the Moon is on the opposite side of the Earth to the Sun, blocking the Sun’s light from reaching the Moon.
Gravity and satellites A satelliteis any object that orbits another object. The Moon is anatural satelliteof the Earth and is kept in orbit by the attraction of the Earth’s gravity and by its motion. Anartificial satelliteis an object made by, and put into orbit by, humans. Why do you think satellites stay in orbit, instead of falling back onto the surface of the Earth or drifting off into space?
Orbit height and speed Imagine the mountain in Newton’s thought experiment was lower. If the same amount of gunpowder was used, would a ball shot from the lower mountain travel the same distance as from the high mountain? No. More gunpowder would be needed to make the ball travel the same distance. Therefore, more gunpowder would be needed to make the ball go into orbit. This means that if a satellite orbits the Earth at a lower altitude, it needs to travel faster to stay in orbit.
What is the Hubble Space Telescope? The Hubble Space Telescope (HST) is a satellite in orbit around the Earth. It was deployed from the Space Shuttle Discovery on 24 April 1990. The HST is outside the Earth’s atmosphere and does not experience the same interference as Earth-based telescopes. This means that its images of the Universe are much more detailed than images observed from Earth.
Is Pluto a planet? In 2006, the International Astronomical Union defined a planet as: “a celestial object that orbits the Sun, has enough mass to be spherical, and has cleared the area around its orbit of objects.” This photograph shows Pluto and its moon, Charon. Pluto’s orbit is surrounded by smaller objects which have not been cleared by its gravitational field. Pluto and the other ‘smaller’ planet-like objects such as Eris and Ceres have now been reclassified as ‘Dwarf Planets’.
