The Solar System
Our Solar System is over 250 A.U. in diameter and contains a star (the Sun), orbited by 8 planets, several dwarf planets, an Asteroid belt and many more small rocky objects...
The Formation of the Solar System
The Solar System started forming ~4.5 billion years ago from a huge cloud of dust and gas.
The cloud collapses under gravity until the temperature and pressure at the core is large enough for Nuclear Fusion, forming a star.
Gravity causes the leftover dust and gas to collapse together to form Planets.
Small rocks and dust can be drawn together by gravity to form moons around the Planets.
How the Earth was formed
The video below takes you through the history of our planet, from a could of dust and rock, until modern times.
The Rocky Bodies
There are three main types of small rocky bodies in our solar system:-
Asteroids & Comets are chunks of rock and metals (Asteroids and Meteoroids) or dust and water-ice (Comets) left-over from the creation of the solar system.
Comets - ~750 m to ~20 km
Asteroids - 2m to ~1000 km
Meteoroids - Less than 2m
Comets can be bright enough to be seen with the naked eye, sometimes in broad daylight. Throughout history, Comets have been thought to been omens of great change...
Halley’s Comet features on the Bayeux Tapestry. The comet was seen as an omen of war just before the Norman conquest of Britain in 1066. Without the understanding of Science, it is easy to see how people could believe that Comets could be warnings from the gods, given their short but spectacular appearances in the night sky...
Some examples of 'Great Comets' in recent years
In reality, Comets are simply the leftover remains of dust and gas from the formation of our Solar system, heated by the Sun until they begin to evaporate...
How to make a Comet
Comets are basically dusty snowballs which orbit the Sun. They are made of ices, such as water, carbon dioxide, ammonia and methane, mixed with dust. These materials came from the time when the Solar System was formed. Comets have an icy centre (nucleus) surrounded by a large cloud of gas and dust (called the coma).
The video below shows how to make a model Comet in the classroom:-
The Planets in the Solar System follow (nearly) circular paths. Comets, however, follow a very different path known as an Ellipse. An Ellipse is similar to a circle, but whereas a circle has one focus point, an ellipse has two. In fact, a Circle is a special case of an Ellipse, where both focus points overlap at the centre...
The video below shows a 'how to' guide for drawing Orbital Paths:-
Meteoroids are a class of small rocky body that have also caused lots of wonder throughout history, but unlike comets, meteoroids regularly have an “impact” on the Earth. Meteoroids are the leftover remains of rock and metals from the formation of our Solar system. When a Meteoroid enters the atmosphere, it is travelling incredibly fast, between 11 - 72 kms-1 (160,000 mph). Travelling at this speed through the atmosphere causes the Meteoroid to heat up until it starts to vaporise. This causes the Meteoroid to glow, producing a streak of light across the sky. It is now known as a Meteor. If any of the Meteor survives to impact on the ground, the remains are known as a Meteorite.
The animation below shows the different stages described above:-
Meteor Showers occur when the Earth passes through the debris from a comet, with rates of hundreds of Meteors and hour possible.
Click the image below to open an animation showing the debris cloud from a Comet:-
Meteor Showers appear from the same point in the sky (the Radiant) so are named after the constellation where this is. The image below shows a Sky Map for the Taurid Meteor Shower:-
The image below shows some of the Meteor Showers visible throughout the year:-
When a Meteorite impacts on the ground all of its Kinetic energy is converted in Light, Heat and Sound. This huge release of Energy can create a Impact Crater. The image on the left shows the Barringer Crater in New Mexico, it is ~1 km across.
The Tycho Crater, showing the central peak caused by rebound
How to make a Crater
The video below shows how an Impact Crater can be formed in the classroom:-
The Rosetta Mission was a space probe built by the European Space Agency and was launched in 2004. Along with its lander, Philae, Rosetta became the first mission to successfully land on a Comet. The images below were taken by Rosetta on approach to Comet 67P ( Churyumov-Gerasimenko ).
On the 12th of November 2014, Philae made the first ever successful landing on a Comet. Unfortunately it landed in a crevasse and couldn't recieve sunlight to its solar cells. Though its battery pack ran out two days later, the lander managed to send very important data from the surface of the comet, along with some unique images.
The video below shows an animated walk through of the Rosetta Mission:-