In 2005, collision of deep impact probe with the nucleus of comet tempel 1 was carried out. In this probe the length of Tempel 1's nucleus was about 5km long. In this probe it was revealed that the nucleus behave as a rubble pile which is held together by gravitation.
In this probe speed of Tempel 1 which is moving towards the nucleus was 10km/s. In this probe series of images was recorded and cloud of debris was analyzed,It was discovered that comet is made up of a primordial chunk of solar system material. It was observed that Tempel 1's has tiny grains of silicates, iron compounds, complex hydrocarbons, and clay and carbonates thought to require liquid water to form it was more appropriate for a cosmic souffle, as the nucleus is apparently porous and fluffy.
Tempel 1 is a periodic Jupiter-family comet discovered in 1867 by Wilhelm Tempel which is where it got its name from.It takes 5.5 years for it to complete an orbit of the Sun.
After the probe of the collision which took place in 2005, it was discovered that the comet was held together only by self-gravity rather than by structural bonds between the cometary particles themselves.
