Today we will continue looking at another body that is found in space. The comet. It is a small body that goes around the Sun and once it comes close enough to the Sun, it will be visible from Earth and even looks like it has a 'tail'.
The comet is made out of dust, ice and small rocks.
A very long time ago the philopher Aristotle looked at these 'things with tails/hair' and that is why they were called 'comets'. It is the Greek word for meaning 'hair of the head'.
The two types of comets are 'short term' and 'long term' comets. The first one will orbit once around other planets or the Sun for less than 200 years and the long term comets for more than 200 years.
Lets have a look at a very well known comet - Halley's Comet.
This is the most well know comet in our solar system. It is a 'short term comet' because it takes less than 200 years to complete one orbit around the Sun.
This comet can only be seen every 74 or 75 years with the naked eye and 'star gazers' from thousands of years back started looking for this comet.
The last time the comet were seen from Earth was in 1986 and will only be visible again in 2061.
Halley’s Comet is named after English astronomer Edmond Halley who first determined its period of orbit. It was the first comet to be recognized as having a periodic orbit.
It gets easier and easier to study the comet every time it appears, since the technology is getting better. Even though the Scientists could learn a lot in 1986 and could prove some things wrong and others right about this comet, they will even be able to gather more information in 2061.
Like all other comets, this one has the tail and a 'fuzzy' glow that is known as the 'coma'. This happens because when the comet comes close to the Sun, the carbon dioxide and ice particles turns from a solid into a gas. This coma over Halley's comet can stretch for over 100 000km.
Watch the video and answer the questions.
- Every how many years is Halley's comet visible?
- What surrounds the comets?
- What happens if the comets goes closer to the Sun?
Watch the following video and set a few of your own questions and also answer it in your own word or make a summary of what you have learned from the video.
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