What is meant by the tail of a comet?
When the solar wind strikes the vapour cloud of a comet, it deflects and scatters the dust and gases, and part of the vapour cloud, with the result that the comet appears to have a ‘Tail”. The size of the tail depends on the density of the dust and gas present in the cloud. The tail is more prominent when the comet is very near the sun.
Is the comet’s tail always situated behind the comet?
The tail is caused by the solar wind which blows from the Sun. hence, the tail always points away from the Sun and has no relation to the direction of motion of the correct. The tail can therefore be at the rear, in front, or at the side of the comet.
How long is the tail of a comet?
Cometary tails can be short or long. However, some comets have been observed to have extremely long tails with the length even exceeding the distance from the Earth to the Sun.
Are there different colours of cometary tails?
Some cometary tails contain very few dust particles and give out a faint blue light. Some other cometary tails contain a large number of dust particles which reflect the Sun’s light, making the tail appear yellow.
Do cometary tails maintain a constant shape?
Cometary Tails do not maintain a constant shape. Some of such shape changes can be spectacular. Tails may remain straight or curved, or lengthen, or may even detach and disappear. Tails can exhibit bright spots which appear like ‘knots” along the tail. Some comets may even multiple tails.
How dense are the gases in a comet’s tail?
It is usually in the order of less than 1000 gas molecules per cubic centimeter. It is, more or less, close to a perfect vacuum. The tail is consequently almost completely transparent and stars can even be seen through it.
What would happen if the Earth were to pass through the tail of a comet?
In 1910, Halley’s Comet was due to approach the Sun and it was thought that the Earth would pass through the tail of the comet. There was a worldwide scare that poisonous gases in the tail of the comet would annihilate all species on Earth. Conan Doyle, the creator of “Sherlock Holmes”, even wrote a story on this theme called “The Poison Belt”. Bur the density of gases in the comet’s tail is extraordinarily low and is incapable of exerting any noticeable effect on any living creature. Over the millions of years of its existence, the Earth must have passed through the tails of many such comets without any apparent ill effects.