Comets

Comets are much larger objects than meteors that are actually still out in space. They can form tails and change positions from night to night. But unfortunately, they are too slow for our eyes to notice that. Therefore, we think they just stay in the same position every night. And as you read in the last paragraph of the last post, comets have a connection with meteors, but they aren't meteors..!

Not long ago, people thought that comets showed that something bad is going to happen to them in the near future. People didn't get how objects in the sky move. So, seeing a comet was something of a shock to them. There are many historical records that record the sight of comets and link them with very bad events.

But today we know that comets are lumps of ice & dust that in a period move toward the center of the solar-system from far away. Some comets make repeated trips. When comets get close enough to the Sun, the heat makes them evaporate slowly. Much dust & gas form long tails we can see from the Earth. Sometimes, these tails can be man kilometers long!

This is Comet Hale-Bopp on the 7th March 1997. The picture is provided by the National Astronomical Observatory of Japan. The yellow arrows show where the comet has released a large amount of dust from its center (nucleus).

I will talk about trips to comets later.