What do all comets have in common?

A comet is an icy small Solar System body that, when passing close to the Sun, heats up and begins to outgas, displaying a coma (atmosphere) and a tail. These phenomena are due to the effects of solar radiation and the solar wind upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of loose collections of ice, dust, and small rocky particles. The coma and tail are much larger and, if sufficiently bright, may be seen from the Earth without the aid of a telescope.

As a comet approaches the inner Solar System, solar radiation causes the volatile materials within the comet to vaporize and stream out of the nucleus, carrying dust away with them.

The tail, made of gases, always points directly away from the Sun because this gas is more strongly affected by the solar wind than is dust, following magnetic field lines rather than an orbital trajectory.

More Info: en.wikipedia.org

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25 Comments

stormejohn

They don't all travel at the same speed, they aren't all made up with the same amount of this or that, they don't all have the same temperature, but they do wag their tail the same direction (away from the solar wind). Simple question.

Satish Chandran

Comet has tail.

Karin Johansson

Ken Putnam, screaming like a little kid.

Mike Hibner

They all have tails when they are "close" to the sun, but their tails are not all the same. Hale-Bopp, you might recall if you're over thirty years old or so, had two tails. They are all made up of rock, dust and ice, though the chemical composition could be vastly different, they all have velocity, though not necessarily the same velocity. They all have temperature, though that is dependent on their distance from the sun and their rotation, and not due to friction, so velocity has no effect on temperature. When the distance from the sun is great, I suspect that their temperatures are all pretty much the same and close to absolute zero, so Temperature is the most accurate answer...

Char

Claude E Lett III, I had no problem or issues with it..

docluci

Easy answerr

ninakamwene

Got this learning trivia. Thank you.

Humberto Carrasco

GOT IT RIGHT

Cora Jeske

Ken Putnam, it's not all the same velocity

Jonathan Morrish

Claude E Lett III, you seem to have misread the question and missed the very important word, COMMON.

Jonathan Morrish

Mary Gini Fudge Chapman, they don’t have a COMMON velocity nor do they have a COMMON chemical composition. However, something they do have in common is that their tails point away from the sun. “Common” is very important in the question and that is what makes the other answers wrong. I do think it could have been phrased a little better but the questioner doesn't appear to be a native English speaker so I think they have done well enough.

mjhiggins

No velocity???

Mary Gini Fudge Chapman

Yes, all comets have tails, they also have velocity and all have a chemical make up. The answer should be "All of these". I'm with Ken Putnam -- I want my points!