Greetings, player55!
The correct Answer is B) dust left behind in the orbit.
However,
A) evaporating gases left behind in the orbit and
E) evaporating gases pushed by the solar wind
*might* be considered correct as well.
From the "Ask A Scientist© Astronomy Archive: The Comet's Tail":
"Comets actually have two tails: the dust tail and the gas or ion
tail. The names should tell you what's in them. Both tails always
point *away* from the Sun, independent of the comet's motion. The
dust tail is formed of solid particles escaping from the cometary
nucleus into their own solar orbits and may be slightly curved. It
shines with reflected sunlight. The ion tail is pushed straight back
from the coma by the solar wind and solar radiation pressure and glows
from the fluorescence of the ionized molecules CO+, N2+, OH+, CO2+,
and CH+. Some comets are also surrounded by huge (bigger than the Sun)
clouds of hydrogen gas."
http://newton.dep.anl.gov/askasci/ast99/ast99312.htm
From the Physics 5 Spring 2001 QUIZ 2 Chapter 4, by Professor Tytler
at the University of California, San Diego Department of Physics:
"2) A comet's tail is an extended feature which can be seen stretched
across a large partof the sky.
a) How is a comet's tail formed? (2 points)
*The Sun evaporates ice on the surface of the comet to form the coma.
The solar wind pushes the evaporated gas and dust away from the comet
to form the tail.
b) Why does a comet's tail always point away from the Sun? (2 points)
*The solar wind comes from the sun and blows the tail away from the
Sun.
c) Halley's Comet can be seen in the sky once every 76 years. The
comet's tail is visible to the naked eye for a few months during this
time. Why is the comet's tail invisible during other times? (2 points)
*When the comet is far away from the sun, the weakened sunlight can't
evaporate the ice in the comet, so there's no tail."
http://216.239.53.100/search?q=cache:hNqOITL14-IC:physics.ucsd.edu/students/courses/spring2001/physics5/files/q2answers.pdf+how+comet%27s+tail+is+formed&hl=en&ie=UTF-8
From Imperial College's Space & Atmospheric Physics Group's Ulysses
website:
"What's a comet's tail made of?
There are two main types of comet tails. They are formed from the gas
and dust given off by the nucleus.
Most of the dust particles given off by the nucleus are tiny. So tiny
is fact that they can be pushed about by the pressure of sunlight
alone. Sunlight pushes back the dust particles, forming a dust tail.
This tail can be seen remotely due to it reflecting sunlight.
The gases given off by the nucleus become electrically charged by
several processes, forming ions. There is a constant stream of charged
particles flowing from the Sun at several hundred kilometres per
second, called the solar wind. As soon as the gas particles are
charged, they are under the influence of this wind, which carries them
away from the Sun. This forms the ion, (or plasma) tail. The ion tail
can be seen because the ions within it fluoresce. The abundant ions
which have the longest lifetimes are CO+ (carbon monoxide) ions -
these glow with a blue colour; hence an ion tail usually appears
blue."
http://www.sp.ph.ic.ac.uk/Ulysses/comet/comet.html
Search Strategy
how comet's tail is formed
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I hope that this Answer has provided you with exactly the information
that you needed!
Regards,
aceresearcher |
