As it nears the sun, the heat and light from the sun begin to melt and then vaporize the comet; small jets of gas and dust eject off the comet, and solar wind pushes it into a tail. The closer to the sun it gets, the greater the effect.
As it moves *away* from the sun, the tail precedes the comet, and the heat the comet receives dwindles; so does the amount of material being ejected, until finally it’s just a dark, nearly invisible lump of ice and rock.
A tail (often two tails -- one of gas, one of dust) becomes visible as a comet approaches the sun. One reason is that proximity to the sun causes vaporization, and solar radiation pressure pushes the loose material away from the sun; a further reason is that solar illumination makes it possible for us to see the tail or tails.
Answers & Comments
Becasue it REFLECTS light fromt eh sun. The farther away it is, the less light it reflects
As it nears the sun, the heat and light from the sun begin to melt and then vaporize the comet; small jets of gas and dust eject off the comet, and solar wind pushes it into a tail. The closer to the sun it gets, the greater the effect.
As it moves *away* from the sun, the tail precedes the comet, and the heat the comet receives dwindles; so does the amount of material being ejected, until finally it’s just a dark, nearly invisible lump of ice and rock.
A tail (often two tails -- one of gas, one of dust) becomes visible as a comet approaches the sun. One reason is that proximity to the sun causes vaporization, and solar radiation pressure pushes the loose material away from the sun; a further reason is that solar illumination makes it possible for us to see the tail or tails.