… comets are basically made of ice? Other elements found in them may include carbon dioxide (CO2), methane (CH4), and ammonia (CH3). Scientists often say that comets are “dirty snowballs”.

… they appeared close to 4.6 billion years ago? This was around the same time that the first giant planets began to take shape.

… comets’ “tails” are made of gas and dust? When they move, it is common for them to leave a trail in the sky. This happens because of the heat from the sun, which makes part of the comet evaporate.

… there are comets that always “visit” Earth? Halley is the most well-known and can be seen with the naked eye every 75 or 76 years. Most of the time, its brightness is quite impressive. Our next chance to see it will be in 2061.

… comets are different from asteroids? People often confuse the two. To avoid making this mistake, just remember that comets are ice balls while asteroids are rocks, which look like the stones we see around here.

Sources: Aventuras na História, Exame, Guia dos Curiousos, Super Interessante, and Terra Educação

Questions

1) When will we be able to see Halley from Earth again?
a) In 2022
b) In 2071
c) In 2032
d) In 2061

2) Are you interested in observing the Universe? Explain your answer.

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