Read the following passage and then choose the best answer A, B, C or D.
Comets are bodies that move around in space. They are something likes stars or small planets that move around the sun. Comets are surrounded by gases and the sun makes those gases look very bright. Dust can get caught in the gas around the comet and make the comet look like it has a tails.
Halley's Comet is the most famous comet, but we can't see it very often. In fact, it can only be seen from the Earth when it moves close the sun. This means that this beautiful comet only comes into our sky every 77 years or so. The last time Halley's Comet was invisible from the Earth was in 1991. Did you see it?
Halley's Comet was named after the English astronomer Edmond Halley. An astronomer studies the star and planets in the solar system. Edmond Halley was born in London, England, in 1656. He studies astronomy at Oxford University. In 1676, he left the university to study the astronomy of the Southern Hemisphere. He wrote a brook about the arrangement of the stars in the sky and the movement of the planets. He made the first accurate map of the stars we see in the sky. He also observed the moon and studied how the Moon affects the ocean tides. He helped find a way to measure distances in space. This measurement was used by other scientists to learn about the size of our solar system and the distances of many star and planets from the Earth.
Halley especially liked to study comets. He read about comets and observed them in the sky. He learned about the way they moved around the Sun — each comet follows a different path around the Sun and travels at its own speed. The path and speed of a body as it moves in space is called its orbit. Halley calculated the orbits of comets that he read about or saw himself. He found the orbits for twenty-four comets.
Halley also noticed that the paths of a comet seen in 1531 and of a comet seen in 1607 were identical to the path of a comet he had observed in 1682. He concluded that these three comets were, in fact, the same comet. Halley predicted that the comet would come again in 1758, and it did! This comet was named “Halley’s Comet” and can be seen from Earth. The first reports of this comet in history were made in 240 B.C. by Chinese astronomers, so we know that it has been orbiting the Sun to more than 2,000 years. Halley’s Comet is not the only comet in our sky, but it is the only one that appears regularly and can be predicted. It is also one of the brightest comets, and people can see it without a telescope.
Like comets, the Earth also travels around the Sun. Sometimes the orbit of t Earth passes through the path of Hailey’s Comet. Like comets, the Earth also travels around the Sun. Sometimes the orbit of the Earth passes through the path of Hailey’s Comet. When this When this happens, dust left behind from the comet falls to Earth. The dust burns and makes brilliant lights like falling stars in the sky. You can see this happen every year in May and October. Astronomers predict that Hailey’s Comet will enter our sky again in 2061. Who do you think will see it?
Comets may look like they have a tail because ______
A. gases surround the comet
B. dust can get caught in the gas around the comet
C. the Sun is very bright
D. they appear like bright white stars in the sky
