Урок №101 Summative assessment for the 4 th term Цели обучения
Reading Task 3. Read the text and match the headings to the paragraphs. One heading is extra
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Урок №101 Summative assessment for the 4 th term Цели обучения п
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Task 3. Read the text and match the headings to the paragraphs. One heading is extra. Black Holes Black holes are considered amongst the most mysterious objects in the universe. What are they and what can we learn from them? A black hole is a region of space where gravity is so strong that nothing can escape the region once it has been pulled into it. Ever. In space, the only objects that can form black holes are large stars ‒ stars many times larger than our own Sun. At the end of their lives, these stars collapse under their own weight and all their matter gets pressed into a tiny area. While the original star may have been millions of miles wide, the resulting black hole is just a few miles across. It is this huge amount of material squeezed into a small area that gives black holes their super-strong gravity. Black holes are invisible; remember, nothing can escape from a black hole, not even light! However, scientists are able to find them by studying their effects on the objects around them. When something gets too close, it is swallowed up by the black hole. The central point of a black hole is where gravity is strongest. Black holes have a reputation for sucking in everything around them ‒ a bit like a vacuum cleaner! But that’s not very accurate. Black holes are better compared to a waterfall: the nearer you get to the edge, the harder it is to resist being pulled over it. Stars and planets actually have to get very close to a black hole to be sucked in by its gravity. From a great distance, the gravity of a black hole is no different to the gravity of a star of the same mass. In other words, if the Sun were ever to become a black hole (which it couldn’t: only stars much larger than our Sun can end their lives as black holes), there would still be no danger of Earth falling into it. Why not? Because the black hole would have the same gravity as the Sun so if the Earth did not move any closer, the black hole’s gravity would not be strong enough to pull it in. Black holes are everywhere. Astronomers believe there are millions of black holes in the Milky Way Galaxy alone. But don’t worry. The nearest known black hole to Earth is 1.600 light years away ‒ far too distant to affect us. The gravity of black holes is so strong that scientists believe strange things happen near them. Albert Einstein proved that gravity affects time and space. For instance, if you approach a black hole, scientists think that time will seem to slow down. And at the centre of a black hole, they believe time stops altogether and the laws of physics no longer apply. No one knows how or why time could come to an end inside black holes. By studying black holes, scientists hope to one day discover new secrets about time, space and our universe! A Time travel ‒ fact or fiction? B What can we learn from black holes? C What does a black hole look like? D What is a black hole? E How common are black holes? F How do black holes form? G How do black holes affect things near them? жүктеу/скачать 51,48 Kb. Достарыңызбен бөлісу:
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