سوال ۱۹ کنکور ارشد فیزیک ۱۴۰۱

PART C: Reading Comprehension — PASSAGE 1

Paragraph 1. Black holes are regions of space-time with huge amounts of gravity. Scientists originally thought that nothing could escape the boundaries of these massive objects, including light. The precise nature of black holes has been challenged ever since Albert Einstein’s general theory of relativity gave rise to the possibility of their existence. Among the most famous findings was English physicist Stephen Hawking’s prediction that some particles are actually emitted at the edge of a black hole.

Paragraph 2. Physicists have also explored the workings of vacuums. In the early 1970s, as Hawking was describing how light can escape a black hole’s gravitational pull, Canadian physicist William Unruh proposed that a photodetector accelerated fast enough could “see” light in a vacuum. New research from Dartmouth advances these theories by detailing a way to produce and detect light that was previously thought to be unobservable.

Paragraph 3. “In an everyday sense, the findings seem to surprisingly suggest the ability to produce light from the empty vacuum,” says Miles Blencowe, the Eleanor and A. Kelvin Smith Distinguished Professor in Physics and the study’s senior researcher. “We have, in essence, produced something from nothing; the thought of that is just very cool.”

Paragraph 4. In classical physics, the vacuum is thought of as the absence of matter, light, and energy. In quantum physics, the vacuum is not so empty, but filled with photons that fluctuate in and out of existence. However, such light is virtually impossible to measure.

19- The phrase “in essence” in paragraph 3 is similar in meaning to ...........