Listening Practice Question#13

Theme: Black Holes, Sound Waves in Space, Perseus Galaxy Cluster, Effects of Black Holes on Surrounding Gas, Future Research in Astrophysics

Questions

Scenario:

Voice By ondoku3.com

Questions:

1. What is the primary topic of the lecture?
   • A) The formation of black holes
   • B) The discovery of a new galaxy cluster
   • C) The effect of black holes on star formation
   • D) The recent discovery of sound waves from a black hole
2. According to the professor, why do black holes not produce sound in space naturally?
   • A) Because black holes absorb all sound
   • B) Because sound waves cannot escape the black hole’s gravity
   • C) Because space is a vacuum and doesn’t transmit sound waves
   • D) Because black holes are too far from Earth
3. How did scientists make the sound waves from the black hole audible to humans?
   • A) By recording the sound waves directly in space
   • B) By converting light waves into sound
   • C) By enhancing the volume of the waves
   • D) By increasing their frequency by 57 or 58 octaves
4. What do the ‘acoustic’ oscillations mentioned in the lecture refer to?
   • A) Light waves from the black hole
   • B) Magnetic fields around the black hole
   • C) Pressure waves interacting with the surrounding hot gas
   • D) Sound waves traveling through space
5. What is one possible implication of the sound waves produced by the black hole?
   • A) They could help in discovering new galaxies
   • B) They may influence the heating of the cluster’s gas and regulate star formation
   • C) They could provide new evidence of alien life
   • D) They might change the gravitational pull of the black hole
6. What does the professor suggest about future research on this topic?
   • A) It will focus on finding more black holes
   • B) It will concentrate on other forms of waves in space
   • C) It will attempt to make black holes visible
   • D) It will help understand the processes influenced by sound waves in the cluster’s gas

Transcripts

Professor: Today, we’re going to explore an intriguing discovery in astrophysics related to black holes. Recently, astronomers using NASA’s Chandra X-ray Observatory have managed to convert sound waves emanating from a supermassive black hole into audible sound. This discovery was made in the Perseus galaxy cluster, which is located about 240 million light-years away from Earth.

Now, the black hole itself doesn’t produce sound as we know it, because space is a vacuum and doesn’t transmit sound waves. Instead, what we’re talking about are pressure waves caused by the intense gravitational forces of the black hole, which then interact with the surrounding hot gas. These waves can be thought of as a form of ‘acoustic’ oscillations in the cluster’s gas.

To make these waves audible to the human ear, scientists had to increase their frequency by 57 or 58 octaves, as the original waves are far below the threshold of human hearing. This adjustment allows us to “hear” the black hole in a way, giving us an incredible new perspective on these cosmic phenomena.

Another interesting aspect of this discovery is the potential for studying how these sound waves can influence the heating of the cluster’s gas and the regulation of star formation. Since the black hole is so powerful, the waves it produces could have far-reaching effects on its environment. In the coming years, further research will help us understand these processes better.

Answers and Explanations

1. What is the primary topic of the lecture?
   Answer: D) The recent discovery of sound waves from a black hole
   Explanation: The primary topic of the lecture is about the recent discovery of sound waves emanating from a black hole. The professor begins the lecture by introducing this discovery and then goes into detail about how these sound waves were observed and interpreted.
2. According to the professor, why do black holes not produce sound in space naturally?
   Answer: C) Because space is a vacuum and doesn’t transmit sound waves
   Explanation: The professor mentions that space is a vacuum, meaning there is no medium like air to transmit sound waves. Therefore, sound as we know it cannot naturally occur in space, including around black holes.
3. How did scientists make the sound waves from the black hole audible to humans?
   Answer: D) By increasing their frequency by 57 or 58 octaves
   Explanation: The lecture explains that scientists had to increase the frequency of the sound waves by 57 or 58 octaves to make them audible to the human ear. This adjustment was necessary because the original sound waves were far below the human hearing threshold.
4. What do the ‘acoustic’ oscillations mentioned in the lecture refer to?
   Answer: C) Pressure waves interacting with the surrounding hot gas
   Explanation: The ‘acoustic’ oscillations refer to pressure waves generated by the black hole’s intense gravitational forces. These waves interact with the hot gas surrounding the black hole, creating a form of sound-like waves in the cluster’s gas.
5. What is one possible implication of the sound waves produced by the black hole?
   Answer: B) They may influence the heating of the cluster’s gas and regulate star formation
   Explanation: The professor suggests that the sound waves might influence the heating of the gas in the galaxy cluster and possibly regulate star formation, indicating their far-reaching effects on the black hole’s environment.
6. What does the professor suggest about future research on this topic?
   Answer: D) It will help understand the processes influenced by sound waves in the cluster’s gas
   Explanation: The professor mentions that future research will focus on understanding the processes that these sound waves influence, particularly in relation to the heating of gas and the regulation of star formation in the galaxy cluster.

References

1. Fabian, A. C., Sanders, J. S., Allen, S. W., et al. (2003). A deep Chandra observation of the Perseus cluster: shocks, ripples, and conduction. Monthly Notices of the Royal Astronomical Society, 344(3), L43–L47.
2. Sanders, J. S., Fabian, A. C., Taylor, G. B. (2005). Detection of Waves in the Intracluster Medium of the Perseus Cluster. Monthly Notices of the Royal Astronomical Society, 356(4), 1022-1030.
3. NASA Chandra X-ray Observatory. Black Hole Sound Waves [Website].
   URL: https://chandra.harvard.edu/photo/2003/perseus/