NOVA Black Hole Apocalypse Astronomy Practice Test

These questions are part of the practice quiz. Start practicing

• Pre-eminent astrophysicists in the 1930s-50s believed that black holes were actually real.
• Which method is used to infer the presence of black holes by their influence on surrounding matter?
• What observational evidence supports the existence of supermassive black holes at galaxy centers?
• The outward pressure that prevents a star from collapsing is produced by which process?
• What is a gravitational wave?
• What is the significance of the photon sphere radius in the Schwarzschild metric?
• What components contribute to emission from an active galactic nucleus?
• What is the photon ring in black hole imaging?
• How does time behave for an observer near a black hole compared with someone on Earth?
• What did the Event Horizon Telescope image of M87* demonstrate?
• What does spacetime curvature imply about motion near a black hole?
• What are relativistic jets, and what mechanism is hypothesized to power them?
• What is the typical emission mechanism for jets in radio galaxies?
• Which statement best describes Hawking radiation?
• Which element marks the beginning of fusion in stars?
• How much power did the collision emit relative to the visible universe?
• How do telescopes like the Event Horizon Telescope achieve the resolution needed to image a black hole shadow?
• In astrophysics, what does the spectral fingerprint allow scientists to determine?
• Rocket-mounted Geiger counters later discovered what kind of radiation in space?
• The gravitational-wave signal traveled to Earth from a distance of approximately how many light-years?
• Which structure around Cygnus X-1 is directly involved in feeding matter toward the black hole?
• Gravitational-wave templates are used to do what in detections of BH mergers?
• How does the mass of a black hole affect the size of its shadow as seen from Earth?
• What does the cosmic censorship conjecture assert in black hole physics?
• At what speed would a moving apple become free falling?
• Stars with masses greater than or equal to how many solar masses will collapse into a black hole?
• Why are black holes considered laboratories for fundamental physics?
• Matter closest to the black hole in Cygnus X-1 orbits at approximately what fraction of the speed of light?
• The collapse of a massive star creates what type of explosion?
• In a Schwarzschild (non-rotating) black hole, where is the photon sphere located?
• Quasars are named because they appear star-like but emit energy in which part of the spectrum?
• Kip Thorne's famous bet was with which physicist?
• Among the listed electromagnetic waves, which has the highest energy photons?
• Which statement best describes the relationship between 'quasi-stellar' appearance and energy output for quasars?
• What is the photon sphere around a black hole?
• In 1931, what did Karl Jansky discover?
• Why are black holes often detected via X-ray binaries?
• What was the first X-ray source found in the constellation Cygnus?
• What role do Sagittarius A* observations play in our understanding of black holes?
• Which statement best describes what a quasar is?
• What does the M-sigma relation describe in the context of supermassive black holes and their host galaxies?
• The statement 'The black hole collision emitted some light, but was too dim to be seen from Earth' is:
• According to Levin, what surrounds Cygnus X-1?
• What is the event horizon, and why is it considered the point of no return?
• Why did Sir Richard Wooley think that black holes were 'fanciful'?
• The waves detected came from the merger of what?
• According to Einstein's 1915 theory of general relativity, gravity...
• What observational milestone provided a direct image of a black hole shadow?
• Which example demonstrates the minuscule angle to be measured in parallax experiments?
• In what year did Einstein publish the general theory of relativity?
• According to Jana Levin, the waves from the merging black holes resemble which analogy?
• Who did Kip Thorne make a bet with?
• How do black holes grow their mass in galaxies?
• According to Levin, what did Einstein realize about gravity?
• Which statement about the black hole shadow is true?
• In spectroscopy, what does a 'fingerprint' refer to?
• According to Levin, pairs of orbiting stars locked together by gravity are called what?
• What did the first detection GW150914 by LIGO confirm about black holes?
• How do cosmic rays interact with matter near a black hole?
• A tidal disruption event occurs when a star is torn apart by tidal forces near a black hole, producing a luminous flare as debris accretes.
• What do the orbits of stars around Sgr A* reveal about the Milky Way’s central black hole?
• The mass unit used for the invisible partner in the estimate is which?
• According to N. Imara, the life of a star depends upon which property?
• According to Swartzchild, what appeared when a star's mass was concentrated into a single point?
• Why were quasars named 'quasi-stellar radio sources'?
• What is the photon ring around a black hole?
• Which statement best describes Schwarzschild's contribution?
• Levin states that gravitational waves squeeze and stretch which part of reality?
• Which methods are used to estimate a black hole's spin?
• The red and blue color change of moving stars is named what?
• What is the Eddington luminosity, and why is it important for accretion onto black holes?
• What is the consequence of spacetime curvature for the path of light and matter near a black hole?
• What is the role of numerical relativity in modeling black hole mergers?
• What is spaghettification, and what causes it near a black hole?
• From the perspective of an observer on a spaceship near a black hole, how long would it appear to take for a spacewalking astronaut to reach the event horizon?
• What is the significance of the 'test of no-hair theorem' in black hole physics?
• What was Karl Swartzchild the first to do?
• Which statement accurately describes how spin orientation affects the ISCO around a rotating black hole?
• In P. Natarajan's depiction, Cygnus X-1 is likened to what kind of creature that breathes and eats fire?
• Which feature of QPOs makes them useful for probing black hole properties.
• According to Levin, the number of black holes found in our galaxy is at least how many?
• How have gravitational waves provided evidence for black hole mergers?
• Cygnus X-1 is associated with which constellation?
• What does gravitational redshift imply for light escaping from a strong gravitational field near a black hole?
• For about 400 years, nearly all observations of the universe were in what form?
• How do measurements of stellar orbits around Sgr A* constrain the presence of alternative compact objects (like boson stars) versus a BH?
• What was Murdin's estimate of the mass of the invisible partner (in solar masses)?
• What is the term for the tidal stretching of an object as it falls into a black hole?
• According to E. Gilkman, stars are born in what kind of grouping?
• Which statement is true about energy extraction from rotating black holes?
• What are quasi-periodic oscillations (QPOs), and what can they tell us about black holes?
• X-rays from Cygnus X-1 are produced because particles collide and heat up to what scale?
• How do non-thermal high-energy emissions from accretion disks inform us about the physics of matter at extreme densities and speeds?
• What role do magnetic fields play in black hole accretion and jet physics?
• The speed of gravitational waves matches the speed of which quantity?
• Reid's ten-telescope solution has a diameter of the size of which object?
• What quantity is absolutely fundamental in astronomy?
• What does the shadow represent when viewing a black hole image?
• What did graduate student Jocelyn Bell Burnell discover in 1967?
• According to Levin, how can black holes be investigated?
• The discovery of radio emissions from the sky led to the development of which branch of astronomy?
• Which author is associated with the claim that the life of a star depends upon mass?
• In a Kerr black hole, there is an outer event horizon and an inner Cauchy horizon, whereas a Schwarzschild black hole has only one horizon.
• Which element is a "dead end" for massive stars?
• Which statement about gravity in general relativity is true?
• According to Levin, Newton's laws of motion work have become outdated and no longer used.
• What best describes the overall nature of black holes as indicated by Levin?
• Where is the ergosphere located relative to the event horizon, and what energy process does it enable?
• What does the acronym QUASi-stellAR radio sourceS stand for?
• Gravitational waves propagate at what speed?
• One of the most striking and enigmatic features of Cygnus X-1 is what?
• What does the term 'shadow' imply about light-bending around a black hole?
• What was Einstein's 'extremely simple' concept about the mass of objects?
• Which term completes the following sentence: Electromagnetic radiation includes waves of many different ____________?
• On what date did LIGO record the gravitational-wave signal?
• Levin's statement about Milky Way black holes implies which of the following?
• According to Levin, what are black holes?
• What does the no-hair theorem say about the exterior description of black holes?
• In the inner region near a black hole, how fast do the closest orbiting particles move relative to light speed?
• The material describes a lifecycle where hydrogen fusion is followed by an explosion and then a black hole. Which option best summarizes this described lifecycle?
• Which author described gravitational waves as squeezing and stretching the fabric of space?
• How does gravitational time dilation affect a clock falling toward a black hole as seen by a distant observer?
• What term describes the unique spectral pattern used to identify elements in stars?
• Which element do all stars start out fusing?
• Cygnus X-1's interaction with its companion star results in what mass-exchange process?
• A confirmed deviation from the no-hair theorem would most strongly suggest the presence of what?
• How does escape velocity relate to black holes?
• The star discovered by P. Murdin had a period of ________ days.
• What distinguishes a quiescent black hole from an active galactic nucleus (AGN)?
• Swartzchild discovered that any mass compressed into a small enough space creates what we today call...
• What is a black hole shadow, and how is it formed?
• What is the significance of the 'shadow diameter' of a black hole in testing GR?
• What is Cygnus X-1 doing to its companion star?
• What is the term for the bending of light caused by a black hole's strong gravity?
• How is Hawking radiation related to black hole mass?
• How does the shadow size relate to the black hole’s properties?
• According to Levin, for a long time, what was one of the greatest mysteries?
• What two kinds of space signals were identified by early radio astronomy and space-based detectors?
• Which observation tests the predictions of general relativity near a supermassive black hole?
• In a star, what balances the inward crush of gravity?
• What role does the ergosphere play in energy extraction from a rotating black hole?
• Which author is associated with describing Cygnus X-1 as a breathing, fire-eating demon?
• The unstoppable collapse of the remaining core of a massive star results in...
• How does gravitational lensing help us observe black holes?
• True or False: Our eyes perceive only a narrow part of the electromagnetic spectrum.
• The energy release of the event was described as 50 times the energy of what?
• Which statement about a black hole's event horizon is true?
• Which observational concept relies on observing from two different vantage points to determine distance?
• Which statement correctly distinguishes the event horizon from the apparent horizon in black hole spacetimes?
• The 5.6-day period mentioned refers to which kind of astronomical measurement?
• What spectral property reveals the chemical makeup of stars?
• How are stars distributed?
• Define the Schwarzschild radius and give its approximate expression in terms of mass.
• What provides two different vantage points to observe the parallax of a distant star such as Cygnus X-1?
• In Schwarzschild spacetime, the photon sphere is located at what radius relative to the Schwarzschild radius?
• What is a photon ring?
• What energy regime is notably strong in quasars relative to many stars?
• Which theory describes gravity as the curvature of spacetime?
• Which high-energy messengers can be produced by cosmic-ray interactions near black holes?
• If a star has 12 solar masses, what is its likely fate according to the mass threshold discussed?
• According to Levin, a black hole can do which trio of actions?
• Which statement best distinguishes a Schwarzschild black hole from a Kerr black hole in terms of horizon structure and rotational effects?
• How do accretion disks produce X-ray emission around black holes?
• Which process uses atoms to power stars?
• Why does Cygnus X-1 emit X-rays?
• How does spin orientation affect the ISCO around a rotating black hole?
• What is the inner horizon inside a Kerr black hole called?
• What is Hawking radiation, and how does it relate to black hole evaporation?
• What is the primary purpose of the Event Horizon Telescope?
• What evidence supports frame-dragging near rotating black holes?
• What term refers to the infinitely small point where space and time break down inside a black hole?
• What angular scale is needed to resolve a black hole shadow with Earth-based interferometry?
• What region around a rotating black hole enables energy extraction via frame dragging?
• At 6,000 light-years away, Cygnus X-1 corresponds to approximately how many solar masses?
• Who coined the term "black hole", based on an infamous Calcutta prison?
• Which scientist is associated with linking gravity to black holes in the material?
• Which statement best captures the 'quasi-stellar' aspect of quasars?
• What are the key phases in a gravitational wave signal from a binary black hole merger?