Hi space.com community!
I just solved nice quizz about black holes, with 8/9 accuracy, and I want to give you the link so that you can check your own knowledge:
The article informs us that new black hole has been found, some 5 thousand ly from Earth, but what makes it interesting is that this is the first case of an isolated black hole discovery. Usually, black holes are detected as member of a binary system or, in other words, as the companion of the neutron star. Estimates say that there is around 100 million stellar black holes in the Milky Way which means that one day when we become able to make Dyson sphere there will be plenty of SBH to use as an energy source just in our galaxy. Woohoo!
The quizz is below the article.
I have correctly answered all questions except 4th: 4) When stars die, they become black holes if they have masses of at least - a) half the mass of the Sun (I immediately discarded this answer), b) three times the mass of the Sun or c) twice the mass of the Sun. I couldn`t decide between b) and c) because I know that Chandrasekhar limit is 1.4 solar masses. Therefore, I have chosen answer c) or "twice", as closer to the Chandrasekhar limit. Moreover, there are black holes having two solar masses. It was wrong. The correct answer is b) or three times the mass of the Sun. I checked it and learned that there is another limit called the Tolman–Oppenheimer–Volkoff limit which applies to the stars, while Chandrasekhar limit applies to the white dwarf star. Anyway, I am pleased with 8/9 which is solid 88.9%.
Second thing I want`t to clear is the comment I received from an acquaintance. I said that NASA Parker probe is exploring the Sun as we speak. He asked how is that possible due to the high temperatures? I replied that probe is checking outer layer not the core and that the engineers certainly used special materials and some internal cooling system.
This is the link about mission overview and technical specifications:
parkersolarprobe.jhuapl.edu
Parker probe will get as close as aproxx. 6 million kilometers near the Sun (periphelion). That is Sun`s atmosphere not the Sun itself. Sun itself has 15 millions of degrees Celsius in the core and 5500 degrees at it surface. In order to sustain the atmospheric temperature of 1400 degrees Celsius, it has 11 cm thick carbon composite shield. Probe will travel around the Sun at the speed of 430.000 miles per hour or 700.000 kilometers per hour. I didn`t find data about internal cooling system which NASA obviously keeps as a secret but I guess that there must be somekind of a cooling device containing liquid Helium or equivalent.
I just solved nice quizz about black holes, with 8/9 accuracy, and I want to give you the link so that you can check your own knowledge:
The article informs us that new black hole has been found, some 5 thousand ly from Earth, but what makes it interesting is that this is the first case of an isolated black hole discovery. Usually, black holes are detected as member of a binary system or, in other words, as the companion of the neutron star. Estimates say that there is around 100 million stellar black holes in the Milky Way which means that one day when we become able to make Dyson sphere there will be plenty of SBH to use as an energy source just in our galaxy. Woohoo!
The quizz is below the article.
I have correctly answered all questions except 4th: 4) When stars die, they become black holes if they have masses of at least - a) half the mass of the Sun (I immediately discarded this answer), b) three times the mass of the Sun or c) twice the mass of the Sun. I couldn`t decide between b) and c) because I know that Chandrasekhar limit is 1.4 solar masses. Therefore, I have chosen answer c) or "twice", as closer to the Chandrasekhar limit. Moreover, there are black holes having two solar masses. It was wrong. The correct answer is b) or three times the mass of the Sun. I checked it and learned that there is another limit called the Tolman–Oppenheimer–Volkoff limit which applies to the stars, while Chandrasekhar limit applies to the white dwarf star. Anyway, I am pleased with 8/9 which is solid 88.9%.
Second thing I want`t to clear is the comment I received from an acquaintance. I said that NASA Parker probe is exploring the Sun as we speak. He asked how is that possible due to the high temperatures? I replied that probe is checking outer layer not the core and that the engineers certainly used special materials and some internal cooling system.
This is the link about mission overview and technical specifications:
Parker Solar Probe: The Mission
Parker Solar Probe will swoop to within 4 million miles of the Sun's surface, facing heat and radiation like no spacecraft before it. Launched on Aug. 12, 2018, Parker Solar Probe will provide new data on solar activity and make critical contributions to our ability to forecast major...
Parker probe will get as close as aproxx. 6 million kilometers near the Sun (periphelion). That is Sun`s atmosphere not the Sun itself. Sun itself has 15 millions of degrees Celsius in the core and 5500 degrees at it surface. In order to sustain the atmospheric temperature of 1400 degrees Celsius, it has 11 cm thick carbon composite shield. Probe will travel around the Sun at the speed of 430.000 miles per hour or 700.000 kilometers per hour. I didn`t find data about internal cooling system which NASA obviously keeps as a secret but I guess that there must be somekind of a cooling device containing liquid Helium or equivalent.
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