Black holes, Neutron star, White dwarf, Brown dwarf: General Knowledge USA Quiz.

By knowledgeterminal - December 15, 2018

Section one: USA map pointing (states and capital)



Section two: World map pointing (countries and capital)

Europe



Section three: USA historical events


1801–1805
The First Barbary War ( Tripolitanian War/ the Barbary Coast War) was the first of two Barbary Wars, in which the United States and Sweden fought against the four North African states Tripoli, Algiers, and Tunis and Sultanate of Morocco ("Barbary States"). Pirates from the Barbary States were seizing American merchant ships and holding the crews for ransom, demanding the U.S. pay tribute to the Barbary rulers. This led to the war which ended with peace treaty.




Section four: world historical events

1271
Kublai established the Yuan dynasty which ruled over present-day Mongolia, China, Korea as d the role of Emperor of China. Kublai was the fourth son of Tolui and a grandson of Genghis Khan., By 1279, the Mongol conquest of the Song dynasty was completed and Kublai became the first non-Han emperor to conquer all of China.




Section five: Black holes, Neutron star, White dwarf, Brown dwarf





1)       A Star shines due to fusion of hydrogen into helium in its core, releasing energy in the form of gamma rays which loose some energy and become photon when they reach the surface (after 100000 years)

2)       Stars are maintaining a balance between gravity trying to collapse them and their internal heat trying to swell them. Averaged sized star like the Sun lasts for 10 billion years and ends by expanding briefly and then blowing away its outer layers leaving behind the gravitationally compressed core. Under pressure and temperature Hydrogen fusion makes helium, helium fusion makes carbon. Lower-mass stars stop at carbon. (hydrogen less in 2 billion years)

3)       But more massive stars die (within 100 million years ) with a huge bang. If the star has more than about 8 times the Sun’s mass, it can create temperatures in its core in excess of 500 million degrees Celsius, and then carbon will fuse into neon, magnesium, and some sodium to oxygen to silicon (2-3 billion degrees) can fuse to iron. When iron fuses it actually sucks up energy instead of creating it which shrinking, compressing the core, heating it up even more. The gravity of the core is so strong that the outer parts crash down on the inner part very fast, the core collapses gravity becomes extremely intense



a.    Neutron star



i.      Death of (before collapse had a total of between 10 and 29 solar masses.) 1.4 and 2.8 times the Sun’s mass star. Explosion occurs and a ball is left behind composed almost entirely of neutrons.

ii.     Milliseconds ago it was fusing silicon into iron, but now it’s collapsed under its own immensely powerful gravity.

iii.    The collapse takes a fraction of a second, but a lot happens in that fraction of a second

iv.    If the core has a mass more than about 1.4 times the mass of the Sun electron degeneracy (No two electrons can occupy identical states, even under the pressure of a collapsing star) fails to stop the collapse

v.     Under these huge pressures Protons, electrons, and other subatomic particles merge to form neutrons

vi.    Neutrons resist being squeezed too tightly together (neutron degeneracy)  

vii.   If the core is less than about 2.8 times the Sun’s mass, the collapse stops generating a huge shock wave, which, along with a flood of energetic subatomic particles called neutrinos, blasts outwards, blowing up the star

viii.  Its mass would be more than Sun, with volume of sphere 20 km across

ix.    The first neutron star was detected in 1965

x.     Pulsars are neutron stars flashing (twin beams of energy away from the star) in brightness as they spin coupled with their incredibly strong magnetic fields




b.    White dwarf



i.      Death of star 1.4 times the mass of the Sun, it becomes a white dwarf which a very hot ball of super-compressed matter about the size of the Earth (composed of carbon and oxygen)

ii.     nearest known white dwarf is Sirius B, at 8.6 light years

iii.    White dwarfs are the final evolutionary state of stars whose mass is about 10 solar masses. ( 97% of stars in the Milky Way.)

iv.    A black dwarf is a hypothetical stellar residue of a white dwarf after it has cooled sufficiently that it does not emit heat or light. The time required for a white dwarf to become black dwarf is longer than the current age of the universe (13.8 billion years) so no black dwarfs exist in the universe now




c.     Black hole



i.      When mass is MORE than 2.8 times the Sun’s, the gravity of the core can actually overcome the tremendous resistance of the neutrons and continue its collapse.

ii.     There is literally nothing in the Universe that can stop the collapse.

iii.    A neutron star, have an escape velocity of 150,000 km/sec – that’s half the speed of light (compared to The Sun with an escape velocity of over 600 km/sec. )

iv.    It’s like an infinitely deep HOLE, and no light can come out, so it’s BLACK.

v.     That region of space, that surface around the black hole where the escape velocity is the speed of light, is called the EVENT HORIZON as any event that happens inside can’t be known

vi.    Black holes also come in different sizes. The kind I’ve been talking about has a minimum mass of about 3 times the Sun’s, and might get as high as a dozen or more times the Sun’s mass, if the parent star was big enough. We call these stellar-mass black holes. If it happens to gobble down more matter, it gets more massive, and the event horizon grows as well.

vii.   The black hole gets bigger. In the 1970s it was first proposed that black holes could form in the centers of galaxies, and  the first one was discovered, in the center of Milky Way whose mass is 4.3 million times the mass of the Sun


d.    Brown dwarf



i.      A planetary body having mass less than about 0.075 times the Sun’s mass, roughly 75 times the mass of Jupiter, it would fail to fuse hydrogen to helium but it would radiate its heat away.

ii.     Very low mass stars are red (the most common type of star in the Milky Way), which emit light in the infrared e.g. Proxima Centauri

Section six: quiz

QUESTIONS

1.       According to the UN,who is the most widely translated author in the world?
2.       Which philosopher is best known for his statement cogito ergo sum ( I think therefore I am?
3.       Philosophy comes from the Greek philosophia, meaning what?
4.       Metaphysics is the study of what?
5.       What is the pen name of Eric Arthur Blair?

ANSWERS

1. Agatha Christie
2. René Descartes
3. Love Of Wisdom
4. Existence
5. George Orwell

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