The Big Bang Flashcards
What is Olbers’ Paradox and its relevance to the Big Bang theory?
Olbers’ Paradox questions why the night sky is dark if the universe is infinite and eternal. The Big Bang theory addresses this by suggesting a finite universe.
What did Lemaître propose in 1927 about the universe?
Lemaître proposed that the universe began with a “cosmic egg” explosion, explaining the expansion that prevents gravitational collapse.
What did Hubble’s observations in 1929 reveal?
Hubble discovered the red shift in distant galaxies, indicating they are moving away, supporting the concept of an expanding universe.
What causes the red shift observed in light from galaxies?
The red shift is caused by the Doppler effect, where light shifts towards red as galaxies move away from us.
How are distances in space measured?
Methods include triangulation using Earth’s orbit, parallax for stars within our galaxy, luminosity of pulsating stars, and supernova explosions as distance markers.
What is the velocity-distance relationship in galaxies?
Distant galaxies recede faster than closer ones, supporting the idea that all galaxies originated from a single point.
How is the age of the universe estimated?
By using the ratio of distance to recession velocity, the universe’s age is estimated to be around 13.7 billion years.
What is the significance of background glow in supporting the Big Bang theory?
The background glow, or cosmic microwave background radiation, supports the Big Bang theory as it is consistent with radiation from an object at 2.73°K.
How does the Big Bang theory explain the universal blackbody radiation?
After the Big Bang, protons and electrons cooled to form neutral atoms, and the radiation from this era has cooled to 2.73°K as the universe expanded.
What chemical composition evidence supports the Big Bang theory?
The universe mainly consisted of hydrogen (H) and helium (He) with a predicted 10:1 ratio, matching observed ratios.
What did the Hubble Space Telescope discover in 1998 about the universe’s expansion?
It discovered that the expansion of the universe is accelerating.
What is dark energy?
Dark energy is a theoretical form of energy that explains the accelerating expansion of the universe, comprising about 70% of the universe’s composition.
What is dark matter and its significance?
Dark matter is an invisible mass that explains cosmological observations, making up about six times more mass than “normal” matter.
What is the composition of the universe in terms of dark energy, dark matter, and “normal” matter?
“Normal” matter and energy constitute about 4%, while dark energy and dark matter form the majority of the universe.
What occurred about 100,000 years after the Big Bang?
Formation of helium and hydrogen gas, with free electrons trapped around positively charged nuclei, and the universe lit only by the Big Bang’s afterglow.
