The Big Bang Theory
What is the Big Bang Theory
The universe formed during a single event in which all matter and energy suddenly expanded from an extremely small point called a singularity
Name 2 pieces of evidence supporting the Big Bang.
Any 2 of the following:
Measurable expansion of the universe (Red shift of galaxies)
Cosmic microwave background radiation
Relative abundance of hydrogen and helium
What powers a star?
The Hertzsprung Russel diagram is a scatter plot of the stars of the galaxies. What are the two properties plotted on the axes?
Temperature and luminosity (brightness)
What galaxy is our solar system located in?
The Milky Way Galaxy
About how long ago did the Big Bang occur?
13.7 billion years ago
Do the majority of stars and galaxies exhibit red shift or blue shift? Why?
In nucleosynthesis reaction that fuels our sun, 4 ____________ atoms combine to form 1 ___________ atom
hydrogen.......helium
What are the 4 main regions of the Hertzsprung-Russel diagram?
Main sequence
Giant
Supergiant
White Dwarf
Name the three types of galaxies
Spiral, elliptical, irregular
What were the first three elements to form after the Big Bang?
Hydrogen, Helium and Lithium
Explain why the relative abundance of hydrogen and helium in the universe is consistent with the Big Bang theory
Hydrogen and helium are the lightest elements. According to the Big Bang Theory, they were the first to form, and so they are the most abundant in the universe.
What property of a star determines whether it ends as a white dwarf, a neutron star or a black hole?
Its initial mass
Describe the general trend between temperature and luminosity for Main Sequence stars on the Hertzsprung-Russel diagram.
What type (shape) of galaxy is the Milky Way?
Spiral
Why do scientists study distant galaxies to gain a better understanding of the beginnings of the universe.
Light from distant galaxies must travel for millions or billions of years before we are able to detect it. So, when we look at images of galaxies far away, we are actually seeing what these galaxies looked like long ago.
Explain why cosmic microwave background radiation is consistent with the Big Bang Theory
All the light in the universe was released at once. Microwave background radiation is all about the same wavelength, implying that it was all generated during a single event.
What are sunspots? What causes them?
Sunspots are darker areas on the sun. They correspond to areas of lower temperatures.
A star's spectrum is marked by vertical black lines. What causes the black lines to appear on the spectrum?
Elements in the star absorb specific wavelengths of light. These correspond to the black lines on a star's spectrum.
Name two main features of a spiral galaxy
A central bulge and spiral arms.
About 380,000 years.
Define the Doppler Effect
A change in wave frequency as an object emitting a wave moves toward or away from an observer
What causes auroras (Northern and Southern lights)?
The electromagnetic radiation from coronal mass ejections is bent toward the poles by Earth's magnetic field.
White dwarfs have very high temperatures but very low luminosity (brightness). Why?
They are the collapsed cores of stars. So, they are very hot, but very small, so they have low luminosity (brightness).
Name two main differences between spiral and elliptical galaxies
They have different shapes
Elliptical galaxies are older and contain less gas and dust than spiral galaxies.