Notes 5 Exam Flashcards
- The unit of distance called the parsec is equal to how many light years?
3.26156 light years
A parsec is equal how many kilometers?
30.857 x 10^12
A parsec is equal to how many Astronomical Units?
206.26 x 10^3 astronomical units
How many Astronomical Units is Earth from the Sun?
1
it is the distance between the earth and sun
How big is the Sloan Great Wall?
400+ mega parsecs long
How does the size of the Sloan Great Wall compare to a cluster of galaxies?
Virgo cluster is about 2.2 Mpc
Approximately, how many galaxies are gravitationally bound in the Local Group of galaxies?
1300-2000 members
Where in the universe is the Milky Way located?
-
What is Olber’s paradox?
The paradox is that a static, infinitely old universe with an infinite number of stars distributed in an infinitely large space would be bright rather than dark.
How did Hubble’s Law resolve Olber’s paradox?
HUBBLE’S LAW DEMONSTRATES THAT THE UNIVERSE IS NOT STATIC. THE UNIVERSE IS DYNAMIC. IT CHANGES IN TIME.
What observations suggest that the universe is expanding?
The observation that galaxies are moving away from each other is interpreted as the expansion of space.
What is Hubble’s constant?
H_o is Hubble’s constant
The measurement of the cosmic background radiation describes a universe with which properties (/implies what about our universe)?
The universe is homogeneous and isotropic
What do the observations of Type I supernovae suggest regarding the expansion of the universe?
Studies of Type Ia supernovae demonstrate that the universe’s expansion (Hubble law) isn’t just a simple expansion at a constant rate. These supernovae imply that the acceleration rate is increasing in time!
Is the matter identified in the periodic table of elements a form of dark matter?
no
What is the relative abundance of different kinds of energy in the universe in the Big Bang cosmological model?
It contains 4.6% ordinary matter, about 23% dark matter and 72% dark energy
How old are the dimensions of space and time?
about 13.7 billion years ago
Does science have a successful model to describe the universe during the Planck era?
No
Do hydrogen nuclei form before or after the first second of the evolution of the cosmos?
before the first second
during one millisecond
Did fusion reactions in the early universe stop because the temperature of the universe was too great or too low?
too low
Did light energy dominate the dynamics of the evolution of the universe before or after matter dominated the dynamics of the universe?
after
What is the Sloan Great Wall?
the largest known structure in the universe
Does the universe contain more dark matter or more ordinary matter (atomic)?
more dark matter
What is the Planck time?
It is the time required for light to travel, in a vacuum, a distance of 1 Planck length
How have the forces of nature changed over time?
During the Planck time all four forces of nature are unified. At the end of the Planck epoch, gravity breaks from the electronuclear force (electromagnetism, weak force and strong force combined) and Grand Unification models describe the evolution of the universe.
