Exam 17: Modern Cosmology and the Origin of Structure

In some particle physics theories,the universe must have more than three spatial dimensions,but we experience only three.Why would we not see the other spatial dimensions?

Observations of Type Ia supernovae in distant galaxies confirm that the expansion of the universe is decreasing over time.

The figure below shows scale factor R_U as a function of time over the age of the universe.Ignoring the presence of dark energy,which curve would represent an implausible open universe?

Our current ideas on galaxy formation suggest that the visible parts of galaxies:

If $\varOmega$ _matter = 0.5 today and there were no dark energy,the universe would:

According to superstring theory,how are different varieties of elementary particles similar? How do they differ?

What is the fundamental difference between the two basic types of dark matter? List an example of each type.

By the time the universe was 5 minutes old,approximately 24 percent of the normal matter in it had been turned into:

What can simultaneously solve both the flatness and horizon problems in cosmology?

Current numerical models suggest that most of the universe is composed of hot dark matter.

Examine the figure below.String theory requires six spatial dimensions beyond the familiar three.Where might the extra dimensions required by string theory be?

What does the large-scale structure of the universe look most like?

How do astronomers explain the formation of elliptical galaxies?

Directly after the Big Bang,the universe was filled with a variety of charged particles,antiparticles,and photons.

In a closed (spherical)universe,the sum of the angles in a triangle is:

Why can't dark matter halos collapse to be the same size as the visible parts of galaxies?

At what stage in the universe's history do we think the asymmetry between matter and antimatter was created?

Is Einstein's "biggest blunder" still considered a mistake?

Examine the figure below and then describe how elliptical galaxies form.

Is the theory behind Type IV multiverses testable?