Questions for “Huge arc of galaxies is surprising and puzzling cosmologists”

Observations of thousands of galaxies taken by the Sloan Digital Sky Survey system (pictured) helped reveal what seems to be a giant arc of galaxies. That arc is more than 3 billion light-years long.

Patrick Gaulme/Sloan Digital Sky Survey (CC BY 4.0)

To accompany “Huge arc of galaxies is surprising and puzzling cosmologists


Before Reading:

1.  What is a galaxy? Name a particularly well-known example. Name as many members of that galaxy as you can.

During Reading:

1.  How big is the newfound arc?

2.  Describe the “standard model” of the cosmos. Why would the new arc seem to challenge that model, according to the story?

3.  How did Alexia Lopez and her colleagues find the Great Arc?

4.  What is the Sloan Digital Sky Survey?

5.  On what aspects of the survey did the scientists focus, and how far away are those celestial objects? What is responsible for the particular light signature of those celestial objects?

6.  Why does Subir Sarkar caution that Great Arc might not be real?

7.  Why does Alexia Lopez argue that the Great Arc alone is not what challenges the standard model of the cosmos?

After Reading:

1.  If the Great Arc and other big structures are real, how might these apparent violations of the standard model have developed? (Hint: What is the Big Bang and how did it set up the early universe? Also, consider what basic forces are at work controlling the movements of things in the universe.)