Dark matter in galaxies and clusters of galaxies is purely ...

[saraeharris]

Dark matter in galaxies and clusters of galaxies is purely hypothetical because we have no way of detecting its presence.
 
  Indicate whether the statement is true or false

Question 2

Consider the following statement, and explain whether or not it is sensible: If you had a very fast spaceship, you could travel to the celestial sphere in about 100 years.
 
  What will be an ideal response?

[frankwu0507]

Answer to Question 1

FALSE

Answer to Question 2

This statement does not make sense because the celestial sphere is a concept and not a physical object.

[saraeharris]

Excellent

[bitingbit]

Gracias!