How can scientists test their ideas about the origin of the universe if they cant physically interact with or study it

Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? the cloud is extremely hot. the cloud is visible primarily because it reflects light from nearby stars. the cloud is cool and lies between you and a hot star. the cloud is cool and very dense, so that you cannot see any objects that lie behind it.

Current vs. forcewhat type of relationship does this graph show?

To find the mass defect for uranium-238 several calculations must be made. which is the calculation that should be made first? assume atomic number for uranium-238 is 92. a. 92(1.0073) x 92(1.0087) = b. 92(1.0073) x 146(1.0087) = c. 146(1.0073) x 238(1.0087) = d. 238(1.0073) x 238(1.0087) =