Author Question: Process of Science: Given that Einstein's equations naturally showed the possibility of an ... (Read 20 times)

TFauchery · **on:** Jul 27, 2018

Process of Science: Given that Einstein's equations naturally showed the possibility of an accelerating Universe, why have astronomers only recently found strong evidence for dark energy?

What will be an ideal response?

Question 2

Elements heavier than hydrogen and helium constitute about ________ of the mass of the interstellar medium.

A) 0.002
B) 2
C) 70
D) 98

medine · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

The difference between a coasting and accelerating expansion is only apparent at very large lookback times. It therefore requires careful observations of white dwarf supernovae in distant galaxies. This only became possible a little over a decade ago. Similarly, we have only recently gained the instrumentation possible to study the tiny fluctuations in the cosmic microwave background that also point to a flat Universe that is indicative of dark energy.

Answer to Question 2

B