Question

At present, cosmologists expect the universe to _____. gradually stop its expansion and then begin to shrink in size gradually stop its expansion and then remain at a constant size continue to expand and heat up continue to expand and cool

Answer 1

The answer is to expand and cool forever.

Answer 2

Answer:

The correct answer is option D, continue to expand and cool

Explanation:

The concept of expanding universe was first time discovered by Einstein's theory . The solutions obtained through his relativity theory has red shifting of light when they come from distant objects travelling all through the expanding universe. Further in 1929, it was proved by Edwin Hubble that universe is expanding when he plotted the curve between the red shift against the relative distance.  

Form this it was further linked that  due to expansion of universe there can be effect of red shift in the spectrum of the light as the wavelength would have become longer than earlier  which would lead to decrease in temperature associated with spectrum and thus the universe keep on cooling continuously as it expands continuously.