At what cosmic time was/is star formation density at its peak?
-At present time.
-Within the first billion years after the Big Bang.
-At about few billion years after the Big Bang.
-About few billion years ago.
http://www.nature.com/nature/journal/v469/n7331/fig_tab/nature09717_F4.html
I am not certain you meant star formation density, however, here is indicates a maximum about 3billion years ago.
Qwerty, remember the honor code in Coursera.
To determine at what cosmic time star formation density was at its peak, we need to consider observations and studies of the history of star formation in the universe. Scientists have been able to estimate the rate of star formation by observing galaxies at different distances from us.
Based on current understanding, the peak of star formation density occurred within the first billion years after the Big Bang. During this period, the universe was relatively young and composed mainly of hydrogen and helium. As time progressed and galaxies formed, the rate of star formation gradually decreased.
Therefore, the correct answer is: Within the first billion years after the Big Bang.