Question

1. scientists have estimated the numbers of stars that have been formed since the universe began. the number of stars that are formed in each time period is called the star formation rate. the graph shows the results of these estimates. star formation rate sun forms present day 0 2000 4000 6000 8000 10000 12000 14000 age of the universe in millions of years (a). describe the trends in the results. 3 (b) describe what is meant by the term stellar nursery. 2

Explanation:

Part (a)

Step1: Analyze early period (0 - ~2000 million years)

From 0 to around 2000 million years (age of universe), the star formation rate increases rapidly. The graph shows a steep upward curve in this interval.

Step2: Analyze middle period (~2000 - 6000 million years)

Between ~2000 and 6000 million years, the star formation rate continues to increase but maybe at a slightly different (less steep) rate until it reaches a peak around 6000 million years.

Step3: Analyze late period (after 6000 million years)

After 6000 million years (including when the Sun forms and up to present day), the star formation rate decreases. The graph shows a downward curve from the peak at 6000 million years to the present day. Also, note the Sun forms around 10000 million years, and the rate is still decreasing then.

A stellar nursery is a region in space (usually a nebula, like a molecular cloud) where the conditions (such as density of gas and dust, temperature, gravitational forces) are suitable for the formation of new stars. Matter (gas, dust) in these regions collapses under gravity, leading to the birth of stars.

Answer:

From the start of the universe (0 million years) to around 2000 million years, the star formation rate increases rapidly. Then, from ~2000 to 6000 million years, it continues to increase (more gradually) until reaching a peak at ~6000 million years. After 6000 million years (including when the Sun forms at ~10000 million years and up to present day), the star formation rate decreases.

Part (b)