Via FutureLearn

Reblogged from Bettie's Books:
The Milky Way
The Milky Way © Kevin Key/Shutterstock, 2014

How many inhabitants are there in the ocean?

At the end of the video in the previous step, Jon suggested that there are roughly the same number of microbes in a 100 litre bathtub of surface water as there are stars in our galaxy.

According to calculations, the global ocean contains approximately 4.4 x 1028 living microbial cells. Find out more.

(For anyone not familiar with notation such as 1028, 4.4. x 1028 means 44000000000000000000000000000 living microbial cells, or forty-four octillion if you prefer!).

How do you think that compares with the numbers of stars in the observable universe (that is to say in the multitude of galaxies that can be detected from Earth)?

Try to find the most reliable internet source you can that states a figure for the number of stars in the observable Universe or, if you are really confident, work out how you could calculate or estimate that number.

If you use Twitter we would like you to tell us what you think the answer is by voting. If you don’t use Twitter you can still participate; please post your thoughts and votes in the comments section.

If you think there are more stars in the observable Universe than living microbial cells in the global ocean then Tweet or post using the hashtag #UoSmorestars.

If you think there are more living microbial cells in the global ocean than stars in the visible Universe then Tweet or post using the hashtag #UoSmoremicrobes.