In other words, how much of what volume of what mix of microalgaes would be enough to terraform an earthlike planet in, say, 100 years?

  • $\begingroup$ You will need to rephraise the question...terraforming a planet is to make it earth like. Why terraform an already earth like planet. Define the planet that needs terraforming. What type of atmosphere does it currently have? I assume earthlike means 70% water? How big is it? $\endgroup$
    – Twelfth
    Mar 25, 2016 at 6:16
  • $\begingroup$ As Twelth indicates, there are many information missing. Many the type of planet you already have, its environment, etc. I'd recommend reading the tour and some relevant sections of the {help] to get more familiar with the site. $\endgroup$ Mar 25, 2016 at 11:39

1 Answer 1


It couldn't be done in a 100 years. As science currently understands it, Cyanobacteria or blue-green algae became the first microbes to produce oxygen by photosynthesis, perhaps as long ago as 3.5 billion years ago and certainly by 2.7 billion years ago. However, there was long time – hundreds of millions of years – before Earth’s atmosphere first gained significant amounts oxygen, some 2.4 billion to 2.3 billion years ago. It took another one billion years for oxygen levels to rise high enough to enable the evolution of animals.


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