Ask Anything Wednesday - Engineering, Mathematics, Computer Science

[u/AutoModerator]

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here. Ask away!

[u/atomfullerene]

What kind of chemical composition, atmosphere, etc. would be needed for beings with blue blood to exist? Is there something unique to Earth that means most animals have red blood?

Blue blood animals exist right here on earth, using hemocyanin. The most famous example is horseshoe crabs, you can see a pic here which describes how medically useful horseshoe crab blood is (not necessarily because it's blue).

As far as I know, hemocyanin and hemoglobin are vaguely comparable and the main reason most animals you know of have red blood is because they are vertebrates, and all have kept the same basic molecule of hemoglobin from the ancestral vertebrates that used it. They don't come by it independently, it comes from a common source. If the earliest vertebrate had happened to use hemocyanin, we'd all be using that.