Question: Is it true that if we travelled in time (either into the future or the past) we would bring some bacteria that doesn't exist yet (past) or has died out (future) to the time we travelled to therefore causing a lot of the population to die out or get affected because they are not used to it however we would not be harmed?

Jordan Kirby answered on 6 Mar 2019: last edited 6 Mar 2019 6:58 am

Hi Chase,

Really cool question (i love hypothetical microbe questions like this!)
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The best way to look at this question would be to use what happened when the Europeans first traveled to America for the first time (Not quite as snazzy as time travel but the model is exactly the same). The Europeans brought with them a multitude of “Old world diseases”, the big 5 being;
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Smallpox (Virus)
Cholera (Bacteria)
Bubonic plaque (Bacteria)
Tuberculosis (Bacteria)
Measles (Virus)
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which completely decimated the population of the New world (America) , simply because these diseases didn’t exist there. The diseases brought across killed 90% of their population and the explorers who brought them were relatively unaffected (since they came from cities where they were exposed constantly to such diseases).
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It is very likely if you did travel into the past or future with a bad case of the flu or a bacterial lung infection, then like the America example we just talked about you would likely infect the population who are susceptible to this disease… although in the far future i’m sure they would have treatments available and in the past you are likely yourself to catch something way worse than anything you could bring back (Im looking at you smallpox!).
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So moral of this story is if you wanna time travel go forwards not backwards! (Also bringing new diseases into unprepared and susceptible populations will cause a lot of infections!)
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I Hope this answered your question, if not lemme know in the comments!