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A comment on There Probably Have Been Aliens. Parent comment

Re:There Probably Have Been Aliens by Nadya on Monday January 23, 2017 @12:56PM (#13464168)
>Its also worth mentioning that FTL travel probably isn't in the cards and even if we consider exploratory advanced civilizations, they most likely would not get far by the time they hit their extinction event anyway.

Another possibility is that we've simply explored in the wrong directions.

    ___________________________________________
    |                               Us --> Exploring this direction
    |
    |     [Millions of lightyears of space between Us and Them]
    |
    |             Them
    |                 |                   
    |                 |                    
    |                 |
    |                 v
    |  Exploring this direction
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Re:There Probably Have Been Aliens by nickpsecurity on Monday January 23, 2017 @01:27PM (#13464499)
It happens to people in Walmarts. They're a lot smaller. Certainly could happen with races looking for each other in space with the timescale that energy takes to cross it. Another thing that popped in my mind are the nuclear submarines looking for each other while emitting almost no sound or energy. It's just a void with a tiny piece of data here or there that must be assembled into evidence of others' presence. This can happen even when they're fairly close to each other.
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Re:There Probably Have Been Aliens by marcosdumay on Monday January 23, 2017 @01:16PM (#13464386)
Our galaxy is pretty much bounded. If any race started spread a few millions of years ago, they should be exploring (and exploiting) the entire galaxy already.
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Re:There Probably Have Been Aliens by Nadya on Monday January 23, 2017 @01:29PM (#13464516)
Did you mean universe? Our galaxy is a spec of dust. Our local galaxy cluster is also just a spec of dust. For how large the universe is - even a supercluster is a spec of dust. The universe is mind boggingly massive.

The observable universe has an estimated diameter of 93 billion light-years. A few million years might be enough to explore nearby galaxies. For example, to explore just our Local Supercluster you would need approximately 65,000,000 years [0]. Travelling at the speed of light.

E: Virgo is further than Ursa Major. Updated 55,000,000-->65,000,000.

E2: I always refer people to this video in regards to aliens, space, and time. I forgot to in this post, so here it is now: https://www.youtube.com/watch?v=HPl10L40pBM

[0] https://upload.wikimedia.org/wikipedia/commons/e/e2/Local_su...

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