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santiagobasultotoday at 6:42 AM1 replyview on HN

Some time ago I had the following shower thought: "the Speed of Light is pretty slow"

How i got there:

The closest major galaxy to the Milky Way is Andromeda, and is 2.5 million! light-years away. And this is the CLOSEST galaxy, the universe is extremely big.

Of course that as you get closer to C, the traveling object will experience time dilation (relative to observer), so the time passed will be less. At 99.999% C, the traveler would take ~11,000 years to arrive to Andromeda.

So again, even at 99.999% C, 11K years seems like a LONG time to reach even the closest galaxy.

My reasoning was: the speed of light is pretty damn slow.

But then I realized: no, it's not the speed of light that is slow, is my frame of reference.

For us humans, 11,000 years seems like A LONG time, but for the universe is not that long.

The universe's age is estimated to be 13.8 billion years. 11,000 years is 0.0000007971 of the age of the universe.

An average human lives 70 years, 0.0000007971 of that lifespan is approximately ~0.4 hours, or 29 minutes, so it's not that bad.

So yeah, frame of reference matters.


Replies

atlimartoday at 7:23 AM

> At 99.999% C, the traveler would take ~11,000 years

if we add more 9s, is it possible to reduce that number to within a human lifespan?

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