I've been reading this thread since it started, and it's quite a good read.
I have a background in physics
(studied it at degree level) but I don't profess to be an expert.
I think we need a reality check here though.
I'm sure no one is doubting that the OP saw
'something' but the chances are that it's from a distant world are infinitesimally small.
The vast distances we're talking about here are unimaginable to us mere Earth dwellers, and I would go further to say that it would be prohibitively costly in energy terms for any
'conventional' being, flying in a physical craft.
(By conventional, I mean fleshy, organic beings in 'metal' type ships with mass)
Of course there might some kind of hitherto unknown quantum matter or an inter-dimensional transportation method that exists that exhibits no mass, and therefore, in theory could travel at velocities approaching the speed of light, but would we Earthlings even see this exotic 'matter'?
Would we even know if they were in our dimension?
I digress, lets do some maths.
Take our nearest star
(not the Sun) - Alpha Centauri A, which is approximately 4.22 light years away, that's about 5,879,000,000,000 or 5.879
million million miles away!
The speed of light is 186,000 miles per second, which is 669,600,000 miles per hour
(to put it in Earth bound context) - that's approx 669 and a half
million miles an hour!
Our own space shuttle
(admittedly low tech compared to our advanced alien friends) could reach 17,500 miles per hour in low Earth orbit, and so would take well over 38 thousand years to reach Alpha Centauri A.
But just think about the fuel and resources needed to power this trip.
Think about the gravity...indeed, for us, it would be necessary to attain a constant acceleration of one G for half the journey, and then for the latter half, a reverse acceleration of one G, so that our fragile, biological functions would not be compromised...and this is assuming that our 'ship' could attain these incredible speeds, with some kind of exotic power supply.
There would have to be a fully sustainable eco-system, which would have to support many hundreds of generations of people on this journey.
The older generation would need to teach and train the newer generations on all aspects of the journey, without errors, for thousands of years.
So if our advanced friends were to have the technology to travel at speeds even approaching 1/1000th the speed of light
(which is unbelievably fast) it would still take a thousand years to travel from Alpha Centauri A., and the resources needed would be unimaginably vast
(assuming alien resources naturally - which I'm sure are more 'efficient' than our own space food/fuel etc)
This is assuming of course that there is intelligent, advanced life on a planet orbiting Alpha Centauri A.
If we're talking further, then I'm afraid the numbers just don't add up...they're too fantastical.
I'm not opposed to the idea of alien life, but the inter-galactic distances which would need to be travelled, are utterly unattainable for any life form anywhere in the universe.
@Dave70D is right....it's a pair of trainers!!