I imagine it like looking at a a forest, you see the first couple trees very clear, and the farther you look into the forest you see less and less trees, because the view is blocked? So how can we see stars so far deep into space? Wouldn’t the stars block each others view?
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Simply put, the objects infront, are so massive that light tends to follow the curve of space around that object.
This affect is called Gravitational Lensing.
There’s two effects going on.
First, one space is just…really…really empty. Like if the sun was the size of a single grain of sand the nearest star would be about *20 miles* away. With that density, the only limiting factor in how far we can see is the speed of light and the age of the universe. i.e. only light emitted 13.5 billion years ago can even reach us.
Second, there is something called gravitational lensing. Where a big object will bend light and allow us to see things behind them.
If they were as dense as a forest, sure, but they aren’t.
Take a look at this picutre:
[http://darksitefinder.com/wp-content/uploads/2016/02/IMGP8189-copy.jpg](http://darksitefinder.com/wp-content/uploads/2016/02/IMGP8189-copy.jpg)
That kind of cool looking stripe running down diagonally? That’s the galaxy. The whole galaxy. And it’s basically transclucent. That’s how not-dense the galaxy is, that you can look through the whole thing *sideways* and still see the other side.
All of the viewpoints that end on stars you are already seeing: those are the stars in the picture. All that dark stuff? Empty space. Nothing to see there without advanced telescopes and then you’re seeing extremely distant galaxies which are huge.
Wow, I’m high and have gone down a rabbit hole on this one.
Currently tripping trying to work out:
– we can only see back as far as time itself, 13.8 billion years, which means we can see out as far as 13.8b light years
– since that time, it’s estimated that space has expanded to 45b light years
So when we look back as far as possible, what are we seeing? As space stretches in all directions, wouldn’t it take light emitted 13.8b years ago longer than 13.8b years to get to us, as now there’s more space to get to us?
Edit: I’m reading https://www.quora.com/How-is-it-possible-to-see-so-far-into-space
This is called Olbers Paradox. If space is infinite then eventually each point in the sky would have a star behind it and the sky would be very bright. The resolution is that the universe has only been around for 13.x billion years and stars further than a certain distance haven’t had time for the light from them to get to us yet. In the areas that are close enough that light has had time to get to us, stars are pretty sparse and we see a lot of black sky.
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