PV Gap

Oscar Said:

We discovered .. "light from some of the earliest stars to form in the Universe." How is this possible?

We Answered:

ok, i'll answer q2 first. our solar system never was 13 billion light years away, it was always here, that object 13 billion light years away, used to be closer to us but since then the space has expanded pushing us apart when that object first gave off light our solar system didn't even exist and our galaxy would have been considerably different. it also would have been much closer to that object.

as space expanded though the light got redshifted, likely all the way into the ifnra red, or at least pretty close.

you are starting off with an incorrect principle, namely that we were once right next to this object, and we were, about 600 million years before it existed and something like 9 billion years before we did.

that light has been traveling since 13 billion years ago, if we look any direction we could see 13 billion years back, in fact we can even see further than that to a time shortly after the big bang.

so that would mean that our observable universe is about 26-28 billion light years across. but that is only what we can observe, by the time we see that far away, those distant things have already moved eve further away, so the universe would probably be closer to double that amount or maybe even more since the universe seems to be accelerating in its growth.

i don't actually know if i answered your question yet.

the light was emitted by the object long before the earth existed, but our galaxy was still quite a ways away from that object when it emitted the light we see now. in that time period we have moved away from it and now that light has caught up with us. know what i mean?

13 billion years is quite old, but the big bang is even older maybe even a billion years older, everythign had been expanding by quite an amount by the time that object came into being.

ok now as for gravitational lensing. light travels in a straight line, but space isn't straight, it is curved by mass, so as light travels near some mass it follows its straight line, that is now curved, due to the mass. so the light seems to bend. of course lenses bend light into a focus to enlarge an image, a gravitational lens does a similar thing, but not as neatly, it still does enable us to see objects even further away than we can normally see.