386,000 per/sec.
You are right on. If you reverse the situation, a being on another planet could be pointing one of these at the earth and just now be seeing the time of Christ walking the earth or Moses, or even further back to the birth of Joan Rivers.
” ... other things, like gravity waves, travel a lot slower than the speed of light!”
Actually, gravity waves are today theorized to be associated to the propagation of massless elementary particles called gravitons. According to quantum field theory, all massless elementary particles, including the photon and graviton, propagate (in vacuum) at the same speed, about 3 times 10^8 meters per second. This is called the speed of light, although it is the (vacuum) propagation speed of any massless elementary particle, not just the photon. Through the wave-particle duality of quantum mechanics, this means that, in turn, the associated waves (electromagnetic waves in the case of the photon, and gravitational waves in the case of the graviton) also travel at the same speed, the speed of light.
(Although photons and gravitons are both massless and propagate at the same speed, there are important differences between them, the most significant being that photons are what are called spin-1 particles and gravitons are spin-2 particles, which turns out to ultimately provide the basis for why photons mediate electromagnetic interactions and gravitons mediate gravitational interactions.)
Except you don't know for sure were time began. So looking at the furthest object away isn't looking backwards in time. It's looking past the moment where time began back into the present.
Of course if this 'big bang" started at the furthest point in the universe that we can see, then it would be looking back in time, but it's not likely it did, and I've yet to read where in this universe these "scientists" think time, the epicenter of the big bang, began. THAT would be the furtherst back in time we could see. Anything past that point is looking towards the present the further out you go.
Darn, here I come screwing up years of theory that took bags and bags of weed smoking to come up with...
669,600,000 miles per hour. Not just a good idea, it’s the law.