It is theoretically possible to see dinosaurs
It is theoretically possible to see yourself being born, dinosaurs walking around 65 million years ago, the pyramids being built, Hitler rising to power, or even the Earth being formed. Since the farther away you observe Earth, the farther back in time you are looking, you could very well theoretically see into Earth's past if you had a large enough telescope. For example, if an alien species 65 million light years away had such a telescope and were observing Earth right now, they wouldn't be seeing us (the year 2016), as it would have taken light 65 million years to reach their telescope, thus they would literally be seeing dinosaurs walking around. We are always looking into the past, even if you are looking at someone right in front of you technically speaking you are observing them in the past. When we look up at the moon you are actually seeing the moon 2.5 seconds ago. This logic holds true for observers viewing the Earth as well, so if you could somehow teleport to a planet 25 light years away and look back at Earth you would see the world in the year 1991 and you could even see yourself come into existence. Although this is all theoretically possible there are a few hiccups, for one you would need a GIANT ASS telescope. To put it in perspective how big, to see 25 light years away with a telescope to the ground-level on a planet you would need a telescope 100,000,000 km wide. Sounds crazy, but we already have telescopes on Earth in the process of being built that utilize the diameter of the Earth by staging telescopes in specific locations all around the globe to act as one. If we can make telescopes 12,800 km wide with present day technology (that's the diameter of the Earth) then advanced human civilizations should be able to amplify this by exponential magnitudes utilizing telescopic probes in space that sync up to create telescopes far greater and more powerful than we can even imagine. Another issue is we can't just teleport to a planet that's 65 million light years away to look back at Earth and see the dinosaurs, because even travelling at light speed it would take us 65 million years to get to such a planet. However because of Einstein's general relativity which allows spacetime to be bent and maneuvered, it would also make it feasible for advanced human civilizations to warp spacetime in a way that they could travel great distances not by moving themselves there, but by contracting and distorting the spacetime between said distance.
Props to you if you read all that! I just think this fact of nature is one of the coolest things in our universe, the notion that one day it may be possible to quite literally glimpse into our past is unbelievable. The more and more we discover about the universe, the more we realize that even our wildest dreams are a reality.
17 Comments • Newest first
@greatbolshy: ik your joking, but earth is actually almost 2,017 years old.
As I was reading through that I was wondering when you were gonna tackle the pesky issue of traveling a distance in less time than it would take light to travel there
lol ya ok. the earth is 7000 years old so how do u expect people to see earth 65 million years ago
Interesting topic, and I've thought of this many times. In addition to the ISS, GPS satellites have to adjust for the time dilation as well. Another interesting thing about relativity is that the higher in elevation you live on Earth relative to someone else, the further into the future you'll travel through time compared to them (albeit by a fraction of a microsecond) since you have a greater circumference to navigate for every rotation of the Earth, thus are traveling at a faster speed. I've always been a proponent of the split timeline theory, since if you think about it in four-dimensional terms, two things moving at different speeds will never be at the same point on the W-axis, and now that we have fiber Internet speed, I think it's hypothetically possible that if you sent information from one computer at a high altitude down to one at a lower altitude at nearly the speed of light, fast enough to break the time dilation, the information could get sent backward through time, thereby altering the past very slightly via the so called "butterfly effect", thereby splitting the timeline. It makes me wonder if high-powered telescopes (such as the Hubble) would pick up different things depending on how fast they're traveling.
@fradddd: Nice to see you too man! I hope all is well
Yes, you can. THEORETICALLY.
Also, nice to see you.
@upcomingnerd: Haha didn't mean to come off that way bro, and I forgot about that thread! I haven't checked it since I made it, gonna go read the comments in it now
@trueatheist: That's why I said 'though', in my second paragraph. Which made my first paragraph wrong. lol Almost as if you read my first paragraph and got into a huff to prove me wrong. While I realized my mistake as I was working it out while writing.
Before you log off, be sure to post in the fitness thread as that's one I enjoy discussing on.
I've heard of this. Another problem arises with the possibility of some type of effect, for example a black hole even, that could disperse the light, making it impossible to actually view it as it was. Light isn't immutable. Otherwise, it's an interesting concept, since you can say that technically and theoretically you see into the past by the nature of the relationship between eyesight and light. Very exciting stuff.
@upcomingnerd: This is what you're not understanding. If a star 65 million light years away were to blow up right now, we would not see it right now. We would see it 65 million years in the future. 1 light year = How far light can travel in 1 year. Therefore if there is an explosion 65 million light years away how would you see it instantly? It would take a long time for the light from that explosion to reach our eyes. When we look up at the stars most of those stars are millions of light years away, some may not even exist right now. This is a very well understood concept in physics that Albert Einstein famously proved over 100 years ago.
There are copious amounts of tests we have done which prove beyond a doubt this to be the case,
http://en.wikipedia.org/wiki/Tests_of_general_relativity
You can read about some of them here and everything on that wiki page is sourced from scientific peer reviewed papers that you can go directly to at the bottom of the page.
If you can find a single piece of evidence which disapproves Einstein's general relativity then I'd recommend calling the media as you would become an instant billionaire for disproving the work of tens of thousands of scientists over the last 100 years.
@trueatheist: No time for that atm but I see what you're saying now. But I don't think that, the further you go away from earth at this point in time that you'd see back before this present time. You may see the time which is now and after but never before.
Though if I looked out the window right now and the moon was seen but in reality it had already blown up in that 2.5 second window then 2.5 seconds or 65 million lightyears really is no different.
A conundrum for sure but a useless one to me. We, certainly not in our life times are ever going to be that distance away or have the means to test such a theory. So it will stay a fantasy and a waste of time. Though as you said, advanced human civs. Which will probably never happen the way the earth is going, we'll (humans) be lucky to make it another thousand years.
@upcomingnerd: I'd recommend reading up on general relativity. When you look at the moon you are looking at the moon 2.5 seconds ago, this is a fact. Computers on the international space station need to be adjusted and time dilation taken into account for these reasons.
Let me just clarify something.. Are you disputing the fact that it takes light time to travel somewhere..?
@trueatheist: Well that math has been proven. When you look back into the past with that math, let me know.
@upcomingnerd: It's really not fantasy, it's physics and math. The same math that allows you to type that on your computer right now. They're not making up anything lol.. These are equations that have been around for decades.
Sounds like fantasy to me. Bunch of overpaid scientist with nothing to do but make up nonsense when they can't even solve issues we have here right on earth.
Read everything and was expecting a troll post at first but now I'm impressed.
Everyone & everything is about 10 - 100 milliseconds in the future, except your brain.