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Do you believe that time travel exists or will exist someday?
If it did, what would you try to change about the past?
I'm an astrophysicist. Here's a very easy explanation why:
Time travel is not possible. But teleportation is possible (based on our understanding of general relativity).
It's known as the grandfather paradox. Imagine you time travelled and went to the time when your grandfather was a little boy. Then you kill him. And then you come back to the present. If your grandfather is dead, your father was born. If he wasn't born, then you weren't born. Then who went to the past and killed him? No one. So he must be alive. But if he is alive, as no one went and changed the past, then your father was born and you were born. But you went to the past and killed your grandfather. This makes no sense. This is why time travel isn't possible.
But we can look into the past using telescopes good enough. The further the thing we're observing is away from us, the further we are looking into its past (light takes time to travel). This is why we use the term "light year". It's a unit of distance. 1 light year is the distance travelled by light in 1 year. The speed of light is approximately 3×10⁸ m/s. This is physically the fastest speed in the universe. Because light (and the other electromagnetic waves, who also have the same speed) has 0 mass and "infinite" surface area, which no other thing has. So it's basically what we call the "universal speed limit".
Also, google: moving spotlight theory.
You might be wondering what if we send a good enough telescope (I'm saying "good enough" because our present telescopes are not good enough to resolve such small things) far away from the earth and then look into the past. But no, the light from the past has already left. As it is the fastest, and it is not possible to travel at the speed of light or faster, you won't be able to overtake it. But if you could teleport the telescope to somewhere far enough without using any time, then it might be possible. For example, if you put the telescope 20 light years away, you will see the earth 20 years ago.
Time travel may not be possible, but teleportation is. I'm not going to go into quantum physics; it's for particle physicists. I'm an astrophysicist. I'll talk about wormholes. They are depicted quite often in science fiction. Also, teleportation in quantum physics might be boring for usual people because it involves things smaller than what our eyes can see. But the cool thing is, quantum teleportation has already been achieved.
I am talking about that theory. Two points on a paper. Then you fold them so that they're on top of each other. Then the pencil is inserted. After bending space-time, after the spaceship has went, the space returns to normal. Watch interstellar or event horizon (fun fact: event horizon is a real thing. It means the point of no return in a black hole where gravity is so strong that the thing needs to travel faster than the speed of light to escape, which is not possible) movies. They talk about this theory. We need gravity to make this. Gravity is not a thing in itself, it is an effect. The effect is a force exerted by anything that has mass. All matter — everything has mass (for this theory, assume light also has mass for simplicity). So we need a lot of matter to have that much gravity. A lot of matter. Probably more matter than we have in our solar system. Also, a wormhole is often compared with a black hole. But remember, they aren't similar nor opposites. The opposite of a black hole is a white hole (which remains theoretical). We have never observed a wormhole or a white hole, but according to our understanding of physics, they are possible. To "make" a wormhole we will also need negative energy. And negative mass. Negative energy (don't confuse it with negative charge) and negative mass are not possible. At least, they haven't been observed. Also, a big wormhole would collapse into a black hole before anything could travel through it. It needs to have a smaller mass than needed to make a wormhole. Which again, is smaller than what our eyes can see. But if there is so little mass, where will gravity come from? What will create it? Here we have another paradox. Also, there are other questions. Is it actually possible to travel faster than the speed of light, even if by teleportation? Some scientists do not agree. Only an event big enough to exert such a force is just after the big bang (Google big bang theory physics). It is assumed that strings of negative energy in the cosmic web after the big bang. But again, it's a hypothesis. But this means that we cannot create wormholes, but we can find them. This could also work. We could travel to the nearest wormhole by space (referring to the phrase "by road") and then use it to go to the further point (the other end of the tunnel). So the distance (in light years) between the two "openings of the tunnel" will be the amount of time in the past we will be able to see. And the time will start from the time the thing enters the wormhole. But it is unlikely that a wormhole is anywhere near us, so it would probably take too long for us to reach one and look into the past.
This is the magic of astrophysics. Everything is connected and we can keep going on and on. This is the science of finding answers to the biggest questions — are we alone (do aliens exist)? How big is the universe? Is time travel possible? Is teleportation possible? What are we made of? How were we made? How old is the universe? The past, present, future. Also, astrophysics helps us a lot in real life. For example, three of the most important technologies in your phone — camera, Bluetooth and WiFi were invented by astronomers (means the same as astrophysicists. But there are also people like astrochemists or astrobiologists. So using the term "astronomers" is better). Cameras for taking pictures of the sky and WiFi to detect primordial black holes — very small black holes (that's a story for later). Bluetooth for transferring large amounts of information from telescope to telescope. Also, astronomy (don't confuse it with astrology, which is predicting the future, Gemini, horoscope etc which are useless lies) helps us develop our understanding of everything in general. Even the speed of light, which is essential for almost any science including engineering and other Earth-based stuff, was first measured using astronomy in the 16th or 17th century (using telescope and observing eclipses of Jupiter's moon Io). Google "ole romer's determination of the speed of light".
do you want to join my discord i like hearing you talk about space it's cool
Thank a lot but I don't have discord. I'm a bit old fashioned...
Theoretically possible, from our technological standpoint impossible to implement.
When we can warp spacetime then it will definitely be on the table. Until then maybe we can send a beam of protons back in time.
Since all timelines exist at once but on different dimensions (which is how time travel would ever be possible) it already exists. People from this particular timeline might not be able to travel but people currently in the timeline where it exists can travel to here.
But wouldnt that either strand them in our timeline or break our time in order for it to be possible?
It already exists
If an object travels fast enough then yes, time will be effected.
Backwards in time, no, not that we know of.
I wish I could time travel to the past.
I remember being told by my 6th grade science teacher that a method of time travel had been discovered. This was in 2007. Not sure if she got confused or if there was something discovered they thought could eventually lead to finding a time travel method, but obviously her information wasn't accurate.
I can't say whether it will ever be a possibility or not, because I just don't know enough about it, nor about the future. However, I think it likely isn't meant to be.
Ill go back and tell the founders dont let no black ppl here!
If it's possible then going back would create a new timeline that would be influenced differently. It's likely not possible to go back in time but I think it's possible there are alternate realities that happened differently.
im still livin in 1996
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