Waste less time on Facebook — follow Brilliant.

time paradox

if a person travels backwards in time and kills himself, then will he exist in the present world or not. this is the time paradox but has it been solved and what are the current knowledge on it

Note by Mohammed Khan
4 years, 6 months ago

No vote yet
4 votes


Sort by:

Top Newest

There are rules about time travel in our current physical framework. The most important rule is: no, you can't do it. You can read about the conjecture of chronology protection by Hawking. (The reference by Visser at the bottom of this page is pretty good, he wrote a book on this stuff, although it starts to get more technical than most students are equipped to handle after the first few pages). We at Brilliant thank our lucky stars for chronology protection, as this is what allows us to publish solutions without the students then reading them, going back in time, and answering all the problems correctly without thinking.

David Mattingly Staff - 4 years, 6 months ago

Log in to reply

i think he cant kill himself as he as alive in the present...... similarly if a person is dead in present then even if we go back in past we cant stop him from dying ....... as it is not possible to bring back soul to someone's body

Avinash Mishra - 4 years, 6 months ago

Log in to reply

this is grand father paradox , so if you travel in past I think it is not possible as suggested by Einstien time can slow down stop but not back . I will give you proof that when a past time travel wormhole is made the nature it self destroy it because the radiation in universe go into wormhole and destroy it . So it is not possible

Zahid Shekh Mohammed - 4 years, 6 months ago

Log in to reply

Double sided mirror slow close it with a watch in front of it. Out of 11 only one travels backwards (counterclockwise)

Rickie Ruiz - 1 year, 3 months ago

Log in to reply

are you kidding me ...no one can travel into the past...i guess u r also haunted by the two words-" what if"..???

Shubham Agrawal - 4 years, 5 months ago

Log in to reply

One idea, I believe, is that there are many parallel universes that branch off from quantum actions (I'm sourcing this from a fictional book called Hominids, by Robert J. Sawyer, but there are many different forms of parallel universe theory). If this is true, then there must be a large number of different parallel universes, and going back in time to kill oneself would be more likely the entrance of a universe in which this individual doesn't exist in the future because his past was killed.

So paradox might be only if you went to the past and killed yourself in a single universe, but time isn't exactly linear, so going back in time would sort of be not really going back in "time" just into a scenario that emulates the past. Essentially, no going to the past because it's probably not really the past but some warped other dimension that looks just like the past.

Conjectures, conjectures, but no one has a time machine that can go back in time, so we'll likely not know for a while...

Matt Wang - 4 years, 6 months ago

Log in to reply

good thought though...thnx

Mohammed Khan - 4 years, 6 months ago

Log in to reply

The thing is , you can't travel backwards in time , only forward .

Milan Radović - 4 years, 6 months ago

Log in to reply

but if we can create a time machine we can go back in time bcoz past is the time which had olready happened infact it would be hard to go in future....

Riya Gupta - 4 years, 6 months ago

Log in to reply

The theories that exist in the present do prove that travelling to future is possible.... By circling in a definate radius around a black hole with a great speed which is though a bit impractical with present technologies they call a black hole a natural time machine Correct me if I m wrong

Juzer Khamosi - 4 years, 6 months ago

Log in to reply

@Juzer Khamosi it's said that you can probably move through time inside black hole singularity, but you no longer can move through space. As you can never leave anymore, you are outside of cause and effect. Just think like you are in your own dimension, unable to do anything to affect anything

Afkar Aulia - 4 years, 6 months ago

Log in to reply

@Juzer Khamosi but if we consider blackhole a tym machine then why tym stops in blackhole ?

and if it stops there how we'll be able to go in future? m getting confused!

Riya Gupta - 4 years, 6 months ago

Log in to reply


Problem Loading...

Note Loading...

Set Loading...