

Could Higgs Particle be a Time-Traveling Assassin? - davidchua
http://news.discovery.com/space/could-higgs-go-back-in-time-kill-its-grandfather-110316.html#mkcpgn=hknws1

======
danparsonson
If travelling backwards in time _is_ possible, Novikov's Self Consistency
Principle is a neat explanation of how the Grandfather Paradox may be avoided:
[http://en.wikipedia.org/wiki/Grandfather_paradox#Novikov_sel...](http://en.wikipedia.org/wiki/Grandfather_paradox#Novikov_self-
consistency_principle).

Basically, the idea is that if you are alive and capable of travelling
backwards in time to attempt (directly or indirectly) your own murder, then
your attempt has to fail by virtue of the fact that you're alive in the
present. There's a nice thought experiment with a billiard ball here:
[http://en.wikipedia.org/wiki/Novikov_self-
consistency_princi...](http://en.wikipedia.org/wiki/Novikov_self-
consistency_principle#History_of_the_principle)

~~~
nazgulnarsil
that's just a stable time loop. an unstable one would be one that splits into
multiple futures.

------
michaelcampbell
Why is the grandfather paradox the grandfather paradox and not the
father/mother paradox? Why go back a generation more than is necessary? I've
always seen it staged in this way and have never understood why.

------
maeon3
If your going to think about time travel and how it really works I think you
will also have to simultaneously tackle the "double slit experiment" the
phenomenon where a single electron exists in an infinite number of
superpositions, all modifying its own existence, while coming to rest as a
collapsed wave form as a single particle.

The double slit experiment proves to us that a one-universe linear view of
time doesn't work. For a particle to seemingly interact with ITSELF, then go
back, pick one route, and hit the wall as a particle means that quantum events
seem to thumb its nose at our notion of time.

<http://www.youtube.com/watch?v=DfPeprQ7oGc>

If you want do some time traveling yourself, use a laser pointer and three
mechanical pencil leads:

[http://www.youtube.com/watch?v=UANVMIajqlA&feature=relat...](http://www.youtube.com/watch?v=UANVMIajqlA&feature=related)

~~~
cheez
That's the part that gets me: the particle seemingly interacting with itself.
How do you know that it is indeed the same particle interacting with
itself??!!

~~~
maeon3
Because even when you fire electrons one at a time through 2 slits, the same
wave pattern is seen to emerge. It appears as though a single electron
explores every one of its options before it chooses a single route. The
exploration process seems to leave footprints in a universe we can't see which
causes the electron to behave strangely.

~~~
cheez
I need to do this experiment for myself. I just don't believe it...

------
maeon3
We all travel through time at varying speeds all the time:

There are two twin brothers. One brother goes on a space journey traveling at
99% of the speed of light. The space traveler stays on his journey for one
year, whereupon he returns to Earth. On Earth, however, seven years have
elapsed, so his twin brother is 7 years older at the time of his arrival. This
is due to the fact that time is stretched by factor 7 at approx. 99% of the
speed of light, which means that in the space traveler’s reference frame, one
year is equivalent to seven years on earth. Yet, time appears to have passed
normally to both brothers.

Question: Did the traveler go forward in time or did the Earthbound brother go
backward in time when they meet up later?

Question: How is it possible that one of the brothers shifted 7 years and yet
they can meet in the same universe?

~~~
Nick_C
Are you asking to learn, or to provoke others to think?

If you were asking, reply and I'll dig up some links about how c is the speed
of the universe and equals 1, spacetime and mass, and how velocity changes the
relationship of time in spacetime.

~~~
maeon3
I'd rather you answer the first one, how a person can move forward in time
while staying in visual contact of the person staying behind. If you can
answer that and prove it, then you will have made an amazing contribution to
the understanding of the universe.

Two kids are on a merry go round, one in the center, one on the edge, the edge
is traveling at .99 speed of light, when they communicate via cellphone, one
voice sounds very deep and low, the other sounds fast like a chipmunk. Yet if
you were to sample the sound relative to each point, you would hear a normal
voice, because of some bizarre principle.

~~~
Nick_C
(I have to make some assumptions about your understanding of relativity.) The
big breakthrough that Einstein made in general relativity was the 'relative'
bit. There is no absolute thing of 'time', no universal tick of a clock. There
is the time as experience by the traveller and the time as experienced by the
brother. So there is no discontinuity that has to be merged when they meet.

It seems to me your question makes an implicit assumption that there is a
universal tick that is thrown out of whack when the brothers meet. But there
isn't, so the question is invalid.

I wonder if perhaps you regard space as one thing and time as a separate
thing. It might help to throw that out and regard it as a four-dimensional
object called spacetime.

For the merry-go-round, I'm not sure why you say one voice sounds low and the
other high. They won't. Einstein's big thought experiment was to realise that
the speed of light is constant no matter the speed of the observer.

As an aside, it is an unfortunate historical artifact that we call c the speed
of light. It isn't. C is the "speed" of any massless particle in spacetime; it
is unitless and equals 1. Photons are massless so they travel at c.

[http://www.reddit.com/r/askscience/comments/g6zbd/if_we_depa...](http://www.reddit.com/r/askscience/comments/g6zbd/if_we_depart_earth_at_the_speed_of_light_and/)

[http://www.reddit.com/r/askscience/comments/fu5io/help_me_un...](http://www.reddit.com/r/askscience/comments/fu5io/help_me_understand_time/)

------
gcb
Article fails to do the most basic association with the paradox.

What if the operator halts the collision when he detects said signal?

