I came across an article this
morning, that’s more about quantum physics than astronomy, but it was so
fascinating that I just had to share it with you all. Physicists may have
discovered a way that the future can alter the past! Yup, you read that right, what
you do today could affect what you did yesterday! How can this happen? Quantum
physicists are studying the ideas of non-locality and causality. Non-locality
is the idea that two particles can be entangled such that an action on one
automatically affects the actions of another. Kind of like two train carts tied
together, if I move one the other moves as well. Causality is the idea that
tiny particles exist with unknown properties until someone makes a measurement
of one of those properties, and these measurements can be strong (I know for
sure this is true about the particle) or weak (I think this might be true).
For example, lets say you glance super quickly
at an unknown street sign, then look away. You might notice that the sign had a
reddish color to it (weak measurement). You look quickly again, and notice
there is also some white (weak measurement). Repeat the process and eventually
you might figure out that you are looking at a stop sign. Then you stare
directly at it for a few seconds (strong measurement) and for sure decide that
it is a stop sign. The idea of causality states that the street sign’s
properties are unknown (what type of sign is it?) and the signs location is
unknown (where is it?) until you look at it and decide it’s a certain one in a
certain spot. So how can observing an object properties today affect it
yesterday? Try this thought experiment below
A friend and I live in Upstate New
York, and we live 50 miles apart. You don’t know where exactly we live, but
only that our houses are 50 miles apart and that our bodies are always 50 miles
apart no matter what (we are entangles that way). Now you decide you want to
figure out where I currently am. You can’t do this by calling or asking me, you
have to put tiny bits of information together to figure out where I am (weak
measurements). Ok, so you know that I just posted this blog, and therefore, I
must be somewhere where there is wifi. You just made one tiny measurement of
where I am, without defining exactly where I am. There are tons of place with
wifi, so I could be at any one of those places. Measurement number 2, again I’m
writing this blog post , so I must be at a computer (for the sake of argument,
lets assume it must be a desktop computer). So now, with two measurements,
you’ve narrowed down where I am (somewhere with wifi and a desktop computer),
but still don’t know exactly where I am. Let’s pretend you were able to make a
whole bunch of other measurements and finally figure out that I am at the local
library, 10 miles from my house. Now that you’ve made a solid measurement of
where I am, you have fixed me in place, and thus fixed my friend in a place
exactly 50 miles away from me. Since I am 10 miles from my house, my friend
must also be 10 miles from her house (because we are always 50 miles apart).
But how did she get there? Sometime in the past, she must have drove from her
house, to a point 10 miles away from her house. But we didn’t know or decide
that she was 10 miles from home until we figured out where I was located, just
now. The act of deciding that I am 10 miles from my house right now, put my
friend 10 miles from her house, and thus altered the past in such a way that
caused her to drive 10 miles away from her house sometime in the past. So my
action of being at the library today, had an affect on what my friend did in
the past, or in other words, the future (today or tomorrows actions) had an affect
on what happened yesterday!
So what does this all mean? Are your actions today changing the past? Well, physicists aren’t really sure. They think
they see this occurring for special particles that are entangled together and
have certain kinds of properties. It doesn’t necessarily work on a human scale.
But if we understand what’s going on in the quantum world, we may someday be
able to use it in the “real” world…
Here is a link to a nice article
explaining this in more detail: http://physicsworld.com/cws/article/news/2012/aug/03/can-the-future-affect-the-past
