If parallel universesexist, here's how we could actually find the evidence
Imaginea physicist sitting in a chamber with a gun pointed directly at herhead.
Every few seconds, the spindirection of a random particle in the room is measured. If the particle isspinning one direction then the gun goes off and the physicist dies. If theparticle is spinning in the opposite direction, there's just a clicking soundand the physicist survives.
She has a 50/50 chance of surviving,right?
It mightnot be that simple if we live in a multiverse — the idea that multipleuniverses, apart from the one we call home, exist.
This scenario with thephysicist and the gun is the start of a famous thought experiment called"quantum suicide," and it's one way for physicists to consider if wereally are living in just one of many (and potentially infinitely many)universes.
This thought experiment relies onquantum mechanics and the idea that there is no single objective reality.Everything that we see around us is just one possible configuration ofall the probabilities of any one thing happening. One interpretation of quantummechanics is that all the other arrangements of probabilities could exist intheir own separate universe. So if you follow the thought experiment allthe way through with this idea in mind, then the second that first particle ismeasured, the universe splits into two universes, based on two possible outcomes: onein which the physicist lives and one in which she dies.
Her survival is now tied to aquantum probability, so she'll be both dead and alive at once — just indifferent universes. If a new universe splits off every time a particleis measured and the gun either fires or doesn't, then in one of thoseuniverses, the physicist will end up surviving, say 50 particle measurements.You can think of this as flipping a coin 50 times in a row. You have anextremely low likelihood of getting heads each of those 50 times — less than a1 quadrillion chance, but it is possible.
And if it happens, that's enough forthe physicist to conclude that the multiverse is real, and effectively shebecomes immortal in the universe in which the gun never goes off. Butshe also becomes the only person who knows that parallel universes exist.
Thisprobably sounds like the plot of a sci-fi movie, but there are other, morereasonable-sounding versions of the multiverse that are backed up bymath and are potentially testable.
"Some people conflateparallel universes with jumping through a portal into another world, orsomething like that," Matthew Johnston, a physicist at the PerimeterInstitute, told Business Insider. "But it's not really like that atall."
Some physicists have theorized adifferent version of the multiverse. This version arises from string theory andthe idea that there are many more dimensions that we don't have access to(think Matthew McConaughey in the fifth dimension in "Interstellar"). Some physicists think parallel universes lurkin those extra dimensions.
This multiverse idea is testabletoo.
Physicists will be searching formini black holes when the Large Hadron Collider turns back on this month.It's impossible for the LHC to produce any type of black hole that wouldbe remotely dangerous, but this theory speculates that microscopic black holesthat disappear almost immediately could be generated from the high-powerparticle collisions in the LHC. The presence of black holes would indicate thatgravity from our universe is seeping into extra dimensions.
"As gravity can flow outof our universe into the extra dimensions, such a model can be tested by thedetection of mini black holes at the LHC," physicist Mir Faizal toldPhys.org. "We have calculated the energy at which we expect to detectthese mini black holes in gravity's rainbow [a new theory]. If we do detectmini black holes at this energy, then we will know that both gravity's rainbowand extra dimensions are correct."
That would be compelling evidencefor both string theory and parallel universes, and it would help explain whygravity seems to be so much weaker than the other fundamental forces.
Still, there's no hard evidence yet.And some still doubt that these universes exist.
"I only believe in things withconcrete, verifiable experimental evidence supporting them, and that's not thecase right now with the concept of parallel universes," Brian Greene, atheoretical physicist at Columbia University, said in a video discussingthe multiverse.
The key,though, is that physicists are getting away from just philosophical discussionsof the multiverse, Johnson said. They're actually putting the idea to the test.
Some are still betting on the moreradical and so far untestable versions of multiverse theory. Tegmark has jokedthat he'll try the quantum suicide experiment when he's old and no one willmiss him when he's gone.
We hope that he doesn't.
Article Source: http://www.businessinsider.com/do-we-live-in-a-parallel-universe-2015-4
Image Source: https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcQDydWvwCXMAzrQzzcrx-mOUKF90RtnsVXTXvThnRGryQ4VBb8D
VOCABULARY WORDS:
1. Chamber(n.) ~ a room in a house, especially a bedroom
2. Scenario (n.) ~ an expected orsupposed situation
3. Configuration (n.) ~ the arrangementof parts or elements in a pattern
4. Split off (idiom) ~ to sever connectionwith something
5. Immortal (adj.) ~ not subject todeath
6. Back up(phrasal verb) ~ to support
7. Conflate (v.) ~ to bring together
8. Lurk (v.)~ to wait out of view
QUESTIONS FOR DISCUSSION:
1. What is a parallel universe?
2. Do you believe in the possibility ofits existence?
3. What do you think is the reason forscientists’ interest on parallel universe and the space in general?
