Tag Archives: modal realism

The answer seems obvious – one!

After all, we have a unique set of genes that separate us from everyone else in the universe.

But what if there are multiple universes?

A new study has taken the scientific community by storm this week. Ranga-Ram Chary, a researcher based out of the California Institute of Technology, claims to have evidence that our universe may have collided with an alternate one. He extensively mapped out the cosmic microwave background (CMB), which is the light emitted during the early Big Bang stage of the universe, and removed stars, gas, and dust, effectively leaving nothing but noise. However, Chary discovered patches of unexpectedly brilliant light. The implication of these light signatures is that they appeared when a universe with a different baryon-to-photon ratio bumped into our own universe, leaving their “fingerprints” behind.

Let’s not get carried away just yet. After all, Chary concludes that there is a 30% chance that the emissions are not unusual, and his paper is yet to undergo peer review. But the idea that yet-to-be-observed universes could be out there has intrigued humans for years. Hugh Everett first formulated the many-worlds hypothesis in 1957, which states that there may be an infinite number of universes and that every event with multiple outcomes occurs in a different inaccessible branch of the multiverse. We have developed newer, more sophisticated theories since then, such as the model of eternal inflation – the idea that the universe has always been expanding and thus creating pocket universes, which are infinitely far apart.

Generally speaking, the multiverse hypothesis and the notion that there exists a set of infinitely possible universes that are beyond the realm of what we can experience is a hotly debated topic. After all, how can we test a theory that allows for all possible outcomes?  Physicist Paul Davies argues, “For a start, how is the existence of the other universes to be tested? To be sure, all cosmologists accept that there are some regions of the universe that lie beyond the reach of our telescopes, but somewhere on the slippery slope between that and the idea that there are an infinite number of universes, credibility reaches a limit. As one slips down that slope, more and more must be accepted on faith, and less and less is open to scientific verification.”

The multiverse question is not only one explored by quantum mechanics but also by philosophy. Modal realism is an idea propagated by David Lewis which suggests that all possible worlds are just as real as the one we are actually experiencing, and saying our world is the actual one is simply our way of distinguishing it from others.

The multiverse hypothesis demands an inconceivably great burden of proof and we may never know if it is true in any of its infinite forms. Yet, nothing perplexes the human mind more than attempting to explore ideas that are virtually impossible to validate. One thing I do know: the multiverse is freaking awesome.

Minute Physics explains the science behind parallel universes: 

Tim Cheung