Science & Environment
11:22 am
Mon April 7, 2014

Seven Things to Know About Our Universe

The Andromeda galaxy is our largest galactic neighbor, measuring 260,000 light-years across.
The Andromeda galaxy is our largest galactic neighbor, measuring 260,000 light-years across.
Credit NASA/JPL-Caltech

We’ve long thought of our universe as all-encompassing, the only one. But modern physics suggests ours may be just one of many.

In his new book, Accidental Universe: The World You Thought You Knew, MIT physicist and author Dr. Alan Lightman explores our universe in seven essays, each delving into one facet of our corner of the multiverse:

  1. Accidental: We’ve long thought of our universe as all-encompassing, the only one. But modern physics - specifically string theory and eternal expansion theory - suggests ours may be just one of many. While mind-boggling and somewhat disconcerting to many (physicists and lay people, alike) the multi-verse concept helps address what's known as the fine-tuning problem: why is our universe so perfectly suited for life? The scientific answer: it's an accident, or rather, a simple matter of statistical probability. With infinite universes following an infinite variety of physical laws, some small number will hit our sweet spot. And, by definition, that's where we've ended up.
  2. Temporary: Nothing is forever. Not youth, not diamonds, not even the happy accident that is our solar system. In another six billion years or so, the sun will run out of hydrogen, expand into a red giant, and swallow up Mercury, Venus, and probably Earth (which will long since - as in a few billion years - have become too hot to support life). 
  3. Gargantuan: Ours may not be the only universe, but it's still awesomely large ... and getting bigger every second. Just as we start from a single cell, the universe started from a dense particle even smaller than atom. In the intervening 13.8 billion years, it's done a lot of growing. Our ability to explore our world at both it's largest and smallest scales, and with increasing accuracy, is a measure of our progress as scientific beings.
  4. Symmetry: We find symmetry everywhere in nature, from snowflakes to starfish, and physicists even think it's a fundamental property of our universe. We humans are drawn to symmetry, we emulate it, but with a twist. We prefer symmetry that is ever so slightly imperfect - side-parted hair styles, a painting with one asymmetrical element. And even in this we are perfectly matched to our universe, because in a world of absolute symmetry, sub-atomic particles would be without mass. The importance of the Higgs Boson is that it resolves this conundrum, by breaking symmetry (enabling symmetry in the first place) and conferring mass to all other particles.
  5. Lawful: While other universes may operate on totally different premises, the physical laws of our universe appear to be constant through space and time. In fact, that's a fundamental underpinning of scientific study, what Lightman calls the Central Doctrine of Science. Ironically, though, it is ultimately untestable and must be accepted on faith.
  6. Spiritual: A man of science and an atheist himself, Lightman is nonetheless quick to point out that there are questions and entire realms of knowledge outside the purview of science.
  7. Disembodied: Technology enables us to learn about our world in ways unimaginable centuries, or even decades, ago. But Lightman argues, as many others have, that the omnipresence of technology in our daily lives also puts us at a distance from each other, and the world around us. He ends the book with a plea to reconnect, and a vision of what future generations might consider normal.
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