From Here to Infinity: A Vision For the Future of Science by Martin Rees

Author:Martin Rees [Rees, Martin]
Language: eng
Format: epub
ISBN: 9780393083989
Google: aJVVMSKyqHIC
Amazon: 0393083985
Goodreads: 16175533
Publisher: W. W. Norton & Company
Published: 2012-05-23T05:00:00+00:00

3

WHAT WE’LL

NEVER KNOW

While struggling to prepare my lectures for BBC radio, I had a fantasy. Suppose I had a time machine. I could fast forward into the future, turn on the radio, listen to the broadcast version, take notes—and then reverse back to the present and start writing. Well, there was plainly no such quick fix—but could there ever be?

Arthur C. Clarke noted that any sufficiently advanced technology is indistinguishable from magic. We can’t now envision what artifacts might exist centuries hence, any more than a Roman could imagine today’s SatNav and mobile phones. Nevertheless, a physicist would confidently assert that time machines will remain forever fiction. That’s because changing the past would lead to paradoxes—­infanticide would violate logic as well as ethics if the victim was your grandmother. So, what is the demarcation between concepts that seem crazy now but might be realized eventually and things that are forever impossible? Are there limits to how much we can ever predict? Are there scientific problems that will forever baffle us—phenomena that simply transcend human understanding?

Einstein averred that “the most incomprehensible thing about the universe is that it is comprehensible.” He was right to be astonished. Our minds evolved to cope with life on the African savannah, but they can also comprehend the microworld of atoms and the vastness of the cosmos. We marvel at the fact that the universe isn’t anarchic—that atoms obey the same laws in distant galaxies as in the lab. Our cosmic horizons have vastly enlarged. Our Sun is one of a hundred billion stars in our galaxy, which is itself one of many billion galaxies in range of our telescopes. And this entire panorama emerged from a hot, dense beginning nearly 14 billion years ago. Some inferences about the early universe are as evidence-based as anything a geologist might tell you about the history of our Earth; we can make confident and precise statements about how hot and dense things were in the first few seconds of our universe’s expansion, even just a microsecond after the big bang. But, as always in science, each advance brings into focus some new questions that couldn’t previously have even been posed. We now confront the mystery of the very beginning (if indeed there was one). It’s a mystery because, right back in the first tiny fraction of a second, conditions would have been far hotter and denser than we can simulate in the lab. We don’t know the physical laws that then prevailed, so we lose any foothold in experiment.

Einstein himself made one of the biggest advances in our comprehension. More than 200 years before him, Isaac Newton had shown that the gravity that makes apples fall is the same force that holds planets in their orbits. Einstein went much further. He didn’t prove Newton wrong—Newton’s mathematics is good enough to program space flights to distant planets—but he transcended Newton by offering insights into gravity that made it seem more natural and linked it to the nature of space and time, and the universe itself.

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