The Cosmos Explained by Charles Liu

Author:Charles Liu
Language: eng
Format: epub
Publisher: Ivy Press
Published: 2022-05-15T00:00:00+00:00

BIOGRAPHY

In 1995, Swiss astronomers Michel Mayor (b. 1942) and Didier Queloz (b. 1966) discovered the first planet orbiting a Sun-like star other than our own by tracing the influence of its gravitational pull on the motion of its host star 51 Pegasi. For their work, which opened the floodgates of exoplanetary discovery, they were awarded the 2019 Nobel Prize in Physics.

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3.8 Billion Years Ago

Birth of Life on Earth

For 10 billion years, we have watched the universe evolve.

Once a blazing-hot crucible, the cosmos cooled until it was a hospitable environment for individual objects to form inside it. In vast gaseous nurseries, stars were born; they aged, reproduced and died. They spent their lives in vast galactic ecosystems that varied widely in size, shape and activity. Planetary systems formed, enveloped in the environments produced by their host stars; within them planets were born, each the product of its composition and surroundings, all slowly cooling as they stabilized and evolved.

Now, on Earth, as the planet itself ages and evolves, new objects are forming with a remarkable property: the ability to preserve and communicate so much information that they can reproduce themselves almost exactly, just by carefully processing the available resources around them. Certain environmental conditions on Earth made these objects possible: the right mix of light and heavy elements, steady warm temperatures and lots of liquid water. Over billions of years, these carbon-based reproducers will evolve into millions of varieties and spread across the Earth, fundamentally altering and shaping their planet.

Life as we know it is unusually adept at both accurate reproduction and adaptation to new environments – so good, in fact, that we tend to assume it must be uniquely special in the universe. We have already seen enough of cosmic history, though, to know that natural processes following the same basic physical rules can result in dazzlingly beautiful and complex phenomena of many kinds, including some that would have been unimaginable had we not actually observed their existence. Does life on Earth fall into such a category – amazing for sure, yet in a cosmic sense completely ordinary?

To answer that question, it would certainly help if we could find another example of a planet on which organisms like us exist. The technology to find extraterrestrial life isn’t quite there yet, but we’re close; among the thousands of planets astronomers have found in the past quarter of a century, a handful seem to be quite similar to Earth. In a few decades, our telescopes and detectors may be able to show definitively that one or more of them are home to things we would recognize as being alive.

Until then, we have plenty of mysteries to solve when it comes to our own cosmic genealogy. As just one example, stars evolve over eons, and each new generation can take millions of millennia to mature; some organisms on Earth, by contrast, can have great-grandchildren in less than an hour. What were the physical and environmental conditions billions of years ago that led to the

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