Physics, Earth & Space
NASA’s Parker Probe Kisses the Sun — And Rightly So
NASA’s Parker Solar Probe is about to make history. Again. Already it’s become the fastest manmade object ever built. That occurred on October 29 as it plunged toward the sun. And thanks in part to its dizzying speed, it will achieve Perihelion #1 tonight, its first close fly-by of our host star. In this moment — 10:28 pm EST — it will be closer to the sun than any object ever built by man. Almost twice as close.
In the months to follow, the probe will make several more orbits around the sun, getting closer and closer on later flybys until it is seven time closer than any space probe before it. At its peak velocity Parker will rip through space at a blistering 430,000 mph.
The $1.5 billion probe, NASA explains, “will travel through the Sun’s atmosphere” and face “brutal heat and radiation conditions.”
Why bother? There’s the urge to boldly go where no one has gone before. Also, Parker promises to unlock some longstanding mysteries about solar winds and the sun’s atmosphere. But it’s more than that, I’m convinced.
The sun has always held a special fascination for humankind. Most of us know of Stonehenge, that ancient stone monument to the sun on the Wilshire Downs in southern England. Less well known is the fact that thousands of ancient constructions around the world are also aligned to our closest star, either on the solar solstices or on the spring and autumn equinoxes. Examples abound, including the Sphinx at Giza, the bas-reliefs in the Angkor Wat temple complex in Cambodia, and whole cities in pre-Columbian Mesoamerica.
Many ancient cultures considered the sun a living deity. Today we neither worship nor build monuments to it. But if there is any object in the natural world worthy of awe, it must surely be the sun. This is particularly true for us and other creatures William Broad calls “light eaters,” earthlings whose existence depends on the sun’s radiance.
If you took away the sun, after a short time the Earth’s surface would be a lifeless frozen waste only a few degrees above absolute zero — far colder than the center of the Antarctic. Every atom and molecule on the Earth’s surface would be immobilized. That much is widely understood. Less widely known: a mysterious suite of coincidences in the nature of things render the Earth’s surface a supremely fit habitat for advanced carbon-based life forms like ourselves — coincidences that are, on any consideration, ludicrously improbable.
A Fusion Bomb Stunningly Fit for Life
We should feel very lucky. The sun is a giant fusion bomb, converting hydrogen to helium in an ongoing chain reaction in its dense, ultra-hot core. But fortunately for us, the electromagnetic radiation emitted by this runaway fusion bomb (and that of most other stars) is almost entirely light and heat (or infrared). These have precisely the characteristics needed for advanced life to thrive on the Earth’s surface.
The crucial visual band, which has the right energy levels for photochemistry, occupies only a tiny part of the EM spectrum. To grasp just how small, picture just a few playing cards in a stack stretching from here to beyond the Andromeda galaxy. Andromeda is more than 2.5 million light years away. This playing card illustration, then, represents a fraction so small as to be beyond ordinary human comprehension.
And here is the key point: It’s thanks only to the fine-tuning of the laws and constants of nature that we live in a universe awash in radiation from this tiny swath of the electromagnetic spectrum — the life-permitting swath.
Sunlight is also just right for the high-acuity vision we enjoy, thanks to another set of extraordinary coincidences in the characteristics of visual light. And it goes beyond vision. Sunlight is just right in a host of ways for beings of our size and upright android design — for beings who possess the gift of sight, breathe oxygen, and inhabit the terrestrial surface of a planet like the Earth.
A Cosmic Home Fine-Tuned for Us
Indeed, the story of the utility of sunlight and the vastly improbable coincidences that make possible our specific type of being is a tale far more extraordinary than any told by the ancient sun-worshippers or conceived in the most esoteric visions of the gurus and seers of the past. It’s the story I tell in my latest book, Children of Light: The Astonishing Properties of Sunlight that Make Us Possible.
As I note there, building on a series of related books, the fine-tuning of sunlight for advanced creatures like ourselves is just one instance of fine-tuning among a growing list in the natural sciences.
No matter how unfashionable the notion may be in some intellectual circles, the evidence is unequivocal: Ours is a cosmos whose laws appear finely tuned for our type of life — for advanced, carbon-based “light eaters” possessing the technologically enabling miracle of sight. Whatever the cause and whatever the ultimate explanation, nature appears to be fine-tuned to an astonishing degree for beings of our biology.
Dr. Denton holds a PhD from King’s College London and is a Senior Fellow with Discovery Institute’s Center for Science & Culture. He is author of the new book Children of Light: The Astonishing Properties of Sunlight that Make Us Possible. A version of this article first appeared at The Stream. It is published here with the permission of Michael Denton.
Image credit: NASA/Johns Hopkins APL/Steve Gribben, via NASA.