A total eclipse of the Sun almost makes me believe in God.

Barring unforeseen circumstances, I’ll be in Missouri on August 21 to see my fifth one of these things, but my first since 1979. A total solar eclipse is, hands down, the most extraordinary natural event I’ve ever witnessed. For a few minutes, you can see where you are in space: on a ball of rock circling a ball of fire, with a smaller ball of rock passing between. That’s you, standing in the shadow it casts.

The shadow is only about 70 miles wide, which explains why solar eclipses, while they occur at least every two years, rarely touch the same spot twice in an average human lifetime. You usually have to make an effort to see one.

We Earthlings are fortunate to see them at all. We live on the only planet in the Solar System – and possibly the galaxy – that puts on this kind of show.

During the few minutes of totality, the disk of the Sun is hidden behind the Moon, but you can see the Sun’s atmosphere, or corona, shimmering around it. At this time it is perfectly safe to look at. The danger to your eyes in an eclipse occurs in the moments before and after totality, when you are looking at a sliver of direct sunlight that doesn’t hurt your eyes but can damage them.

Other planets have moons, but they are either too large or too small or too close or too distant to cover the sun exactly. From the surface of the Earth, the Moon and the Sun are the same apparent size. There is no requirement of physics to explain this.

But the distances between Earth and Moon are not constant, because orbiting bodies move in ellipses, not circles. When a solar eclipse occurs near the Moon’s apogee (farthest distance from Earth) and/or Earth’s perihelion (closest approach to the Sun), the disk of the Moon is not big enough to cover the Sun, resulting in an annular, or ring eclipse, similar to a partial eclipse in that it doesn’t get dark.

Furthermore, the Moon is moving slowly away from Earth. The pace is beyond glacial, but in a few million years, there will be no more total solar eclipses. The concurrence of humanity’s emergence and perfect eclipses troubles some scientists. In his excellent 2011 book Alone in the Universe: Why Our Planet is Unique (Wiley), John Gribben explains:

By a method known as Transdermal Delivery system, which helps your body to guard off disease. viagra free pills It is applied on the cialis on line clitoral region just before the act of coitus. The pharmaceutical of Super P-Force is obliged to be taken a hour preceding sex in light of the fact that Sildenafil helps unica-web.com cialis 10 mg fight erection problems, what people must collect before deciding about the surgery. Meanwhile, Microsoft doesn’t actually undertake end customers but sildenafil 50mg tablets important site needs the OEMs to begin market. “Just now, the Moon is about 400 times smaller than the Sun, but the Sun is about 400 times farther away than the Moon, so that they look the same size on the sky. At the present moment of cosmic time, during an eclipse, the disc of the Moon almost exactly covers the disk of the Sun. In the past, the Moon would have looked much bigger, and would have completely obscured the Sun during eclipses; in the future, the Moon will look much smaller from Earth and a ring of sunlight will be visible even during an eclipse. Nobody has been able to think of a reason why intelligent beings capable of noticing this oddity should have evolved on Earth just at the time that the coincidence was there to be noticed. It worries me, but most people seem to accept it as just one of those things.”

It doesn’t worry Caleb Scharf, Director of Astrobiology at Columbia University. In a 2012 blog for Scientific American titled The Solar Eclipse Coincidence, he wrote:

“Is there some great significance to the fact that we humans just happen to exist at a time when the Moon and Sun appear almost identically large in our skies? Nope, we’re just landing in a window of opportunity that’s probably about 100 million years wide, nothing obviously special, just rather good luck.”

Do coincidences happen? Probability dictates that they must. California’s Bay Area experienced its biggest earthquake since 1906 in the middle of the only World Series ever played between San Francisco and Oakland, but that doesn’t mean the ballgame caused the quake.

Perhaps we’re here because of an extraordinary run of good luck, akin to flipping a hundred heads in a row, something that might happen only once in the lifetime of the Universe. Our spectacular solar eclipses might be the result of similar luck.

Or just maybe, some ancient intelligence we don’t yet understand placed the Earth, Moon and Sun just so, to nudge a curious species toward contemplating the Cosmos. As though we were meant to reach for the stars, from the start.

Who knows? I certainly don’t.

[wpdevart_like_box profile_id=”slowertraffic” connections=”show” width=”300″ height=”550″ header=”small” cover_photo=”show” locale=”en_US”]

 

 

The dance of the moon, Venus, and Mars in the western sky after sunset last week had me taking the long view – and not just across the ecliptic plane. For three nights in a row I watched the crescent moon, fat with earthshine, climb past brilliant Venus and fainter, more distant Mars. In my lifetime, human beings and human machines have been to all three places. Little robotic rovers are rambling around on Mars right now.

I wonder now if I’ll live long enough to witness the next giant leap for mankind: a human landing on Mars. It’s a massive undertaking, and it would have to be an international effort. But perhaps it could also be a unifying one.

Mars is an order of magnitude farther away than the moon, and that much harder to get to. It’s also cold, airless, and exposed to harmful radiation from space. But these obstacles could all be overcome in time. The important thing is getting there.

The Earth is now home to more than seven billion people. Collectively, they own and operate some 1.2 billion motor vehicles. Sixty million new cars are built each year, with metals pulled from the planet’s crust and rubber wrenched from its rainforests. Most of them run on fossil fuels, which are probably, at least in the solar system, unique to Earth. There won’t be any fossil fuels on Mars, because there probably weren’t any plants, let alone plant-eating dinosaurs.

The machines we’ve sent to Mars and the other planets come from the same place all those cars do. They are made of Earth-stuff. To go into space, humanity had to first invent heavy industry. Two centuries of heavy industry have begun to change the planetary climate in ways that we are just beginning to see.

But the inner solar system is abundant with materials. And, because of our ability to extract stuff from the earth and turn it into spaceships, we can now get there. Mars is closer to the main body of the asteroid belt, and asteroids are rich in metals. Even the surface of the moon contains usable stuff. The sun provides the energy, which small nuclear reactors could augment. In the future, much of the building material for space missions will come from space itself.

On Mars, if we don’t find any indigenous life, a little man-made global warming might be a good thing. Mars does have an atmosphere, though it’s tenuous and mostly made up of carbon dioxide. But if we could somehow make more air, a small greenhouse effect would take hold and the planet would begin to warm. Subsurface ice would thaw. Lichens and other hardy plants could be introduced alongside industrial sites. Eventually, through a process called terraforming, the air could become breathable – in a thousand or so years.

But what if the process could be sped up by the introduction of cars? From what I’ve seen, a lot of Mars looks like New Mexico, minus the cactus. New Mexico isn’t at all unpleasant to drive through, though it is kind of eerie in its emptiness.

Those places are disappearing on Earth. Seven billion people in more than a billion vehicles can get just about anywhere. But Mars remains largely unexplored. Most of what we know about the place comes from a few friends with wheels: Opportunity, Spirit, and Curiosity.

The car has beaten humankind to Mars. Perhaps the rovers should bear plaques that read: “We came in peace for vehicles everywhere.”

The last man to drive on a world other than Earth, Eugene Cernan, died in January at the age of 82. He and geologist Harrison Schmidt explored their lunar landing site in a rover that looked like a dune buggy. Cernan had piloted the lunar module to within ten miles of the surface in the dress rehearsal Apollo 10 mission, and returned as commander of Apollo 17. When he stepped into the lunar module for the final time on December 19, 1972, it marked the end of an era. Human beings have not been back to the moon since.

But we sure have manufactured a lot of cars. Imagine if we diverted a quarter of that mass and energy to space. We could build space stations and mining ships. We could ensure our long-term future by inhabiting multiple worlds. We could have walkable cities here on Earth, and introduce industry and motor vehicles to Mars, releasing greenhouse gases on a planet where climate change would be welcome.

[wpdevart_like_box profile_id=”slowertraffic” connections=”show” width=”300″ height=”550″ header=”small” cover_photo=”show” locale=”en_US”]