Yesterday, I got sunburned. It ‘s the first time it’s happened in a while.
We went swimming in Lake Erie on one of those days where the sun is beating down with relentless intensity, but the humidity was low, the temperature stayed in the 80s, and the water was cool. It was a perfect day for swimming, and we floated and back stroked and paddled around on a fine summer day.
I knew I was getting some sun. I could sense it on my back and shoulders, which are the sun’s big targets. By the end of the day, as we enjoyed a beer at the Erie Kai saloon, I could feel the heat radiating off my skin — but it was a good feeling.
In childhood, the first sunburn of the season was an annual rite of passage. Age and wisdom have caused me to get away from that tradition, but having a sunburn still says summer to me.
We decided to get something to hang on the door that leads from the brick alleyway into our back yard. I’ve always liked sunburst figures, and Kish found an excellent one — a jovial, star-cheeked, chin-dimpled Sun to grace the entrance and greet us as we head to a place where we really enjoy hanging out. I particularly like the look of it during that very short time period each day when the real sun reaches just the right point in the sky for its rays to fall unimpeded by tree or brick to warm the door and our smiling Sun.
Residents of central Ohio were astonished today when our accustomed cloud cover vanished and a large, flaming orb unexpectedly appeared in the sky.
The object is so bright that it is creating sharp, dark outlines of objects, like tree limbs, mailboxes, and even people, on the ground. It is so dazzling that mortal man cannot look at it directly without being blinded. If you wish to walk around in the brilliance, you must shield your eyes to avoid being stupefied.
It is unclear whether the object is dangerous, but there are warning signs that it may be hazardous. It appears to radiate some kind of energy, because exposure to the object leaves the back of your neck feeling warm and tingly. It also exerts a curious attraction. People seem to want to go outside and bask in the object’s brightness. Neighbors who have long remained indoors are outside and have discarded their coats. Have the authorities been notified?
Venus is on the move today and tomorrow. It’s traveling slowly across the face of the Sun, on a journey that astronomers call being “in transit” — as if Venus were hopping a subway to get from one side of the solar system to another.
These kind of astronomical events are very cool, because they happen so rarely. There’s a “music of the spheres” sort of celestial harmony to Venus’ journey that reflects a special, highly unusual confluence of positioning of the Sun, Venus, and Earth. It won’t happen again for 105 years. By then, we hope, the European debt crisis will have been resolved. In fact, some astrologers are saying that the transit of Venus might help to solve such problems. It’s is supposed to herald in a new era of spiritual and technological revolution . . . or, it’s supposed to strongly accentuate feelings of love and hate. With astrology, it always seems to be one or the other.
As with any solar celestial phenomenon, the news stories always caution people not to look directly at old Sol. It’s hard to believe anyone would try to use the naked eye to check out the Venus transit, because Venus will be only a small speck against the enormous disk of the Sun. You supposedly can see it safely by creating one of those pinhole-in-a-box projectors that the news stories typically mention in these circumstances. I tried to make one of those devices when there was a solar eclipse during my childhood, and I gave up in frustration when it didn’t work. This time, I’ll just rely on the photos, and in the meantime wish Venus well on her cross-town travel.
NASA’s Messenger spacecraft has achieved orbit around Mercury. It will remain in orbit for about a year and will circle Mercury 730 times. Its mission includes taking photographs, collecting data about Mercury’s surface and atmosphere, and trying to figure out why the planet is so dense. Scientists currently believe that two-thirds of the planet’s core must be some kind of iron composite.
Mercury’s density is just one of many intriguing aspects of the planet. It is the closest planet to the Sun — if you could stand on Mercury, the Sun would look at least three times larger than it appears from the surface of Earth — and it experiences extraordinary heat variations. When Mercury’s surface is exposed to the Sun, temperatures can reach levels sufficient to melt lead; on the dark side, temperatures can drop to -280 degrees Fahrenheit because there is no atmosphere to retain the heat. Mercury has the fastest orbit of any planet, circling the Sun once every 88 days. In addition to being blasted by heat, its surface is scourged by the solar wind and pockmarked with craters from countless collisions with comets, asteroids, meteors, and other space debris attracted by the Sun’s immense gravity.
The extreme conditions on Mercury posed significant engineering challenges for mission engineers. How do you design a spacecraft that is durable enough to be launched, hardy enough to be flung around planets in order to reach the right velocity and insertion point for orbit, and tough enough to stand up to Mercury’s metal-melting temperatures, yet capable of performing scientific experiments that require delicate measurements by sensitive instruments and then transmitting the results of those experiments back to Earth? One answer was to use ceramic shielding and mirrored surfaces to guard instruments and reflect heat rather than absorb it. Another answer is for the spacecraft to do its transmission duties when it is farthest away from the planet and least exposed to the intense heat.
The Messenger mission is another example of how we get great “bang for the buck” from unmanned space exploration, and how the exceptional engineering work that characterizes such missions can help point the way to technological breakthroughs and creative solutions to engineering problems on Earth.