Monday, July 20, 2009

Apollo 11

I don’t have anything original to say about the Apollo moon landings, but they did influence my life and so this anniversary is an occasion to reflect.

When Neil Armstrong stepped out of the lunar module and onto the moon, I had just turned seven. I barely remember watching the great event on TV, and I’m sure its significance didn’t sink in at the time. My parents were more interested in the other big news of the late 60’s: the Vietnam war, the civil rights movement, political assassinations. My brother and I were more interested in whether the Cardinals would get to the World Series.

But as I got a little older, and the Apollo landings continued, I began to show serious geekish tendencies. I bought and assembled plastic models of spaceships. I checked out all the astronomy books from my grade school library, and learned to identify the stars and constellations. In art class I drew pictures of imagined rockets that would take people to every planet in the Solar System. Eventually I grew up and became a scientist.

The moon landings had little direct impact on science. Sure, we learned more about the moon’s geology, but there were no big surprises. The real impact of the moon landings was cultural. Bob Park said it best:
How can Apollo 11 be described? It was a feat of skill and daring unmatched in history. The Apollo moon landing transcended the struggle between the United States and the Soviet Union for world domination. It was a source of pride and inspiration for the whole human race, symbolizing the heights that humans are capable of reaching and overshadowing every space mission before or since.

The problem with putting on a great show is that everyone expects an encore. Where shall we go next?

And our Solar System offers no good answer to that question. The next nearest world after the moon is a hundred times farther away. That world is Venus, where the CO2 atmosphere has created a run-away greenhouse effect, scorching the surface with temperatures high enough to melt lead--and with an atmospheric pressure that would crush a nuclear submarine. Humans will never walk on Venus.

How about Mars? It’s only a little farther than Venus, and much more hospitable: very little atmosphere, and about as cold as Antarctica. Astronauts in spacesuits would be no worse off there than on the moon. The problem is the distance.

It took three days for the Apollo astronauts to reach the moon. Traveling at the same speed, it would take about a year to reach Mars. Ah, but that was 40 years ago. Surely rocket technology has improved exponentially since then, so we can travel much faster...?  

Actually, no. Rocket technology was already quite mature by 1969, and the laws of physics don’t permit any major, straightforward improvements. Perhaps we could shorten the travel time to a few months, but nobody has any idea how to get to Mars faster than that. We could probably keep a crew alive on such a long flight, but only at tremendous cost.

So human space flight has retreated to low-earth orbit, just above the atmosphere. Since 1972, no human has traveled farther from earth’s surface than Cape Canaveral is from Houston. Most of the scientific research that goes on during these orbital missions is aimed at understanding how the human body deteriorates during long periods of weightlessness.

Besides months of weightlessness, astronauts bound for Mars would be exposed to the serious radiation hazards of interplanetary space. And even if these hazards can be mitigated, the risk in such a journey would be tremendous. If anything goes wrong (think Apollo 13), the chance of a successful bailout is inversely proportional to the distance from earth. A failed mission to Mars would be a tragedy not just for the crew, but for all of humanity.

If the real goal is to inspire our children, I think there are better ways. It’s the robotic spacecraft that do NASA’s scientific work, touring the Solar System and peering at the distant universe from above earth’s obscuring atmosphere. Many of the technologies used by these spacecraft, to see and sense and transmit data, have advanced exponentially since 1969. Instead of watching a fuzzy transmission on TV, today’s children can use the internet to explore the surface of Mars or visualize the patterns in the cosmic background radiation.

Let us therefore celebrate human space flight by giving it a hero’s funeral--and get on with the business of exploring the universe with 21st Century technology.

Sunday, July 5, 2009

iPhone Astronomy

When I gave up my Palm Z-22 for an iPhone in March of last year, one of the few things I sacrificed was a free little astronomy app that would draw a chart of the planets and constellations for any date and time.

Third-party apps for the iPhone became available a few months later, and among the initial offerings were four good astronomy apps. They cost $9 to $12 each, but they were far more powerful than what I’d had before. Over the year since then, two of these apps have been greatly improved and three others have been introduced. The most powerful of them now costs $19, but there are good choices for $5 to $6 and one of the apps also comes in a pretty good free version.

I have no idea whether these apps are stimulating more interest in astronomy among the general public, but I sure hope so. They’re affordable, fun to use, and instantly available whenever you find yourself out under the stars wondering what you’re looking at. Although astronomy software for full-sized computers is more powerful still, it’s often more expensive and harder to use--besides being tied to a large, power-hungry device that you can’t slip into your pocket.

The iPhone (and iPod Touch) user interface is ideally suited for this kind of software. On the screen you see a map of the sky, automatically adjusted for your current location. The amount you see at any one time is limited by the screen’s small size, but you can move the map around and zoom in and out instantly, using intuitive finger gestures. The better apps are so easy to use that even if I’m sitting at my computer, I prefer to pull out my iPhone to look up the time of sunset or the phase of the moon or the best time to view the Andromeda Galaxy.

In a modest effort to promote these apps, I decided last winter to write a review of them. Not a quick off-the-cuff review, but a thorough review of all seven apps, with a detailed comparison table and lots of screen shots. Otherwise, how are users supposed to choose among the seven apps--or even know that they have so many choices? (There’s no easy way to even find them all on the iTunes Store, which outgrew its primitive organizational scheme long ago. Astronomy apps are variously categorized under Education, Navigation, and Reference.)

The review project ended up being a little too ambitious, and I’ve had trouble keeping the review up to date. Still, there are hundreds of people out there who have read the review, and I’m getting a steady trickle of email thanking me for it. If a few more people fall in love with astronomy as a result, it will have been time well spent.

Astronomy is just one of many subjects where computing makes more sense on a mobile device than on a bulky computer. Another is trail maps and nature guides, as I mentioned recently. I get the sense that most of us, including the software developers, are still adjusting to this paradigm shift, and I look forward to the next generation of useful mobile apps.