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October 13, 2002
Contents
1. Meanderings
2. Interstellar probes
3. Bookends
1. Meanderings
Greetings from a rapidly color-changing Minnesota, somewhere near Lake Wobegon. As promised, a picture of me and my newly wedded daughter has been posted on my web site with mine host wearing his kilt for the occasion. A traditional Scottish wedding in Glasgow, it all went off splendidly I'm happy to say.
3. Bookends
One of the more minor fallouts from last September's events was the cancellation of the Exobiology Principal Investigators Conference at NASA Ames in California at which I was due to put in an appearance. This has now been rescheduled for the second week of January and I'll be on stage at the public meeting on Jan 7th (Tuesday night) with the grandfather of SETI, Frank Drake, and Ian Crawford, a fellow Brit from University College London. It's funny how these things happen but I think I've been cast rather in the role of the guy who thinks the universe is teeming with life. Actually, the title of my book "Life Everywhere" wasn't meant to imply that there was life everywhere, only that it was about life in general, but I suppose "Life Wherever It Happens To Be" doesn't have quite the same punch to it! Anyhow, Ian, I think, is going to be taking the more pessimistic view that advanced life, and intelligence in particular, is probably pretty rare out there, while I'm going to be wading in with arguments that it might be more common. Frank Drake will be preventing any fights breaking out and moderating questions from the audience. Should be fun.
2. Interstellar probes
Pioneers 10 and 11 and Voyagers 1 and 2, having long since finished their main business at the giant planets, Jupiter through Neptune, are now star-bound. Pretty slowly, by Starship Enterprise standards, it has to be said. You can get the latest on Pioneer 10 at this NASA page where you'll find that the spacecraft is currently just over 12 billion km (7.5 billion miles or 81.3 AU, where 1 AU or astronomical unit = average Earth-Sun distance), from the Sun, moving at 12.2 km/s (27,400 mph). This is a nifty little page, by the way, which gives you the latest data from P10 and even lets you listen to the signals picked up from it. Pioneer 10 is heading roughly in the direction of the bright red star Aldebaran in the constellation Taurus the Bull, which is about 65 light-years away. That's quite a journey. Aldebaran's light might take "only" 65 years to get here at 300,000 km/s, but P10 is traveling at 12.2/300,000 or 0.00004 of light-speed so that it has a little matter of 1.6 million years or so before it comes within shouting distance of Aldebaran. Even then, it isn't going to approach within a couple of light-years of the big star, so any Aldebaranians who happen to be around would need amazingly sensitive equipment to be able to pick up it.
Contact with Pioneer 11 (the first flier-by of Saturn) was lost back in November 1995, so distance info isn't updated for it any more. According to my back-of-envelope calculation (subject to a wide margin of error!), it's now about 59.2 AU out. And it's plodding along, cosmically speaking, in the direction of Aquila the Eagle. On the off-chance that any aliens do intercept the twin Pioneers, however, both have a plaque which I have some blurb about here.
What about the Voyagers? Both are still alive and well and carry out a few science experiments as they travel along. NASA isn't offering quite the week-by-week data on V1 and 2 that they were a while ago, but you can still find good info about the background to the missions and data as recent as March 2002 at this NASA page.
Voyager 2, which did the "grand tour" of Jupiter, Saturn, Uranus, and Neptune, is currently about 67 AU out, while V1 is traveling a bit faster and is pushing 86 AU — 12.9 billion km (8.1 billion miles). That makes V1 the most distant manmade object ever. To see what direction there're heading in, go this NASA page and click on the neat graphics. You'll see that both are moving toward the nearer (upstream) edge of the so-called "heliopause," which is the outer boundary of the Sun's magnetic influence. Before that they'll cross the "termination shock" and after the heliopause they have some way to go before they cross the "bow shock" and enter true interstellar space. It's hoped that data from the Voyagers will help chart the location of these structures over the next couple of decades, before the probes' nuclear-powered batteries go dead. If either of the Voyagers fall into the hands of extraterrestrials they'll be able to reveal quite a bit about where they came from and who build them. For more on this, check out this site. And what about future interstellar spacecraft? There's been no shortage of ideas. One of the best researched potential missions was Project Daedalus — a proposed 50-year flight to nearby Barnard's Star — which you can read more about here.
On a shorter timescale, NASA is mulling the possibilities of dipping its toe into interstellar space with a purpose-built craft, several ideas for which you can check out here. For those interested in manned missions to the stars, you can read about some of the possible ways this could be achieved in my new encyclopedia. Or, if you simply can't wait to see what might be waiting for us out there, try startrek.com!
Excitement mounts (in the Darling household, at least!) as the pub date of "The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity" draws close. Only about four weeks to go now. For the latest blurb, details of entries, etc, follow the "Spaceflight" link on the front page of my web site.
Until next time,
Best wishes,
David Darling