My dog, Reggie, is extraordinarily cute. I know this because the ultimate arbiters of asthetics – teenagers girls – in my neighborhood 'ooed' and 'awwed' over her the other night. During the admiring session, one of the girls asked me about Reggie's breed.

I could have more easily answered a question about an effective exit strategy from Iraq. Reggie's kind of a, well, half this and half that, with another quarter of something thrown in for good measure.

So it was with some interest I noted a piece in the journal Science about a group of Seattle geneticists using DNA to "uncover the roots of dogs' family trees." The Oregonian reports that the researchers found such large genetic differences among breeds that "DNA markers alone correctly identified the breed of 409 of the dogs." They also discovered four distinct breeding groups.

The first group to emerge from that project is a set of dogs of Asian and African origin ... The mastiff and related dogs fill the second grouping [including German shepards for some reason] ... The third genetically similar group includes many herding dogs, such as the Belgian sheepdog and collie, as well as Irish wolfhounds, greyhounds, borzois and Saint Bernards. The final group included dogs that have been bred relatively recently in Europe, mostly for hunting – scent hounds, terriers, spaniels, pointers and retrievers.

Not only will this info help dog breeders sort out the real bluebloods from those Johnny-come-lately breeds, but the article claims that this research will also help scientists find genes that they say cause certain ailments that affect "both dogs and humans." And it could also illuminate how DNA affects behavior and personality. (Hmmm. So maybe that's why when my wife says 'fetch' I have this uncontrollable urge to, well, go the store and get a half gallon of milk.)

This study comes on the heels of a study earlier this month that reported "on an average basis, it's possible to match dogs with their owners, based on criteria of owner selections and purebred characteristics."

So not only do we act like our dogs, we look like them too.

On June 8 Venus will take 6 hours, 12 minutes and 30 seconds to pass in front of the Sun. The last transit was 1882. Of course, where you stand, and how you protect your eyes from the sun's harmful radiation, are critical.

First, the obvious. You will only be able to see the transit during daylight hours. (See figure 3) If it’s nighttime in your part of the planet, you’re out of luck (sort of – see below).

Venus nudges against the east face of the sun at precisely 05:13:29 Greenwich Universal Time (that’s 5:13 a.m. in Greenwich, England). Astronomers call this first contact. In North America it means that when the sun rises Venus will already be more than half-way across our solar system's furnace, and by 7:25 a.m. EDT, will no longer be in front of the sun. If you live west of St. Louis (except Alaska, which is far enough north to catch part of the transit) you’ll have to wait until April of 2012 for your next opportunity.

Thanks to the Web, no matter where you live, you can watch the entire transit live. The European Southern Observatory based in Chile will have it live on their website. Viewing a virtual image of the transit means no concerns about solar filters to portect the eyes. Go there now and book mark the page.

I plan to be up 1:13 a.m. in Boston to log on and watch the first contact as well as what is called second contact at 1:32:55 a.m. Boston time (5:32:55 a.m. Greenich or Universal time) when the complete orb of Venus slips completely inside the Sun's circumference.

A word of caution -and I'm speculating here - but it will be interesting to see if the observatory's servers will be up to the traffic and have the bandwidth to meet the demands that I am sure will be made upon it.

Solar filters

We’ve written many times about not looking directly at the sun. Adults and most teenagers know this. The concern is with younger children who are hearing about a transit or an eclipse for the first time and don't realize the potentially harmful effects that may occur by looking directly into the sun with the naked eye.

So, to repeat: Watch young children. Be very carefull. Looking at the sun without a proper solar filter is the equivalent of putting your eyeballs in a microwave oven and turning it on high. Enough said.

Obviously, the safest way to watch the transit is to go to the website mentioned above. But the thrill of actually seeing a planet move in front of a star, not virtually but literally, warrants the effort. Many high school and university science classes will have safe viewing sites. Check them out on the web or in your local newspaper. If you have an astronomy enthusiast as a friend he or she will likely be setting up a telescope – with a certified filter. Ask to grab a peek.

One of the most widely available filters for safe solar viewing is shade number 14 welder's glass, which can be obtained from welding supply outlets. Another inexpensive alternative is aluminized mylar that is manufactured specifically for solar observation.

Unlike the welding glass, mylar can be cut to fit any viewing device. If you are thinking of buying or making a filter for observing the transit of Venus be sure to closely read the following two excellent articles from Sky & Telescope magazine: "Solar Filter Safety;" and
"Solar filter suppliers."

See related articles: Captain Cook, the transit of Venus, and a little trip to Tahiti; Here comes the Sun - and Venus; Check out Venus at its brightest

Over the past few years, while Microsoft Internet Explorer has come to dominate the Web browser audience (with former champ Netscape staggering behind), there has been a third browser that has quietly gone about its business, often without fanfare, slowly winning over more and more fans: it's called Opera.

Hardcore netjunkies know lots about Opera, created by a Norwegian company in 1994. When it first appeared, it looked more like an interesting experiment, rather than a viable alternative to the big guys. Opera has always had a "small footprint" on a computer - a very small file size. Downloading and installing Internet Explorer takes A LOT of space if you go for all its bells and whistles.

The newest version of Opera (7.5) is only 3.5 megabytes.

Let me repeat that: 3.5 megabytes. It is the Gettysburg Address of Web browsers. Not a line of code is wasted or in the wrong place. Internet Explorer, on the other hand, is the speech then-Arkansas governor Bill Clinton gave at the Democratic Convention in 1988 that went on so long he was booed off the stage.

Opera is also different in another way: its comes in two flavors. You can download Opera for free. But then you have to accept ads, and reduced capabilities. But for $39 US you can buy a version of Opera that is ad free, and ready to kick some IE butt. (And in a rather cool twist, as The Washington Times notes, you can actually make your Opera browser look like IE ... or Netscape or Safari, or whatever you like. These "skins" are free and can be downloaded from the Opera site.)

The newest Opera version includes a cool new feature: an RSS aggregator built into the browser. RSS stands for (at least among some people) Real Simple Syndication. If you really like a column or blog, say, like this blog, you can sign up for its RSS feed. (It's just above here in the right hand column, labeled XML ... see it?) Before Opera, you needed to select an RSS aggregator to collect all these RSS feeds. As the Associated Press noted last week, "Support for RSS had been available primarily through standalone applications and as plug-ins for Microsoft Corp.'s Internet Explorer. RSS also comes with smaller browsers like OmniWeb for Macintosh computers."

The aggregator allows you to create, in a way, your own online newspaper or magazine - only it's all your choices. In the new Opera, those RSS feeds will go into the browser's e-mail client, which is cool because you're far more likely to see them in your e-mail.

If you haven't tried browser, give it a spin. Kick the tires. If you like it, you can get rid of that huge copy of Internet Explorer - oh, excuse me, it's part of the operating system, how could I forget? Well, you can just let that copy of IE sit there like a wedding present from your great-aunt that has to be kept around just in case she shows up for dinner some night.

I love wi-fi. I spend many the morning padding around the house in my pyjamas, laptop clutched in hand, surfing the Web. All thanks to my dsl connection and a Linksys wireless router. Ah heaven.

But now I'll be able to recreate that Wi-Fi experience at 30,000 feet, although I won't be in my pyjamas. That's because New Scientist reports that Lufthansa, the German airline, started a new service Monday that allows passengers to Web surf or send e-mails from their own Wi-Fi-enabled laptop or handheld computers instead of using the more "limited services" (to put it politely) some airlines offer through their seatback displays.

The system, called FlyNet, has already been installed on five of Lufthansa's fleet, with plans to extend this to all 80 of the German airline's long-haul planes by the end of 2006. Passengers will share a download capability of five megabits per second, while uploading traffic, such as sending emails, will run at one Mbps. This speed of connection is comparable with that used in a small office.

The cost is actually pretty decent. Ten bucks for half and hour, or $30 for the entire flight. (The New Scientist article reminds us that some seatback services charge $16 to send one e-mail.) And when your flying, say from Munich to Los Angeles, you've got some time to burn.

This is possible thanks to the Boeing company Connexion and to ten geostationary satellites circling the Earth at 36,00 kilometers (about 22, 300 miles). Several other airlines have already indicated they are interested in setting up similar services.

But what about all that interference with flight equipment? Will we be endangering the lives of fellow passengers if we check our e-mail, or look for a stock quote? Lufthansa has already considered that, and the service will only be offered at "cruising altitude."

"Meine Damen und Herren, the captain has switch off the seat belt sign. You are now free to find out the latest score in the Red Sox game...."

Captain James Cook, navigator, explorer, and discoverer, still but a lieutenant in the British Navy, witnessed and took measurements of the June 3, 1769 transit of Venus from the south-Pacific island of Tahiti.

Why sail half-way around the world through uncharted waters to land on an as of then unmapped island to do such a thing you ask? The reason was simple, and profound for his times – to determine how far away the Sun was from Earth. In an age of sail, such a fact would be of immense value in navigating the world’s oceans.

First, a thought experiment. Erase from memory all you know of distance. Stand on a flat plain, either day or night and look towards the heavens.

How far away is the Sun, the stars? What in your human experience would offer insight into the unimaginable distances – after all, 93,000,000 miles is the closest star to Earth – you look across. The ancient Greeks, for instance, thought the planet Jupiter (Zeus in Greek mythology) was just a little distance above Mt. Olympus.

Given the limited instrumentation of Cook's day, the exact timing of the transit of Venus was believed to be the only way to precisely fix the distance to the Sun. It offered a solution to a problem of immense consequence by using a methodology known to every schoolboy of that age – geometry.

The principle Cook was to employ dated to the ancient Greek geometers: parallax. Parallax gives a means of measuring distance.

A simple way to conduct a parallax experiment is to just fix on an object across the room from where you are standing. Cover one eye as you look at it. Then, cover that eye and open the other. A "shift" or angle occurs in perception. The two different points of view of the same object, from the same spot, create an optical triangle.

The Greeks proved that if you know the distance from one eye to the other, or the two different points from which you view the same fixed object, plus the angle created by the parallax, it should be possible to figure out the distance to the object viewed.

Of course, you would need one honking large triangle to get a fix on the Sun. The base of your triangle, and the one employed in Cook's time, was the diameter of the Earth. It was impossible to get one any longer. Take a measurement of the transit from two opposite points on the globe, compute the angle and voila! Length of the sides of the triangle would equal the distance from Earth to Sun.

A skilled mathematician and surveyor, the Yorkshire farm lad so impressed his naval superiors by the accuracy of his observations of a solar eclipse in 1766 that he was given command of the ship "Endeavor." His mission: "catch" the transit of Venus for the British Royal Society and King George III.

From his south-Pacific observatory, Cook, in collaboration with others measuring the transit of Venus from other locations on the globe, would become a point at the joining of two sides of a giant triangle. (see figure 2).

Unfortunately for Cook, and scientists of the era, Venus's cloudy cover did not let observers see, or fix, the exact time at which the planet entered and exited the Sun’s orb. Variations in timing the transit were too great to allow for precise computing of the distance to our closest star.

Cook’s expedition came up with a distance of approximately 123 million kilometers to 157 million kilometers. Not the kind of accuracy that NASA could use to send a spacecraft, say, to Mars, but nevertheless, much better than previous estimates. More precise measurements of Earth’s distance from the Sun (an Astronomical Unit or AU by astronomers) would have to wait for better instrumentation and different methodologies than available to Cook.

For an excellent website showing the voyage of Cook to Tahiti, check out - South Seas: voyaging and cross-cultural encounters in the Pacific (1760-1800)

For an extended mathematical discussion of parallax check out: Approximated method for the calculation of the parallax.

Next: Actual times of Venus’s transit of the Sun on June 8.
Previous: Here comes the Sun - and Venus (by Jim Bencivenga)

On June 8, Venus will pass in front of the Sun's face.

Prepare for a media blitz. It will be all transit, all the time as the airwaves, newspapers, and Internet, herald this unique phenomenon of planetary alignment.

Despite saturation coverage, hunker down in the privacy (and awe) of your own imagination. Contemplate the mathematical precision in predicting the transit given the distances and magnitude of the objects involved. No hype should diminish your sense of wonder.

Given that there are more than a billion stars in our Milky Way galaxy and more than a billion billion galaxies in the known universe, just why is one tiny - about 80% the size of Earth - little planet’s passing in front of a star such a big deal? Because we are conscious of it. Venus’s passing in front of our Sun is not an unrecorded, inanimate event. (See figure 1)

In our tiny little corner of the universe we sojourn with our sister planet and we simultaneously imagine our own Earth as it orbits the Sun, sustained by the hostile fire of our star's nuclear explosions that seed life-giving photosynthesis across the frigid emptiness of space.

Only six transits of Venus have occurred since the telescope was invented in the early seventeenth century: (1631, 1639) (1761, 1769) (1874, 1882). Notice, that transits occur in pairs with eight year separations between the two transits in the pair. (So you’ve got a second chance in case you miss this one next month. More than likely you’ll want to come back and see it again.)

Intervals of about 105 or 122 years elapse before a pair of transits occurs. More than one century will elapse before they occur again. You may grow tired of hearing: "The last time Venus transited the Sun was in the year 1882; no living human has ever seen this event." Don't!

More compelling: Few humans – maybe hundreds - have ever seen Venus cross the Sun's disk (more on this in a future blog).

A few facts: the only planets that can transit the Sun are those with orbits smaller than Earth's orbit, i.e., Mercury and Venus. Mercury, being much closer to the Sun, makes 13 to 14 transits a century. We had one a year ago on May 7.

Photos of Venus taken by some of the world's great telescopes will amplify the image of this cloud-covered sojourner crossing a sea of fire. Viewing the transit of this tiny black dot will heighten awareness of the size, scale and velocity of planets. Ultimately, we will connect our own water planet in relation to the myriad of stars that fill the heavens, all of which are yoked by the same laws of motion and gravity.

There is much more to say. Rather than attempt to do so in one comprehensive article we plan to update – to blog this blog – from now until June 8th. We will offer tips on how to safely view the transit; where on the planet it will be visible, with exact times; links to websites on the subject; and a photo gallery from professional and amateur alike of some of the better pictures taken of the transit.

One final thought. Another message you will hear over and over: "Never look directly at the sun with the naked eye or unfiltered telescope." This one you can't hear enough. The temptation will be to sneak a peak. It is up to every adult to keep children from the optical equivalent of playing in traffic. (Parents and teachers should verbally beat youngsters over the head with this advice.)

Next: Captain Cook and Venus. (by Jim Bencivenga)