Slogging on

And slugging it out for another month and half, perhaps longer.

Fifty-five -- forty-five is a number that breathes another wisp into Mrs. Clinton's sails, while not helping her in the delegate count enough to make her continuing campaign anything but that of a spoiler.

(The) margin in Pennsylvania was probably not sufficient to alter the basic dynamics of the race, but it made clear that the contest will continue.

The media meme became all about the point spread and the over/under was seven or eight points, even as much as ten. So Clinton met those expectations, and the result is that Obama's inability to land the knockout blow is officially a sign of weakness. Since Iowa, he shows little ability to attract white voters with incomes under $50,000, the so-called blue-collar voter. These are likely the people -- also known by their aged label of Reagan Democrats -- who would abandon him in the fall.

If that's not enough cause for concern ...

“This is exactly what I was afraid was going to happen,” said Gov. Phil Bredesen of Tennessee, a Democrat who has not endorsed anyone in the race. “They are going to just keep standing there and pounding each other and bloodying each other, and no one is winning. It underlines the need to find some way to bring this to conclusion.”

And:

“We have problems going both ways, but that is going to get healed,” saiid Joe Trippi, who was a senior adviser to the presidential campaign of John Edwards, who quit the race earlier this year. “If it doesn’t get healed, we have problems.”

Next up: Indiana and North Carolina on May 6. Speaking of both Edwards and NC, Howard Fineman stated (during MSNBC's election coverage) that Elizabeth Edwards would be campaing with Hillary in North Carolina. Take that for what you wish, but my perception is that, if accurate, it changes the game to Clinton's advantage in a state where Obama is expected to make up for the delegate-count and popular-vote losses he suffered last night.

Update (from elsewhere around the 'sphere): Since Greg brought it up, I wonder what the internals are on the Dunder-Mifflin voting bloc. Martha and Bradley are celebrating -- and soliciting; Neil and jobsanger point out the obvious. Hal live-blogged the results. And Jerome has nine suggestions for both campaigns in the post-Pennsylvania wrap-up.

Happy EarthDay

Earth Day -- April 22 -- each year marks the anniversary of the birth of the modern environmental movement in 1970.

Among other things, 1970 in the United States brought with it the Kent State shootings, the advent of fiber optics, "Bridge Over Troubled Water," Apollo 13, the Beatles' last album, the death of Jimi Hendrix, the birth of Mariah Carey, and the meltdown of fuel rods in the Savannah River nuclear plant near Aiken, South Carolina -- an incident not acknowledged for 18 years.

It was into such a world that the very first Earth Day was born.

Earth Day founder Gaylord Nelson, then a U.S. Senator from Wisconsin, proposed the first nationwide environmental protest "to shake up the political establishment and force this issue onto the national agenda. " "It was a gamble," he recalls, "but it worked."

At the time, Americans were slurping leaded gas through massive V8 sedans. Industry belched out smoke and sludge with little fear of legal consequences or bad press. Air pollution was commonly accepted as the smell of prosperity. Environment was a word that appeared more often in spelling bees than on the evening news.

Earth Day 1970 turned that all around.

Here's information on Earth Day at the Houston Zoo.

Mercury, Wednesday

Mercury just passed superior conjunction on April 16, but in the days to come it will bolt out to become easily visible low in the west-northwest at dusk. On Wednesday evening, April 23, Mercury should be visible within about 30 minutes after sunset if your sky is quite clear. Mercury will be shining at magnitude �1.6, slightly brighter than Sirius (the brightest of all stars). In fact, at that particular hour of the day, Mercury will be the brightest object in the sky!

So, if your sky is free of any horizon haze and there are no tall obstructions to your view (like trees or buildings) you should have no trouble in seeing it as a very bright "star" shining with just a trace of a yellowish-orange tinge. By April 30, Mercury will be setting as late as 85 minutes after the Sun. That evening, binoculars may show the Pleiades star cluster 4 degrees directly above it. (Your clenched fist held at arm's length measures about 10 degrees in width.)

In the evenings that follow, Mercury will slowly diminish in brightness, but it will also slowly gain altitude as it gradually moves away from the vicinity of the Sun. This is just the start of Mercury's best apparition of the year for mid-northern viewers. On the evening of May 6, be sure to look for a delicately thin sliver of a 1.5-day old crescent Moon sitting just a couple of degrees above and slightly to Mercury's right.

Much more.