In some parts of the world, it's already Sunday — and there hasn't been any sign that the end of the world was starting as predicted. But you already knew that'd be the way it went down, didn't you?

For years, Family Radio preacher Harold Camping has been telling his flock that the Rapture would gather up 200 million Christian believers to heaven and kick off five months of tribulation for the rest of us, heralded by a massive earthquake. Can you imagine the panic that might ensue if a significant quake actually did strike today? There's always a chance of that, of course. But as it turns out, the day has been relatively quiet in seismic terms.

Readings from the U.S. Geological Survey have turned up only a few quakes worthy of any note around the world, and nothing anywhere near major. If you check the USGS' chart of seismic activity, the blue squares denote quakes that have occurred over the past 24 hours, and the red squares stand for tremors in the past hour. The size of the square represents how big the quake was ... and there are no big squares.

USGS

This chart from the U.S. Geological Survey traces earthquakes stronger than magnitude 4.5 throughout the world over the past week, as of 11 a.m. ET Saturday. Yellow squares denote quakes up to a week ago, blue squares denote quakes up to a day ago, and red squares are quakes in the previous hour. The strongest quakes have been slightly higher than 5 in magnitude, which is in the normal range for those regions.

There's no word yet from Camping, and his followers are likely still hunkered down wondering if the end will come. But other folks are starting to go about their business, which is a good thing.

On the Cosmic Log Facebook page, correspondents around the world are voicing a sense of relief. One woman writes, "Jesus Himself said that no one would know the day or hour, but only His Father in Heaven. Besides, I'm getting married today at 3:00."

Best wishes to the bride ... and to all of you.

Noel Celis / AFP - Getty Images

A passenger jeep on a street in Manila, the Philippine capital, drives past a banner that reads "Judgment Day 21 May 2011." The day passed without incident in the Pacific.

Update for 7:30 p.m. ET: A couple of fairly significant seismic events were recorded later in the day, including a 5.8 quake in Japan and a 5.8 quake in New Zealand's Kermadec Islands. These happened to occur on Sunday as reckoned by local time, and on Saturday according to GMT. None of the events could be called Rapture-worthy unless Camping and his followers end up grasping at straws.

More about the Rapture rumblings:

• Why we're enraptured by the Rapture hype
• Rapture prophet says he'll be watching the action on TV
• Digital Life: Post-rapture video reveals stunning lack of zombies
• The Last Word: Only hours to go until the (fake) Rapture
• End of Days? Believers enter the final stretch
• End of the world? How about a party instead?
• Slate: 144 scenarios for America's apocalypse
• Pet sitting offered during Rapture
• Doomsday facts (or fictions)

Even though Saturday is already finished with in some parts of the world, I'll still be blogging about the Rapture hype until the day is totally finished, and probably even longer. You can follow the updates by checking CosmicLog.com/Rapture. You can also connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. And for something completely different, check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

If you're reading this, the Rapture still hasn't happened yet.

The preacher behind the Saturday Rapture prediction, Family Radio's Harold Camping, has said that a great earthquake would herald the beginning of the end-time tribulation around suppertime — that is, around 6 p.m. That tick of the clock has come and gone in parts of the Pacific, including Kiribati and New Zealand.

The precise timing of doomsday can be a squishy concept: Some accounts claim that the big quake has been predicted for 6 p.m. Pacific time, which is still more than 18 hours away. But I think most of us already suspect it won't make much of a difference whether we're talking about Kiribati time or California time, don't we? In any case, if you want to keep track of seismic activity around the world, you can check in with Earthquake.USGS.gov.

This whole exercise serves as a good reminder to keep your disaster preparedness kit up to date. Rapture aside, you never know when the next big earthquake, power outage or zombie apocalypse will come along.

Happy Saturday to you! I'll be blogging about the Rapture hype over the weekend, and you can follow the updates by checking CosmicLog.com/Rapture. You can also connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. And for something completely different, check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

For a lot of people, the end of the world is serious business, even if they may not think that Saturday is the day. I'd like to apologize in advance to those people for the following links to levity:

• XKCD on the Rapture
• Rapture Gopher says ...
• Rapture excuse bingo card
• Rapture delivery failure notice
• Flowchart: Will you be raptured?
• Some grey bloke on the Rapture
• Rapture for gamers and twitterers
• The Onion: World to end on Saturday
• The Oatmeal: How God is managing the Rapture

I'll be blogging about the Rapture hype over the weekend, and you can follow the updates by checking CosmicLog.com/Rapture. You can also connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. And for something completely different, check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

If you're reading this, the Rapture hasn't happened yet.

If it had happened, you might have been taken up to heaven with 200 million other members of the elect. (Or is that 144,000?) The alternative is even spookier: being left behind to face five months of tribulation leading up to the end of the world and Jesus' judgment. (Or is that seven years?)

The prediction that the end times would begin in earnest on May 21, 2011, was made years ago by Harold Camping — the preacher who heads Family Radio, a worldwide religious broadcasting concern. His prophecy is based on calculations so kooky that other end-time prophets say he's giving them a bad name. 

The real question is: Why has there been so much buzz over Saturday's scheduled Rapture?

"Obviously, what could be a bigger news story than the end of the world?" University of York historian Nicholas Guyatt, author of the book "Have a Nice Doomsday," told me. "It's absurd to think the world is going to end on Saturday, but even if there's an infinitesimally small chance that it's true, we should be interested."

One thing that sets Camping apart from most end-timers is that he sets actual dates. That runs counter to the usual Christian interpretation of the end times, which focuses on a passage in Matthew in which Jesus says "you do not know the day or the hour." It also runs counter to the lessons learned from centuries of failed doomsday predictions.

"Even among evangelists who believe in the Rapture,  most of them know we're not supposed to be trying to set dates," said Jerry Jenkins, co-author of the popular "Left Behind" apocalyptic book series.  "For one thing, it's going to make us look foolish on Sunday."

Jenkins jokingly acknowledges he's "one of those kooks who really believes it's going to happen one of these days." The 16-novel series he wrote with minister Tim LaHaye provides a fictional account of the end times, going all the way to the Second Coming. The tale is based on an interpretation of the end times known as pre-tribulation dispensationalism — which starts with some believers instantly disappearing in the Rapture while leaving others to fight it out with the Antichrist and his minions.

"It'd be a horrifying and chaotic event," Jenkins said. "I'm still a little confused whether Camping thinks that's going to happen, or whether there'll be an earthquake."

Nonsense from numbers
Jenkins and many others are also confused over how Camping came up with his prediction. This year-old posting from Church of God News runs the numbers: Saturday supposedly marks 7,000 years since the Noah's Ark flood, and 722,500 days since Jesus' crucifixion. By Camping's numerology, 722,500 represents (5 x 10 x 17) x (5 x 10 x 17), or the square of atonement times completeness times heaven. 

"Now the above is utter nonsense," the Church of God News' Bob Thiel wrote. That sounds about right.

Jenkins says such number-based predictions "happen fairly frequently" in the end-time game. "It's sort of seasonal," he said.

In fact, Camping himself predicted years ago that the world would end in 1994. When the prediction failed, Camping said he got his initial calculations wrong and corrected the figures to come up with Saturday's doomsday date.

Guyatt noted that prophets have been predicting the end times, and getting the dates wrong, for hundreds of years. One of the best-known examples in America is the "Great Disappointment" of 1844. Baptist preacher William Miller predicted that the "Second Advent" would come on Oct. 22 of that year (after a couple of abortive predictions for earlier dates). He attracted as many as 50,000 adherents by the time the big day came. Nothing happened, of course. The result? Derision, church burnings, vandalism, even tar-and-feathering. Miller continued to await the Second Advent until his death five years later.

Miller's theology contributed to the later rise of denominations such as the Seventh-Day Adventists and Jehovah's Witnesses, but those churches did away with the date-setting.

Bart Ehrman, a professor of religious studies at the University of North Carolina at Chapel Hill and author of the newly published book "Forged," notes that the scriptural foundations for modern-day end-time scenarios are shaky. "In the Apocalypse, there's no reference to the Rapture at all," he told me. "The idea of the Rapture comes from the writings of Paul." And many of the details have been "completely made up by theologians, they're not found in the Bible," he said.

Ehrman said he could come up with his own scenario for the end times that would make more sense than Camping's. "What I'm looking for is some very wealthy believer," he joked.

Ah, the money angle. "The thing that's confusing about [Camping's prediction] is that he doesn't seem to be making money off this," Jenkins said.

Funding the Apocalypse
Lots of money is being spent on promoting the Rapture, however. Family Radio's financial records indicate that the nonprofit organization had $122 million in net assets in 2007. The figures for the following year, 2008, show $41 million in expenses, resulting in net assets of $86 million. The 2009 report shows expenses of $37 million and net assets of $72 million. And judging by the billboard ads, bus ads and direct-mail campaigns promoting the Rapture, the spending rate must have risen substantially since those reports were filed. After all, if you're going to heaven on Saturday, why wouldn't you spend it all?

Ehrman noted that this sort of pre-doomsday spending spree has happened before, when he was teaching Bible classes in the 1980s. One of the books that came out back then was "88 Reasons Why the Rapture Will Be in 1988."

"I had students in my classes whose parents literally sold the farm because they didn't need it, and then it didn't happen," he recalled.

Some Family Radio listeners, such as Staten Island retiree Robert Fitzpatrick, have spent tens of thousands of dollars of their own money to promote the Rapture. That worries Jenkins. "There are very well-meaning people who are telling me they're getting rid of their life savings," he said. "I wonder who's going to take care of them when it's all over?"

Gerry Broome / AP file

Allison Warden shows off her car, emblazoned with messages about Saturday's scheduled Rapture. Warden, of Raleigh, N.C., has been helping organize a pre-Rapture campaign using billboards, postcards and other media in cities across the U.S.

The big spending spree is one big reason why this particular date has gotten so much traction. But end-time tales do not live by billboard ads alone. Guyatt says this time in history is particularly well-suited for doomsayers.

"Whenever anything really bad happens, it kind of gives their case a little support," Guyatt said. "So if you think of the turbulent times we've had over the past decade — 9/11, Iraq and Afghanistan — it kind of feeds on that. Maybe it's not formal, but we have an affinity with the view that the world is becoming a more dangerous place, or maybe our days are numbered."

And every Twitter tweet, Facebook update, Rapture party invitation — for that matter, every blog post — turns up the wattage ever so slightly on the doomsday spotlight. "What's given this traction is the billboards and the media," Guyatt said. "At some point the ball is rolling, and we help tip it a bit further, because of you, because of us."

How imminent is 'imminent'?
Leave it to the veteran end-timers, who have been through all this before, to provide perspective. "I applaud the discussion," Jenkins said. "I think people should be thinking about this."

Jenkins' writing partner, Tim LaHaye, has said on many occasions that events such as the Japan earthquake and tsunami are signaling that the end is near. The way Jenkins sees it, the end of the world could well be imminent, but "our definition of 'imminent' is clearly not the same as God's."

"If he waits one more day in his mercy, it could be a thousand years in our time," he said.

So what will Jenkins be doing on Saturday?

"We're just going to carry on with the usual activities," he told me. "One of our granddaughters is going to have a ballgame."

More about the Rapture rumblings:

• Rapture prophet says he'll be watching the action on TV
• Digital Life: Post-rapture video reveals stunning lack of zombies
• The Last Word: Only hours to go until the (fake) Rapture
• End of Days? Believers enter the final stretch
• End of the world? How about a party instead?
• Slate: 144 scenarios for America's apocalypse
• Pet sitting offered during Rapture
• Doomsday facts (or fictions)

In some parts of the world, it's already Saturday. I'll be blogging about the Rapture hype over the weekend, and you can follow the updates by checking CosmicLog.com/Rapture. You can also connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. And for something completely different, check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Claudia Marcelloni / CERN

A worker stands beneath the ATLAS detector's calorimeter during this month's maintenance break at the Large Hadron Collider.

The world's most powerful particle collider will be kept running through 2012 rather than taking next year off for an overhaul, Europe's CERN particle physics lab announced today. The change in plans means scientists at the Large Hadron Collider will have more time to track down the Higgs boson and other mysteries of the universe before the extended break — and it also means the machine should be shut down just in time for the Maya apocalypse.

Not that there's anything to the doomsday date. There's no reason why the world should end on Dec. 21, 2012, with or without the LHC. Some folks think dramatic, world-shattering changes will occur on that day because it marks the end of the Maya "long-count" calendar, but that myth has no basis in historical or cosmological reality. (And experts say the date may have been miscalculated, anyway.) Some folks also think the LHC could bring on doomsday by creating catastrophe-causing black holes or strangelets — but there's no evidence for that, either.

The real significance of the LHC's operation in 2012 is that scientists are so pleased with the way the machine has been running that they want to keep up the scientific momentum.

"With the LHC running so well in 2010, and further improvements in performance expected, there's a real chance that exciting new physics may be within our sights by the end of the year," Sergio Bertolucci, CERN's research director, said in today's news release. "For example, if nature is kind to us and the lightest supersymmetric particle, or the Higgs boson, is within reach of the LHC's current energy, the data we expect to collect by the end of 2012 will put them within our grasp."

Right now, the LHC is closed for maintenance, but it's due to start up again in February. The new schedule, approved by the CERN's managers over the past few days, calls for operations to resume at the tried-and-true energy of 3.5 trillion electron volts per beam. CERN expects to increase the LHC's data collection rate by at least a factor of three over the next year, potentially allowing scientists to see the first hints of new phenomena by the end of the year. But one year would not provide enough time to "turn those hints into a discovery," CERN said.

So instead of shutting the LHC down for a yearlong series of upgrades, as previously planned, CERN said it would take a "short technical stop" at the end of 2011, then go back into operation for 2012. The big upgrades would be done during 2013, and in 2014 the LHC would be back in business at its full design energy of 7 TeV per beam.

One of the LHC project's primary goals is to detect the Higgs boson, which is the only particle predicted by current theory that has yet to be found. The Higgs particle, along with its associated field, is thought to play a role in endowing some particles with mass while leaving others (such as photons) to go massless. Research at the LHC could shed new light on other fundamental questions as well: Are there whole classes of supersymmetric particles (or "sparticles") that have gone undetected to date? Might some of those sparticles account for dark matter, which can't be seen but can be detected by its gravitational influence? Is it possible that we live in a world of 10 or 11 dimensions? Why does it look as if matter won out over antimatter when the universe came into being? What's the nature of the primordial soup that existed just an instant after the big bang?

For more about the LHC and its role in solving the mysteries of the universe, delve into our special section about "The Big Bang Machine." And for more from the 2012 watch, check out these stories:

• Stressed by storms and supernovas?
• Solar cycle sparks doomsday buzz
• Alien invaders vs. the truth squad
• The end is not near 

If you're looking for an additional antidote to 2012 hysteria, check out 2012hoax.org. Join the Cosmic Log community by hitting the "like" button on the blog's Facebook page or following b0yle on Twitter. You'll even find a reference to 2012 hype in a chapter of my book, "The Case for Pluto."

As if the Maya apocalypse wasn't enough to worry about, talk of a potential California superstorm or a catastrophic supernova have given a further boost to 2012 paranoia. Heck, even Hollywood is making a cameo in the 2012 saga.

Doomsayers have predicted that a global catastrophe, or at least some kind of global change-over, could occur in 2012, but they're likely to end up as wrong as those who predicted a Y2K meltdown or a Second Coming in 1844. (Jesus' failure to appear during that year left thousands of Millerite Christians in the lurch and led to what is now known as the Great Disappointment.)

Just in case you need to build up your resistance to 2012 hype, here's the first in a series of roundups relating to the doomsday buzz:

Superstorm:
When scientists and emergency response experts developed their "ARkStorm" meteorological model for the California coast, the point was to figure out a worst-case scenario for weather disaster planning, which would parallel the planning for a seismic "Big One" in the Golden State. They came up with a doozy, proposing that Pacific weather patterns could produce "atmospheric rivers" that dump rain onto the West Coast for 40 days and 40 nights. ("ARk" stands for "Atmospheric River 1000.")

Experts say such a hurricane-style storm occurred over a 45-day period in 1861-1862, causing severe flooding and turning the Sacramento Valley into an inland sea. Today, that kind of storm could cause $300 billion to $400 billion in damage. The video above paints an apocalyptic picture, made worse because "the public at large does not comprehend the extreme danger the storm poses."

Well, they comprehend it now. All this talk of a superstorm scared the bejeebers out of a lot of people, and it's now become woven into the fabric of 2012 fears. Just do a search for "2012 California superstorm" and you'll see what I mean. There's already a backlash as well: Over at the "Watts Up With That?" blog, Anthony Watts takes the U.S. Geological Survey to task for getting into the "weather porn" business. "I don't dispute the historical evidence of the 1861-62 flooding, but scaring the crap out of the public won't really help them plan effectively."

We don't really have to wait until 2012 for a wakeup call on the threats posed by severe storms: All you have to do is look at what's been happening in Australia and Brazil this month.

USGS

A color-coded map shows rainfall levels that could be caused by a hypothetical "ARkStorm" hitting the California coast. The shades of purple indicate accumulations of more than 50 inches.

Supernovas:
Will the star Betelgeuse blow up by 2012, creating a supernova so bright it'll look as if there are two suns in the sky? We addressed this seven months ago: Sure, the red supergiant could potentially explode sometime in the next 10,000 years, or maybe 100,000 years, based on observations of its mass-shedding activity. But no one can really predict precisely when it'll go supernova, and when it does, it's shouldn't have a dramatic effect on Earth.

So why is Betelgeuse back on the 2012 scene? The reason is that it's just so darn tempting to bring up that date anytime a cosmic blow-up is being discussed. That aspect is amply addressed today by Bad Astronomy's Phil Plait as well as Discovery News' Ian O'Neill. Heck, some folks are still trying to talk up the idea that Betelgeuse is going bonkers because it's part of the Maya prophecy for 2012. This won't be the last time we here from "Beetlejuice, Beetlejuice, Beetlejuice!"

Superstars:
What do you get when you cross celebrity buzz with 2012 buzz? You get some widely re-quoted quotes from "Green Hornet" star Seth Rogen, who recounts a movie meeting during which "Star Wars" creator George Lucas "seriously proceeds to talk for around 25 minutes about how he thinks the world is gonna end in the year 2012, like, for real."

Despite Rogen's protestations, it's not clear whether Lucas was joking, or Rogen was joking, or whether it's just one of those weird Hollywood things. The most interesting spin on the anecdote comes from the New York Daily News, which details how various celebrities (from Ashton Kutcher and Woody Harrelson to Lil Wayne) feel about the impending apocalypse.

You can bet that we'll have more installments of "2012 Watch" over the next couple of years, and I think I'll make a habit of ending every installment with my favorite piece of advice from Douglas Adams' "Hitchhiker's Guide to the Galaxy": DON'T PANIC!

More on 2012:

• The end is not near
• Alien invaders vs. the truth squad
• Solar cycle sparks doomsday buzz
• French village flooded by doomsday survivalists
• 'End of the world' delayed ... by Mayan calendar

If you're looking for an additional antidote to 2012 hysteria, check out 2012hoax.org. Join the Cosmic Log community by hitting the "like" button on the blog's Facebook page or following b0yle on Twitter. You'll even find a reference to 2012 hype in a chapter of my book, "The Case for Pluto."

Sukanya Chakrabarti / UC-Berkeley

The distribution of HI hydrogen in the Whirlpool Galaxy, as determined by the THINGS VLA survey, extends far beyond the visible stars in the galaxy and its satellite companion (marked by cross). Analysis of perturbations in the hydrogen distribution can be used to predict the location of such hard-to-spot satellite galaxies.

The search for Planet X may be problematic, but astronomers believe there's a "Galaxy X" lurking on the other side of the Milky Way.

Based on an analysis of our home galaxy's distribution of cold atomic hydrogen gas, two astronomers at the University of California at Berkeley are predicting that a previously undetected dwarf galaxy, about 1 percent the mass of the total Milky Way, should lie about 300,000 light-years out from the center of the Milky Way ... in an area that's obscured by intervening gas and dust.

Such a galaxy hasn't been detected directly — yet — but postdoctoral fellow Sukanya Chakrabarti and Leo Blitz are betting that it's out there nevertheless.

"This is the first time in my profession that I'm really going out on a limb and making a very specific prediction," Chakrabarti told me.

This month, a request is being put in for observing time on the infrared-sensitive Spitzer Space Telescope, as part of its GLIMPSE survey. If the request is approved, Chakrabarti and Blitz should find out sometime this year whether their bet has paid off. The payoff could be big: If Galaxy X is found, its existence could explain a curious discrepancy in the current theoretical model for dark matter distribution in the universe.

And if the bet goes bad? "Even if we're wrong, we'll learn something significant, because it could be due to the shape of the dark matter halo," she said.

Chakrabarti discussed her research, which has been submitted to the Astrophysical Journal, at the American Astronomical Society's winter meeting in Seattle today.

Reading the ripples
Our Milky Way is surrounded by about 80 known or suspected dwarf galaxies, known as satellite galaxies. Some of them are well-known in their own right, such as the Large and Small Magellanic Clouds. The problem is that there don't seem to be enough of them. The best model for dark matter distribution at large scales predicts that, at the scale of the Milky Way, there should be hundreds or perhaps even thousands of dwarf galaxies.

Chakrabarti and Blitz suggest that the "missing" dwarf galaxies may be so small and dim that they're obscured by the dust of the bigger galaxies in their neighborhood. The dwarfs may even be made primarily of invisible dark matter. But even then, they should create disturbances, or ripples, in the much larger pool of hydrogen gas within the disk of a galaxy. The gas is gravitationally bound to the galaxy, but extends much farther out than the galaxy's visible stars — sometimes as much as five times farther out.

That cold hydrogen gas can be mapped by radio telescopes.

"The method is like inferring the size and speed of a ship by looking at its wake," Blitz explained in a news release. "You see the waves from a lot of boats, but you have to be able to separate out the wake of a medium or small ship from that of an ocean liner."

To test the idea, the researchers looked at high-resolution radio data for the Whirlpool Galaxy and another galaxy known as NGC 1512, collected as part of the Very Large Array's THINGS and THINGS-SOUTH surveys. When Chakrabarti fed the data into her mathematical model, the results accurately predicted the locations of two known satellite galaxies. The Whirlpool satellite was a third the mass of the primary galaxy, while the NGC 1512 satellite was one-hundredth the mass of the big galaxy.

Chakrabarti said her model should work with galaxies as small as a thousandth of the primary galaxy's mass.

When she and Blitz checked radio data for the Milky Way, the model pointed to a dwarf satellite galaxy that's around 3 billion to 10 billion solar masses, or roughly one-hundredth the mass of the Milky Way. The galaxy should be on the opposite side of the Milky Way, somewhere in the constellations of Norma or Circinus, just west of the galactic center in Sagittarius when viewed from Earth.

NASA's Spitzer Space Telescope would be well-suited for spotting such a galaxy, because its infrared camera can see objects that are obscured by dust in visible-light wavelengths. While Chakrabarti and Blitz wait to find out whether Spitzer will be able to look for Galaxy X, they're also checking dozens of other galaxies to make sure their mathematical model holds up.

Planet X vs. Galaxy X
Chakrabarti likes to compare her quest to the search for unseen planets in the 19th century. Most famously, the French mathematician Urbain Le Verrier predicted the position of a new planet in 1846 purely by analyzing its gravitational effect on other celestial bodies. When the German astronomer Johann Gottfried Galle looked where Le Verrier predicted, he found the planet Neptune almost immediately.

That success sparked a search for a supposed planet within the orbit of Mercury, called Vulcan. (It turned out, however, that Mercury's perturbations were explained instead as a consequence of Albert Einstein's general relativity theory.) The discovery of Neptune also led Percival Lowell to start searching for a planet even farther out, which he called "Planet X." That quest eventually resulted in the discovery of Pluto in 1930. (You can read all about the quest for Planet X in my book, "The Case for Pluto.")

Some observers suggest that there could be yet another Planet X still out there — perhaps a giant planet on the far edge of the solar system. And some have even claimed that an as-yet-undetected planet is heading our way for a close encounter in (gasp!) 2012. There's no chance of that happening, but NASA's Wide-field Infrared Survey Explorer, or WISE, would be capable of seeing a distant Planet X if it's the size of Jupiter or bigger.

The WISE mission's principal investigator, Edward Wright of the University of California at Los Angeles, told me that such a Planet X would be detected as a brown dwarf candidate, moving across the background of stars. More than 1,000 brown dwarf candidates are being checked right now, and if any of them "are moving a lot, then you'll hear from us," Wright said.

Chakrabarti marveled at the difference between the 19th-century search for Planet X and the 21st-century search for Galaxy X.

"In the 1800s, all Le Verrier had was one solar system," she said, "whereas we can now go and test the statistical viability of this method on a very large sample of galaxies."

More about dark matter and Planet X:

• The darkest mystery of them all
• Gallery: Dark matter revealed!
• New dark matter map created for big galaxies
• Large 'Planet X' may lurk beyond Pluto

Connect with the Cosmic Log community by "liking" our Facebook page, or by following msnbc.com's science editor, Alan Boyle, on Twitter (@boyle).