• Forget the movies: 9 real ways the world could end

    P. Carril / ESA

    Asteroids zip past Earth in this artist's conception. But scientists are worried about a real one slamming into the planet.

    By Tia Ghose
    LiveScience

    From catastrophic climate change to hostile aliens, Hollywood routinely envisions apocalyptic endings to humanity's stint on planet Earth.

    For instance, in the movie "After Earth," which opened in theaters Friday, a series of earthquakes, floods, tsunamis and other natural disasters makes the planet inhospitable to humans, who resettle on a new world called Nova Prime.

    Although the movie may be pure fantasy, many scientists are worried about other perilous scenarios — some of which are even scarier than anything that's been depicted on the silver screen.

    From pandemic fungus to robot insurrection, here are nine apocalyptic visions that scientists foresee. [Doom and Gloom: Top 10 Post-Apocalyptic Worlds]

    1. Global warming
    The mother of all apocalyptic fears, climate change is the biggest threat facing the planet, many scientists say. Climate change could make extreme weather more severe, increase droughts in some areas, change the distribution of animals and diseases across the globe, and cause low-lying areas of the planet to be submerged in the wake of rising sea levels. The cascade of changes could lead to political instability, severe drought, famine, ecosystem collapse and other changes that make Earth a decidedly inhospitable place to live.

    2. Asteroid!
    It's the mainstay of disaster movies, but scientists are legitimately worried that a space rock could wipe out Earth. A meteor impact probably doomed the dinosaurs, and in the Tunguska event, a massive meteoroid damaged about 770 square miles (2,000 square kilometers) of the Siberian forest in 1908. Even more frightening, perhaps, is that astronomers only know about a fraction of the space rocks lurking in the solar system.

    3. Pandemic threat
    New deadly pathogens crop up every year: Recent pandemics have included outbreaks of SARS (severe acute respiratory syndrome), bird flu and, most recently, a coronavirus called MERS that originated in Saudi Arabia. And because of our highly interconnected, global economy, a deadly disease could spread like wildfire.

    "The threat of a global pandemic is very real," said Joseph Miller, co-author (along with Ken Miller) of the textbook "Biology" (Prentice Hall, 2010).

    4. Fungus among us
    Though bacterial threats are dangerous, fungal threats are even scarier, said David Wake, curator at the Museum of Vertebrate Zoology at the University of California, Berkeley.

    "We've had a new amphibian fungal disease that has just had devastating effects," Wake said of the chytrid fungus that is wiping out frogs across the United States.

    An equally fatal fungus in humans would be catastrophic. And though bacteria are deadly, antibiotics are plentiful. By comparison, we know much less about treating fungal infections, Wake told LiveScience.

    5. Engineered disease
    Natural diseases aren't the only ones to fear.

    In 2011, the scientific community was outraged that researchers had engineered a mutant version of the bird flu H5N1 that was transmissible in ferrets and transmitted via the air. The results sparked fears that engineered deadly diseases could inadvertently escape from the lab or be intentionally released, leading to a global pandemic.

    6. Nuclear war
    Many scientists are still worried about the classic end-of-the-world threat: global nuclear war. Beyond North Korean leader Kim Jong Un's saber rattling and Iran's secretive nuclear efforts, massive stockpiles of nuclear weapons around the globe could wreak destruction if they were to get into the wrong hands. Last year, the Bulletin of the Atomic Scientists, a nontechnical magazine on global security founded in 1945 by former Manhattan project physicists, moved the Doomsday Clock, at five minutes to midnight. The Doomsday Clock shows how close humanity is to destruction via nuclear or biological weapons or global climate change. [7 Strange Cultural Facts About North Korea]

    7. Robot ascension
    "The Terminator" may be science fiction, but killing machines are not far from reality. The United Nations recently called for a ban on killer robots — presumably because experts worried that several countries are developing them.

    Many computer scientists think the singularity, the point at which artificial intelligence overtakes human intelligence, is near. Whether those robots will be benevolent helpers or the scourge of humanity is still up for debate. But a lot can go wrong when there are hyperintelligent robots armed with lethal weapons running around.

    8. Overpopulation
    The fear of an overpopulated globe has been around since the 18th century, when Thomas Malthus predicted that population growth would cause mass starvation and overtax the planet. With the global population at 7 billion and counting, many conservationists think population growth is one of the key threats to the planet. Of course, not everyone agrees: Many think population growth will stabilize in the next 50 years, and that humanity will innovate its way out of the negative consequences of the overcrowding that does occur.

    9. Snowball effect
    Though each of these scenarios could happen, most scientists think a snowball effect of multiple events is more likely, Miller said. For instance, global warming could increase the prevalence of pathogens while also causing widespread shifts in climate. Meanwhile, ecosystem collapse could make it slightly harder to produce food, with no bees to pollinate crops or trees to filter agricultural water. So, instead of an epic catastrophe, several relatively small factors would slightly worsen life on Earth until it gradually degraded, Miller said.

    In that scenario, the downfall of Earth is not dramatic, "like being attacked by a saber-toothed tiger," Miller told LiveScience. "It's more like being nibbled to death by ducks."

    Follow Tia Ghose on Twitterand Google+. Follow LiveScience @livescience, Facebook and Google+. Original article on LiveScience.com.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Why the buzz over St. Malachy's 'last pope' prophecy outdoes 2012 hype

    Patricia Drury via Flickr

    A statue of St. Malachy of Armagh (1094-1148) stands on the grounds of St. Malachy Catholic Church in Sterling Heights, Mich. Centuries-old prophecies that have been attributed to St. Malachy are causing a stir due to Pope Benedict XVI's surprise abdication announcement.

    By Alan Boyle, Science Editor, NBC News


    Just when you thought it was safe to go out of the bunker, there's a fresh wave of doomsday buzz over a purported 12th-century prophecy suggesting that the next pope will be the last pope before the end of the world. St. Malachy's "Prophecy of the Popes" has no credence in the Roman Catholic Church, but its effect could well be longer-lasting than the hype that surrounded the 2012 Maya apocalypse — especially if the papal conclave goes with one of the favored candidates for Benedict XVI's successor.

    The text that's been attributed to Malachy came to light in 1595, in a book by Benedictine monk Arnold de Wyon. Supposedly, Malachy experienced a vision of future popes during a trip to Rome in 1139, and wrote down a series of 112 cryptic phrases that described each pope in turn. The text was said to have lain unnoticed in Rome's archives until Wyon published it.

    Doomsday fans have found ways to link each phrase to a corresponding pope through the centuries. That includes John Paul II, who is associated with phrase No. 110, "From the labor of the sun," because he was born on the day of a solar eclipse and was entombed on the day of a solar eclipse as well. Benedict XVI, No. 111, is supposedly "glory of the olive" because some members of a branch of the monastic order founded by St. Benedict are known as Olivetans.

    Then there's No. 112: "In the extreme persecution of the Holy Roman Church, there will sit ... Peter the Roman, who will nourish the sheep in many tribulations; when they are finished, the city of seven hills will be destroyed, and the dreadful judge will judge his people. The end."

    The end? This could be the beginning for a doomsday meme that hangs over a whole generation, if it's taken seriously. There's already a 586-page book about the coming apocalypse, titled "Petrus Romanus." One theologian, Michael K. Lake, is quoted as saying that "Catholic and evangelical scholars have dreaded this moment for centuries."

    In fact, the Catholic Church doesn't put any stock in the prophecies, for a variety of reasons. One of the biggest red flags is that no mention was made about the papal prophecies until the 1590s — not even by St. Bernard of Clairvaux, a close friend of Malachy's who wrote his biography and hailed his gift of prophecy. And then there's always the biblical dictum that no one knows the day or the hour for doomsday — a rule of thumb that works for believers as well as non-believers.

    Most experts have concluded that the text was made up to boost a 16th-century cardinal's bid to become pope.

    But if the coming papal conclave really wanted to drum up the doomsday talk, as well as sales for "Petrus Romanus," all they'd have to do is elect one of the leading candidates: Ghanaian Cardinal Peter Turkson, a member of the Roman Curia. Even though church tradition would forbid any pope from taking the name Peter II, Turkson could arguably be described as Peter the Roman. Others suggest that he could be the "young red black one" mentioned in the similarly cryptic doomsday prophecies of Nostradamus.

    Whomever the conclave picks, there'll surely be a way to connect him somehow with "Peter the Roman" — after all, isn't every pope a successor to St. Peter, based in Rome? "Any pope can be thought of as the latest Peter in the line," Tom Horn, one of the authors of "Petrus Romanus," said a couple of months ago on the "Coast to Coast AM" radio show.

    Which means we might have to deal with 2012-style doomsaying as long as the next guy is in office. What do you think?

    Dearly departed doomsdays:

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

    This story was originally published on Tue Feb 12, 2013 6:20 PM EST

  • Another doomsday threat dies out: Asteroid Apophis won't hit us in 2036

    Apophis, nicknamed the "Doomsday Asteroid," was once considered a potential threat, but now scientists realize the chance of the asteroid colliding with Earth is negligible. NBC's Brian Williams reports.

    By Alan Boyle, Science Editor, NBC News


    Radar observations made during this week's close encounter with the asteroid Apophis have ruled out the risk of a catastrophic cosmic collision in 2036, NASA says. Experts say it'll be much farther away at that time than it is right now.

    The crucial readings came on Wednesday when the space rock, which is thought to measure at least 885 feet (270 meters wide), approached within 9 million miles (14.5 million kilometers) of Earth. NASA is monitoring Apophis with its 230-foot (70-meter) Goldstone radio dish in California. Optical readings also have come in from the Magdalena Ridge Observatory in New Mexico and the Pan-STARRS observatory in Hawaii.

    The bottom line? "We have effectively ruled out the possibility of an Earth impact by Apophis in 2036," Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory, said today in the all-clear news release. "The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future."

    Jon Giorgini, who developed JPL's online Horizons database to keep track of solar system objects, would go even further. He says that according to calculations based on the Goldstone data, Apophis will probably pass by Earth at a distance of 36 million miles (58 million kilometers, or 0.39 AU), and absolutely no closer than 14 million miles (22 million kilometers, or 0.15 AU). "That is a very extreme minimum," he told NBC News. "Nothing else plausible can get you closer."

    Apophis, a.k.a. 2004 MN4, created a huge splash when it was discovered in 2004 because the initial assessment of its orbit gave a 1-in-40 chance of Earth impact in 2029. That would be catastrophic: The space rock is big enough to wipe out a city if it struck land, or create killer tsunami waves if it splashed into the ocean.

    Additional orbital data quickly eliminated the risk for 2029, but showed that it would pass within 20,000 miles (32,000 kilometers) of our planet at that time. That's so close that Earth's gravitational field will perturb Apophis' orbit. The experts worried that if the asteroid passed through a particular half-mile-wide zone in space, known as a "keyhole," its orbit would be perturbed just enough to set up a smash-up during the 2036 encounter. Fortunately, the latest observations indicate that Apophis will miss the keyhole by a long shot.

    Did I just hear a cosmic sigh of relief?

    UH / IA

    The asteroid Apophis, highlighted here by a white circle, was discovered in June 2004.

    There are still a few uncertainties surrounding Apophis: Astronomers don't yet have enough data to determine how the asteroid is spinning or how solar radiation is affecting its orbital path — a phenomenon known as the Yarkovsky effect. Giorgini said that even under the worst-case scenario, the effect won't push Apophis into a collision in 2036. But there could conceivably be other risky encounters in the decades or centuries ahead.

    "There's a non-linear amplification that can really move it around more," Giorgini said.

    Also, there are questions about Apophis' exact size. Just this week, readings from the European Space Agency's Herschel space telescope suggested that the asteroid may be nearly 20 percent bigger than previously thought. But that larger size estimate is based on the assumption that Apophis is a spheroid, and astronomers already know that it's elongated.

    "We're not seeing that larger size in the radar data," Giorgini said.

    By the end of next month, continued radar observations from Goldstone as well as the Arecibo Observatory in Puerto Rico should give astronomers a much better fix on Apophis' spin and its size. When those factors are fully accounted for, the Jet Propulsion Observatory will update its official risk assessment for Apophis — and could take this bad boy off the hit list for good.

    Update for 6:30 p.m. ET: Clark Chapman, senior scientist at the Southwest Research Institute, weighed in on the current state of the asteroid hunt in an email:

    "One thing you should be aware of, and might mention, is that the next Planetary Defense Conference, an every-two-year international meeting, will be held April 15-19 in Flagstaff, Arizona. ... Some presentations are already listed in the program, which should be finalized a week from now, which is the due date for abstracts.

    "An interesting tie-in with the new observations of Apophis is that a similar thing happened with 2011 AG5 a few weeks ago, when observations with the huge Gemini telescope in Hawaii showed that it would, in 2023, miss the roughly 350-km-wide 'keyhole' and, therefore, not strike the Earth in 2040.  Prior to these critical observations, the chance of a 2040 impact was unusually high (though still low in everyday terms) at 1 in 500.

    "A point to be realized is that while the chances of impact in these cases are very low by ordinary standards, they aren't zero, and the consequences of an impact could be very terrible, so it is important to plan and prepare for the possibility of impact until it is ruled out.

    "It was important to get these observations of AG5 in the autumn of 2012, because if it had turned out that AG5 was actually on an impact trajectory, it would have given us an additional year to mount a deflection mission and succeed in deflecting it from the 2023 keyhole. Without making a major observational effort with a very large telescope this autumn, the next routine observational opportunity wasn't until this coming autumn."

    Update for 8:30 p.m. ET: One of NASA's experts on the asteroid threat and two former NASA astronauts have weighed in on the report about Apophis. David Morrison of NASA's Ames Research Center sent these comments via email:

    "One possible angle is the recent proposal from [NASA Administrator] Charlie Bolden, based on a Keck study, that we retrieve a 7-meter carbonaceous near-Earth asteroid and bring it into lunar orbit. There are many questions about this idea, but the one I have in mind is our assumed ability, without Sentinel, to find 7-meter C-type asteroids in Earthlike orbits. If you can't find them, you can’t protect against them, or do anything with them as potential resources." 

    Now here's an email from Ed Lu, a veteran of two space shuttle missions and an extended stay on the International Space Station. Lu now serves as chairman and CEO of the B612 Foundation, which is planning to launch the Sentinel space telescope to track half a million near-Earth asteroids:

    "While it is great that Apophis is much better understood, and we know it won't hit us in 2036, the greatest danger from an asteroid strike is from the ones we haven't yet found.  Of asteroids larger than the one that struck Tunguska in 1908, we know of less than 1 percent of them.  And as David Morrison points out, we can't protect ourselves from the unknown asteroids (or make use of them either). The B612 Foundation Sentinel Space Telescope is going to work on finding and tracking these asteroids."

    And here are some comments from Apollo 9 astronaut Rusty Schweickart, who has played a key role in raising awareness about the threats and opportunities presented by near-Earth objects. It was Schweickart who warned in the wake of Hurricane Katrina that asteroids like Apophis could spark a much more devastating "cosmic Katrina":    

    "I'm hoping that you don’t follow the bad (surprisingly wide) precedent of stating that [the risk from] Apophis has been eliminated.  Please look on the JPL risk page  and especially the more detailed info and note that 1) The 2036 impact possibility is, while significantly reduced, still possible, and 2) that the 2068 impact possibility is now elevated ... to a level that exceeds what the 2036 impact was prior to this apparition.

    "There’s certainly good news re the 2036 impact decreasing in probability ... but frankly it was 1 in 234,000 prior to the new observations ... not exactly an impact probability to worry one. (There are many NEOs with higher impact probability ... but no one pays attention to them ... they aren't the 'poster child' that Apophis is.) My personal reaction was one of surprise that the new 2036 impact was not zero!

    "But/And ... there are more radar observations to integrate in ... as well as optical tracking both now and for the next several years.  Apophis isn't going away ... the impact possibilities are simply shifting around a bit with refinement of the tracking data. 2036 is now less probable; 2068 is now more probable (but still very low).

    "Until JPL and the other guys get more data (enough to really define the Yarkovsky effect), we really won’t be able to get definitive data for longer time scales that we can rely on."

    JPL's Giorgini said the risk assessment that Schweickart mentioned won't be full updated until after Goldstone and Arecibo finish their observational campaign in mid-February — so there may still be a non-zero risk listed until then. But Giorgini is confident that the 2036 risk will disappear when all the observations are factored in. (As of this writing, the estimated risk of collision is listed at 1 chance out of 10,989,000.) But you're right, Rusty: In order to eliminate the risk completely, astronomers will have to get more data about Apophis' physical characteristics. And then there are all those other unknown killer asteroids that might be out to get us...

    More doomsday worries addressed:

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.