FBI

The FBI says a 1950 flying-saucer memo rates as the most popular file in its online document repository.

The FBI says it never followed up on the most popular file in its online reading room — a one-page UFO memo that passes along a second- or third-hand report about flying saucers and alien passengers that were supposedly recovered in New Mexico.

The memo, dated March 22, 1950, has been viewed almost a million times over the past two years, the FBI said this week in a blog posting. It was written by Guy Hottel, who was the head of the FBI's field office in Washington at the time, and addressed to FBI Director J. Edgar Hoover.

In the memo, Hottel discusses an account provided to an FBI agent ... that was attributed to an informant ... who purportedly heard from an Air Force investigator ... that "three so-called flying saucers had been recovered in New Mexico."

"They were described as being circular in shape with raised centers, approximately 50 feet in diameter," the memo read. "Each one was occupied by three bodies of human shape but only three feet tall, dressed in metallic cloth of a very fine texture. Each body was bandaged in a manner similar to the blackout suits used by speed fliers and test pilots."

Hottel said he was told that the saucers' control systems might have been disrupted by interference from "a very high-powered radar set-up" that the government had in the area. But he admitted in the memo that "no further evaluation was attempted" by the informant, whose name is blacked out in the online document.

The Hottel memo has been in the public record since the 1970s, but it created a huge splash in 2011 when it was added to the FBI Vault, an online repository of public records. Here's how The Sun, a British tabloid, characterized the memo in a headline from those days: "Aliens Exist, Say Real-Life X-Files."

Monday's posting was written to counter such characterizations. The FBI denied that the memo constituted evidence for the existence of extraterrestrial spacecraft — and said Hottel's report was never taken all that seriously. Instead, it was considered "an unconfirmed report that the FBI never even followed up on."

The FBI said there was no reason to believe that the memo referred to another famous UFO saga, the purported discovery of a crashed alien spaceship in Roswell, N.M., in 1947. "The Hottel memo is dated nearly three years after the infamous events in Roswell," it said. 

The bureau acknowledged that for a few years after the Roswell incident, Hoover followed up on an Air Force request by ordering his agents to verify any UFO sightings. "That practice ended in July 1950, four months after the Hottel memo, suggesting that our Washington Field Office didn't think enough of that flying saucer story to look into it," the posting said.

There's an alternate explanation for the Hottel memo that makes a lot more sense. Two years ago, when the memo was added to the Vault, paranormal investigator Ben Radford noted that the informant's story matched the description of a UFO hoax that was concocted by a man named Silas Newton. In 1950, Newton was telling tales about flying saucers that had crashed at a radar station near the Arizona-New Mexico border. Newton was later convicted of fraud, and died in 1972.

Ironically, there's a whole different section of the FBI Vault that's devoted to Newton, whom the bureau described as "a wealthy oil producer and con man." To get the story about the connections between Newton's tales and the Hottel memos, check out this thorough debunking on the Above Top Secret forum.

Even though the FBI says the memo "does not prove the existence of UFOs," it's not confirming the Silas Newton story, either. "Some people believe the memo repeats a hoax that was circulating at that time, but the Bureau's files have no information to verify that story," it said.

What do you think FBI Agent Fox Mulder would say? "The truth is out there"? Or "Trust no one"? Feel free to weigh in with your own verdict in the comment section below.  

Update for 6:35 p.m.: Mark Allin, chief operating officer for The Above Network, says the truth is out there, in the form of the Above Top Secret analysis that I mentioned earlier. "The short story is, without a doubt, 'Case Closed,'" Allin said today in an email. "The memo is based on a hoax that was carried out by a convicted con man named Silas Newton, and it was debunked years ago. It's a pretty good and interesting hoax story, to be certain, but there is no value in it beyond that."

More about UFOs:

• US Army missile test sparks UFO reports
• Gallery: UFO cases that still stir up a buzz
• Cosmic Log archive on UFOs

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.

Did Oscar-winning actor Russell Crowe really capture photos of a UFO outside his office in Australia, passing over Sydney's Royal Botanic Gardens? Or was it just a sailboat passing by?

In a series of Twitter updates, Crowe — who won the best-actor Oscar for his role in "Gladiator" and recently starred in another Oscar-nominated film, "Les Miserables" — insists that the pictures are real and that they don't show reflections or lens flare. What the YouTube video does show is a series of three timed-exposure photos, with a flat red light moving across the frame.

Crowe said the pictures were taken by a camera (a Canon 5D with no flash, to be precise) that was set up on the balcony of his office in the Sydney suburb of Woolloomooloo to capture pictures of fruit bats rising from the gardens. "This was a big surprise," Crowe wrote.

Some commenters quickly speculated that the UFO was nothing more than reflections from a light, perhaps from a beacon on a sailboat that was passing through nearby Woolloomooloo Bay. But Crowe defended the sighting: "The camera is on a balcony, not behind glass," he told one questioner. "Can't be a lens flare because it moves, camera is fixed," he said in another tweet.

Unless Crowe 'fesses up to a publicity stunt, or accepts one of the alternate explanations offered by skeptics, this sighting is likely to go into a big thick folder of unsolved celebrity UFO files. The conversation also rates a place among Crowe's most entertaining tweets. For what it's worth, here's another one from the Twitter files: "Due to a hangover of massive proportions ... anything I say on Leno tonight needs to be taken with a pinch of salt ... and a slice of lime."

I'll drink to that.

Update for 8 p.m. ET March 6: Facebook friend Tom Jorgenson came up with what seems to be the best explanation for the red light: It's reflected sunlight from a plane passing across the scene near sunset. You can make out what appears to be the outline of the plane's fuselage and tail. The exposure setting may have made the time-lapse pictures look more dramatic. To confirm that hypothesis, you'd have to check the time for the photo-taking session (at sunset) and the orientation of the camera (pointing to reflect the sun's rays into the camera lens). But I think we have a winner. What do you think?

Update for 12:13 a.m. ET March 7: OK, here's a much better explanation. ParaBreakdown's Phil Poling shows why Russell Crowe's UFO is most likely to be a series of long-exposure photos of an Unidentified Floating Object ... which now appears to have been identified. The YouTube video below breaks it down:

More from Cosmic Log's UFO files:

• Exploding UFO looks like weather balloon
• Middle East UFO linked to Russian missile test
• Cosmic Log archive on UFOs

Tip o' the Log to Huffington Post UK for the ParaBreakdown video.

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 Wed Mar 6, 2013 5:52 PM EST

A smartphone video that shows a bright orb exploding in the sky sparked a UFO mystery in Sacramento, Calif., but it looks as if the mystery has been solved: It was a weather balloon.

That may sound like the quintessential cover story from the flying-saucer conspiracy, but in this case, the explanation makes perfect sense.

The video was shot through the eyepiece of a telescope by Elijah Prychodzko around 5 p.m. on Dec. 20, and aired by Sacramento's CBS13 television station on New Year's Eve. The first video clip shows the orb in the sky with a smaller object swinging around it. Prychodzko calling his nephew over to take a look, and then turned back to shoot another video clip.

"Oh my God, it just blew up!" Prychodzko can be heard saying. The video showed a haze of fragments floating in the air.

In its account of the Sacramento UFO incident, The Huffington Post said "nobody has come forward to officially explain the event." On the Above Top Secret forum, however, the discussion quickly turned to weather balloons. The most telling message was this one, attributed to the National Weather Service's Upper Air Observations Program:

"...It is very likely a weather balloon that burst. The small dot 'orbiting' the balloon was the radiosonde that was attached below it with about 70 to 100 feet of string.

"The weather balloon was likely released by the National Weather Service (NWS) upper air station in Oakland, California, at about 3:00 p.m. local time.

"Here is a video of a NWS weather balloon burst taken by a NWS meteorologist through a telescope: http://www.youtube.com/watch?v=0lG3zr0yaJw"

ESRL / NOAA

Here's a sharper image of a research balloon in flight with an ozonesonde / radiosonde instrument package attached. This balloon was launched from a National Weather Service facility at the airport in Hilo, Hawaii.

George Cline, observation program officer for the National Weather Service's office in Sacramento, confirmed that the Oakland station releases its balloons at around 3 p.m. and 3 a.m. PT — and that the flights last about an hour and a half. He noted that the timing for Prychodzko's reported sighting fits the afternoon timeline.

"That would put it right around the time for a balloon burst," Cline told NBC News.

More UFO cases put in context:

• Did UFOs fly over S.F. Bay and Brooklyn?
• Chinese UFO linked to rocket
• UFO case solved in Cincinnati
• Middle East UFO linked to Russian missile test
• Cosmic Log archive on UFOs

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.

For a few days, the strange case of the Cincinnati Lights intrigued UFO fans, but it looks as if the person who took the original video has come up with the likeliest answer: The spooky lights floating through the sky are best explained as skydivers doing a show during a football game at a nearby high school.

The Sept. 28 light show was certainly reminiscent of more celebrated UFO cases, such as the Phoenix Lights of 1997 — but it was also similar to the El Paso Lights of 2010, which were similarly traced to skydivers using pyrotechnics. This time, it was the video shooter (known on YouTube as Galuyasdi) who figured out that a Start Skydiving team was doing a pyro show for La Salle High School's homecoming game at just about the time that the sighting took place. (La Salle lost to Moeller; sorry about that, Lancers.)

Even though this case appears to be solved, echoes of the Cincinnati Lights are still reverberating among UFO fans. It's always harder to track down the likely cause of a UFO sighting than to put up a video and just leave it at that. Hats off to the videographer and fellow investigators who solved their own mystery before it became a full-fledged UFO meme.

More cases from the UFO files:

• UFO seen in Middle East, linked to missile test
• Video from Chilean air base stirs up UFO buzz
• Book claims Soviets played role in Roswell UFO incident
• Cosmic Log archive on UFOs

A swirling spiral of light seen in the skies over Israel, Syria and other Middle East countries on Thursday night has been linked to a Russian intercontinental ballistic missile test.

Hundreds of Israelis jammed police hotlines with reports of the unidentified flying object, according to Ynetnews. Sighting reports came from Lebanon and even Armenia and Turkey. Versions of the video, captioned in Arabic, began appearing on YouTube.

Some of the reports that popped up on Twitter suggested that the lights in the sky were seen as a good omen for Syria's revolution. Others worried that it was a bad omen for Syria, potentially signaling the use of chemical weapons.

The actual explanation is almost certainly more mundane: The Voice of Russia reported that the country's Strategic Missile Forces conducted a test of the Topol ICBM from the Kapustin Yar firing range near Astrakhan in southern Russia on Thursday. Such a launch could theoretically be seen from areas of the Middle East and the Caucasus.

Citing a report from RIA Novosti, the radio service said the missile "accurately hit its target" in a Kazakh firing range. However, Ynetnews quoted Yigal Pat-El, chairman of the Israel Astronomical Association, as saying the missile "most likely spun out of control, and its remnants and the fuel was what people saw."

The video was reminiscent of other "space spirals" that occur when rocket stages release burning fuel as they spin. One such spiral was sighted over Norway in 2009, and turned out to be caused by a failed ballistic missile test. In that case, the missile that went awry was a Bulava ICBM, launched from a submarine in the White Sea.

Another spiral was sighted in Russia the following night and captured on video. That one was caused by a Topol missile test, but the test was reported as a success. At the time, NBC News space analyst James Oberg said he had indications that the Topol's "third-stage spin is a 'feature,' not a malfunction, and may be associated with guidance, or decoy deploy, or enhancing hardness against U.S. boost-phase antimissile weapons."

Update for 3 p.m. ET June 8: In an email, Oberg says the video appears to show the normal ascent of a Russian ICBM. Here's his explanation:

"The 'spiral' does not look to me to be a sign of a 'failed missile test' — it has been a common visual feature of Russian missile launches for more than 30 years and seems associated with a roll maneuver to 'dump' unwanted surplus thrust for short-range test flights. Since you can't shut down a solid fuel rocket early, you need to find a way to dump thrust so you don't overshoot a target.

"One way is to open portals on the sides of the rocket as it burns — sending much of the thrust out to the sides. Two opposite facing portals are usually installed, to counterbalance the thrust and not knock it off course.

"A careful analysis of the infamous 'Norway spiral' several years ago shows twin plumes emerging from the central object, in opposite directions. An alternate method is just to pitch the rocket off 'straight ahead' and then corkscrew, so as to spray some of the thrust off to the sides and keep your speed down to what you really need. Otherwise you'll overshoot your intended target.

"This launch was from the Volga River Kapustin Yar test range, active since 1947, but ICBM tests are infrequent. Direction was east, headed for the Sary Shagan impact zone in Kazakhstan, normally used only for testing anti-missile radars and interceptor missiles. That's hardly more than 2,000 kilometers away, so the test clearly wasn't of the missile itself but of its warhead's 'penaids' — penetration aids to frustrate tracking and targeting by U.S. anti-missile systems. This would result in a very unusual trajectory to get up to full ICBM speed without overshooting the target zone — probably lofted a lot higher than normal and then headed back down towards the target zone while still thrusting.

"The range from Kazakhstan to Israel isn't that great — the missile got 'above the horizon' from Israel pretty quickly, even with Earth's curvature.

"Another contributing factor: It's June — near the time of the 'midnight sun' in northern latitudes. That means sunlight is streaming over the pole, throughout the night. Something in the northern sky above the atmosphere over Kazakhstan would be backlit by that sunlight.

"These 'accidental' factors combined to make this show possible. And the widespread availability of pocket camcorders made recording it much more common than in the past."

Other rocket-related UFO sightings:

• December 2009: Another 'UFO' from Russia
• January 2010: Did missile test spark Chinese UFO sightings?
• June 2010: 'UFO' over Australia was likely caused by SpaceX rocket

Tip o' the Log to Huffington Post's Craig Kanalley. Twitter updates on the sighting are using the hashtag #MideastUFO.

Alan Boyle is msnbc.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. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Is this truly the video that UFO skeptics have been dreading? Actually, a compilation of 17-month-old video clips from a Chilean military air show is stirring up predictable responses from both sides of the UFO debate, but no dread.

For those who are inclined to believe that some unidentified flying objects exhibit characteristics beyond what our technology seems capable of, the El Bosque case could represent the latest, greatest evidence for flying saucers.

"This is a very, very unusual case, and I'm hoping that this case will help move forward the recognition that there really is something here that's worthy of further study. ... It has the possibility of being a breakthrough case," said investigative journalist Leslie Kean, the author of the book "UFOs: Generals, Pilots and Government Officials Go On the Record."

But for those who think even the toughest cases can be explained away as video glitches, bugs or other tricks of the eye, the El Bosque case is just more of the same. 

"They're 'unexplained cases' only if you ignore the explanation," self-described debunker Robert Sheaffer told me. "That's what's going to happen in this case."

Genesis of an anomaly
The case goes back to an air show that was staged in November 2010, at Chile's Air Force academy, which is headquartered at the El Bosque Air Force Base in Santiago. Nothing untoward was noticed by anybody during the show itself, but Kean said an engineer at the nearby aircraft factory noticed an anomalous spot as he was sifting through video taken from the show, looking for an image that could be used as a poster photo.

The spot appeared to move quickly from frame to frame, and the engineer thought it looked enough like some sort of craft to notify the Chilean government agency in charge of investigating anomalous aerial phenomena, known by the Spanish acronym CEFAA.

The way Kean tells it, CEFAA investigators looked around for other video clips of the event and pieced together six additional views of the spot-shaped phenomena. Ricardo Bermudez, a retired Chilean Air Force general who is now CEFAA's director, told a UFO conference last month that his agency consulted with other officials, image-processing experts and "non-believer astronomers." CEFAA's conclusion was that the spots were caused by an object traveling through the scene at speeds in excess of 4,000 mph — so fast that it went unnoticed by air-show spectators.

"Humans inside this object could not survive," Kean and a co-author, former New York Times investigative reporter Ralph Blumenthal, wrote in a Huffington Post report appearing on Tuesday. "And, somehow, it made no sonic boom..."

Kean told me that the El Bosque case was notable for several reasons: "I think what's exceptional about this is that the investigation was thoroughly managed by a government agency."  Also, she said, "it's something you can actually see with your own eyes." The fact that the object shows up on seven videos from the same event, recorded from different vantage points, adds to the intrigue, she said.

The El Bosque case fits the pattern that Kean laid out in her book, in which she highlights UFO accounts from experienced pilots, military observers and government officials. Even measured by that standard, the Chilean case stands out, Kean said. "In some ways, I think it's more explosive than many of the cases in the book," she told me.

Skeptics unconvinced
In their article, Kean and Blumenthal wondered whether El Bosque would turn out to be "the case UFO skeptics have been dreading" — but experts on the other side of the UFO debate said their skepticism was unshaken.

"It's a tiny thing in a low-res video," astronomer Phil Plait, the myth-buster behind the Bad Astronomy blog, told me in an email. "If this is the best she can come up with, dread is not exactly what I feel."

Sheaffer, a columnist for The Skeptical Inquirer magazine and author of the book "UFO Sightings," joked about the reference to dread. "I'm shaking," he told me during a telephone interview. "You just can't see it on the phone."

Sheaffer said there wasn't yet enough data available to judge what really happened at El Bosque. "It's going to be like the Phoenix Lights in 1997. We're going to have to go and sit down and look at it," he said. (Coincidentally, Kean and Blumenthal's story came out on the 15th anniversary of the Phoenix Lights incident in Arizona.)

Some of the key missing points in the story have to do with the six other videos that are said to show the flying spot. Kean said that as far as she knew, those videos have not been seen by anyone outside CEFAA's investigative group. Another must-have for outside investigators would be the identity of the shooters behind the seven videos. If they turned out to be seven random people, with no relationship to one another, that would at least argue against the incident being an intentional hoax, Sheaffer said.

The fact that no one reported hearing or seeing anything out of the ordinary during the air show itself would suggest that the anomalous object is a trick of the eye — or, more accurately, a trick of the video.

For some of the denizens of the Above Top Secret online forum, the nature of the spot, or spots, was obvious: It's a bug, or bugs. An insect flying at regular speed through the foreground of the video could have been misinterpreted as an aircraft flying at super-fast speed through the background. One forum member posted several animated GIF images showing a similar effect. Different bugs could conceivably have flown through the viewing fields of different cameras, leading to the impression that the same super-fast craft was shown in each video — particularly if the six videos identified during CEFAA's follow-up were pulled out of a larger set.

"Maybe we'll find out it's a bug, but I seriously doubt it," Kean told me. She said she took Bermudez and his fellow investigators at their word. "All I know is that people who know way more about photo analysis than I have ruled that out," Kean said.

Even though Kean has made a name for herself as a UFO writer, she insisted that she's not wedded to a woo-woo explanation. "I just wanted to get this story out there," she said. "I'm hoping that some American scientists will now take on the analysis of this."

Update for 8:30 p.m. ET: I'm getting additional information from both sides of the debate. Leslie Kean sent me a follow-up email on the bug hypothesis:

"I went back to the CEFAA official re the bugs, and he said that's what they all thought at first when they got the first film (the one I posted). But when they went and got additional footage from very different vantage points which showed the same thing, they knew that was impossible.  I don't think they're that stupid to claim this is a UFO if it was a bug, given that so many experts looked at it."

And there's this from UFO skeptic Tim Printy:

"I am very skeptical of this story the more I read it. There are no high-quality videos available, and the frame grabs/brief clips I have seen appear to be vague and indistinct.  The idea they may be birds, insects or possibly a small Mylar balloon has crossed my mind but I can't tell much from the data at hand. 

"There are some big red flags for me:

"1) This happened over a year ago and people are still working on analyzing this? If the evidence was truly that good, it would take a few months at best to come up with a reasonable analysis to demonstrate it was something not of this earth. 

"2) It is being leaked out to various UFO blogs instead of publishing in a scientific journal. If it were good evidence, that is where it would appear, and not the Huffington Post.

"3) The videos are unavailable to be analyzed from outside sources. Perhaps they learned from the Mexican Air Force video debacle. Once the videos were revealed in sufficient length, many people identified the source of the images as being from oil wells in the gulf.  A lot of people had egg on their face from that one. NARCAP was initially involved with that one, but then later stated they could not properly analyze the video because of the provenance being questionable or some excuse similar to that. 

"4) The videos have no provenance. We don't know what has been done to them since the day of the event.

"Just my thoughts on this one. I can probably come up with a few more red flags, but I would rather wait for the report to appear or the raw videos to surface.  Meanwhile, I will hit my snooze button while the UFOlogists proclaim it the latest 'smoking gun.' So far all of these 'smoking guns' have turned out to be empty water pistols that have never fired a squirt."

More about UFOs:

• Were Soviets behind the Roswell UFO?
• UFO sighted in Russia ... right on time
• Jerusalem videos spark UFO buzz
• James Oberg: UFO book based on questionable foundation
• Leslie Kean: Skeptic misses point behind UFO book
• Share your UFO stories
• UFO cases that generate buzz
• Best places to spot UFOs
• Cosmic Log archive on UFOs

Alan Boyle is msnbc.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. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Christian Turner

The X-47B, a stealth drone under development for the U.S. Navy, successfully retracted its landing gear and flew in its cruise configuration for the first time on Sept. 30.

A stealth U.S. Navy drone — one designed to take off from and land on moving aircraft carriers at sea — successfully retracted its landing gear and flew in cruise configuration for the first time, engineers announced today. 

The test flight at Edwards Air Force Base on Sept. 30 also helped validate the hardware and software that will allow the X-47B to land with precision at sea, among the harshest aviation environments known, said the drone's maker, Northrop Grumman.

The tail-less plane is 38 feet long and has a 62-foot wingspan. In the images released today it looks like a UFO straight out of a 1950s cartoon. 

The military is hoping unmanned aircraft will allow aircraft carriers to remain out of reach of land-based missile systems while they launch airstrikes and reconnaissance missions. 

Northrop Grumman

Earlier photo of X-47B, photographed from above while sitting on runway.

First flight of the X-47B took place in February. The latest test flight is part of on-going "envelope expansion" flights used to demonstrate the aircraft performance under a variety altitude, speed and fuel-load conditions. 

"Reaching this critical test point demonstrates the growing maturity of the air system and its readiness to move to the next phase of flight testing," Janis Pamiljans, vice president and Navy UCAS program manager for Northrop Grumman's Aerospace Systems sector, said in statement.

The aircraft will transition to Naval Air Station in Patuxent River, Md., later this year for further land-based testing, and will move to at-sea demonstrations in 2013. By 2014, Northrop Grumman intends to demonstrate autonomous in-air refueling.

More on Navy technology:

• New, stealthy Navy drone makes its maiden flight
• Navy gets fix for speed need
• Navy raygun disables boat with new high energy laser
• Navy sees spying, not flying, future with drones
• New robotic stealth fighter jet set to soar

Investigative journalist Annie Jacobsen's new book, "Area 51," suggests that the Soviets stirred up the Roswell UFO incident in 1947 by sending flying disks into New Mexico with child-size aviators on board, as a warning that they could spark a UFO panic if they wanted to.

But will that explanation fly?

Jacobsen's revelation is based on an account from just one unnamed source. This source said he was an engineer with the company EG&G at Area 51,  the hush-hush military research site in Nevada. He told Jacobsen that he studied the remnants of the Roswell crash in 1951, along with four other EG&G engineers.

There are no documents to confirm the account — because, Jacobsen says, this was one of the most tightly held secrets of the Cold War. Even though that confirmation is lacking, Jacobsen says she stands by her source's amazing account. "He had nothing to gain and everything to lose by telling me," she told me, "but it was a matter of conscience for him."

Michael Hiller

Annie Jacobsen is the author of "Area 51."

Jacobsen's source recounted what he says he saw, as well as what he was told and what he surmised based on that information. Here's the scenario presented in "Area 51: An Uncensored History of America's Top Secret Military Base," based on the source's account:

• After World War II, the Soviets capitalized on the work being done on stealthy flying-wing aircraft by a group of Nazi German engineers headed by two brothers, Walter and Reimar Horten. They developed disk-shaped flying machines that could sporadically evade radar detection. The U.S. military perfected such technology at Area 51 over the decades that followed to produce planes such as the F-117 stealth attack aircraft.
• Soviet leaders were spooked by the U.S. military's use of the atom bomb to bring the war to a quick close. They were a couple of years away from developing their own atomic weapons, based on secrets stolen from the U.S. bomb effort. The Roswell incident was aimed at warning the Truman administration that the Soviets could create a UFO hoax, stirring up fears similar to those that were sparked inadvertently by the fictional "War of the Worlds" radio broadcast in 1938.
• Jacobsen's source believes that the Soviets dispatched flying-disk drone aircraft from a mothership flying near Alaska. Intermittent radar signals were picked up by U.S. installations, but the disks were nevertheless able to enter U.S. airspace and come down near Roswell, N.M.
• "Child-size aviators" were aboard the disks: humans, seemingly about 13 years old, who may have been surgically or biologically altered to give them enlarged heads and eyes. Jacobsen quotes her source as saying he was told that the alien look-alikes were the result of experiments conducted by Nazi mad scientist Josef Mengele. The bodies were recovered from the wreckage, and two of them were alive but comatose.
• The wreckage and the bodies were transported from New Mexico to Wright-Patterson Air Force Base in Ohio for study, then transferred again to Area 51 in Nevada. This is where Jacobsen's source saw them in 1951. The source is quoted as saying he saw Russian writing stamped on a ring that went around the inside of the aircraft, and that he saw the child-size bodies on a life support system.
• When Jacobsen asked why President Harry Truman didn't report all this in 1947, she said the source replied, "Because we were doing the same thing." She notes in the book that the Atomic Energy Commission and the Defense Department carried out human experiments on the effects of radiation, and suggests that the hundreds of experiments revealed in 1995 were just the tip of the iceberg. "I believe that a lot of what the Atomic Energy Commission did was reckless and dangerous," she told me.

This latest explanation runs counter to the scenarios put forward by the federal government — first, that the Roswell wreckage came from a weather balloon, and then that it was debris from a crash-test dummy drop as well as a balloon-borne experiment to monitor nuclear blasts. It also runs counter to the long-held claims by UFO activists that the crash actually represented a covered-up visitation by extraterrestrials.

Drawing fire from both sides
As such, Jacobsen's Roswell account is taking fire from UFO skeptics as well as those who give the alien scenario more credence. In a novel twist, Clifford Clift of the Mutual UFO Network told the Santa Fe New Mexican that the linkage to German aerospace technology was too tenuous to be believed.

Little, Brown & Co. / Hachette

"Area 51: An Uncensored History of America's Top Secret Military Base" delves into decades' worth of hush-hush programs.

"After researching the claim, I found little truth in this theory," he said. "It is a stretch. One of my concerns is if they wanted to create panic, why in New Mexico and not in New York where there are more people to panic? I would suggest it is another conspiracy theory, and heavens, MUFON knows about conspiracy theories. They do sell books."

Peter Davenport of the National UFO Reporting Center said he also was skeptical about Jacobsen's account, although he stressed that he hasn't yet read the entire book.

"People have been studying the Roswell case for decades now," he told the New Mexican. "They've got deathbed testimony. They've got testimony from military officers who were involved, eyewitnesses. I think I'll go with the latter, rather than this young lady who penned this new book."

Investigator Kal Korff — who took aim at the alien claims in his 1997 book, "Roswell UFO Crash" — said he wasn't buying the "Area 51" story either. "Of all the crazy ideas as to what is behind Roswell, this is one of the most extreme out there," he told me in an email.

Beyond the substance of the story, there's the issue of basing such a dramatic story on one person's account. "I would never report anything related to UFOs based on only one unnamed source!" journalist Leslie Kean, the author of "UFOs: Generals, Pilots and Government Officials Go on the Record," wrote in a Facebook update.

Jacobsen told me that getting the story out of even one of the five engineers who were involved in the Area 51 follow-up to the Roswell incident was a months-long job.

"What's important to understand is that all of the top five EG&G engineers had top secret clearances and also Q clearances. ... So you're dealing with the most upper-echelon clearances you could possibly have within the federal government, in the Atomic Energy Commission. Your 'need-to-know' is so strict that you only know what you know. ... To suggest that the five engineers could stand around and discuss, 'Hey, what do you think is,' is a bit naive," she said. "It's 'take this craft apart and put it back together ... take these bodies and move them over here.' And that is about the extent of it."

It's also important to understand that there's a lot more to "Area 51" than Roswell. The Roswell tale, which takes up about 30 pages of the 544-page book, is the only one that depends on a single unnamed source, Jacobsen said. Most of the book focuses on the stories behind formerly secret programs ranging from nuclear bomb tests to the development of the U-2 and A-12 Oxcart spy planes. To this day, military officials avoid referring to Area 51 by that name.

The gorilla-mask scenario
So if the Roswell UFO wasn't an alien (or Soviet) intruder, and if you don't buy the official explanation that it was a balloon experiment, what else might it have been? One of the alternate explanations is that the "UFO" was indeed a flying disk, but that it was a U.S. rather than a Soviet experimental craft. In this scenario, the alien-looking bodies might have been dummies designed to create a preposterous cover story.

Jacobsen herself refers to a similar disinformation strategy that the Air Force used in 1942, when the first jet aircraft were being developed at California's Muroc dry lake bed. She said one of the test pilots for the Bell XP-59A jet plane, Jack Woolams, put on a gorilla mask when he went on a flight — just in case other pilots training on different planes came flying nearby to take a look.

"Instead of seeing Woolams, the pilot saw a gorilla flying an airplane — an airplane that had no propeller," Jacobsen wrote. "The stunned pilot landed and went straight to the local bar and ordered a stiff drink. He told the other pilots what he'd definitely seen with his own eyes. His colleagues told him he was drunk, that he was an embarrassment, that he should go home."

Thus was the secret of the Bell XP-59A preserved, even from the other fliers at the Muroc base (now known as Edwards Air Force Base).

Were the Roswell aliens actually dummies, the equivalent of pilots wearing gorilla masks? Or is Jacobsen's source correct? Is the truth more monstrous than people thought? Even though the eyewitnesses are dying off, Jacobsen believes the real story may be contained within the hundreds of millions of documents about "black" projects that are still said to be classified.

She notes that all of the sources she consulted while researching "Area 51" told her they knew much more than they were telling. "Everyone always ends with, 'Well, Annie, I've actually told you 5 percent of what I know,'" Jacobsen said.

Is the truth out there? Or will it remain mired in reams upon reams of conjecture and disinformation? Feel free to weigh in with your comments below.

More about UFOs:

• UFO reports come from Russia ... right on time
• Why we love to fear E.T.
• Jerusalem videos stir UFO buzz
• Year of the UFO? Let's get real
• Still more from Cosmic Log's UFO files
• Search for UFOs on msnbc.com

You can connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. Also, give a look to  "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Retired Air Force Capt. Robert Salas says he was at Malmstrom Air Force Base in Montana when UFOs hovered over the base in 1967 and nuclear missile launch systems somehow went non-operational. So you might think that watching the latest alien-attack movie, "Battle: Los Angeles," would cause him some sleepless nights.

Not really.

Salas doesn't think the aliens are in any mood to launch a globe-shattering strike like the one in the movie. "If they were going to attack, they would have done it by now," said Salas, who serves as a consultant for the film project. "They could have caused a lot more destruction ... but all they did was shut our missiles down."

For the folks who truly believe we've been visited by extraterrestrial craft, "Battle: Los Angeles" (opening Friday) and other E.T. thrillers provide additional opportunities to keep UFOs in the public consciousness. Which is why Salas is touting the film. "I think the public is taking more of an interest in this subject," Salas told me this week. "Of course, just about all these movies are going to be a little on the extreme side, but it continues to be of interest."

Even if you're not ready to give credence to reports of alien visitations, there are plenty of stories in the news that serve to stoke the interest in strange phenomena. William Birnes, who is the publisher of UFO magazine and a consultant for "UFO Hunters" as well as other TV projects, pointed to three such stories from just the past month.

• Last week, the British government released 8,500 pages' worth of reports on UFO sightings, ranging from obvious misunderstandings to still-unsolved mysteries. "What it shows is that there are active discussions and investigations going on among the defense departments of First World governments about the existence of extraterrestrial craft and the potential threat to national security," Birnes said. "The back-door message is, 'Yes, we are monitoring this, and although we haven't found anything yet, if you thought that your government wasn't concernedf about the existence of UFOs, we are.'"
• Scientists have been debating whether or not meteorites linked to the early solar system contain microbes from beyond Earth. "The UFO community eats this stuff up," Birnes said. "They love this. Why? Because it is scientific validation for one of the premises of the UFO community's investigation of whether there's life out there in the universe. ... When people laugh at us and say, 'Oh, you guys wear tinfoil hats, [we can say] our own government is spending a lot of money on this."
• IBM's Watson supercomputer vanquished two of the top human champions on TV's "Jeopardy" trivia game show. "That's a real fear ... creating a machine that will start using this amoral machine logic," Birnes said. "They figure out that since human beings are doing the polluting, they'll get rid of us."

Over the decades, fear has been a strong theme in E.T. movies. On one level, extraterrestrial tales serve as a convenient backdrop on which to project our own all-too-real worries. In the 1950s, movies such as "The Day the Earth Stood Still," "War of the Worlds" and "Invasion of the Body Snatchers" were seen as Cold War parables. (All three movies inspired recent remakes that haven't stood up quite as well as parables for environmental or virological threats.)

On another level, evil-E.T. movies and other fear-inducing flicks may serve as "practice runs" for dealing with real-life threats. Psychologists have hypothesized that we're hard-wired to seek out scary experiences that unfold in a safe environment. Just as early humans gathered around the fire to hear about fights with saber-toothed cats, we gather in front of screens to watch the aliens blast LAX.

Not all movie E.T.s are terrifying, of course. The cartoon Martians in another movie opening this week, "Mars Needs Moms," get the Disney treatment. And in the 1982 movie "E.T.," the alien is the good guy and the humans are the bad guys ... which is what makes this "E.T.-X" trailer on YouTube so funny:

But for every cuddly E.T., there's an evil "Independence Day" overlord plus an rampaging "Alien" predator. Birnes said "Battle: Los Angeles" combines two of the genre's most potent fear factors: relentless killer machines (think "Terminator") and goo-filled super-insects (think "Starship Troopers").

"What are human beings most afraid of, in terms of some existential threat to the human race?" he asked. "Creatures that are repellent. Exoskeletal types of insects, primarily because we and the insects are fighting for control of the planet, in a sense."

The movie plays off yet another monster-movie meme: the unstoppable attack from above. Birnes said "Battle: Los Angeles" echoed one of the better-known chapters in UFO lore, known as "The Battle of Los Angeles."

In 1942, the city weathered what was thought at the time to be an aerlal artillery barrage, waged by phantom forces that couldn't be brought down. At first, the authorities thought it was a Japanese air raid, but the "battle" was eventually attributed to war jitters that sparked spontaneous rounds of anti-aircraft fire and flares from L.A.'s defenders.

At least that's what the authorities said. UFO aficionados, however, put the Battle of Los Angeles in the same category as Salas' close encounter in 1967, and the rash of flying-saucer sightings reported in Washington in 1952. "There's solid, solid evidence that UFOs really have interfered with the military," Birnes insisted.

That's a claim I'm not ready to agree with, though it sounds good as a movie P.R. campaign. I do, however, agree with Birnes' view that E.T. movies have an enduring hold on the popular psyche. "Science fiction movies are made because there's a huge market for science fiction," Birnes told me. "'Battle: Los Angeles' is really John Wayne meets 'Independence Day.'"

So it's time to saddle up. For solid, solid evidence that this is the year of E.T. in Hollywood, check out this list of other upcoming releases:

• "Paul" (March 18): Slacker movie where the alien (Paul) is one of the slackers. (Official movie site)
• "Apollo 18" (April 22): Why did NASA stop doing moonshots, and why was the agency's plan to send astronauts back to the moon canceled last year? Surely not because the missions were too expensive. It's because of the murderous aliens that astronauts ran across during their super-secret Apollo 18 mission. Of course. (Official movie site)
• "Super 8" (June 10): Kids use a Super 8 camera to make their own zombie movie in 1979, and stumble across a catastrophic train derailment that sets loose some hazardous alien cargo being transported from Area 51 to Wright-Patterson Air Force Base. (Official movie site) 
• "Transformers: Dark of the Moon" (July 1): Those lovable Transformers battle over an alien spacecraft hidden on the moon ... wrecking Earth and rewriting the story of Apollo 11 in the process. (Official movie site)
• "Cowboys & Aliens" (July 29): The Reese's Peanut Butter Cup of movie genres ... a star-studded Wild West posse is all that stands in the way of an alien takeover of the planet in 1873. You got cowboys in my sci-fi movie! (Official movie site)
• "The Darkest Hour" (Aug. 5): American kids in Moscow fight back against an alien invasion. 
• "The Thing" (Oct. 14): Prequel to the 1982 John Carpenter film (which itself was a remake) about a murderous E.T. that crash-lands in Antarctica.
• "Area 51" (Date not yet set): Faux documentary about teens who break into super-secret Area 51 and leave behind "found footage," a la "Paranormal Activity."

Extra credit: If you see "Battle: Los Angeles," take note of the smoke rings. Robert Salas told me that he was recently looking at purported UFO pictures taken by highway maintenance engineer Rex Heflin in California in 1965. The photos show a hat-shaped object in the sky that apparently left behind a dark, unexplained smoke ring when it zoomed off. Then Salas watched an advance screening of "Battle: Los Angeles," in which alien missiles rain down on Earth. "As I was watching the movie, lo and behold, these objects were leaving big smoke rings," Salas said.

More on aliens:

• If aliens attack: Visitors to Earth will likely be robots
• Lesson one: The aliens never, ever come in peace 
• UFO book criticized | Author strikes back
• Six signs that alien life may actually exist
• How would alien life change your life?
• Search for "extraterrestrials" on msnbc.com

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto."