Sandro Vannini / National Geographic

This "shabti," or funerary servant figure, is from the antechamber of Tutankhamun's tomb. Shabtis were inscribed with a spell from the Book of the Dead that ensured the king would do no forced labor in the afterlife. The figure is part of the "Tutankhamun: The Golden King and the Great Pharaohs," an exhibit that is winding up its U.S. tour in Seattle.

Two major exhibits of ancient artifacts relating to the best-known figures from ancient Egypt, King Tut and Cleopatra, are in the last stages of their U.S. tours — and their departure could signal the end of an era.

"Cleopatra: The Exhibition" opened at the California Science Center in Los Angeles on Wednesday, while "Tutankhamun: The Golden King and the Great Pharaohs" began its run at the Pacific Science Center in Seattle today. By the end of next year, the more than 250 artifacts from the two exhibitions will be back in Egypt, possibly for good.

The return to Egypt marks the end of a Tut-centric "Comeback Tour" that began back in 2005 and sparked the kind of enthusiasm that was seen back in the 1970s, during an earlier Tut exhibit. Like that 1976-1979 "Treasures of Tutankhamun" show, millions have turned out to see the glittering gold and the 3,300-year-old artifacts associated with the boy-king's short reign. More than 90,000 advance tickets already have been sold for this year's Seattle exhibit.

Transplanting Tut-mania
Among the featured objects in Seattle are a 10-foot-tall statue of the pharaoh, Tut's golden sandals and the golden funerary mask of King Psusennes I. (Tut's golden mask, which was such a hit since the '70s, was judged too fragile and valuable to travel out of Egypt this time around.)

After Seattle, the more than 100 artifacts will go to the Grand Egyptian Museum in Giza, which is currently under construction and due for completion in 2015. At one time, Egyptian officials saw the revenue generated by traveling exhibits as a means to cover the museum construction costs. But last year's revolution dealt a heavy blow to the country's tourist industry, and now officials think it's more important to bring museumgoers to the treasures in Egypt than to bring the treasures to museumgoers outside Egypt.

"They're eager to see these [artifacts] return to Egypt," said Bryan Harris, vice president of sales and marketing for Arts and Exhibitions International, which helped organize the Tut tour. And they're eager for tourists to follow Tut's trail.

That came through loud and clear during a Seattle news conference on Wednesday. "Please, we need your help," Antiquities Minister Mohammed Ibrahim said. "We need you to support our revolution. We need you to support our movement toward peace and democracy."

Cleopatra's sunken treasures
The stars of the Tut exhibit are artifacts that were found 90 years ago in a long-hidden tomb by British archaeologist Howard Carter, but it's a different story for the more than 150 "Cleopatra" artifacts now on display in Los Angeles. They were brought to the surface just in the past few years during underwater excavations at the sunken sites of Alexandria, Heracleion and Canopus.

"All those artifacts were completely covered by sediment," French archaeologist Franck Goddio, leader of the underwater excavation, told me.

Slideshow: In search of Cleopatra’s palace

Christoph Gerigk / AP

Divers explore the submerged ruins of a palace and temple in Alexandria's harbor.

Launch slideshow

The project made a splash, so to speak, when the "Cleopatra" tour was first announced a couple of years ago, and since then it's been on display in Philadelphia, Cincinnati and Milwaukee. One more U.S. city, yet to be determined, could join the list after Los Angeles. But by the end of 2013, the statues, jewelry, coins and other items will be distributed among several Egyptian museums, Goddio said. Egyptian authorities are considering the construction of an underwater museum in Alexandria Harbor, and if that project goes forward, "all the artifacts will go in that museum," he said.

Goddio said the artifacts recovered so far suggest that Hellenistic Egypt, the culture in which Cleopatra lived during the first century B.C., was less Greek and much more Egyptian than experts previously thought. "The Egyptian sensitivity is much stronger than what it was thought to be at that time," he said. And that's all the more reason for present-day Egyptian officials to want those treasures back in their home country.

Fortunately, Goddio and others have been able to continue their work amid all of Egypt's political changes, including the run-up to this week's presidential elections there.

"Up to now, the authority has not changed," he told me, "and it's not expected that there will be any change from a scientific view." So even though the long-traveling treasures may be going home for good, there might be fresh archaeological finds available for future road trips.

And after all, Egypt isn't the only place that offers archaeological wonders. Just this month, for example, Penn Museum opened a "Maya 2012" exhibit featuring sculptures and replicas of monuments from the Maya civilization.

Harris acknowledges that Egypt doesn't hold a monopoly on ancient mysteries and marvels. Nevertheless, he says there's something special about old King Tut. "An exhibit like 'Tutankhamun' is really like lightning in a bottle," he told me. "For some reason, Egyptian culture, and particularly Tutankhamun, seems to captivate the imagination more than any other. ... To be honest, there's only one."

More about Egyptian treasures:

• 'King Tut' makes last stop in Seattle
• Spots on Tut's tomb suggest hasty burial
• Slideshow: King Tut's treasures in context
• Mummies and statues point to Cleopatra's tomb
• Video: Book paints Cleopatra as 'shrewd' and 'brutal'

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 or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Exploratorium

Paul Doherty, a senior staff scientist at the Exploratorium, Paul Doherty, sets up telescopes for observations of the 2001 total solar eclipse in Zambia. This year features an annular solar eclipse in May, a transit of Venus in June, and a total solar eclipse in November.

Over the next several weeks, skywatchers will thrill to a couple of astronomical wonders playing out in daytime skies: a solar eclipse on May 20 — and then, on June 5, a "micro-eclipse" of the sun that involves the planet Venus.

As senior staff scientist at San Francisco's Exploratorium, Paul Doherty will be keeping a careful eye on both of those wonders (with appropriate eye protection, of course). He'll let you in on his eclipse-chasing secrets on Wednesday night during a "Virtually Speaking Science" chat on BlogTalkRadio and in the Second Life virtual world. I'll be the host for the hourlong show, starting at 9 p.m. (6 p.m. PT/SLT).

Doherty says the solar eclipse and the micro-eclipse will be well worth chasing.

"By all means, go out of your way to see 'em," he told me this week. "They are rare events ... You'll have things to talk about for years after."

Each event offers a special kind of rarity: This month's eclipse is of the annular variety, which means that the moon's disk isn't quite big enough to cover the sun completely. At its darkest, the moon's black circle will be surrounded by a spectacular "ring of fire." That sight can be seen only along a narrow track running along Earth's surface, from China across the Pacific to the western United States. But a partial solar eclipse will be visible across a much wider swath of territory. It'll take about three and a half hours for the moon's umbral shadow to race across Earth's surface, from 6:06 to 9:39 p.m. ET.

Next month's micro-eclipse, more formally known as a transit of Venus, is even rarer. The planet's tiny black disk will march across the sun over the course of several hours (roughly from 6 p.m. ET June 5 to 12:50 a.m. ET June 6). Most of the world will get in on at least part of the show, but the best viewing will be had once again from the Asia-Pacific region. This will be the last transit of Venus most of us will ever get a chance to see: The next one is due in the year 2117.

Even if you're not in the viewing zone, or the skies are cloudy, you can still get in on these events via online presentations that will be sponsored by a variety of organizations — including the Exploratorium, of course. The combination museum and science center is planning a webcast of the transit as well as a Second Life teach-in timed to coincide with the annular eclipse. Doherty will be in on all the action — in Nevada for the eclipse, and at San Francisco HQ for the transit.

Jeroen Frans

Second Life residents watch a virtual presentation about eclipses on Exploratorium Island, in an image by Jeroen Frans (a.k.a. Frans Charming) of VesuviusGroup.com.

Over the past 40 years, Doherty has been chasing astronomical events in locales ranging from Cape Cod to Zaire. In this first of two postings about the coming attractions, Doherty discusses the appeal of eclipses and transits, plus a little bit of the science behind them. Here's an edited transcript of the Q&A:

Cosmic Log: You've been in on a number of solar eclipses in your time — what is it that draws someone to become an eclipse-chaser? A lot of people talk about how sun-observing satellites have come so far that eclipses aren't as crucial for scientific observations as they used to be. So what's the appeal?

Paul Doherty: It's certainly true that an eclipse is not a scientifically significant as it was a century ago, but I will tell you there's something special about the experience of an eclipse — even a partial eclipse. You'll be outdoors, looking around, and you'll notice that the light is getting very strange. There's a beautiful clear sky, and it starts to get dim. Your body knows that something really different is happening. It's great for people to know what's causing that feeling: The moon is blocking the sun. (But don't look at it directly with your unprotected eyes.)

Then, for totality, you have the experience of seeing a clear sky go dark at midday, so that the brightest planets and stars are visible. You see that black disk where the sun should be, surrounded by bright rays like big fat spider legs of white around the sun. That will set the hair on your back standing up, even if you're a scientist and you know what this is. It is just so awesome to see it.

So I look at modern eclipses as places for people to come in contact with a great event in our solar system, and it shouldn't be missed.

Q: Do you find that it's an inspirational experience? Do eclipse-chasers go on to "harder drugs" in astronomy?

A: I've met so many eclipse-chasers who are already into the harder stuff. You just can't tell which came first. But I'm sure that the sight of a total eclipse just inspires them. I've seen eight solar eclipses myself, and I keep running across the same people. I know that they're inspired to really take time out of their lives, and take money out of their bank accounts, and invest it in these few minutes of a great experience, surrounded by an hour of interesting shading in the sky, surrounded by days of travel to wonderful places on Earth and meeting people with the same passion they have.

Q: What are the differences between a total solar eclipse like the one in November, and an annular eclipse like the one this month?

A: The moon is in an elliptical orbit around the earth. When the moon is at its farthest point from the earth, its angular size in the sky is a little smaller, and when it's close to the earth, it's a little bigger. Also, the earth is in an elliptical orbit around the sun. It gets smaller and bigger. When the moon is farthest from the earth, it's small enough in the sky that it cannot totally block the bright part of the surface of the sun called the photosphere. That's where the bright light comes from on the sun. At that point, the rim of the photosphere shines around the edge of the moon. That light is so bright that it can damage your eyes if you look at it without eye protection. It overwhelms the dim light coming from the chromosphere and the corona of the sun.

But during a total solar eclipse, the moon is big enough in angular size to block out the photosphere completely, and with your naked eye you can see this million-degree gas glowing in the corona, like rays reaching out quite a ways from the sun. You can see the red chromosphere quite near the edge of the moon. You can even see prominences reaching out from the sun and moving during the course of the eclipse. The total eclipse offers many more things to see than the annular eclipse does.

However, an annular eclipse provides you with a bright circle of the sun. Let's say that sunlight is streaming through the leaves of a tree, and you look at the ground. Normally, you'd see round circles of light at your feet. During an annular eclipse, those all become the letter "O." That is really something, to look at the ground underneath a tree and see it covered with bright Cheerios.

If you're not on the center line of annularity, and it's a partial solar eclipse, then those images become the letter "D," or a really nice letter "C."

There are more total solar eclipses than there are annular eclipses, because it takes this special combination of the moon being a little farther away from the earth than average, and the sun a little closer, to create this annular eclipse opportunity.

Q: It seems as if people in the know are getting as excited about next month's transit of Venus as they are about the eclipse. Why is that?

A: Well, the transit of Venus is a much rarer occurrence. And it is kind of a micro-eclipse. Venus is one-thirtieth the diameter of the sun in angular size, and it's moving across the sun's disk in this stately procession that lasts six hours. It happens in this amazing pattern: There'll be one transit, and then eight years later there'll be another one, and then it's 121.5 years, then eight years, then 105.5 years. It's a really weird pattern.

You wouldn't even notice a transit was happening unless someone told you. The light on the ground is not going to change. You're not going to see anything. But it's different if you know it's happening, like Jeremiah Horrocks did in 1639. He noted that Johannes Kepler, his hero, missed the calculation that Venus was going to transit the face of the sun. Horrocks actually set up a telescope to project the sun's image into his darkened room, and became the first person ever to see a transit of Venus and record it.

Now, knowing what we do, we can tell you that on this day, at this time, if you project an image of the sun safely or use a sun-viewing filter, you can see this tiny black disk going across the face of the sun. That's interesting — but what's really interesting is that in 1761, they used the transit observations to measure the size of the solar system. Good old Halley, of Halley's Comet, figured out how to do that. They did it kind of roughly, during transits.

Q: And even today, astronomers are using alien transits to learn about new planets beyond our solar system...

A: That's right. In 1761, a Russian astronomer named Mikhail Lomonosov discovered the atmosphere of Venus during a transit. He noted that as Venus approached first contact with the sun's disk, it was completely surrounded by a bright glow, which was the sunlight being refracted by Venus' atmosphere and being sent to Earth. That's how scientists first detected Venus' atmosphere. And during the transit eight years ago, scientists used the sunlight going through the atmosphere of Venus to measure its composition.

We're doing that exact same thing with exoplanets. We're studying the light going through the atmosphere of those exoplanets, and we've actually found the constituents of the atmospheres of some of those exoplanets. They've found water vapor, and carbon dioxide, and sodium gas. We're using the very same techniques we used on Venus to study the air of exoplanets.

On Wednesday, we'll talk about some of the best places in America to see this month's annular eclipse, how to pick out an advantageous viewing spot near you, and how to make sure you see the eclipse and the transit safely. Then, be sure to tune in "Virtually Speaking Science" on BlogTalkRadio or in Second Life — and bring lots of questions. Paul Doherty (a.k.a. Patio Plasma) and I will be at the StellaNova Small Auditorium, courtesy of the Meta Institute for Computational Astrophysics, starting at 9 p.m. ET (6 p.m. PT/SLT) on Wednesday. If you miss the live event, don't worry: It'll be archived by "Virtually Speaking" on BlogTalkRadio as well as iTunes.

On Friday, head on over to the Cosmic Log Facebook page for our weekly "Where in the Cosmos" picture puzzle. If you're the first to solve the riddle, you'll be eligible to receive a pair of sun-viewing safety glasses for this month's eclipse and next month's transit. In the meantime, check out these podcasts from previous episodes of "Virtually Speaking Science," plus links to eclipse-related resources:

• Veronica Ann Zabala-Aliberto on spaceflight and Yuri's Night
• JPL's Dave Beaty on the search for life on Mars
• Shawn Lawrence Otto on science and politics
• Ig Nobel impresario Marc Abrahams on silly science
• Rocket scientist Robert Zubrin on Mars exploration
• Propulsion expert Marc Millis on interstellar spaceflight
• Sean Carroll on the puzzling frontiers of physics
• Rand Simberg on the private-enterprise vision for spaceflight
• Martin Hoffert on the future of energy policy
• George Djorgovski on science in virtual worlds
• Alan Stern on suborbital research and NASA's mission to Pluto
• Col. 'Coyote' Smith on the outlook for space solar power
• Tim Pickens on rocket ventures and the Google Lunar X Prize

More about eclipses:

• Interactive graphic: What causes a solar eclipse?
• 12 must-see skywatching events in 2012
• All about solar eclipses on msnbc.com

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 or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Museum of Mathematics

An artist's conception shows the Museum of Mathematics, which is slated to open in Manhattan in 2012.

The man behind an innovative interactive museum devoted exclusively to mathematics promises that it will be a "place where it's safe to be a geek" — but also something more: a place where non-geeks can experience the true joy of math.

"There's this whole force of fun and beauty that most people don't get a chance to experience," said Glen Whitney, a 42-year-old mathematician who left his job at a hedge fund three years ago to start up the Museum of Mathematics.

Whitney's dream is taking shape even now in a 19,000-square-foot space at 11 E. 26th St. in Manhattan: He and the rest of the MoMath team have already raised $22 million toward their capital goal of $30 million, and the museum is on track to open in late 2012. But they're not waiting until then to spread the good word: The museum organizers have been sending a traveling exhibit called the "Math Midway" around the country for the past couple of years. (The exhibit was featured at this month's World Science Festival in New York and opens at the Discovery Center for Science and Technology in Southern California on Saturday.)

They're also open-sourcing the exhibit plans so that any museum around the world can put up their own version of a MoMath display. "The mission of the museum is to create the greatest amount of exciting, hands-on, informal mathematical opportunities that are out there in the world," Whitney told me.

The Math Midway is serving as a sort of beta test for the opportunities that will be offered when the actual museum opens. One of the biggest crowd-pleasers so far is a square-wheeled tricycle that's built to ride smoothly on a scalloped track. "There's a mathematical principle that says there's a road for every wheel," Whitney explained. The trike illustrates how that principle, which involves geometric shapes known as catenary curves, can work in the real world.

"We already know that people will line up for this," Whitney said. "It's become a bit of an icon for the Math Museum."

Another exhibit features puzzle pieces that are designed to fit together on cylinders, spheres and a shape that's curved like the mouth of a trumpet. "It basically lets you see how the curvature of the space you're in affects the kinds of patterns you can make," Whitney said. On a flat surface, you can fit six equilateral triangles around a single point ... but on the horn-shaped surface, you can fit seven.

"In every exhibit, we try to pack a surprise punch," Whitney said.

Although the museum is designed to appeal to all ages, the team is paying special attention to how well the exhibits go over with students in the fourth through the eighth grade.

"That's our sweet spot, for a very simple reason," Whitney said. "If you look at the trajectory of students going through the curriculum, things seem more or less fine up to the fourth grade. That period from the fourth to the eight grade is where we see a decline in the engagement of the students. Why are we opening a math museum in the first place? It's because we see cultural issues in this country."

International studies have shown that 15-year-old students in the U.S. perform well below the global average when it comes to math — specifically, 25th place out of 34 countries in 2009, when the Program for International Student Assessment's most recent test was conducted. Education Secretary Arne Duncan said the results were "an absolute wakeup call for America."

Whitney has been awake and aware of this problem for a long time. He believes the standard sequence of math classes is way too limiting, and fails to engage students as much as they could be engaged. "Mathematics is actually much broader and richer than the list of topics that one reaches through the normal curriculum," he said.

He hopes the Museum of Mathematics can play an integral role in turning the tide. Will the exhibits make math geeks out of non-geeks? Whitney doesn't obsess too much over those labels.

"We just want to create a place where it's OK to really love math and be enthusiastic and be engaged with it," he told me. "If you want to call that being a geek, then that's a geek. What we don't want is for students to end up three or four years later disavowing any interest in those beautiful surprises because they see signals telling them, 'Oh, that's not something we should be talking about.'"

Is it going to be a hard sell to get kids to go to a math museum? Or is this just what the doctor ordered? (Yes, Whitney has his Ph.D. in mathematical logic from UCLA.) Feel free to weigh in with your comments below. 

Extra credit: While you're waiting for the museum to open, here are some recently published books that put an unorthodox spin on math:

• "The Mathematics of Life": Ian Stewart explains how mathematicians and biologists are working together on some of the most difficult problems the human race has ever tackled — including the unraveling of the genome, the structure of viruses, the spread of disease, the interaction of environmental factors and the origin of life itself.
• "One, Two, Three: Absolutely Elementary Mathematics": David Berlinski goes back to basics and explains the foundation of arithmetic, right down to the origins of the plus and minus signs. But don't get the idea that Berlinski is dumbing down the subject: This book touches upon the contributions by David Hilbert, Giuseppe Peano, Bertrand Russell and other brainy people through the ages.
• "Loving + Hating Mathematics: Challenging the Myths of Mathematical Life": Reuben Hersh and Vera John-Steiner delve into the lifestyles of the not-necessarily-rich but famous mathematicians, in an effort to explain "why the most rational of human endeavors is at the same time one of the most emotional."

Looking for geeky places to go? Check out this report from the author of "The Geek Atlas," this roundup of top tech destinations and this list of shrines to innovation. 

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.

Just in time for the holiday travel crush, concern is on the rise about radiation exposure from the X-ray full-body scanners that are being deployed around the U.S. in an effort to thwart terrorist attacks.

The controversial technology works by bouncing an X-ray beam off a person to create a full-body image that reveals contours, including natural curves as well as any bumps and protrusions from potential weapons that might escape a metal detector such as plastics and ceramics.

The image is displayed on a computer screen in a private room. The person's face is never shown -- and their identity, in theory, is unknown to the airport screener. Passengers can skip the scan and opt instead for a pat-down, which is criticized for being overly personal in the groin area.

Privacy concerns about the scans and pat-down reached fever pitch in recent days when San Diego software engineer John Tyner refused both -- and captured the action with his cell phone's video camera. His blog posts and YouTube videos about the encounter went viral.

While Tyner received a full refund for his ticket and gained Web celebrity status, other interested parties -- ranging from pilots and passengers to esteemed scientists -- are worried that radiation exposure from the X-rays could increase risk of cancers.

The Transportation Security Administration says the amount of radiation from scans amounts to about a thousandth of the amount a person receives from a standard chest X-ray.

Peter Rez, a physics professor at Arizona State University in Tempe, did his own calculations and found the exposure to be about one-fiftieth to one-hundredth the amount of a standard chest X-ray. He calculated the risk of getting cancer from a single scan at about 1 in 30 million, "which puts it somewhat less than being killed by being struck by lightning in any one year," he told me.

While the risk of getting a fatal cancer from the screening is minuscule, it's about equal to the probability that an airplane will get blown up by a terrorist, he added. "So my view is there is not a case to be made for deploying them to prevent such a low probability event."

A group of scientists at the University of California at San Francisco laid out their concerns in a letter to the U.S. Food and Drug Administration, highlighting in particular the potential for the X-ray dose concentrated on the skin to pose a health concern for children and other vulnerable populations, such as people with HIV.

"We are unanimous in believing that the potential health consequences need to be rigorously studied before these scanners are adopted. Modifications that reduce radiation exposure need to be explored as soon as possible," the letter said. Among the signers were David Agard, John Sedat (a professor emeritus) and Robert Stroud, all professors of biochemistry and biophysics; and Marc Shuman, professor of medicine.

In response, the Food and Drug Administration said the technology has been reviewed Sandia National Laboratories, the FDA, National Institute for Standards and Technology and Johns Hopkins University.

"In summary, the potential health risks from a full-body screening with a general-use X-ray security system are minuscule. Several groups of recognized experts have been assembled and have analyzed the radiation safety issues associated with this technology. ... As a result of these evidence-based, responsible actions, we are confident that full-body X-ray security products and practices do not pose a significant risk to the public health," the FDA said.

Arizona State University's Rez voiced other concerns: What's the potential for one of the scanners to fail, given that they will run all day, every day at airports across the country? When that happens, are safety mechanisms in place to prevent overexposure to radiation? Rez also said that the scanners are "useless for detecting explosives."

Janet Napolitano, secretary of the Department of Homeland Security, weighed in on the controversy with an op-ed on Monday in USA Today. She reiterated the government's view that independent evaluations show the technology to be safe and hammered home why the federal government deems the scans and pat-downs necessary:

"Each and every one of the security measures we implement serves an important goal: providing safe and efficient air travel for the millions of people who rely on our aviation system every day."

The question remains, though, are these X-ray scanners more harmful than helpful? Feel free to weigh in with your comments below.

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on http://twitter.com/b0yle.