"Opossums are marsupials, just like kangaroos."I think opossums get a bum rap. People think just because they look kind of funny, walk kind of funny, have beady eyes and sharp teeth, and can emit the most foul-smelling scent you've ever had the misfortune of coming across, that they are kind of "icky."

But they are just trying to make a living like everybody else. They need those teeth to crush bone – which means that they are good for clearing out those unwanted rodents in your neighborhood. (No, they are not rodents themselves; opossums are marsupials… that’s right, just like kangaroos!). Their eyes… well, they just look that way and they're not particularly useful, however these critters have an excellent sense of smell and hearing to make up for it. As for that smell that they emit, they only do that when they're fighting for their lives. Believe me, if you could spew a foul stench when some unsavory character is harassing you, you'd do it! And let me take this moment to clear up a very common misconception: no, opossums cannot hang by their tails, though they can use them to balance themselves and gather bedding materials for their nests.

The truth is, if you ever get the chance to know one like we did, you'll see they are really sweet creatures. Most of the times that they find themselves in direct conflict with humans, it’s the human's fault. Their habitats are shrinking due to our development plans, which forces them to live closer and closer to us. If you leave your pet food outside… well, who doesn't take a free snack when it's offered up? And the poor creatures only live for two to four years, so please folks, give the opossums a break!

Watch the Cool Critters: Opossums television story online.

Credit: Deutsches Bundesarchiv (German Federal Archive)
A storm of protest broke out a month or so ago when a fertility clinic in Los Angeles announced it would start helping women choose what their babies might look like. The ruckus was loud enough that the clinic has since backed off on this service.

And this is probably a good thing. I am not sure this is a road we want to go down– it smacks a bit too much of Hitler and a perfect race.

Of course, we've started down this road a ways already. We aren't able to shape anyone's DNA yet. We don't have the technology to do this in any safe or reliable way and frankly, it'll probably be a long time before we can.

But we can take a peek at an embryo's DNA if the egg has been fertilized outside of the body. The process is called preimplantation genetic diagnosis or PGD. Using PGD, scientists can look through a number of embryos' DNA and pick the one(s) the parents want.

Right now we can't scan all of an embryo's DNA. We have to pick and choose what part of the DNA to look at.

For example, PGD is often used to make sure that an embryo has all 46 chromosomes. This service increases the chances for a successful birth for women who are going through repeated miscarriages.

Of course, if we can look at the chromosomes, we can also tell whether the embryo is a boy or a girl. Often this is done to select for girls in families that carry male specific genetic diseases like Duchenne muscular dystrophy. But it is also done for the less life threatening goal of an even number of boys and girls in a family (gender balancing).

PGD can also be used to make sure an embryo did not inherit specific diseases like cystic fibrosis or sickle cell anemia that might run in the parents' families. These diseases can be screened for by looking for specific DNA differences in certain genes. Which is what this fertility clinic wanted to do for hair, skin and eye color genes.

Let's say a parent wants a redhead with brown eyes. The clinic would screen for certain versions of the HERC2 gene that mean brown eyes and certain versions of the MC1R gene that indicate red hair. When they found an embryo with the right combination of traits, then that embryo would be selected for implantation.

Remember, the people at the clinic can't change the DNA of the embryo. They can only sort through the genes that are already in the pool. So if one parent doesn't carry a red hair version of MC1R, then the parents can't have a red haired child.

Even without this ability, the furor over the fertility clinic's service raises a very important discussion point– where do we draw the line with PGD? And who should draw that line?

Obviously eye color is going too far (or is it?) and preventing an early death from a genetic disease is OK. But is it OK to look at gender for family balancing? This is allowed in the U.S. right now but is not permitted in most other countries.

What about conditions like high cholesterol? Or diseases that kill later in life like Huntington’s disease? Or traits like height, weight, or intelligence? Who gets to decide?

Today QUEST takes you behind the scenes to see the most powerful microscope in the world, which happens to be in our very own backyard in Berkeley. This transmission electron microscope lives at the National Center for Electron Microscopy, at the Lawrence Berkeley National Lab. The microscope can produce images of things that are the size of half an atom of hydrogen. And hydrogen has the smallest atoms of any element – so that's pretty small.

The microscope is so big that it was hauled into the Center on a crane. It's housed in its own room, which is insulated to maintain an ideal temperature, and it's mounted on springs to isolate it from vibrations that make images blurry.

The TEAM 0.5, as the microscope is called, excels at producing clear images of atoms sitting side by side. This makes it very useful for the scientists who investigate the properties of the materials that we use to build everyday objects like computers and airplanes. In fact, the images they produce with the microscope may one day help build stronger, lighter airplanes, and smaller, faster computers.

Watch the World's Most Powerful Microscope television story online.

Wine making is indeed an art form, but it is increasingly becoming more scientific. I knew growing wine grapes requires a lot of attention to detail — there is the terroir, pests and diseases and all those microclimates. But who would have known, driving down Hwy 29, the main thoroughfare through the Napa Valley, that many of those vineyards are totally wired.

In our radio story, we feature the stylishly high tech Vineyard 29 and the Robert Mondavi Winery, but scores of other wineries are using a similar toolbox of technology to help them monitor the soil's water content to grow better grapes. The technology ends up conserving water, too. Remote sensing, ground penetrating radar and satellite technology have helped Mondavi cut back on water use by 30% in recent years.

Winemakers are using some of the same technology that NASA uses to study Mars and engineers use to build hi-rises and freeways. A typical toolbox includes multi-spectral imaging, weather stations, neutron moisture probes, and pressure bombs and there is a plethora of newer technologies in the pipeline. But enough with all the high tech gizmos. How does wine from high tech vines taste? The answer might be found in the success of the winery. Mondavi has won numerous awards over the years and there is a two-year waiting list just to purchase Vineyard 29 wines.

Check out our slide show to see some of these technologies or listen to our radio report on high tech in the vineyards.

Our new "Donate Now" screen at the end of our stories
makes it a snap to support QUEST.You've heard it before – KQED runs on donations from our viewers and listeners. More than half of our budget comes from people like you, and this is what makes it extremely special in our community.

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Becoming a KQED member is one option, but what if you're not from around here? Maybe you're just not a joiner. Or you really want to support a specific program– like QUEST– that matters to you.

We hear that. So we're trying something new. Enter the QUEST microdonation pilot program.

At the end of all new videos on the QUEST website, you can donate $5 (or another prime number of your choice), in a simple one-time transaction via credit card or PayPal. No pledge, no need to call in, no requirement to become a member.

If we received one $5 donation a year from everyone who watches our stories online, we'd collect enough to produce a whole new season of QUEST! Of course, if you just want to give straight away, we won't stop you. You may proceed directly to our microdonation page.

This is a pilot project for us to test results and we're anxious to hear what you think. Please leave any comments that you might have here or email donation@kqed.org — and please spread the word to your (generous) friends!

Apophis is about the same size as the asteroid that blasted
the mile-wide Barringer Crater in Arizona.
Credit: David Roddy, USGSFriday the 13th, April, 2029: If you're superstitious, this might not be a good day to schedule a near-Earth asteroid encounter. But, as it happens, that's the day that the Near Earth Asteroid (NEA) Apophis will make a very close flyby of Earth–a once in 800 years event for an asteroid Apophis' size.

Fortunately, scientists have already predicted, 20 years in advance, that this is our lucky day: Apophis won't hit the Earth at that time. Rest assured (pretty much).

Discovered in 2004, Apophis is an asteroid about 270 meters across that orbits the Sun at distances ranging from about one astronomical unit (1 AU; the distance between Earth and the Sun) and about three quarters of an AU. Apophis orbits the Sun once every 323 days.

After its initial discovery, before our knowledge of its orbital trajectory had been refined, astronomers had predicted that there was a small chance it could hit the Earth on April 13, 2029, but as we got a clearer picture of its orbit the probability dwindled to practically nothing. Instead, Apophis will pass by Earth no closer than about 18,000 miles. Whew! Disaster averted, and we didn't even have to send Bruce Willis to deal with it.

But wait–that's not all. Though Apophis almost certainly won't hit us in 2029, there's a chance that this close encounter will set the asteroid up for an impact with Earth in 2036–something like 1 in 45,000.

So, if we know there won't be an impact in 2029, why don't we know whether or not there will be one in 2036? Why all the suspense?

Here's where I pull out my pinball analogy. Think of a pinball machine. The play zone around your flippers represents near-Earth space, the various bumpers up in the field represent all the planets, the Sun, and other large asteroids of the Solar System, and the pinball represents a Near Earth Asteroid, like Apophis.

When the pinball inevitably comes into the play zone, there are two possibilities: either it will hit (or be hit by) one of your flippers and thus be deflected back into the field where it will bounce around some more between bumpers, or it will sail right through that dreaded "window" between the tips of the flippers and fall into the end pocket–which represents Terra Firma and a catastrophe if a NEA falls there. As any pinball player knows, it's nearly impossible to predict exactly what path the pinball will follow into the play zone until it gets close.

It's a lot like that with a NEA in the Solar System: as it orbits around the Sun, its course is influenced by the gravitational pull of planets, large asteroids, and potentially smaller asteroids that it might pass close to. A very small deviation in a NEA's direction or speed can, over time, "amplify" into a very large difference in position much farther down the road.

Given the 2029 close encounter with Earth, though we're reasonably confident Apophis won't hit us on that pass, we don't know precisely how that encounter will alter Apophis' orbit. The gravitational interaction between Earth and a NEA passing close by is a complex one, with many variables, not the least of which is Earth's non-uniform gravitational field.

If Apophis passes Earth through precisely the right "window" in 2029–say, right between the flipper tips–then it could be set up for an impact at its 2036 encounter. That window, called a gravitational keyhole, is only about 600 meters across for the 2029 encounter.

As we gather more data on Apophis, we'll get a better prediction for what may happen in 2036–but right now the odds are that it will ultimately miss us at that time. That's a good thing, too, because at that time Bruce Willis will be 81 years old… and even John Glenn was only 80 when he returned to space…

A LED flashlight powered by a battery made using five pennies.

Oops! Are we gonna get in trouble? In order to make our Five-Cent LED Battery we needed to sand the faces off 4 pennies. According to United States Code, TITLE 18, PART I, CHAPTER 17, § 331. Mutilation, diminution, and falsification of coins:

"Whoever fraudulently alters, defaces, mutilates, impairs, diminishes, falsifies, scales, or lightens any of the coins coined at the mints of the United States, or any foreign coins which are by law made current or are in actual use or circulation as money within the United States; or whoever fraudulently possesses, passes, utters, publishes, or sells, or attempts to pass, utter, publish, or sell, or brings into the United States, any such coin, knowing the same to be altered, defaced, mutilated, impaired, diminished, falsified, scaled, or lightened— Shall be fined under this title or imprisoned not more than five years, or both."

Gulp! Fraudulently? I don’t think we did it "Fraudulently." (Ahem) And I just want to say for the record that we did not force anyone to deface currency of the United States. In fact, if pushed came to shove I will say that we discouraged the practice and in fact actually pleaded with everyone at the Exploratorium, hoodlums that they are, to come up with another means of making a Five-Cent battery. But they brazenly went forward, stopping only briefly to maniacally cackle and call me names like "Goody Two-shoes" and thumb their noses at me. Needless to say they shamelessly went ahead with their outlaw ways. Oh, they are bad to the bone! We were as innocent as you all out there. I tried to stop them! That's what I will say! That or I’ll say that the "pennies" we were using were actually fake "prop" pennies that we got at the local novelty shop. Either way, you can't prove anything!

Now, if you don't want to risk being outside the laws of the United States, the Exploratorium has put together quite a fun project list of fun things to do and make. To the best of my knowledge, the majority of them won't get you in trouble with the authorities. They can teach you things like how to make musical instruments out of normal household junk, how to make a bottle blast off or how to build a motorized toy that dances, using a recycled CD and a DC motor. Really cool stuff!

Be good out there and stay out of trouble.

Watch the Quest Lab: The Five-cent Battery television story online.

A few weeks ago, this asteroid came really close to hitting Earth.On March 3rd, 2009 at 1:40PM GMT, just a mere month after we'd finished the Asteroid Hunters segment, an asteroid of up to 165 feet in diameter snuck up on us, coming within approximately 37,000 miles from a direct impact with Earth. That's almost seven times closer than the distance to the Moon and about twice the distance of some communications satellites that orbit the earth.

Called “2009 DD45”, the asteroid was estimated to be around the same size as the one that exploded in the atmosphere near the Podkamennaya Tunguska River in remote Siberia on June 30th, 1908, flattening 80 million trees across eight hundred square miles of remote forest. Of course, if an asteroid of this size were to hit a city or in an ocean offshore from a populated area, tens of thousands of people would likely die.

Then, just as the last of the night sky observers were completing their collective sighs of relief, on March 17th, 2009 another Tunguska-class asteroid, 2009 FH, passed by about 53,000 miles from Earth. Thankfully, neither of these asteroids actually hit us. But astronomers didn’t even observe 2009 DD45 until 4 days before its closest approach. It's orbit was calculated and it was determined that it would miss the Earth. But it's likely that asteroids of this size are fairly frequently buzzing by the Earth. And until recently, most of them have been undetected.

In 1998, NASA started the Spaceguard Survey which set out to discover 90% of those Near Earth Asteroids (NEAs) 1 km in diameter and larger. An impact by an asteroid this size would likely cause global destruction and an end to much of life as we know it so it’s definitely reassuring that 10 years after its inception, the Spaceguard Survey had found about 80% (CK) of them. But unfortunately, once we’ve found them, there’s still no international concensus or infrastructure in place in how to deflect or destroy them. But the Survey is limited by its mandate to find those mass extinction-sized asteroids as well as by the size and sophistication of the telescopes that are dedicated to searching the skies.

As former Apollo 9 astronaut, Rusty Schweickart said in a recent phone conversation, "in the process of finding the big ones, you also find a bunch of small ones, and the smaller ones are obviously far more numerous than the large ones." But it will take many more resources and new telescopes to continue searching for and tracking the smaller ones. And unfortunately, once we’ve found them, there's still no international consensus or infrastructure in place in how to deflect or destroy them. Raising awareness and building alliances amongst governments and space agencies is Schweikart's current "mission". He founded the B612 Foundation and Association of Space Explorers to tackle these goals on different fronts.

The message that I hope is conveyed with the Asteroid Hunters TV segment is that we are not immune from asteroid impacts here on Earth. Rusty Schweikart puts it best in a portion of his interview that didn’t make it into the final program:

"Well, asteroids and comets are good news and bad news, you know? But for them we wouldn’t be here, and on the other hand, if we don't actually take some action now, at some point we won’t be here anymore, because there's no question that we will be hit by asteroids, and we’ll probably be hit by, we would be hit by comets as well. Unless, we use the technology that we have and the brains that we have in order to protect the Earth from asteroid impacts, and we can do that. We can basically now, with current technology, assure that no asteroid ever hits the Earth again. That can do any serious damage."
-Rusty Schweikart

Here's a little exercise from Rusty that you can do to get a sense of what we know today about exactly what's out there:

• Go to: neo.jpl.nasa.gov/risk
• See two tables, the first table says "Recently Observed Objects" and the table below says "Objects not recently observed." You’ll notice in the bottom table that Apophis is the 4th one listed.
• Click on "Apophis". At the top you see a bunch of boxes, like the diameter at .27 km, or 270 meters.
• Down below that you see 3 lines, those are the 3 potential impacts. The first one is April 13, 2036. Go over to the right on that line you'll see the column "Impact Probability" is 2.3 x 10-5 – click on that. So there is the probability, 1 in 43,000 of that particular impact.
• Now if you go back to the main table you can do the same thing with every single one of those lines.
• Now go to the very top of the page and hit "Discovery Statistics." Scroll down to a blue and red graph "Known Near-Earth Asteroids". This shows the discovery rate beginning back in 1980 going up to almost current time. Notice the knee in that curve in 1998 – that’s when the Spaceguard Survey began.
• Scroll down to table just below the graph and look across that table to the far right side, to see that a a total of 6166 NEOs (of ALL sizes) have been discovered.

Rusty concludes that, "…what we really care about is not only the things that large, we care about things that can hurt us. Things that can hurt us go down to 40 to 45 meters or so. Instead of there being 940 of them, there are more like 600,000 of them. So the new charge for NASA, which they have so far ignored, is to find 90% of the objects 140 meters and larger by 2020. You can't reasonably set a goal to find everything down to 40 meters because it's just beyond the capability of telescopes and the money available. So NASA, working with Congress, set the goal at 140 meters. Now nevertheless, when you are looking for 140 meter objects, it’s going to take bigger telescopes than the ones to find a kilometer. Therefore we are going to find many many smaller objects as well. So 10 to 15 years from now, instead of that number on the far right hand column being 6000, it will be 1 million."

Watch the Asteroid Hunters television story online.

Scientists gather samples on the ocean floor.
Credit: Roger Linington.There's nothing new about looking to nature to cure disease – we've been doing it for thousands of years, with good results. (Two recent examples: The active ingredient in aspirin was first identified in the bark of the willow tree. And we have the Pacific yew tree to thank for one of the strongest anti-cancer drugs out there, Taxol.)

What's different about the work being done at the UC Santa Cruz Chemical Screening Center is that it a) looks to a largely unexplored medical resource: the ocean, and b) uses robots, rather than "forlorn-looking grad students" (to quote Center director Scott Lokey) to run the tests.

Here's a video I shot of one of those robots in action, with Lokey narrating.

One thing that didn't make it into the piece is that these researchers — including Lokey and Roger Linington — aren't just studying every disease they can think of. They focus on the diseases that commercial drug companies tend to neglect because there's so little profit in treating them – things like African sleeping sickness and cholera. So far, they're seeing progress on both, as well as breast cancer.

Listen to the Medicine from the Ocean Floor radio report online and check out images from this story in an online slideshow.

Cool the Earth is an organization that reaches into elementary school classrooms and Girl Scout troops all over the country, and they're working to make saving energy and being good stewards of our natural resources fun. Participating schools are given a packet of materials to kick off the program with an all school assembly, where characters like Koda the polar bear, Earth, Mother Nature, and Mr. Carbon (boo! hiss!) introduce the topic of global warming and how human actions contribute to the problem. The kids are inspired to save Koda's icy homeland by getting rid of the villain Mr. Carbon.

The students are given a small book of action coupons to take home that recommend tips such as powering down home electronics that use energy when officially "off" but are still in standby mode by unplugging the device or turning off the power at a power strip. Students can earn rewards in the form of prize cards featuring Wasteful Wendy, Rennie Reusable and other characters, for actions such as getting their families to eat one pound less of beef in a week, thereby saving 130,000 gallons of water (the water to grow the crops to feed the cattle, and so on.)

Monthly highlights focus on a particular action, and an Action Banner tracks the progress of the whole school, charting the amount of energy saved and the amount of greenhouse gases avoided. School teachers can go online to access materials, get advice from the staff of Cool the Earth, or just brag about how their school is doing.

The program is working because it employs an age-old motivational strategy– get to the parents through their kids. And the results are tangible. The program so far can account for more than 25 million pounds of carbon emissions avoided. There are 149 schools involved in the program so far, and there is a waiting list for participation. Almost 23,000 students are involved– translating into many more thousands of parents, brothers, and sisters.