A capped column snowflake with a collection of rime

If you saw something like this falling from the sky, you might think that the weather outside was indeed frightful. But this dumbbell shaped object is, in fact, a super-magnified snowflake — yes, a snowflake. Not so frightful after all.

This particular snowflake is a capped column, one of many types of snowflakes. The fuzzy texture on its two hexagonal ends is called rime.

Sometimes, when a snowflake, or snow crystal, passes through a cloud on its way down to earth, it collides with super-cold water droplets—clouds, after all, are just a bunch of coalesced drops of water. This collision causes the cloud’s water droplets to freeze and stick to the surface of the snow crystal. When these frozen droplets accumulate on the crystal’s surface, the snowflake becomes bedecked with rime.

If a snow crystal collects too much rime, its original identity can be obscured. Snowflakes that experience this type of identity crisis are called graupel.

This snowflake’s portrait was taken by a low temperature scanning electron microscope.

Photo: Electron and Confocal Microscopy Laboratory, Agricultural Research Service, U. S. Department of Agriculture

Running short of worries? Then ponder the super-volcanoes — earth-bombs that can vomit 10 or 100 or 1,000 cubic kilometers of molten rock. Super-volcanoes can change history by creating rivers of red-hot ash moving at highway speed, spreading dust across hundreds of kilometers and spewing vapors that block the sun, destroy crops and start famines.

A volcano may go dormant for thousands of years after such a huge eruption, so they may be even harder to predict than smaller ones — which are also unpredictable at this point…

But this week, Nature published a new analysis of Santorini, a Mediterranean monster, that shows the movement of molten rock that preceded the eruption.

Santorini’s sudden release of 40 to 60 cubic kilometers of rock and ash was followed by a giant collapse that left a characteristic ring of hills called a caldera. Thousands may have died in the eruption, which laid down a 60-meter layer of ash and rock.

Eruptions of this general size happen about every 300 years, says Timothy Druitt, a volcanologist at the Université Blaise Pascal in France, who lead the current study. The most recent was in 1815 at Tambora, in Indonesia.

Druitt’s new analysis of crystals within the frozen magma offers a rough schedule for the entry of molten magma into a holding tank — the magma chamber — below the volcano, which is a precursor to eruption.

Caldera-forming eruptions rival earthquakes and tsunamis as the deadliest natural disasters. “People who work in the field know these volcanoes are not rare, even on a human time scale,” says Druitt, but “we have never been able to monitor one of these big eruptions during the long buildup phase, so we are not really sure how that happens.”

The crystal analysis detects microscopic changes in chemical composition, offering a unique, after-the-fact picture of the gestation of eruption.

In the crystals

As crystals grow in the cooling magma, atoms of trace elements diffuse within them, and both growth and diffusion are affected by conditions within the hot magma, says Druitt. “These crystals grow progressively, and as they do, their chemical composition changes according to the composition of the magma around them, and the temperature and amount of water in the magma.”

The crystals revealed that a big gob of magma — perhaps 10 percent of the magma chamber’s total contents — entered in the decades before the eruption. “Looking at the crystals in this magma, we were able to reconstruct very crudely events taking place in the last few decades prior to the eruption,” Druitt says.

That final addition probably made the magma chamber unstable, leading to the eruption, Druitt explains.

If such a late, large magma movement proves typical of super-volcanoes, that could contribute to a distant early warning system for mega-eruptions, based on more conventional methods, such as seismic monitoring.

Distant early warning

But the findings also carried a caution, Druitt says, since Santorini was apparently dormant for about 18,000 years before the last apoplectic outburst. “That is a slightly alarming result. There are lot of these big caldera systems, but most are in a stage of repose.”

The upshot is more proof that a dormant volcano can still be a dangerous one, he adds. “We can imagine that a big caldera in a remote region of the world, such as the Andes, which is not monitored very well, could reawaken pretty quickly on a human time scale.”

The crystal method gives after-the-fact data on an eruption. Current attempts to anticipate eruptions rely on data about earth shaking, deformation of the crust, and release of gases.

“It’s a very timely topic, and solid science in terms of the measurements and observations,” says Bradley Singer, a volcanologist and professor of geoscience at University of Wisconsin-Madison. “They admit that there are issues about the time scales,” largely because the diffusion of strontium and titanium is imperfectly understood in the hot magma.

The study’s title, however, specifies that the final growth of the magma chamber occurs on “Decadal to monthly timescales,” Singer notes. “It could be centuries or even longer, which implies that we’d have a longer time prior to the eruption” to worry about the effects of the rising magma.

Singer concurs on the importance of understanding the relationship of magma flows, instability and eruption, and says the crystal analysis is gaining traction in volcanology.

That’s just as well, since giant caldera-forming volcanoes may be frighteningly common. The one at Yellowstone, for example, released 1,000 cubic kilometers of rock 640,000 years ago. Wouldn’t you want to know if something like that was building on your continent?

If many scientific quests should be marked with an academic form of caution tape: “Progress = 2 steps forward + step back,” cosmologists have been in steady retreat for decades.

The “cosmo” girls (and mainly boys) who explore the origin and fate of the universe were once mocked as data-free arm wavers. Then, in 1964, cosmo was promoted into a science by the discovery that echoes of the Big Bang were rattling around the universe.

The unexpected arrival of data — of fingerprints of the ultimate past — allowed observational astronomers to budge the theorists in the search for the origin and fate of everything.

Here’s the big picture of cosmology: Big Bang creates matter, which expands for an instant faster than light (please hold your questions for the end). Matter proceeds to form galaxies, black holes, stars and weird beams of energy.

In 1929, Edwin Hubble discovered that the universe was expanding: The further the object, the faster it recedes from us.

The biggest explanation of all began to leak when astronomers noticed that galaxies were spinning so fast that they should fly apart as their centrifugal force overwhelmed the gravity that their mass created.

Galaxies have not gotten the memo, and they are calmly rotating rather than flying apart.

Desperate, cosmologists cooked up the idea that a vast quantity of matter was missing. Was invisible. Was “dark.”

Dark matter was the first tragedy inflicted by data on cosmo theory.

When cosmologists tried to decide if gravity would eventually recall the far-flung stars and galaxies back into a “big crunch,” they found something utterly inexplicable: In 1998, two scientific teams announced that the rate of expansion was rising.

Some anti-gravity force — some “dark energy” — was apparently to blame.

If dark matter is hard to find, dark energy is hard to envision.

As the news about dark energy sank in, the prospect of figuring out what’s what melted faster than a frozen butter sculpture in July.

Today, the embarrassing accounting of our cosmological conundrum says that, astronomers, with all their fancy education and ultra-slick telescopes, can only see 4 percent of the universe.

Most scientific books proceed from the unknown and proceed to make it known. But The 4% Universe, ensnared in the twin realm of darknesses, does the opposite. It’s deeply unsatisfying, but as any cosmologist would say, so is that 4 percent picture.

The 4% Universe documents a more familiar form of dark energy — the thirst for headlines among two gangs of “bickering eggheads” that more or less independently found the accelerating expansion.

Without shying away from scientific subtleties, Richard Panek has written a biography of dark matter and dark energy, and of the legion of physicists and astronomers who chased the ultimate question mark. You’ll meet star-chasers, careerists, self-promoters and lone geniuses intent on answering a simple question: What’s out there?

– David J. Tenenbaum

2010 marked the completion of a bizarre telescope composed mainly of ancient ice. One billion tons of ice.

Buried a mile deep in the ice at the South Pole, IceCube is the world’s strangest telescope. Composed of water, it’s looking for the neutrino, nature’s most unusual particle. Eighty years after the neutrino was “invented” to balance a physics equation, it remains ultra-difficult to detect, measure and understand.

IceCube is focused mainly on particles that come all the way through the Earth. In other words, this telescope looks down.

Scientists say neutrinos can pass unscathed through a long bar of lead. How long? Say, one light year long — about 10 trillion kilometers. Because neutrinos can slip through everything in their path, including stars, galaxies and vast clouds of dust, they are unrivaled tattle-tales of ancient explosions in the deep universe.

The bad news is that the same property makes neutrinos extremely difficult to see.

But if you can somehow observe the neutrino’s insanely rare interaction with matter, you could learn something about the universe, and the gargantuan energy released by exploding stars.

Roots of a frozen telescope

That is the promise and the premise of IceCube, a $271-million project intended to solve a problem posed in 1930, when physicist Wolfgang Pauli proposed a new and rather odd particle. Tiny, energetic, with no electric charge and not necessarily any mass, it would be virtually undetectable.

Pauli himself admitted “I have done a terrible thing. I have postulated a particle that cannot be detected.”¹

The “now-you-don’t-see-it-and-you-never-will” neutrino was tailor-made for controversy; scientists detest what they can’t detect. Pauli’s idea was mocked² as “simply wrong” or “crazy.”

Today, scientists are sure nature is full of these shadowy characters: Rough calculations say a hundred trillion neutrinos whistle through your body every second.

Why make a big deal about neutrinos, which are, after all, less offensive than campaign ads? Because that ability to pass through all manner of interstellar crud allows neutrinos to carry messages from the far reaches of the universe.

Moreover, some neutrinos carry more punch than the wildest gamma ray. And just as you can’t pull a hot coal from a cold fire, you shouldn’t get “hot” neutrinos from “cool” sources like ordinary stars. These neutrinos, in other words, may deliver signals of some hip, blazingly hot stuff — neutron stars, active galactic centers, and exploding stars.

Finally, according to some scenarios, lower-energy neutrinos may comprise a small proportion of the mass — the stuff — of the universe, but they played a key role in the evolution of the universe.

In astronomy, as in love and antiques, “hard-to-get” translates into “most-wanted.” “The hope is that the particle that is almost nothing will tell us almost everything about the universe,” says Francis Halzen, a theoretical physicist at University of Wisconsin-Madison. Halzen directs IceCube, and did the same at IceCube’s predecessor, AMANDA, the Antarctic Muon and Neutrino Detector Array.

Search strategy for an elusive character

Neutrinos may be shy, but once in a great while, they actually hit an atom and produce a subatomic particle called a muon, which is easier to see.

Because the odds of a neutrino hitting anything are so dismal, physicists require bigger targets. It’s the same principle that lottery players use to “beat” the tiny odds of winning by buying hundreds of tickets.

Previous neutrino targets have included tubs of oil or dry-cleaning fluid and 5,000 tons of steel plates salvaged from battleships. To block spurious signals due to cosmic rays rather than neutrinos, these detectors have been sunk in the ocean or placed inside deep mines.

IceCube relies on a two-step detection sequence: First, the tiny percentage of neutrinos that interact with atomic nuclei in the ice produce muons. Second, these muons create Cherenkov light when they interact with matter.

When the detectors see Cherenkov light, they digitize the data and send it through electric cables to the surface for analysis. The detectors are housed inside 5,160 crush-proof glass spheres placed in holes drilled through the ice, and located 1450 to 2450 meters deep.

Another 324 detectors at the surface detect muons made by cosmic rays arriving from the Southern sky.

The Antarctic ice also has little radiation, and the detectors are so deep that air bubbles have been squeezed out, ensuring great optical clarity. Yet while the detectors are shielded from damage, they are under crushing pressure, and if they go bad, they will be busted forever.

IceCube will only look at muons that trigger at least eight detectors, says Halzen, and is most interested in muons moving upward — coming from the Northern Hemisphere. Downward signals can be confusing, as most of them are due to cosmic rays or lower-energy neutrinos, which Earth blocks.

Data from IceCube should suggest where the neutrinos originated and what sort of cosmic engine started them on their journey.

This desire to concentrate on neutrinos rather than cosmic rays explains why this frozen telescope, oddly but logically, looks downward.

What can these neutrinos tell us?

Neutrinos, “invented” to balance a physics equation, have grown to fascinate astrophysicists, galactic voyeurs seeking signals from astonishingly energetic structures and events in the deep universe. The direction and energy of neutrinos from each source should offer clues about the origin:

Image: NASA/JPL-Caltech/STScI/CXC/SAO

Located 10,000 light-years away in the constellation Cassiopeia, Cassiopeia A is the remnant of a massive star that died in a violent supernova 325 years ago. The dead star (turquoise dot in center) became a neutron star surrounded by a shell of junk blasted away in the explosion. Image is a composite from three orbital telescopes: Infrared data from the Spitzer Space Telescope is red; Visible light from the Hubble Space Telescope is yellow; Chandra X-ray Observatory data is green and blue.

Although supernova neutrinos have low energy and are hard to detect, a nearby supernova could light up IceCube enough to overwhelm the system. To prep for a supernova, Reina Maruyama, an assistant professor of physics at University of Wisconsin-Madison, is working to ensure that IceCube can handle this once-in-a-lifetime chance to get good data on a stellar explosion.

If something like the 1987 supernova exploded nearby in our galaxy, Maruyama says, “there would be so many neutrinos, the whole ice would glow. We expect that a few supernovas will occur each century in the galaxy, if one goes off, IceCube has to be ready. We stand to learn a whole lot about how they explode, and about the particle nature of neutrinos.”

Dark matters

Even weirder than neutrinos, IceCube may explore dark matter, a type of, well, something, that comprises 23 percent of the overall universe. A measly 4 percent of matter, including the galaxies, stars and planets, is visible. The balance is an even stranger quantity called dark energy.

The first inkling that some matter is invisible came in the 1930s, when a physicist noticed that galaxies rotate too fast: their visible mass would create too little gravity, and thus they should spin themselves into oblivion.

The explanation for that increased gravity is now called dark matter, and the race is on to detect it.

Since dark matter affects gravity, Maruyama says it must gather in the sun and the galaxies. When dark matter particles collide, they are expected to release a type of neutrino called muon neutrinos. But IceCube found no muon neutrinos coming from the sun and the Milky Way, using a technique that was 1,000 times more sensitive than previous ones.

Does absence make the heart grow fonder?

It depends on your perspective whether that’s good or bad, says Halzen. “There was a big celebration when we published, because we placed limits on that particular type of dark matter, but I looked at it another way: We had gone 1,000 times deeper, and it was very disappointing not to see dark matter.”

However, an experiment in Italy may have seen dark matter interacting with a hunk of sodium iodide, based on an annual variation in the signal. If Earth indeed orbits through a cloud of dark matter, the detector would register alternating downstream and upstream motions that could account for that annual cycle.

The cycle could, however, be due to something unrelated to dark matter.

To answer that riddle, Maruyama wants to place a similar detector deep in the Antarctic ice, and has already piggybacked two prototypes onto IceCube strings. The prototypes are working well enough to justify a larger, more expensive detector, Maruyama says.

If and when the experiment is replicated in Antarctic Ice, Maruyama says, “A positive result would be interesting, and a negative result would be interesting. If we can see a signal with the same timing, that confirms the [Italian] results. If we don’t see a signal, the source must be something aside from dark matter.”

Lurking behind the IceCube project is the tantalizing prospect of learning more about the bizarre particle it detects — the neutrino. We already know that neutrinos have a tiny amount of mass, and that they range in energy through at least 30 orders of magnitude — an unimaginable range of energies. There have been recent — and controversial — reports that neutrinos can travel faster than light — breaking a basic law of physics.

Why so weird?

That’s another indication that neutrinos exist at the edge of the standard model that attempts to explain everything by gravity, electromagnetism, and two nuclear forces, Halzen says. “We are measuring the properties of neutrinos any way we can, and extrapolating to see what the standard model predicts, and looking for variations. The simple way to describe the experiment is that we collect muons and neutrinos, and everything you don’t understand is a discovery, either it’s physics beyond the standard model, or it’s new astrophysics.”

Halzen anticipates spotting an extremely high-energy particle called the GZK neutrino. “These are predicted by theory, and if one hits the detector, we won’t have to do any analysis, we will be able to look at the event display and know that we have made the discovery.” GZK neutrinos are, according to theory, made by cosmic rays that strike photons in the microwave background, Halzen says, and thus could finally reveal the origin of the cosmic rays, one century after their discovery.

Neutrinos are slippery characters; shy, coming in incomprehensible numbers, being emitted by sources we cannot pinpoint. Maruyama notes that neutrinos seemingly change to a different “flavor” without any apparent cause, and says this “oscillation” from one state to another is the strangest part of the neutrino story. “Oscillation could have implications on how the universe evolved to have matter, and not anti-matter,” she says. “These tiny particles could have such an influence on the universe.”

So what?

Why should non-scientists worry about neutrinos? Halzen, who has answered this question many times, says “I have a personal answer. The reason we know our place in the universe is not because of French philosophers, it’s because of physicists. With dark matter and dark energy, we know most of the universe is not made of the same material we are made of. … Is that important to know? I think so.”

IceCube is not intended to produce technology or solve today’s problems, Halzen acknowledges. “This is total curiosity-driven science, and you are allowed not to care. But if you don’t do fundamental research, we’re going to be a developing country, that is clear.”

Particle physics proves that theoretical pursuits can have results that are unpredictable, yet practical and profitable, Halzen says. “My previous job was at CERN [the European particle-physics lab], where people discovered the Web in 1989, to enable collaboration among remote scientists. I think we have paid for all theoretical physics with that one discovery.”

The seas’ most sought-after fish are swimming between a rock and a hard place: the fisherman’s net and an encroaching mass of suffocating water.

A recent study has uncovered a new dose of bad news for ocean fish and the fishing industry. Areas of the deep ocean with little dissolved oxygen, called dead zones, are expanding and, thus, shrinking many fishes’ watery homes.

One driving force behind the predicament is none other than that pesky climate problem.

“Climate change is actually working in tandem with overexploitation of the animals to push these populations into a real dangerous place in terms of population collapse,” said Eric Prince, a fisheries biologist with the National Oceanic and Atmospheric Administration’s Southeast Fisheries Science Center and co-author of the study.

For example, Prince and his colleagues calculated that the Atlantic blue marlin, an economically valuable fish that was a focus of their study, has lost about 15 percent of its habitat from expanding dead zones since 1960. Dwindling habitat threatens not only the lives of fishes, but also the sustainability of the already ailing fishing industry.

Breathing room

Like their above-water brethren, fish need oxygen, which is dissolved in the water. Big, predatory fish, such as the blue marlin, need more dissolved oxygen than most, because they require lots of energy to grow and survive. Without sufficient oxygen, they’ll suffocate.

The level of oxygen in the water thus partly delineates fish habitat boundaries. Dead zones often draw these borders.

As climate change causes open ocean dead zones to balloon, fish habitat deflates.

Diagram modified from one originally published in Deep Sea Research Part I: Oceanographic Research Papers, Vol 57, Issue 4, Lothar Stramma, Sunke Schmidtko, Lisa A. Levin, & Gregory C. Johnson. Ocean oxygen minima expansions and their biological impacts, 587-595, Copyright Elsevier (2010).

Technically known as oxygen minimum zones, dead zones are actually a natural occurrence. Found at depths of between 200 and 1000 meters, they are caused partly by seawater circulation and partly by the decomposition of organic matter, namely deceased sea critters that sink from surface waters.

As aerobic bacteria nosh on the organic matter, they use up the oxygen in the water. Eventually, hypoxia happens—the water becomes so depleted of oxygen that many creatures can’t survive.

Since deep-sea dead zones are insulated from the ocean’s surface, where the water borrows oxygen from the atmosphere, they can only reload with oxygen if currents make a long-distance delivery, according to Sunke Schmidtko, an oceanographer at the University of East Anglia, the other co-author of the study.

Deep-sea dead zones are different from their coastal cousins like the one in the Gulf of Mexico. Coastal dead zones form due to a buildup of agricultural fertilizer that rivers, such as the Mississippi, collect and then flush out to sea, causing abnormal blooms of plant life.

De-fizzing the ocean

But climate change is turning what Mother Nature does normally into a big problem. As the air is getting hotter, so is the water, and warmer water can hold less oxygen than colder water.

This is similar to what happens to a soft drink on a hot day. After sitting in the heat and sun, the fizz fizzles, and you are left with a flat, carbon dioxide-depleted beverage.

Also, warmer surface waters are less likely to sink to the ocean’s lower layers, because warm water is lighter than the colder water below, Schmidtko explained. In other words, as the oxygen-rich surface layers heat up, they could have a harder time delivering oxygen to the deeper ocean.

Schmidtko clarified that oceanographers are still trying to determine how exactly climate change is affecting the ocean, but with their knowledge of how water works, these represent their current speculations.

The rock below

With less oxygen to go around, oxygen minimum zones are swelling and intruding on many fishes’ living zones.

For example, marlins often dive deep to feed, sometimes as far down as 800 meters. However, in the eastern Atlantic’s growing dead zone, which is already one of the largest in the world, Prince found that marlins can’t dive as deep as their west-side counterparts.

“They need to go where the food is and where they can breathe,” he said.

With less breathing room below, the floor of their habitat rises, and they are pinned to the surface layers. With nowhere to go but up, marlins become squished into tighter, testier quarters with other predatory fish and their prey. They also find it harder to dodge a waiting fishing hook or net.

“Concentrating them makes it much easier for overexploitation by [humans],” said Prince.

The increasing concentration of animals at the top could also lead to a boost in the amount of sinking organic matter, which would further worsen the oxygen shortage below.

Softening the hard place above

As a prized catch, Atlantic blue marlins are already victims of overharvesting. In fact, their populations have dropped 60-64 percent over the past three fish generations (14-18 years).

But the growing dead zones can actually fool scientists and fishermen into thinking fish populations are doing just fine, since more fish are squeezed into a smaller area. Thus, to ensure the dead zone-fishing vise does not become their demise, Prince said scientists must more carefully monitor fish populations, as well as the expansion of the dead zones.

While fish stock assessments are starting to incorporate this information, Prince warned the pace needs to quicken.

And if the Earth is to continue warming, as most scientists predict, Schmidtko added that humans should chill out on fishing.

After all, we will never be capable of “ventilating the ocean,” he said.

Sleet is translucent balls of ice that are frozen raindrops. The most common forms of precipitation are rain, snow, freezing rain, and sleet. In Wisconsin, precipitation usually begins as ice particles in a cloud. The temperature conditions below the cloud base determine if the precipitation ends up as rain, snow, freezing rain, and sleet. The altitude of the melting line, or the height where the air temperatures are at freezing, determines the type of precipitation. If the freezing line is above the cloud base, than the ice particles will melt as they fall and we will have rain. If the ground is at, or very near freezing, then the precipitation will be snow, as the ice crystals won’t have enough time to melt. In freezing rain and sleet, the melting line is between the ground and the cloud base, and the ground temperature is below freezing. So, the ice crystals melt and become liquid drops with a temperature near freezing. The main difference between getting freezing rain or sleet is the height of the melting layer and the temperature of the surface. Freezing rain occurs when the liquid drops hit the ground and freeze on contact. Sleet occurs when there is enough time for the liquid drops to refreeze before they hit the ground.

A mixture of rain and snow is not sleet, even though that term is often used in common parlance. A mixture of rain or snow is a term used to describe either wet snow or a mixture of snow and rain.

Photo: LongitudeLatitude

The face of a frigid windchill.

The wind-chill temperature describes the increased loss of heat by the movement of the air. The wind-chill is relevant to humans and other animals that need to maintain a constant body temperature.

The cooling power of the wind cannot be measured with a thermometer; it must be computed. The wind-chill temperature translates your body’s heat losses under the current temperature and wind conditions into the heat loses your body would feel if exposed to the existing air temperature with a 3-knot (or about 3.5 mph) wind.

This is a difficult conversion, and the National Weather Service updated its wind-chill temperature calculation in 2001. According to the new formula, the lowest wind-chill temperature was -54.3° F at 4:00 and 5:00 am on January 20, 1985. On that day, Super Bowl XIX was played in Palo Alto, Cal. The game-time temperature was 53° F.

Last week we were visited for the second time this winter by a sizable snowfall. A reasonable question to ask is where does the water come from to make the snow? A general answer is not available as the variety of snowstorms that we get in Wisconsin result from different sources of water. In fact, even for this last storm in the southern part of the state, the answer depends on where you live. In Madison, the bulk of that water that fell as snow in that last storm most likely originated in or near the Gulf of Mexico, transported northward on southerly winds in advance of the storm center itself. As the air containing the water vapor rose, it condensed or was deposited onto ice particles in the clouds and eventually grew to a sufficient size to fall from the cloud as a snowflake. In Milwaukee, however, an additional source of water vapor to form the snow was Lake Michigan. Air carried over the lake was able to gather more water vapor from the lake surface due to evaporation, thus enhancing the amount of water vapor in the air near Milwaukee. Upon rising, this increased water vapor content led to increased snow amounts there. Finally, the process of transforming water from invisible vapor to ice releases a huge amount of energy to the surrounding atmosphere. In fact, the amount of energy released by this phase change during a 5″ of snowstorm over Dane County alone is enough to power the Madison metro area for 400 days!

No. These storms are individual weather events, which cannot be used to support or refute climate trends. Which also means that the warm weather in Vancouver is not evidence that global warming is occurring. Weather relates to events that will happen over the next few days; climate describes what happens over decades. To make such claims about these storms and climate would be similar to saying “Looks like car accidents rates for WI are going down this year.” after returning from an incident free car ride on a Sunday afternoon. Accident trends are not about individual experiences, and climate and climate trends are not about individual weather events.

It is reasonable to ask, will we see more or less of winter storms in the coming decades with a warmer climate? There is some evidence that a warmer climate will result in more frequent large snowstorms. While the average global temperature 25 years from now will be warmer than current conditions, we will still have winters and summers. A warmer atmosphere means that there will be more water vapor in the atmosphere which could lead to greater snowfall amounts from individual storms during winter. In addition, a warmer world leads to a warmer ocean. So, as winter storms move along the eastern seaboard there could be more evaporation from the warm water. This provides more water for precipitation and more fuel to strengthen the storm.

Conjoined spheres take the shape of a long four-wheeled vehicle,
which drives on a surface of yellow balls.

Buckle your tiny seatbelts. Scientists have created a car at the nano scale.

Just how small is nano? One nanometer equals one billionth of a meter. To help you wrap your head around that, the average sheet of paper is about 100,000 nanometers thick. Measuring in at 4 nanometers by two nanometers, this car is about one billion times smaller than a Volkswagen Golf.

Made from a single molecule, electricity powers the movement of the nano car’s wheels, which can be driven in a straight line and in a controlled manner.

What’s more, the nano car emits neither greenhouse gases nor any noise, a talent it does not share with its bigger cousins.

But like any vehicle, it has its flaws. For example, it has terrible “gas mileage.” Scientists need to refuel it after every half revolution of its wheels. To do so, they give the wheels an electric zap through the sharp, wire tip of a scanning tunneling microscope, an imaging instrument. Also, the nano car can’t drive in reverse.

The nano car is the first foray into designing molecular transport machines, a fancy phrase for microscopic vehicles, which could help scientists carry out tasks at the nano scale.

Photo: Empa