Starry sky with green haze above a moss covered cliff, with waterfall on bottom right and chromatic bow along bottom

The Skogafoss is one of the biggest waterfalls in Iceland, and is especially beautiful in this stunning image under the aurora borealis. The Northern Lights are shining against a great sea of stars, including the constellation Ursa major, or Great Bear, home to the asterism — a recognizable cluster of stars — the Big Dipper. And then there’s the rainbow that’s not really a rainbow.

This colorful arch is actually a moonbow, created by the light of the full moon refracting and reflecting in the water droplets that have drifted away from the waterfall.

Rainbows are created by sunlight refracting in, and reflecting from, raindrops or mist, even if the light and water source are different. The light is first refracted when it enters a water droplet, as the light wave changes direction because it is slowed more on one side than another. Next, it is reflected off the back of the droplet, and finally it is refracted again on its way out.

Upon entering the droplet, the sunlight is separated into different wavelengths, an effect called dispersion. Different wavelengths of light are each different colors. The shorter wavelengths, like blue and purple, are refracted at a greater angle than longer wavelengths, like red and orange. This variation in bending gives rainbows and moonbows their shape.

Photo: Stephane Vetter (Nuits sacrees)

Satellite image of Breidamerkurjökull Glacier in Iceland.

A few hundred years ago, this area was farmed. But from about 1650 to the late 1800s, Vatnajökull expanded and formed Breidamerkurjökull. This period of slight cooling in the Northern Hemisphere is called the Little Ice Age.

Over the past century, Breidamerkurjökull, along with 90 percent of the world’s glaciers, has been receding due to climate change. Glaciers recede when the snow and ice melt in the summer is greater than the accumulation in the winter. Shrinking glaciers contribute to rising sea level, which puts low-elevation coastal areas in jeopardy.

What’s more, declining spring run-off causes increased water shortages in areas that depend on glacial water, such as the U.S. Pacific Northwest and quite a few major South American cities, including Quito, Lima, Santiago and La Paz.

Photo: DigitalGlobe

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

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

Click on the image to follow the flocks of American Pipits throughout the year.

You don’t have to be a birder or ornithologist (a.k.a. a bird scientist) to think this graphic is fascinating. This map shows where American Pipits, a small, sparrow-like bird, can be found throughout the year (click on it to watch the animation of their migration).

The American Pipit likes the open country. During its breeding season, the little birds set up camp in high tundra latitudes, such as the Arctic, and high alpine altitudes, such as the Rocky Mountains. This is why you may notice they nearly disappear from the map in the spring and summer.

In October and November, these itinerant birds stampede southward to the lower 48 states, congregating in habitats such as beaches, marshes, farm fields and short-grass prairies. Hence the explosion of color on the map through the late fall and winter months.

This map is part of the eBird collection, a tool created and managed by the Cornell Lab of Ornithology and Audubon. Using observations submitted by their army of recreational and professional birders, the lab’s scientists create these maps to track which areas of the country are important for bird species at any given time of the year. The maps also show the regions where birds flock, and where just a few fly—the legend indicates the density of the flocks.

The eBird maps contribute to the suite of tools that help scientists better understand the patterns of biodiversity around the world. However, no tool is perfect, and the map does not reveal all the Pipit’s secrets. For example, their spring migration pattern is largely missing from the map. Could that be because all the birders have flocked to the woods in the spring, leaving no one to watch the Pipits depart the fields?

Courtesy: eBird

A tiny little roundworm

Courtesy Kyung Won Kim and Judith Kimble, UW-Madison Biochemistry department and the Howard Hughes Medical Institute.

Minirhizotrons took these photos depicting root growth over a three-week period in the summer of 2011. Image courtesy of ORNL.

Teeny little video cameras called minirhizotrons snapped these photos of wetland plant roots. The cameras will help scientists anticipate how the plants might respond to climate change.

Minirhizotrons give scientists at the Oak Ridge National Laboratory a technological boost by allowing them to study living roots, especially the really small ones, without harming the plants. By tracking the life and death of roots in their real-life soil environments, with a few manipulations here and there, scientists can better understand what effects increasing temperatures and carbon dioxide levels will have on wetland ecosystems.

The specific wetlands in question are bogs, which are carbon-rich, but nutrient-poor environments. In other words, bogs collect a lot of carbon deep in their soil due to large buildups of dead plant matter. However, their soils don’t have a lot of nutrients to give back to living plants, making them tricky places for plants to grow.

Roots are responsible for transporting water and nutrients to the rest of the plant. So, in bogs, they have to work extra hard to keep plants alive.

Scientists will use the minirhizotrons in one of Minnesota’s black spruce bogs to track how roots react to their climate-change-mimicking manipulations.

Bogs cover only 3 percent of the Earth’s surface. So, why should we care what happens to them?

Because they store nearly one-third of our terrestrial carbon. Thus, if the planet continues to warm, scientists predict these bogs will dry out and release tons of carbon into the atmosphere, exacerbating warming.

Yikes.

Image courtesy of ORNL. Source: Method of studying roots rarely used in wetlands improves ecosystem research

Blue and green orb in lower right corner, orange threads protrude from it

One hurdle to treating neurodegenerative diseases is the inability of neurons in the central nervous system to regenerate axons after damage. In glaucoma, retinal ganglion cell (RGC) axons, which make up the optic nerve and serve as cables to pass information from our eyes to our brains, are damaged and thus unable to regenerate. Shown here is a segment of a mouse retina that is sprouting new putative axons, termed neurites, from the RGCs after being cultured in a mixture of growth factors and hormones for one week. This segment is labeled with three different fluorescent probes. The new neurites are labeled with an antibody to a component of the RGC cytoskeleton (red), as well as a marker for cell nuclei (blue) and an antibody to a component of the astroglial cells, or nervous system cells, supporting the RGCs (green). The image was taken on a Ziess Axioplan 2 fluorescent microscope.

Courtesy Kimberly Toops, Ph.D. candidate, UW-Madison department of biomolecular chemistry

Rectangular forms jut out of smooth surface. Courtesy Thomas Eiden, Undergraduate, UW-Madison Department of Nuclear Engineering.

Despite being merely microns thick, these impurity crystals jut like skyscrapers from the surface of NF 616 cast stainless steel, a specialized engineering material. All engineering materials contain small amounts of impurities, which play an important role in the mechanical properties of the material. This image was captured with a Scanning Electron Microscope (SEM).

Courtesy Thomas Eiden, Undergraduate, UW-Madison Department of Nuclear Engineering