Star of Wonder

Science is very good at explaining things and can even solve a mystery that has no remaining witnesses. Science is able to tell us how long ago a frozen cave man lived, and even how he died. One mystery that science has been unable to explain, but has offered many possible solutions to, is the Star of Bethlehem that the Magi followed. The star is mentioned in the gospels, and many biblical events have been confirmed by archaeology. But is the star a legend, a myth, a miracle, or something perfectly logical?

There are several astronomical phenomena that could explain the star. People at the time were very astute when it came to sky watching, as the stars and moon were (and still are) great navigational aids, so anything out of the ordinary appearing in the sky would have been noticed and documented. Some examples of astronomical phenomena that could have occurred on the First Noel include a planetary conjunction, a nova, a supernova, and a comet.

A planetary conjunction is when two or more planets appear very close to each other in the night sky, and may even appear to be a single object. Just such an event- a Jupiter and Saturn conjunction- took place in the year 7 BC, just outside the accepted date of Jesus’s birth (6 BC- 4 BC). The timing is very close and the position in the sky is correct, but the planets were not close enough to appear as a single star and while the conjunction may have led the Magi in the general direction of Bethlehem from Jerusalem, but did not stand over Bethlehem as stated in the Bible. 

Conjunction of Venus and Jupiter, 2015

A nova (“new star”) is star that suddenly flares up many times in magnitude. It is given this term because in most cases, it is a star that ordinarily is not visible to the naked eye. Similar to a nova is a supernova, a star which has exploded. Chinese and Korean records indicate either a nova or supernova occurred in the year 5 BC, which also fits the timeframe for the nativity. Unlike the planets, however, a nova or supernova would remain in a fixed position in the sky. 

Remnants of 1987 supernova (NASA)

A comet is best described as a dirty snowball orbiting the sun. Depending on location and trajectory, they can become visible to the naked eye as they approach the sun. The period of visibility and brightness vary from comet to comet, but as an object in orbit, it would certainly move about the sky. Chinese records indicate a comet appearing in the year 5 BC, which is within the accepted time of Jesus’s birth. The comet’s location in the sky would have it preceding the Magi first to Jerusalem, then to Bethlehem. It even appeared during spring, which is when it is believed he was born, even though we celebrate Christmas in December. That’s a different story for a different blog. 

Comet ISON (NASA)

Over 2000 years later, the great mystery of the Star of Bethlehem may finally have an answer thanks to forensic astronomy and the meticulous records of the Chinese. Was it really a comet, a completely rational cosmic occurrence, which led the Magi to Bethlehem? If so, did divine intervention place the comet where it needed to be at the right time? That question might never be answered.

This week's information comes from two sources. Speculation about conjunctions and comets comes from Colin J. Humphreys and the speculation about novae and supernovae comes from Mark Kidger.

Species of the Month

December’s Species of the Month, like last December’s, is a living symbol of Christmas. Holly, with its green leaves and red berries, has become of a jolly symbol of the most wonderful time of the year. The Species of the Month is American holly, native to the eastern US and lower Midwest.

Scientific name: Ilex opaca

Kingdom: Plantae (plants)

Class:   Magnoliopsida (dicots)

Order: Celastrales (flowering trees)

Range: New York and southern New England south to the Gulf Coast, west to Texas

Habitat: Well-drained forests, coastal areas

Lifespan: About 100 years

Diet: Sunlight and water

Predators: Insects including southern red mite, holly leafminer, and holly midge; fungal diseases; birds may eat the berries and herbivores may browse the leaves.

Conservation Status: No federal protection; listed as Exploitably Vulnerable in New York and Threatened in Pennsylvania.

Winter holly at Gateway National Recreation Area (NPS Facebook photo)

Other Information: American holly is used as an ornamental planting. Its branches are used in Christmas wreaths. The Pilgrims named American holly, based on its similar looks to their familiar English holly, which had been established as a Christmas decoration for some time. A slow grower, it is typically an understory plant, although some have been known to reach 100 feet tall. Because it is usually found in the understory, it is rarely the dominant plant in a forest. However, an excellent example of a holly forest can be found at Sandy Hook, New Jersey. Both male and female hollies flower, but only the females produce berries. Birds are an important method of seed dispersal. Holly’s wood is among the whitest woods on the market. It is not very strong so its commercial use is limited. Small green flowers are hardly noticeable.

This week's holly information comes from the US Forest Service. 

My 2016 Christmas card, featuring holly in my yard

Coastal holly in North Carolina (NPS)

More holly in New Jersey (NPS Facebook photo)

Coca-Cola's Fuzzy Ecology

Remember a few years back when Coke started running their polar bear commercials around Christmas? Not long after that, they added penguins to the mix. I don’t know about the general population, but apparently the marketing people at Coke don’t know much about polar ecology.

Geographically and ecologically incorrect soft drink

Aside from wild animals drinking carbonated beverages, the biggest mistake in the commercial is mixing animals that are literally polar opposites. Polar bears live at the North Pole and penguins live at the South Pole. You could theoretically have them share a Coke, but one or the other would have to travel quite a distance for that to happen. Not all penguins live at the South Pole, but none live at the North Pole. The southernmost polar bear range doesn't even come close to the northernmost penguin's range.

Polar bear in search of seals and Coke
(US Fish and Wildlife Service)

Penguins, seen here being photobombed by a seal.
The seal is hiding from polar bears. (USF&WS)

Polar bears are carnivores that prey mainly on seals, which glide through the water in much the same manner as penguins. I have a feeling that if they shared overlapping range, rather than drinking Coke and playing together, polar bears would have another option for their holiday feasts. Hungry polar bears have been known to chomp on the occasional puffin, which looks like the flying penguin of the north, so it's not too much of a stretch.

I'm Lichen This Blog

This week Nature Minute will take a look at another unsung hero of ecology, the oft-overlooked lichen. There are many different lichens and they can be found just about everywhere. You’ve probably seen lichens. Maybe a greenish-gray circular spot on a rock, or on the bark of a tree (mistakenly referred to as moss).

Last year, I did a two-part series on the importance of soil. Lichen is just as important to life, if not more so, because lichen will frequently colonize bare rock and secrete chemicals that break down the rock. Thus begins the making a toehold for more advanced plant life to follow. This succession is the beginning of soil formation.

Notice above I said “many different lichens” and not “many species of lichens”. That was intentional, because while a lichen is a living organism, it is not a single species, but a symbiotic odd couple relationship between a fungus and an alga (singular of algae). Some lichens will have a green alga, some will have a blue-green alga, and still others will have both.

How does this crazy living arrangement work? The fungus provides the lichen’s structure. The algae provides the food through photosynthesis. In many cases, the fungus and the alga are perfectly capable of living on their own. Yet for some reason, sometimes they chose to live as roommates in a lichen apartment. There must be an evolutionary advantage.

Perhaps it is the chemicals produced by lichens. Very few insects munch on them, although tundra animals will. They are also very hardy, able to withstand complete desiccation. I don’t know of any fungi or algae that can do that on their own.

Because of the separate living components of lichen, it is impossible to trace the evolution of lichens like we can trace other organisms through DNA and the fossil record. So scientists can’t say how this unlikely partnership formed, although they can tell us how new lichens are made. Because it’s different species living together, you can’t just have a male lichen mate with a female lichen. The fungus and alga can reproduce individually, but their offspring won’t necessarily form a new lichen. However, the lichen can form a soredia, a group of the alga’s wrapped up in filaments provided by the fungus. This little ball of oddities rolls off and starts a new lichen. Another way for lichens to “reproduce” is for a piece of lichen to flake off and drift to a new home.

I hope you enjoyed this week’s fascinating look at one of nature’s weirdest partnerships. Now that you know how weird those mundane little blotches are, maybe you’ll take a closer look. Enjoy some lichen photos I’ve taken during my sojourns. Lichen information this week comes from the USForest Service and the University of California’s Museum of Paleontology here and here.

Lichen on a rock in Idaho

Lichen on a rock at Yellowstone NP

Several small patches of lichen on a rock

Lung lobaria lichen on a tree in Washington

Lichen in the branches of a tree in Washington

Lipstick cladonia on a tree stump

False pixie cup on a tree stump