The Coolest Meteorological Term You'll Learn This Week

Two tropical cyclones orbiting around each other in the northwestern Pacific Ocean on July 25, 2017.
Two tropical cyclones orbiting around each other in the northwestern Pacific Ocean on July 25, 2017.
RAMMB/CIRA

What happens when two hurricanes start to invade each other's personal space? It's easy to picture the two hurricanes merging into one megastorm that tears across the ocean with twice the fury of a normal storm, but what really happens is less dramatic (although it is a beautiful sight to spy on with satellites). Two cyclones that get too close to one another start to feel the pull of a force called the Fujiwhara Effect, a term that's all the rage in weather news these days.

The Fujiwhara Effect occurs when two cyclones track close enough to each other that the storms begin orbiting around one another. The counterclockwise winds spiraling around each cyclone force them to participate in what amounts to the world's largest game of Ring Around the Rosie. The effect is named after Sakuhai Fujiwhara, a meteorologist who studied this phenomenon back in the early 1900s.

The extent to which storms are affected by the Fujiwhara Effect depends on the strength and size of each system. The effect will be more pronounced in storms of equal size and strength; when a large and small storm get too close, the bigger storm takes over and sometimes even absorbs its lesser counterpart. The effect can have a major impact on track forecasts for each cyclone. The future of a storm completely depends on its new track and the environment it suddenly finds itself swirling into once the storms break up and go their separate ways.

We've seen some pretty incredible examples of the Fujiwhara Effect over the years. Hurricane Sandy's unusual track was in large part the result of the Fujiwhara Effect; the hurricane was pulled west into New Jersey by a low-pressure system over the southeastern United States. The process is especially common in the northwestern Pacific Ocean, where typhoons fire up in rapid succession during the warmer months. We saw a great example of the effect just this summer when two tropical cyclones interacted with each other a few thousand miles off the coast of Japan.

Weather Channel meteorologist Stu Ostro pulled a fantastic animated loop of two tropical cyclones named Noru and Kulap swirling around each other at the end of July 2017 a few thousand miles off the coast of Japan.

Typhoon Noru was a small but powerful storm that formed at about the same latitude as Kulap, a larger but much weaker storm off to Noru's east. While both storms were moving west in the general direction of Japan, Kulap moved much faster than Noru and eventually caught up with the latter storm. The Fujiwhara Effect caused Typhoon Noru to stop dead in its tracks, completely reverse its course and eventually perform a giant loop over the ocean. Typhoon Noru quickly strengthened and became the dominant cyclone; the storm absorbed Kulap and went on to become a super typhoon with maximum winds equivalent to a category 5 hurricane.

Fossilized Fat Shows 550-Million-Year-Old Sea Creature May Have Been the World's First Animal

Ilya Bobrovskiy, the Australian National University
Ilya Bobrovskiy, the Australian National University

A bizarre sea creature whose fossils look like a cross between a leaf and a fingerprint may be Earth's oldest known animal, dating back 558 million years.

As New Scientist reports, researchers from the Australian National University (ANU) made a fortunate find in a remote region of Russia: a Dickinsonia fossil with fat molecules still attached. These odd, oval-shaped creatures were soft-bodied, had rib structures running down their sides, and grew about 4.5 feet long. They were as “strange as life on another planet,” researchers wrote in the abstract of a new paper published in the journal Science.

Another variety of fossil
Ilya Bobrovskiy, the Australian National University

Although Dickinsonia fossils were first discovered in South Australia in 1946, researchers lacked the organic matter needed to classify this creature. "Scientists have been fighting for more than 75 years over what Dickinsonia and other bizarre fossils of the Edicaran biota were: giant single-celled amoeba, lichen, failed experiments of evolution, or the earliest animals on Earth,” senior author Jochen Brocks, an associate professor at ANU, said in a statement.

With the discovery of cholesterol molecules—which are found in almost all animals, but not in other organisms like bacteria and amoebas—scientists can say that Dickinsonia were animals. The creatures swam the seas during the Ediacaran Period, 635 million to 542 million years ago. More complex organisms like mollusks, worms, and sponges didn’t emerge until 20 million years later.

The fossil with fat molecules was found on cliffs near the White Sea in an area of northwest Russia that was so remote that researchers had to take a helicopter to get there. Collecting the samples was a death-defying feat, too.

“I had to hang over the edge of a cliff on ropes and dig out huge blocks of sandstone, throw them down, wash the sandstone, and repeat this process until I found the fossils I was after,” lead author Ilya Bobrovskiy of ANU said. Considering that this find could change our understanding of Earth’s earliest life forms, it seems the risk was worth it.

[h/t New Scientist]

The Weird, Disturbing World of Snail Sex

iStock
iStock

Romance is rare in the animal kingdom. Instead of wooing their partners before copulating, male ducks force themselves onto females, depositing genetic material with spiky, corkscrew penises. Then, there's tardigrade sex, which is less violent but not exactly heartwarming. Females lay eggs into a husk of dead skin. The male then ejaculates onto the eggs while stroking the female, and the whole process can take up to an hour.

But you can't talk about disturbing mating rituals in nature without mentioning snails. If you're unfamiliar with snail sexuality, you may assume that snail sex falls on the vanilla side: The mollusks, after all, are famous for being slow-moving and they don't even have limbs. But if you have the patience to watch a pair of snails going at it, you'll notice that things get interesting.

The first factor that complicates snail sex is their genitalia. Snails are hermaphrodites, meaning individuals have both a male set and female set of parts, and any two snails can reproduce with each other regardless of sex. But in order for a couple of snails to make little snail babies, one of them needs to take on the role of the female. That's where the love dart comes in.

The love dart, technically called a gypsobelum, isn't exactly the Cupid's arrow the name suggests. It's a nail-clipping-sized spike that snails jab into their partners about 30 minutes before the actual sex act takes place. The sliver is packed with hormones that prepare the receiving snail's body for sperm. Depending on the species, only one snail might release the dart, or they both might in an attempt to avoid becoming the female of the pair. You can watch the action in the video below.

For sex to be successful, both snails must insert their penises into the other's vaginal tracts at the same time. Both snails deposit sperm, and the strength of the love dart ultimately determines whether or not that sperm fertilizes their partner's eggs.

That's assuming the snail survives the little love-stab. In human proportions, the love dart is the equivalent of a 15-inch knife. Fortunately, snails are resilient creatures, and gastropod researcher Joris Koene tells KQED he's only ever seen one snail die from the transfer.

Snails also have a way of making it up to their partners after skewering them with a hormone stick. Their sperm deposit contains a dose of fortifying nutrients, something scientists refer to as a nuptial gift. It may not equal the energy expended during sex, but its enough to give them a small post-coital boost.

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