A paler Uranus emerges in the latest telescope image

Studying the seasons on the planet Uranus takes a while. One year on the distant, bluish gas giant — the time it takes Uranus to go once around the sun — is 84 Earth years.

Photographs from the Hubble Space Telescope provide more details for astronomers to scrutinize about shifting climatic conditions on Uranus, the odd ice giant of a planet. Long-term brightness measurements suggest the northern hemisphere of Uranus, now emerging into sunlight, is brighter than the southern hemisphere, which Voyager 2 observed when it flew by in 1986.

“Is that due to a difference in the thickness of the clouds?” said Heidi B. Hammel, vice president for science at the Association of Universities for Research in Astronomy. “The chemistry of the clouds? The dynamics in the clouds triggered by sunlight? Some complicated combination of all of the above? We frankly don’t know.” The European Space Agency, which collaborates with NASA on the Hubble telescope, offered a comparison between what Uranus looked like in 2014 — seven years after its vernal equinox — and an image taken last year.

In 2014, storms with clouds of methane ice crystals circled the mid-northern latitudes. Eight years later, a haze appeared over the north pole similar to the smog of cities, with small storms near the edge of the polar haze. The causes could include changes in the winds and chemical processes. — KENNETH CHANG

One of the Luckiest Lightning Strikes Ever Recorded

Benjamin Franklin invented lightning rods in the 18th century, and they have been protecting buildings and people from the destructive forces of lightning ever since. But the details of how lightning rods function are still the subject of research.

Although modern lightning protection systems involve extra equipment that makes them more efficient, the lightning rod itself is quite simple: a copper or aluminum rod set above the highest point of a building, with wires connected to the ground. When lightning strikes a building it will preferably pass through the rod — the path of least resistance — and then through the wires into the ground, protecting the building from the extremely high currents and voltages produced by lightning.

But a rod doesn’t wait for the lightning to strike. Less than 1 millisecond before the lightning touches it, the rod, provoked by the presence of the negative discharge of the lightning, sends a positive discharge up to connect to it.

Brazilian researchers recently got lucky, photographing this electric action in São José dos Campos, a city northeast of São Paulo.

The scientists were in the right place, at the right time, and with the right equipment to capture 31 of these upward discharges as they happened. With their location, about 150 yards away from the lightning strikes, and their camera, a device that records 40,000 images a second, they were able to take clear photographs and a slow-motion video of what happens in that instant before the charge from the rod meets the charge from the lightning bolt. The scientists’ study and photos were published in Geophysical Research Letters in December. — NICHOLAS BAKALAR

It’s Not a Stretch: This Dinosaur Had a 50-Foot Neck

Few creatures have pushed anatomy to its limits like sauropods. These supersized dinosaurs moved on pillar-like limbs that supported massive girth, wielded whip-like tails to ward off predators, and used long necks to vacuum up foliage.

While this entire group of dinosaurs is referred to as “long necks,” Mamenchisaurus, which roved around what is now China during the late Jurassic period, would have given other sauropods neck envy. In a new study, researchers estimate that Mamenchisaurus’s neck stretched to a length of nearly 50 feet. Longer than the average school bus, its neck may be the longest neck on an animal ever observed.

In 1987, paleontologists discovered the partial skeleton of a sauropod poking out of the rusty red sandstone of the Shishugou Formation in northwest China. The remains were fragmentary, consisting mostly of a lower jaw, bits of skull, and a couple of vertebrae, but they hinted at an enormous animal that thundered across marshy plains 162 million years ago.

Researchers named the dinosaur Mamenchisaurus sinocanadorum and connected it to several other long-necked sauropods from East Asia.

But Mamenchisaurus’s true size remained an enigma. No other fossilized remains of the sauropod have been excavated, leaving scientists with only those couple of vertebrae to examine.

Andrew Moore, a paleontologist at Stony Brook University who studies sauropod anatomy, said that this was the case for many of the largest dinosaurs. “What’s particularly tantalizing and frustrating is that oftentimes, the longest necks belong to the things that are the least known in the fossil record for the simple reason that it’s really hard to bury something that large,” said Moore, who led the new study.

So he turned to the fossils of several close relatives of Mamenchisaurus, especially Xinjiangtitan, a slightly older sauropod discovered in northwest China in 2013. Remarkably, researchers unearthed Xinjiangtitan’s entire vertebral column. At nearly 44 feet long, it represents the longest complete neck in the fossil record. — JACK TAMISIEA

This article originally appeared in The New York Times.