Orbiting the sun at a distance of 2.8 billion miles (4.5 billion kilometers), Neptune is the fourth-largest planet by diameter and third-largest by mass, having a diameter of 30,598 miles (49,244 kilometers). Strangely, it is slightly more massive than Uranus, which is strange given that the mass of the gas giants should increase the closer you get to the sun. This has led astronomers to predict that Neptune may have formed much closer to the sun than Uranus did. Still, gravitational perturbations from the other gas giants caused its orbit to migrate outwards. In the 174 years since astronomers found Neptune, it has only been visited by a spacecraft on a single occasion, when Voyager 2 passed by the giant planet in 1989. Voyager 2 revealed a truly remarkable and complex world. Neptune is a warmer planet despite it being further from the sun than Uranus. The core of Neptune is predicted to reach temperatures of (7,000 degrees Celsius), while its upper layers reach temperatures as low as minus 328 degrees Fahrenheit (minus 200 degrees Celsius). This gigantic difference in temperature between Neptune’s outer and inner layers is believed to cause Neptune’s dynamic weather system. Voyager 2 measured the fastest known winds in the solar system, reaching speeds of 1,500 miles per hour (2,400 km/h).
Although classified as gas giants, both Uranus and Neptune have enough unique characteristics that they belong to their own classification: ice giants. Unlike Jupiter and Saturn, Uranus and Neptune contain a much higher abundance of ices, such as water, ammonia, and methane. Like Jupiter and Saturn, Neptune is composed mainly of hydrogen and helium. However, hydrogen and helium only make up a fraction of Neptune’s density. Various ices determine the density of Neptune, making it both a gas giant and an ice giant.
Observational History
An Image of Neptune Taken by Voyager 2, NASA
Neptune was the latest planet to be discovered in our solar system and, interestingly, the only one to be found using mathematics rather than a telescope. The discovery of Neptune was tied directly to the discovery of Uranus. In 1781, the astronomer William Herschel discovered the planet Uranus. After the discovery of Uranus, astronomers were puzzled over its orbit. The orbit of Uranus was tilted so that the mass of Uranus and the gravitational pull of the sun could not explain. In 1821, Alexis Bouvard predicted that the orbit of Uranus could be explained if another planet was orbiting the sun outside of Uranus’s orbit. He was able to predict the orbit of this eighth planet, and in 1846, astronomers pointed their telescopes to the sky and found Neptune, just as the math had predicted. Given Neptune’s distance from us, it is not an easy world to study. For over a hundred years, virtually nothing was known about Neptune. Astronomers would not get their first up-close view of Neptune until 1989 when the Voyager 2 spacecraft completed the first-ever flyby of Neptune. To date, the Voyager 2 flyby has been the only mission to Neptune, and it raised far more questions than it answered. Neptune is one of the most mysterious worlds in the solar system, and our knowledge of it is definitely lacking. However, as telescopes have become more powerful, astronomers have observed Neptune in more detail than in the past. Still, most of what is known about Neptune comes from the Voyager 2 flyby.
Orbit And Rotation
The Planets in Our Solar System and their Orbits
The average distance between Neptune and the sun is 2.8 billion miles (4.5 billion kilometers). It takes Neptune nearly 170 Earth years to complete one orbit around the sun at such a vast distance. Since its discovery, Neptune has only completed one full sun rotation. Like all the other planets, Neptune orbits the sun in an ellipse, meaning that the distance between the sun and Neptune changes through the planet’s orbit. Neptune is roughly 2.76 billion miles (4.45 billion kilometers) away from the sun during its closest approach. Neptune is 2.81 billion miles (4.53 billion kilometers) away from the sun during its furthest approach.
Neptune’s orbit and location in the solar system have a profound impact on the solar system’s outer regions. Just beyond the orbit of Neptune is the Kuiper Belt, a vast collection of comets and other forms of planetary debris. Short-period comets primarily come from the Kuiper Belt, and it is the gravitational pull of Neptune that generally pulls them on a trajectory towards the inner solar system.
As a gas giant, Neptune has an interesting rotation. The axis tilt of Neptune is only 28 degrees, which is quite similar to Earth’s 23 degrees. As a result, Neptune experiences seasonal changes similar to Earth’s, the significant difference being their length. Since it takes Neptune 170 years to orbit the sun, its seasons generally last up to 40 Earth years. Since Neptune is primarily composed of gas, Neptune’s atmosphere rotates at a different rate than the planet itself. The actual rotation of a gas giant is generally determined by the rotation of the planet’s magnetic field. Neptune takes roughly 16 hours for the planet to rotate once about its axis. Along Neptune’s equator, it takes the atmosphere 18 years to rotate around the planet. In the polar regions, it takes 12 hours. This difference in rotation is one factor contributing to Neptune’s high wind speeds.
Neptune’s Atmosphere
The Blue-Green Atmosphere of Neptune as Captured by Voyager 2, NASA
The atmosphere of Neptune is similar to that of Uranus and the other gas giants. Neptune’s atmosphere is about 80% hydrogen and 19% helium in its upper layers. The remaining 1% is composed of various ices, the most notable of which is methane. On Uranus, methane in the upper atmosphere absorbs incoming red light and scatters blue light, causing Uranus to be cyan-green. Neptune contains a similar amount of methane as Uranus, which is one reason why Neptune is blue. However, based on what is currently known, Neptune should be the same color as Uranus, yet Neptune is a much deeper blue than its planetary neighbor. As of yet, scientists do not know all the factors that contribute to Neptune’s color.
The atmosphere of Neptune can be divided into two central regions: the troposphere and the stratosphere. The troposphere composes the lower regions of Neptune’s atmosphere, while the stratosphere composes the upper areas. In the troposphere, temperatures increase with altitude. In the stratosphere, the opposite occurs, and temperatures decrease with altitude. Temperatures between the troposphere and stratosphere vary wildly. In the troposphere, temperatures average around 32 degrees Fahrenheit (Zero degrees Celsius), while temperatures in the upper stratosphere drop as low as minus 328 degrees Fahrenheit (minus 200 degrees Celsius). The troposphere is characterized by an abundance of clouds that can form at higher temperatures. Clouds in the troposphere are primarily made of methane, ammonia, and hydrogen sulfide. The troposphere is also where most of Neptune’s weather occurs.
Neptune is home to the fastest recorded winds in the solar system. Voyager 2 recorded wind speeds of over 1,500 miles per hour (2,400 km/h), which happens to be faster than the speed of sound on Earth. If Neptune’s winds were to occur in Earth’s atmosphere, they would be supersonic winds. Interestingly, since air is the medium that sound travels through, the sound speed depends on the density of air. Air density on Neptune is far higher than on Earth, so winds do not exceed the speed of sound on Neptune.
Internal Structure Of Neptune
The True Colors of Neptunes Surface and Cloud, Captured by Voyager 2, NASA
Neptune’s atmosphere composes an estimated 10% to 20% of the distance to Neptune’s core and only about 5% of the planet’s total mass. Below the atmosphere is a world, unlike anything we are familiar with on Earth. At the very bottom of Neptune’s atmosphere, pressures are 100,000 times larger than on Earth. Below the atmosphere is the mantle. On Earth, the mantle is composed mostly of molten rock. On Neptune, the mantle is comprised of various ices such as methane, water, and ammonia. At a depth of around 4,350 miles (7,000 kilometers), pressures and temperatures in the mantle become so extreme that the carbon atoms in methane molecules break apart and form into diamond, which then proceeds to fall through the mantle as a kind of diamond rain. There may even be an ocean of liquid carbon in the lower mantle, where giant diamond bergs float freely.
Below the mantle is the core of Neptune. The core of Neptune is largely a mystery, and so scientists rely on models to predict what may be occurring there. It is assumed that the core of Neptune is rocky, composed mostly of metal and silicate rock. The core itself is likely larger than the Earth and has a mass of around 1.2 Earths. Temperatures are estimated to reach as high as 9,260 degrees Fahrenheit (5,126 degrees Celsius).
Neptune’s Moons
A Composite Image Showing both Neptune and Its Moon Triton, NASA
Neptune is orbited by 14 known moons. Of those 14 moons, only one, called Triton, is large enough to be spherical. Triton comprises roughly 99% of the total mass of Neptune’s entire moon system. Triton has a diameter of 1,680 miles (2,710 kilometers), making it the seventh-largest moon in the solar system. Triton was discovered only 17 days after the discovery of Neptune, yet not much was known about this moon until the Voyager 2 flyby of Neptune. Triton has become one of the strangest, most interesting moons in the solar system. Unlike every other moon, the orbit of Triton is retrograde, meaning it orbits in the opposite direction of Neptune’s rotation. This suggests that Triton never actually formed in orbit around Neptune. Instead, Triton was likely a dwarf planet that formed in the Kuiper Belt and just happened to get caught in Neptune’s gravity. Although the retrograde motion of Triton may not sound significant, it has actually doomed this moon. The orbit of Triton is slowly degrading, and Triton is currently spiraling towards Neptune. In about 3.6 billion years, Triton will be so close to Neptune that it will be ripped apart by Neptune’s gravity.
When Voyager 2 approached Triton in 1989, it recorded the coldest measured temperature in the solar system. The surface of Triton drops to a frigid minus 391 degrees Fahrenheit (minus 235 degrees Celsius). Voyager 2 found clear evidence of geologic activity on Triton despite these cold temperatures. Voyager 2 found evidence of volcanism and tectonic activity and a lack of impact craters. Unfortunately, Voyager 2 was only able to map 40% of Triton’s surface, so Triton is one of the most mysterious worlds in the solar system.
Neptune Fact Sheet
Diameter
30,598 miles (49,244 kilometres)
Mass
17 Earths
Moons
14
Rings
5
Distance from the sun
2.8 billion miles (4.5 billion kilometers)
Length of year
170 Earth years
Length of day
16 hours
Surface temperature
minus 328 degrees Fahrenheit (minus 200 degrees Fahrenheit)
More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.
That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.
“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”
The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.
Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.
Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.
Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.
Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.
Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.
“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”
The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.
North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.
Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”
Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.
Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.
For Dello, the “fingerprints of climate change” were clear.
“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”
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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.
On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.
They call it “Big Sam.”
The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.
It didn’t die alone.
“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.
She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”
“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.
The head alone, she said, is about the size of a baby elephant.
The discovery was a long time coming.
The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.
“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.
When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”
“It contains about 100 to 300 bones per square metre,” she said.
Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.
About a year ago, they found the second adult: Big Sam.
Bamforth said both dinosaurs are believed to have been the elders in the herd.
“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.
“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”
The genders of the two adults are unknown.
Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.
The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.
She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.
“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.
“It’s pretty exciting.”
This report by The Canadian Press was first published Sept. 25, 2024.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
