Tag: storms

Pictures Show A Mysterious Planet Get More Surreal Over Time

Since entering orbit on July 4 2016, NASA’s Juno spacecraft has been revealing a world coated in curling clouds that loop and spiral around one another, creating filigreed bands speckled with roiling oval storms.

Some of these storms dapple the planet’s previously unseen poles, and they all join the best known of the Jovian tempests, a splotch called the Great Red Spot that stretches more than an Earth across.

The new images “look like Van Gogh paintings,” says Juno’s principal investigator Scott Bolton of the Southwest Research Institute.




I kind of expected some of this, because a long time ago, Voyager took pictures, and other spacecraft that have gone near Jupiter have taken some images, but they’re usually global ones and boy, when you get close, and you see these swirls, they look like art.

These stunning clouds are produced by Jupiter’s incredibly complex atmospheric dynamics—things like winds and turbulence—combined with certain chemistries that produce their vibrant colours.

But the precise reason why Jupiter alone is so fantastically painted isn’t clear.

You don’t see that on Saturn, Uranus, or Neptune for some reason,” Bolton says. “Maybe what you’re seeing is the fact that Jupiter is so big that it has triggered some other special dynamics that are star-like, to some extent.”

Streams of clouds spin off a rotating, oval-shaped cloud system in the Jovian southern hemisphere. Citizen scientist Roman Tkachenko reconstructed the colour and cropped the image, which was taken on February 2 from just 9,000 miles above the storm.

Juno is doing more than simply ogling this magnificent planetscape.

Designed to tease out the intricacies of Jupiter’s innards, the spacecraft carries eight instruments that monitor the planet’s gravity, auroras, atmosphere, magnetosphere, cloud depths, and electric fields.

Together, they should help scientists learn more about the planet’s origins and what, exactly, lies beneath those clouds—straight down to the planet’s heart, which could be made from heavy elements or rock wrapped in a fluid form of metallic hydrogen.

So far, though, seeing the planet’s poles for the first time has been one of the highlights of the mission.

This close-up view of Jupiter, taken from a mere 5,400 miles away, captures the turbulent region just west of the Great Red Spot. Citizen scientist Sergey Dushkin processed and cropped the image to draw viewers’ eyes to the dynamic clouds.

These regions are strikingly different from equatorial Jupiter, with a blue tinge, numerous cyclones, and a lack of distinct cloudy bands.

On March 27, Juno swung low over Jupiter during its fourth science orbit, coming within 2,700 miles of those magnificent cloud tops. Images from that orbit will be released soon.

And over its next set of orbits, Juno will continue focusing on Jupiter’s deep atmosphere and interior structure, gathering data that scientists will eventually combine into a global view of this mysterious world.

Until then, we can bask in the beauty of the biggest planet in the solar system.

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Pass it on: Popular Science

‘Megastorms’ That Throw Thousand-Tonne Boulders Over Clifftops May Be On Their Way Back Thanks To Global Warming

Standing atop a 60-foot cliff overlooking the Atlantic, James Hansen — the retired NASA scientist sometimes dubbed the “father of global warming” — examines two small rocks through a magnifying glass.

Towering above him is the source of one of the shards: a huge boulder from a pair locals call “the Cow and the Bull,” the largest of which is estimated to weigh more than 1,000 tons.

The two giants have long been tourist attractions along this rocky coast. Perched not far from the edge of a steep cliff that plunges down into blue water, they raise an obvious question: How did they get up here?




Compounding the mystery, these two are among a series of giant boulders arranged in an almost perfect line across a narrow part of this 110-mile-long, wishbone-shaped island.

Hansen and Paul Hearty — a wiry, hammer-slinging geologist from the University of North Carolina at Wilmington who has joined him here as a guide — have a theory about these rocks.

It’s so provocative — and, frankly, terrifying — that some critics wonder whether the man who helped spawn the whole debate about the dangers of climate change has finally gone too far.

The idea is that Earth’s climate went through a warming period just over 100,000 years ago that was similar in many ways to the warming now attributed to the actions of man.

And the changes during that period were so catastrophic, they spawned massively powerful superstorms, causing violent ocean waves that simply lifted the boulders from below and deposited them atop this cliff.

If this is true, the effort kicking off in Paris this week to hold the world’s nations to strict climate targets may be even more urgent than most people realize.

Hearty, an expert on Bahamas geology, first published in 1997 the idea that Cow and Bull were hurled to their perch by the sea.

Since then, Hansen has given the work much added attention by framing the boulders as Exhibit A for his dire view of climate change — which has drawn doubters in the scientific community.

But as Hansen examines the rocks on a recent morning, Hearty explains some of the evidence.

In particular, Hearty points out that the tiny grains that constitute the boulder rocks are more strongly cemented together and less likely to crumble than other rocks nearby, a sign that the boulders are older than what’s beneath them.

While there is a suggestion in the scientific literature that the boulders were simply left behind after surrounding rocks eroded away, Hearty and another leading Bahamas geology expert, Pascal Kindler of the University of Geneva in Switzerland, agree that the boulders are older than the surface upon which they rest and, thus, probably were moved by the sea.

Even the tourist placard near here takes their side, saying the ocean “lifted them atop the ridge.” But exactly how it could have done that is another matter.

Scientists have tended to attribute odd boulders such as these to tsunamis — there’s little doubt they have the power to move large rocks.

One recent study found that in the Cape Verde islands, 73,000 years ago, a 300-foot-high mega-tsunami carried boulders as large as 700 tons atop a cliff almost as high as the Eiffel Tower.

But more recent studies have also attributed large boulder movements to storms. And now into the fray has stepped Hansen, who, in 1988 testimony before Congress, put the climate issue on the map by contending — correctly, as it turned out — that global warming had already begun.

If he is also right about the boulders, Earth could be in for a rough ride.

And even if not, one thing is clear: Cow and Bull present a scientific mystery whose solution may serve as a reminder of just how violent and dynamic a planet we live on.

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Pass it on: New Scientist

How Do Hurricanes Form? A Step-By-Step Guide.

Whenever hurricane season arrives in the Atlantic Ocean — typically between June and November — a bunch of meteorological terms get hurled around.

Tropical storm. Tropical depression. Category 3 hurricanes. Category 4 hurricanes.

So what’s the difference between all these types of weather events? One way to understand this is to walk through the different stages of a hurricane, step by step.

We’ll use Hurricane Irma, which started out as a wave off the African coast and went on to pound several Caribbean before it hit Florida as a Category 4 storm, as an example:




1) Tropical disturbance: A hurricane in the Atlantic Ocean typically begins life as a lowly “tropical disturbance” — defined as organized thunderstorm activity that stretches at least 100 miles across and maintains its identity for more than 24 hours.

During the summer, these disturbances often start as storms moving westward off the coast of Africa in what are known as “tropical waves.”

If meteorologists think a tropical disturbance may develop further, they’ll designate it as an “investigative area,” or invest.

Irma became a disturbance off the Cape Verde Islands in late August, with forecasters keeping close watch as it headed west.

2) Tropical depression or cyclone: Under the right conditions, a tropical disturbance can develop further and start to spin around a low-pressure center. Once that happens, it’s classified as a “tropical cyclone” or “tropical depression”:

For a tropical depression to form, conditions have to be just right: The water has to be warm enough to fuel the system, with temperatures of 80°F or hotter.

There needs to be enough moisture in the lower and middle part of the atmosphere. Local winds also have to be arranged so that they allow the depression to spin — too much wind shear can tear an aspiring tropical cyclone apart.

3) Tropical storm: This is the next stage. When the pressure in the center of the tropical depression drops, air rushes in, creating strong winds.

If the system strengthens and wind speeds rise past 39 mph, the system is dubbed a “tropical storm” and is given a name.

That’s what happened to Irma on August 30, as it picked up speed in the far Eastern Atlantic and intensified.
The US National Hurricane Center makes the call for when a tropical depression officially becomes a tropical storm.

It relies on data from islands and buoys as well as from reconnaissance aircrafts that fly into the storms to measure wind speed.

4) Hurricane: Tropical storms can intensify quickly if they pass over a region of especially warm water and don’t face much wind shear. As that happens, the pressure in the center drops even further and the winds really pick up.

The system gets rounder and often forms a clearly defined “eye.” Here’s Irma on Wednesday:

When the winds reach sustained speeds of 74 mph or more, the storm system is classified as a hurricane. Hurricanes are categorized according to the Saffir-Simpson Scale based on their wind speed and propensity for damage.

Irma was a Category 5 as of September 5 with wind speeds of 185 miles per hour. That’s serious — major hurricanes can do structural damage to buildings, take down trees, and cause widespread flooding.

Side note: The fact that you need especially warm water here explains why hurricanes only form in the Atlantic during the late summer months.

It also helps explain why global warming may lead to stronger hurricanes, although this gets complicated, since climate change can also affect wind shear that suppresses hurricanes.

5) Back down to tropical storm: Hurricanes can also weaken, however, as they move over land (or cooler water) and no longer have warm, moist air to fuel them.

Once wind speeds drop below 75 miles per hour, the hurricane gets downgraded to a tropical storm — and, later on, a “post-tropical cyclone” as it degrades further.

For example, Hurricane Hermine in 2016 was downgraded to a tropical storm not long after it made landfall in Florida in September.

But then Hermine moved back over the Atlantic Ocean and hit record-warm ocean temperatures there, gathering to hurricane strength again.

It’s worth emphasizing that even tropical cyclones that aren’t hurricanes can still do a great deal of damage by bringing torrential rain, dangerous surf, beach erosion, high winds, and flooding.

In 2012, “superstorm” Sandy was technically no longer a hurricane when it hit the East Coast, but it still proved devastating to the New York and New Jersey coasts.

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Pass it on: Popular Science