Tag Archives: giant

Magnetic field readings point to the structure of Saturn’s interior

Researchers at the Johns Hopkins University have completed a new model of Saturn’s interior, which hints at a thick layer of helium rain that modulates the gas giant’s magnetic field.

Saturn’s interior with stably stratified Helium Insoluble Layer (HIL). Image credits Yi Zheng (HEMI/MICA Extreme Arts Program) / Johns Hopkins University.

The so-called ‘gas giants’ are notoriously hard to peer into, and they remain some of the most mysterious planets out there. Given the extreme environments they represent, it’s likely going to be a while before this changes, and an even longer while before any astronauts can actually go see for themselves.

That doesn’t mean we can’t draw some conclusions based on what we do know, however. And a team from Johns Hopkins University did just that, creating a new digital model looking into Saturn’s interior. This model hints at a temperature difference in the helium rain layer between the planet’s equator (where it is hotter) and the poles (where it gets colder).

Hot waist

“By studying how Saturn formed and how it evolved over time, we can learn a lot about the formation of other planets similar to Saturn within our own solar system, as well as beyond it,” said co-author Sabine Stanley, a Johns Hopkins planetary physicist.

“One thing we discovered was how sensitive the model was to very specific things like temperature,” she adds. “And that means we have a really interesting probe of Saturn’s deep interior as far as 20,000 kilometers down. It’s a kind of X-ray vision.”

Saturn is unique among the other gas giants in that its magnetic field is almost perfectly symmetrical around its axis. Since magnetic fields are generated by structures inside a planet’s body, this tidbit could help us glean some information about Saturn’s interior layout.

Using data recorded by NASA’s Cassini mission, researchers at Johns Hopkins University created detailed computer simulations using software typically employed for weather and climate simulations. The models indicate that there is a heat gradient in Saturn’s interior, with higher temperatures towards the equator. Overall, this could point to the existence of a layer of liquid helium around the planet’s core.

The magnetic field of Saturn seen at the surface. Image credits Ankit Barik / Johns Hopkins University.

This structure creates a dynamo-like mechanism, which goes on to produce the striking magnetic field recorded around Saturn. On Earth, the planet’s iron core and molten metal mantle play the role of dynamo. It was expected that gas giants rely on a different structure to create their magnetic field, given their different chemical composition and extreme mass, but this is the first study to actually pinpoint one candidate structure for this role in gas giants.

Apart from this, the simulations also suggest that a certain level of non-axisymmetry could be present near Saturn’s north and south poles.

“Even though the observations we have from Saturn look perfectly symmetrical, in our computer simulations we can fully interrogate the field,” said Stanley.

Naturally, until we can put a person on Saturn to check, we can’t confirm these findings. Until then, models will have to suffice.

The paper “Recipe for a Saturn‐Like Dynamo” has been published in the journal AGU Advances.

The different types of planets barreling through space

Planets come in all sha… planets come in various sizes. But, some of the most striking characteristics that set them apart are their physical and chemical particularities, which we use to categorize the myriad of planets we’ve found in space.

Image via JPL-Caltech.

I like planets. I like them so much I live on one. They’re heavy enough for gravity to make them round, their orbits are clear of debris, and they don’t burn like stars do. But, there’s a lot of variation in what they are and the experience they offer.

So, today, I’d thought it would be exciting to look at all the different types of planets — some of which we’ve seen in the great expanse of space, some of which we’re only expecting to find. In no particular order, they are:

Brown Dwarfs

Artist’s impression of a T-type brown dwarf named 2MASSJ22282889-431026. The Hubble and Spitzer space telescopes observed the object to learn more about its turbulent atmosphere.
Image credits NASA / JPL-Caltech.

A star is a delicate system where gravity compresses and heats everything up while the nuclear fusion at their core pushes outwards. With too much pressure, electrons can’t move freely, so the reaction stops. With too much ‘boom’, there’s not enough pressure to keep the reaction going.

Teetering on the edge of starhood, brown dwarfs have outgrown any definition of a ‘planet’. Yet, they’re just not quite a star. Ranging from 13 to 80 times the mass of Jupiter, brown dwarfs are immense embers barreling through space, fusing deuterium and lithium to keep themselves slightly alight. However, they need yet more matter to be able to fight their own gravity, so they can’t ignite.

Brown dwarfs aren’t planets. They don’t form like planets — they form like stars. Instead of material slowly clumping together, brown dwarfs are born from clouds of gas collapsing in on themselves.

Gas Giants

Jupiter as snapped by the Juno probe.
Image credits NASA / JPL-Caltech.

The chonk de la chonk, gas giants are the largest planets to ever dot the universe. They are composed primarily (>90%) of hydrogen and helium (the two simplest elements in the periodic table) with traces of other compounds thrown in for good measure. Hydrogen and helium give these planets an overall brown-yellow-ocher palette, with water and ammonia clouds peppering their highest layers white. Owing to the nature of their bodies, these giants are blanketed by wild storms and furious winds.

We don’t know much about their cores, only that it has to be immensely hot (around 20,000 Kelvin, K) and pressurized in there. The main hypotheses hold that gas giants either have molten rocky cores surrounded by roiling oceans of gas, diamond cores, or ones made of super-pressured (metallic) hydrogen nuggets.

Jupiter as snapped by the Juno probe.
Image credits NASA / JPL-Caltech.

They are sometimes called ‘failed stars’ because hydrogen and helium keep stars running, but gas giants don’t have enough mass to spark nuclear fusion. We have two of them in the solar system, Jupiter and Saturn.

Most exoplanets we’ve found so far are gas giants — just because they’re huge and easier to spot.

Ice Giants

Picture of Neptune taken in August 1989, assembled using filtered images taken by Voyager 2.
Image credits NASA / JPL-Caltech / Kevin M. Gill.

Very similar to gas giants but won’t return your texts. Ice giants are believed to swap out hydrogen and helium (under 10% by weight) in favor of oxygen, carbon, nitrogen, and sulfur, which are heavier. Boiled down, we don’t really know what elements these planets are made of — their (admittedly thin) hydrogen envelopes hide the interior of the planets, so we can’t just go and check. This outer layer is believed to closely resemble the nature of gas giants.

Still, it is believed that, while not entirely made of the ice we know and love here on Earth exactly, there is water and water ice in their make-up. They get their name from the fact that most of their constituent matter was solid as the planets were forming, and because planetary scientists refer to elements with freezing points above about 100 K (such as water, ammonia, or methane) as “ices”.

COROT-7c, an exoplanet located approximately 489 light years away in the constellation Monoceros. Seen here in an artistic simulation as a hot mini-Neptune.
Image credits MarioProtIV / Wikimedia.

Ice giants are, as per their name, quite gigantic, but they tend to be smaller than gas giants. However, owing to their much-denser make-up, they are also more massive overall. There are two ice giants in our solar system, Uranus and Neptune. Water, in the form of a supercritical ocean beneath their clouds, is believed to account for roughly two-thirds of their total mass.

Both ice giants and gas giants have primary atmospheres. The gas they’re made from was accreted (captured) as the planets were forming.

Rocky Planets

Artist’s concept of NASA’s Mars Science Laboratory spacecraft approaching Mars.
Image credits NASA / JPL-Caltech.

Also known as terrestrial or telluric planets (from the Latin word for Earth), they are formed primarily of rock and metal. Their main feature is that they have a solid surface. Mercury, Venus, Earth, and Mars, the first four from the Sun, are the rocky planets of our solar system.

To the best of our knowledge rocky planets are formed around a metallic core, although the hypothesis of coreless planets has been floated around.

Atmospheres, if they have one, are secondary — formed from captured comets or created via volcanic or biological activity. Rocky planets also form primary atmospheres but fail to retain them. Secondary atmospheres are much thinner and more pleasant than those of Saturn or Uranus. That’s not to say a secondary atmosphere can’t influence its planet: Venus’s rampant climate disaster is a great example.

Composite image of Mercury’s north pole.
Image credits NASA.

Mercury, with a metallic core of 60–70% of its planetary mass, is as close as we’ve found to an Iron planet. Both those and the much more bling Carbon planets thus remain hypothetical. Another exciting and cool-named hypothetical class of rocky planets are Chthonians, the rock or metal cores of gas giants stripped bare.

Rocky worlds can harbor liquid water, terrain features, and potentially tectonic activity. Tectonically-active planets can also generate a magnetic field.

Comparison of best-fit size of the exoplanet Kepler-10c (middle) with Earth (Left) and Neptune.
Image via Wikimedia.

Such planets come in many different sizes. Earth is Earth-sized, Mercury is only about one third of it, while Kepler-10c is 2.35 times as large as our planet. Density is also a factor. Without going to a planet and studying its interior structure, it’s impossible to accurately estimate its density. As a rule of thumb, however, uncompressed density estimates for a rocky planet tend to be lower the farther away it orbits its star. It’s likely that planets closer to the star would thus have a higher metal (denser) content, while those further away would have higher silicate (lighter) content. Gliese 876 d is 7 to 9 times the mass of Earth.

The first extrasolar rocky planets were discovered in the early 1990s. Ironically, they were found orbiting a pulsar (PSR B1257+12), one of the most violent environments possible for a planet. Their estimated masses were 0.02, 4.3, and 3.9 times that of Earth’s.

Ocean planets

Ganymede, the largest and most massive moon in the Solar System, and its ninth largest body.
Its also an ocean moon.
Image via Wikimedia.

These planets contain a large amount of water, either on the surface or subsurface. They’re an offshoot of the rocky planet, either covered in liquid water or an ice layer over liquid water. We don’t know very much about them or how many there are out there because we can’t yet spot liquid surface water, so we use atmosphere spectrometry as a proxy.

Earth is the only planet on which we’ve confirmed the existence of liquid water at the surface so far. And although water does cover around 71% of the Earth, it only makes up for 0.05% of its mass, so we’re not an Ocean planet. On these latter ones, waters are expected to run so deep that they would turn to (warm) ice even at high temperatures (due to the pressure).

This type of planet remains one of the likeliest to harbor extraterrestrial life.

Dwarf planets

True color image of Pluto taken by the  New Horizons craft.
Image via Wikimedia.

Fan-favorite Pluto, along with Ceres, Haumea, Makemake, and Eris are the dwarf planets of our solar system. Dwarf planets kind of stride the line between planets and natural satellites. They’re large enough to hold their own stable shape, even to hold moons themselves, but not enough to clear their orbit of other material.

Moons

Titan seen in visible light (center) and infrared (exterior).
Image credits NASA / JPL-Caltech / University of Nantes / University of Arizona.

Not technically planets because they orbit another planet, moons are nevertheless telluric bodies that vary in size from ‘large asteroid’ to ‘larger than Mercury’. Titan, Saturn’s largest moon, has its own atmosphere.

There are six planets in the Solar System that sum up to 185 known natural satellites, while Pluto, Haumea, Makemake, and Eris also harbor their own moons.

Rogue planets

These are the planets your parents warned you about.

Rogue planets deserve a mention on this list despite the fact that they don’t orbit a star. They are, for all intents and purposes, planets that orbit the galactic core after being ejected from the planetary system in which they formed. It is also possible that, somehow, they formed free of any stellar host. PSO J318.5−22 is one such planet.

Jupiter.

Hubble snaps breathtaking new image of Jupiter

Jupiter is still pretty, science finds.

Jupiter.

Image credits NASA, ESA / A. Simon (Goddard Space Flight Center) and M.H. Wong (University of California, Berkeley)

The image was taken on June 27, 2019 and centers on the planet’s titanic Great Red Spot. It records Jupiter’s color palette, swirling clouds, and turbulent atmosphere in much higher quality than previously-available images. These elements provide an important glimpse into the processes unfurling in the gas giant’s atmosphere.

Ten year challenge photo

The image was taken in visible light as part of the Outer Planets Atmospheres Legacy program (OPAL). It was snapped with Hubble’s Wide Field Camera 3 when Jupiter was 400 million miles from Earth — near “opposition,” or almost directly opposite the Sun in the sky.

OPAL generates global views of the outer planets each year using the Hubble Telescope, which are meant to provide researchers with the data they need to track changes in their storm, wind, and cloud dynamics.

One of Jupiter’s most striking features is the Great Red Spot, around which the current image focuses. The Spot is a churning storm, rolling counterclockwise between two bands of clouds (above and below the Great Red Spot) which are moving in opposite directions. The red band to the northeast of the Great Red Spot contains clouds moving westward and around the north of the giant tempest. The white clouds to its southwest are moving eastward to the south of the spot. The swirling filaments seen around its outer edge are high-altitude clouds that are being pulled in and around the storm.

Jupiter’s bands are created by differences in the thickness and height of the ammonia ice clouds that blanket its surface, both properties dictated by local variations in atmospheric pressure. The more colorful bands and are generally ‘deeper’ clouds. Lighter bands rise higher and are thicker, generally, than the darker ones. 

Winds between bands can reach speeds of up to 400 miles (644 kilometers) per hour. All of the bands seen in this image are corralled to the north and to the south by powerful, constant jet streams — these remain stable even as the bands change color on the other side of the planet.  The band of deep red and bright white that border the Giant Red Spot also become much fainter on the other side of Jupiter.

You can learn more about how these colors form here.

Giant sloth.

Timeline for giant sloth extinction rewritten by new analysis

The giant sloth may have lived in the slow lane, but it went extinct much faster than previously estimated, a new study reports.

Giant Sloth Bones.

Lithic tool associated with giant ground sloth bones.
Image credits Gustavo Politis, Pablo Messineo.

Researchers at the National University of Central Buenos Aires, Olavarría, Stafford Research, and La Brea Tar Pits and Museum, report that the giant sloth went extinct before the Holocene, the current geological period.

Dirty collagen

Prior research had found that the giant sloth disappeared during the Pleistocene, the geological epoch spanning from about 2.5 million to 11 thousand years ago — the last period of repeated glaciations to grip the Earth (right before the Holocene). However, there was also some evidence pointing to the survival of this species in certain pocket areas (of today’s Pampas, Argentina) up to the Holocene.

The present study comes to invalidate that hypothesis: the giant sloths went completely extinct before the onset of the Holocene, it explains. This new paper used a more stringent testing technique to date the remains of giant sloths found at the Campo Laborde dig site in Argentina. The team recovered collagen from the remains — they note that a single bone had recoverable collagen — that they dated using the radiocarbon technique and used to establish the new timeline for the sloths’ extinction.

The study also provides a glimpse into what went wrong with earlier dating attempts: the collagen used in the current study had been heavily contaminated with compounds leaching from the soil around it. Earlier dating efforts had not taken this contamination into account, they explain, which fouled the results. The team used chemical purification techniques to clean up the collagen before running their analysis, and then extracted specific amino acids that could only have come from the sloth itself, the team explains.

Giant sloth.

Giant sloth.
Image credits Eden, Janine and Jim / Flickr

Their analysis shows that the giant sloth went extinct around 10,570 years ago. This would push the timeline of their disappearance out of the Holocene (previous research found that the animals went extinct around 9,730 years ago, which is during the Holocene).

It’s a distinction that might sound pedantic, but it’s actually quite significant. Humans are currently considered the driving force behind the extinction of many ancient megafauna species, including the giant sloth. The new findings don’t exonerate our ancestors, but they do suggest that they were only part of the problem; their hunting of the giant sloths certainly helped, but it likely happened during a time when the species was buckling, likely under environmental strain from changing climate patterns.

The findings also raise the possibility that other species of huge mammals, especially those in South America (but possibly other places around the globe as well) didn’t make it to the Holocene either. If the collagen in the remains those studies were based on is found to be contaminated, the findings could be off the mark by thousands of years.

The paper “A Late Pleistocene giant ground sloth kill and butchering site in the Pampas” has been published in the journal Science Advances.

Suidobashi Heavy Industries accepts US’s Megabot Inc challenge for a giant robot duel

Earlier this month, Megabots Inc issued a video challenge on Youtube to Suidobashi Heavy Industries, to pit the company’s’ biggest, baddest robots against each other in a duel of giant robots. And grab the popcorn, put the beer on ice and get your geek on, because Japanese robot manufacturer has accepted the challenge from its US competitor, Efe news agency reported.

Weighing in at just under 4,000 kg, Japan’s metal monster will take on the 5,400-kg US contender in what may well be the newest form of entertainment, right from the world of science fiction.In the video Megabot posted presenting its Mark II as “America’s first full-functional, giant piloted robot”, founders Gui Cavalcanti and Matt Oehrlein said they have equipped Mark II with massive paintball guns to fight Suidobashi’s Kuratas model.

Suidobashi founder and CEO Kogoro Kurata released a video a day later, accepting Megabot’s challenge to a duel. Kurata found the proposal interesting, but felt his competitor could be “done better”.

“Just building something huge and sticking guns on it. It’s super American. I cannot let another country win this. Giant robots are Japanese culture,” he said, adding that he wanted to “punch them to scrap and knock them down” he said.

Neither a date nor venue for the event has yet been announced.

 

 

Giant squids take to California

Yes ladies and gents, giant squids are all over the California beaches. Each of the squids weighs about 40 pounds, but some of them reach 60 and even more than that. I haven’t been able to find out what’s up with them, or why they gathered in such numbers, but according to scientists, this happens almost periodically, though they cannot have a totally satisfying explanation. The most plausible guess is that they’ve been brought there by a warm water current.

humboldt-squid

Anyway, there’s no reason to panic or anything, though you might want to avoid taking a swim this week. However, local anglers are absolutely delighted, catching them by the hundreds, and since things probably won’t change, we’re going to be talking thousands pretty soon; they also sometimes get rolled over on land, there they remain stranded and eventually end up rotting.

The searches for “giant squids” have gone through the roof, so I’m guessing a lot of people are interested or quite nervous about this. The squid in case is the Humboldt squid, also name Jumbo Squid, Jumbo Flying Squid, or Diablo Rojo (which is just Spanish for “red devil”). They rarely weight over 100 pounds, and their average lifespan is at about 1 year. Oh, they’re giant by comparison with most squids, but there others that make it pale in comparison. The biggest squid out there is (arguably) the colossal squid.