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at 3:00 AM 0

“It’s more dynamic and alive than Mars,” says UCF planetary scientist Philip Metzger. “The only planet that has more complex geology is the Earth.” The reason Pluto lost its planet status is not valid, according to new research from the University of Central Florida in Orlando.

In 2006, the International Astronomical Union, a global group of astronomy experts, established a definition of a planet that required it to “clear” its orbit, or in other words, be the largest gravitational force in its orbit.

Since Neptune’s gravity influences its neighboring planet Pluto, and Pluto shares its orbit with frozen gases and objects in the Kuiper belt, that meant Pluto was out of planet status. However, in a new study published online Wednesday in the journal Icarus, UCF planetary scientist Philip Metzger, who is with the university’s Florida Space Institute, reported that this standard for classifying planets is not supported in the research literature.

Metzger, who is lead author on the study, reviewed scientific literature from the past 200 years and found only one publication — from 1802 — that used the clearing-orbit requirement to classify planets, and it was based on since-disproven reasoning.

What did NASA's New Horizons discover around Pluto?

He said moons such as Saturn’s Titan and Jupiter’s Europa have been routinely called planets by planetary scientists since the time of Galileo.

“The IAU definition would say that the fundamental object of planetary science, the planet, is supposed to be a defined on the basis of a concept that nobody uses in their research,” Metzger said. “And it would leave out the second-most complex, interesting planet in our solar system.” “We now have a list of well over 100 recent examples of planetary scientists using the word planet in a way that violates the IAU definition, but they are doing it because it’s functionally useful,” he said. “It’s a sloppy definition,” Metzger said of the IAU’s definition. “They didn’t say what they meant by clearing their orbit. If you take that literally, then there are no planets, because no planet clears its orbit.”

The planetary scientist said that the literature review showed that the real division between planets and other celestial bodies, such as asteroids, occurred in the early 1950s when Gerard Kuiper published a paper that made the distinction based on how they were formed.

However, even this reason is no longer considered a factor that determines if a celestial body is a planet, Metzger said.

Study co-author Kirby Runyon, with Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, said the IAU’s definition was erroneous since the literature review showed that clearing orbit is not a standard that is used for distinguishing asteroids from planets, as the IAU claimed when crafting the 2006 definition of planets.

“We showed that this is a false historical claim,” Runyon said. “It is therefore fallacious to apply the same reasoning to Pluto,” he said. Metzger said that the definition of a planet should be based on its intrinsic properties, rather than ones that can change, such as the dynamics of a planet’s orbit. “Dynamics are not constant, they are constantly changing,” Metzger said. “So, they are not the fundamental description of a body, they are just the occupation of a body at a current era.”

Instead, Metzger recommends classifying a planet based on if it is large enough that its gravity allows it to become spherical in shape.

“And that’s not just an arbitrary definition, Metzger said. “It turns out this is an important milestone in the evolution of a planetary body, because apparently when it happens, it initiates active geology in the body.”

Pluto, for instance, has an underground ocean, a multilayer atmosphere, organic compounds, evidence of ancient lakes and multiple moons, he said.

The Daily Galaxy via University of Central Florida

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at 3:50 AM 0
This image of Saturn's famous north polar hexagon, captured by the Cassini orbiter, was first published in 2012.
Credit: NASA/JPL-Caltech/SSI/Hampton University
The weird hexagon swirling around Saturn's north pole is much taller than scientists had thought, a new study suggests.

Researchers have generally regarded the 20,000-mile-wide (32,000 kilometers) hexagon — a jet stream composed of air moving at about 200 mph (320 km/h) — as a lower-atmosphere phenomenon, restricted to the clouds of Saturn's troposphere.

But the bizarre structure actually extends about 180 miles (300 km) above those cloud tops, up into the stratosphere, at least during the northern spring and summer, a new study suggests. [Stunning Photos: Saturn's Weird Hexagon Vortex Storms]

The hexagon, which surrounds a smaller circular vortex situated at the north pole, has existed for at least 38 years; NASA's Voyager 1 and Voyager 2 spacecraft spotted the sharp-cornered feature when they flew by Saturn in 1980 and 1981, respectively.

Scientists started to get much more detailed looks at the hexagon in 2004, when NASA's Cassini spacecraft began orbiting the ringed planet. But Cassini's hexagon observations were pretty much confined to the troposphere for a decade after its arrival; springtime didn't come to Saturn's north until 2009, and low temperatures in the stratosphere continued to compromise measurements by the probe's Composite Infrared Spectrometer (CIRS) instrument for another five years.


We were able to use the CIRS instrument to explore the northern stratosphere for the first time from 2014 onwards," study co-author Sandrine Guerlet of the Laboratoire de Météorologie Dynamique in France, said in a statement from the European Space Agency (ESA).

Those observations have now been newly analyzed. And they revealed a surprise: the presence of a familiar shape high above the clouds.

"As the polar vortex became more and more visible, we noticed it had hexagonal edges, and realized that we were seeing the pre-existing hexagon at much higher altitudes than previously thought," Guerlet added.

The formation of a stratospheric hexagon appears to be tied to the warming brought on by the change of seasons, the research team wrote in the new study. Indeed, Cassini spied a vortex high above the south pole during its early years at Saturn, when that hemisphere was enjoying summer. (Saturn takes 30 Earth years to orbit the sun, so seasons on the ringed planet last about 7.5 years apiece.)

But the southern stratospheric vortex wasn't hexagonal. And neither, for that matter, is the vortex that spins around the south pole lower down, in the tropospheric clouds, the researchers said.

"This could mean that there's a fundamental asymmetry between Saturn's poles that we're yet to understand, or it could mean that the north polar vortex was still developing in our last observations and kept doing so after Cassini's demise," study lead author Leigh Fletcher, of the University of Leicester in England, said in the same statement.

That demise came on Sept. 15, 2017, when mission team members steered Cassini into a fiery death in Saturn's atmosphere. The long-lived orbiter was low on fuel, and the team wanted to make sure Cassini never contaminated the Saturn moons Titan and Enceladus — both of which may be capable of supporting life as we know it — with microbes from Earth.

The asymmetry between north and south is just one vortex-related mystery that scientists are chewing on. Another is the northern feature's striking shape: It's unclear why the jet stream should form into a hexagon. Earth's jet stream has done no such thing, for example.

The $3.9 billion Cassini mission — a joint effort of NASA, ESA and the Italian Space Agency — also dropped a lander called Huygens onto Titan's surface in January 2005. As the new study shows, data gathered during the mission could still help solve some of the ringed planet's perplexing mysteries, even though Huygens and the Cassini orbiter are no longer with us.

"The Cassini spacecraft continued to provide new insights and discoveries right up to the very end. Without a capable spacecraft like Cassini, these mysteries would have remained unexplored," ESA Cassini-Huygens project scientist Nicolas Altobelli said in the same statement. "It shows just what can be accomplished by an international team sending a sophisticated robotic explorer to a previously unexplored destination — with results that keep flowing even when the mission itself has ended."
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at 3:42 AM 0
A wet Mars could have started off near the orbit of Venus before gravitational interactions early in its life drove the Red Planet out to its current orbit.
Credit: NASA/GSFC

Billions of years ago, liquid water flowed across the Martian surface. As the Red Planet lost its atmosphere, it also lost its ability to hold on to that water — or so most theories propose. Now, a new model suggests that Mars would have started off warmer and wetter if it had begun closer to the sun and slowly moved outward.

"Mars starts off on top of Venus; then it dances outward towards Earth," Cole Brown, a researcher at Penn State University, told his colleagues. Working with planetary scientist Darren Williams, also of Penn State, Brown modeled an early solar system where Mars started off in a warmer place. He found that the process was unlikely, but possible — just over 10 percent of the worlds starting out this way successfully worked their way out to where Mars orbits today. He presented the results in June at the 232nd meeting of the American Astronomical Society in Denver. 

"After Mars would escape Venus, that's where things would get interesting," Brown said. [How Did the Solar System Form?]

"A Mars cannon"
The Martian surface is gouged by river-like features and spreading deltas, all of which seem to suggest liquid water once sat on the surface. At almost 4 billion years old, these features are almost as old as the planet itself, hinting that liquid water was short-lived on the Red Planet. 

Four billion years ago, the young sun was dimmer, shining at only about 75 percent of its current brightness. By itself, the newborn star wasn't hot enough to keep Mars warm if the planet were sitting in its current orbit, an average of 142 million miles (229 million kilometers) from the sun, about 1.5 times as far as Earth (1.5 astronomical units, or AU). 

For the planet to have been warm enough to hold water, an atmospheric blanket would have been required, Brown said. With a significant greenhouse effect, an atmosphere would allow the Red Planet to keep liquid water on the surface. Over time, researchers assume that the atmosphere was lost; spacecraft such as NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission are hunting for clues about the disappearing atmosphere.

But Brown wasn't content with this solution. "There may be another way to accomplish this result [of liquid water]," he said.

Brown and Williams noticed that the region near Venus would have been about the right temperature for a planet to hold on to water when the sun was young and dim. Using computer models, they found that the two planets could have evolved together over the course of about 100 million years — a brief enough time for liquid water to form on the surface. The two worlds would have remained tidally locked, keeping an unchanging face pointed toward each other for that brief period of time, until instabilities in their orbit finally drove them apart.

After the escape, Mars would have passed near Venus for multiple orbits. Gravity would have driven Venus inward and sent Mars spiraling outward. In this setting, it wouldn't have taken long for the Red Planet to interact with Earth — and that's where things get difficult.

In the first simulations of this scenario, gravitational interactions with Earth managed to drive the Red Planet out to its current position. But Brown and Williams noticed that the Red Planet occasionally came within 40 Earth radii of our planet — closer than the orbit of the moon. Unfortunately, the original models didn't include a moon, so they didn't chart the potential chaos. So, the pair went back and included a moon in the next iteration.

"It's kind of like if you shot a Mars cannon at the Earth-moon system," Brown said.

The pair ran 10,000 simulations with Mars entering the system at various speeds. They found that the closer Mars came to Earth's surface, the more likely it was to affect the moon — sometimes even driving it out of the system completely. In these simulations, only rarely did Mars come in close enough to affect the system, but "it's a risk we need to be aware of," Brown said.

The close encounters raised some interesting questions. The leading theory for the moon's origin involves a Mars-size object colliding with Earth early in the life of the solar system. The collision would have carved out a chunk of the terrestrial surface that, along with the fragments from the impactor, coalesced into the moon. The process is similar to the one simulated by Brown and Williams, though without the catastrophic impact.

"This almost tells that story, but it does not," Brown said.

The odds are slim that Mars started out near Venus. In more than half of the simulations, a traveling Mars collided with either Venus or Earth, which would have obliterated the Red Planet and any signs of water on the surface. Nearly 20 percent of the time, the Red Planet was ejected from the solar system completely, while another 10 percent of the time, it was tossed into the sun. Only 13 percent of the time was it able to successfully dance between Venus and Earth to arrive at its current position.

For now, the researchers are continuing to explore ways that Mars could have successfully moved into the outer solar system and whether Mars and Venus could have been stable while tidally locked. 
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at 3:27 AM 0
MacCallum is the co-founder and chief technology officer of World View, a company that develops long-duration stratospheric balloons. Credit: World View

WASHINGTON — The new chairman of a commercial space industry group says addressing growing demands for airspace, and conflicts with commercial aviation, will be a major priority for him.

The Commercial Spaceflight Federation (CSF) announced Aug. 29 that Taber MacCallum, the co-founder and chief technology officer of stratospheric ballooning company World View Enterprises, will be the chairman of the board of the industry group. He succeeds Alan Stern, another co-founder of World View who is best known as principal investigator of NASA’s New Horizons mission, who was chairman the past two years.

In an Aug. 30 interview, MacCallum said he was asked to take on the role of chairman after serving as a CSF board officer for two years. “It’s an honor to take the position and help here,” he said. “I couldn’t pick a better year. This next year or two is going to be really exciting.”

That excitement, he said, is based on growth in the industry. Within the next year as many as four companies should begin carrying people into space: Boeing and SpaceX with their commercial crew orbital vehicles, and Blue Origin and Virgin Galactic with suborbital spacecraft. “I grew up on the Arthur Clarke vision of commercial space operating like an airline,” he said, something that those companies are taking a “baby step forward” to realizing.
Taber MacCallum. Credit: World View


That growth in activity, though, presents challenges that he believes the industry, through CSF, will need to address. “We’re going to be an increasingly common user of the airspace that we launch through,” he said. “We need to share that safely and efficiently with the airlines, and work with the FAA to become a real partner with the rest of the industry in how we use that airspace.”

Commercial spaceflight has increasingly become a topic of attention, and concern, for commercial aviation. Launches today can force the closure of affected airspace for up to hours at a time, requiring affected flights to be rerouted. That’s a particular issue for launches from Cape Canaveral, where airspace closures can affect traffic on busy East Coast flight corridors.

During a hearing of the aviation subcommittee of the House Transportation and Infrastructure Committee in June, Tim Canoll, president of the Air Line Pilots Association, cited a 2013 FAA study that found that a single launch caused individual flight delays of up to 23 minutes. That becomes a major problem, he argued, as the number of launches from there increases.

“Given the interest in increasing the number and scale of spaceflight launches, it’s easy to extrapolate the tremendous effect commercial space operations could have on the U.S. airline industry, as well as on its passengers, cargo shippers and workers, if integration isn’t managed correctly,” Canoll said at the hearing.

MacCallum said that the FAA has one of its aviation rulemaking committees looking at the topic, while other efforts are ongoing at ways to reduce both the amount of airspace cordoned off for a launch and its duration. He also advocated for continued development of the NextGen air traffic management system that would, among other things, allow for improved coordination of launches within national airspace.

“Commercial space operators are really the airlines’ greatest ally to getting to next-generation air traffic control,” he said. “NextGen is what enables commercial space to work well within the rest of the national airspace system. Making that relationship work well within the FAA and with the airlines is really a very high priority for us.”

Another priority for CSF, he said, is supporting regulatory reform for the commercial space industry. Space Policy Directive 2, signed by President Trump in May, calls for streamlining launch licensing, commercial remote sensing and other regulations involving the industry.

“That’s been a super opportunity for the industry that I think we’re really able to work with the administration on,” MacCallum said.

He also hopes to expand the ranks of the CSF, which currently has more than 80 members ranging from major aerospace companies to startups and universities. “We need more and more companies to really step up, because as we try to do all of these things, that takes time, effort and resources,” he said. Of particular interest, he added, were companies in the small launch vehicle business as well as suppliers.

MacCallum will retain his job at World View while serving as CSF chairman. That company is “going great,” he said, citing a fundraising round earlier this year and some recent hires, including former Space Systems Loral executive Matteo Genna as senior vice president of engineering and manufacturing.
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at 5:01 PM 0

A carbon cycle anomaly discovered in carbonate rocks of the Neoproterozoic Hüttenberg Formation of north-eastern Namibia follows a pattern similar to that found right after the Great Oxygenation Event, hinting at new evidence for how Earth's atmosphere became fully oxygenated.

By using the Hüttenberg Formation, which formed between a billion and half a billion years ago, to study the time between Earth's change from an anoxic environment (i.e. one lacking oxygen) to a more hospitable environment that heralded the animal kingdom, a team of researchers led by Dr. Huan Cui of the NASA Astrobiology Institute at the University of Wisconsin–Madison discovered a sustained, high level of carbon. This influx of carbon, coupled with changes in other elements, indicates how changing levels of oceanic oxygen may have lent a helping hand to early animal evolution.

The study, published in the journal Precambrian Research, paired new oxygen, sulfur, and strontium isotope data, with carbon isotope data published in 2009, obtained from drill core samples from the Hüttenberg Formation. Together, the data provides further evidence that Earth's oxygen increased in a stepwise fashion, as opposed to being constrained to two major events capping the Proterozoic (a geological epoch that lasted between 2.5 billion and 541 million years ago). The resulting pattern of changing redox reactions (i.e. reactions involving oxygenation and reduction via the exchange of electrons) was named the Hüttenberg Anomaly, after the rock formation in which it was found. [Photos: Ancient Mars Lake Could Have Supported Life]

The University of Maryland's Dr. Alan J. Kaufman, who is the second author of the study and the lead author of the 2009 carbon isotope study, says that the paired data "suggest that the rise of oxygen was oscillatory through this 50- to 75-million year interval associated with the Hüttenberg Anomaly and the Neoproterozoic Oxidation Event or NOE at the end of the Proterozoic." 

The anomaly shows how the carbon isotope ratios (13C/12C) experienced a sustained 12 to 14 parts per thousand increase in abundance for roughly 15 million years before returning to prior low levels. As oxygen levels in the ocean increased, sulfides were converted to sulfates, which some microbes use in their metabolism to digest and recycle organic carbon on the seafloor. The isotopes of oxygen, carbon, and sulfur moved in tandem during the Hüttenberg Anomaly, convincing the scientists that what they were seeing wasn't just a coincidence. 

Wild fluctuations
Although it has long been accepted that high levels of atmospheric oxygen paved the way for animals to populate the Earth, global carbon and oxygen cycles fluctuated wildly during the Proterozoic, between the time when oxygen first accumulated in the atmosphere during the Great Oxygenation Event (GOE) around 2.4 billion years ago, and the time in which they stabilized near to modern levels once animals took the world stage following the NOE, around 500 million years ago. 

During the time between those two events, pulses of unicellular life and variable levels of oxygen in the oceans are thought to have stimulated the evolution of more complex life. These ancient oxygen swings were crucial to the evolution of multicellular life at the Precambrian–Cambrian boundary (541 million years ago; the Cambrian is a geological period that marked the origin and diversification complex animal life on Earth). As pools of oxygenated water grew in the ocean, life was given the opportunity to develop towards a future when oxygen would be at stable and high levels. The Hüttenberg Anomaly represents one such window of opportunity for life.

Kaufman compares the jump in oxygen to another oxygen oasis in time, the Lomagundi event right after the GOE. The Lomagundi event has been described as a false start, when oxygen concentrations rose to levels that could support some life, before decreasing again. It wouldn't be until the NOE that oxygen would rise to modern-day levels. [Ancient Mars Could Have Supported Life (Photos)]

"Here's an isotope anomaly in the Neoproterozoic that is associated broadly in time with the NOE, but which has a rise and fall structure that looks very similar to the GOE," Kaufman tells Astrobiology Magazine. "At both ends of the Proterozoic Eon there was continental rifting, glaciations, and profound carbon fluctuations; just as the GOE was likely responsible for the evolution of simple eukaryotes, the NOE was involved in the evolution of multicellularity."

So the GOE ushered in eukaryotes, which are microbes with cells containing a nucleus wrapped by a membrane, and the NOE ushered in even more complex animals. These exceptional events in Earth's history each harbored an evolutionary test pool that fostered new lifeforms. How exactly the Hüttenberg Anomaly fits into these events or exactly what evolutionary consequence it had still remains to be seen.

Lead researcher Huan Cui analyzing isotopes in the wet lab at the University of Wisconsin–Madison. Oxygen, carbon, strontium and sulfur isotopes during the Neoproterozoic reveal a step-wise pattern of atmospheric oxygen, crucial to the evolution of complex life.
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at 1:51 PM 0


A recent contest challenged participants to create utopian designs of future human Mars settlements, and their creations are stunning.

In the HP Mars Home Planet Rendering Challenge, over 87,000 people from all over the world flexed their creative muscles to design the perfect colony on the Red Planet. Last summer, when HP launched the challenge, the participants started working on their designs, and the winners were announced on Aug. 14.

This challenge wasn't just about creating a pretty, futuristic-looking, idealistic Martian colony. Indeed, the designs also had to show how the settlements would support 1 million colonists. The surface of the Red Planet is harsh, with an extremely thin atmosphere, intense radiation and dust storms that occasionally envelop the planet. (Mars Ice Home: A Red Planet Colony Concept in Pictures)

The participants' designs were judged on originality, creativity, rendering quality and Mars physics (or how the design would realistically work on the actual Martian surface), HP included in a statement. The designs must take into account atmospheric conditions, gravity, the soil, the surface terrain, radiation, drinking water, and air, the statement added.

Open to the public, this challenge had three competitions: Concept, 3D Modeling and Rendering. The participants could submit their designs to one of five categories in either architecture/civil engineering or vehicles/mechanical engineering: still rendering (GPU rendered), still rendering (CPU rendered), animated rendering (GPU rendered), animated rendering (CPU rendered), and virtual-reality or real-time executable. [How Living on Mars Could Challenge Colonists.
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