FYFD

Tag: planetary science

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    Lava and Life

    Kilauea’s 2018 eruption gave us some of the most stunning volcanic footage ever seen, a tradition carried on in this BBC footage. As powerful and destructive as lava is, it’s also critical to life as we know it here on Earth. Volcanoes are a piece of the tectonic activity on our planet that drives the carbon cycle, without which we’d have no oceans or breathable atmosphere. It’s tough to imagine the geological scales over which these cycles act, but fortunately, there are numerical simulations to help! (Image and video credit: BBC Earth)

  • Albedo Effect

    Albedo Effect

    Temperature isn’t the only factor that determines how ice will melt. In this photo, a dark oak leaf absorbed more solar radiation than the reflective ice around it, causing the ice beneath it to melt. Scientifically, this effect is described by albedo; darker, more absorptive surfaces like the leaf have a lower albedo, whereas light, reflective ice and snow have a high albedo and can better resist melting on sunny days. (Image credit: K. James; submitted by Kam-Yung Soh)

  • Shedding Light on Martian Dust Storms

    Shedding Light on Martian Dust Storms

    In 2018, Mars was enveloped by a global dust storm that lasted for months. Although such storms had been seen before, the 2018 storm offered an unprecedented opportunity for observation from five orbiting spacecraft and two operating landers. As researchers comb through that data, they’re gaining new insights into the mechanisms that drive these extreme events.

    At NASA Ames, a team of researchers used observations of dust columns as input to a simulation of Mars’ global climate, then watched as the digital storm unfolded. Simulations like these have an important advantage over observations: the simulations allow scientists to track the transport of dust from one region to another.

    That dust tracking is critical for some of the team’s results. They found feedback patterns between dust lifting and deposition in different regions. For example, early in the storm dust was largely supplied from the Arabia/Sabaea regions, but once that dust was deposited in the Tharsis region, it kicked off a massive lifting event from Tharsis that put twice as much dust into the atmosphere as had landed there. Later, dust deposited back in Arabia by the Tharsis lofting generated new dust uplifts. As long as more dust got lifted than deposited, the intense storms continued. (Image credits: NASA, T. Bertrand/A. Kling/NASA Ames; research credit: T. Bertrand et al.; see also JGR Planets and AGU; submitted by Kam-Yung Soh)

  • Jupiter in Infrared

    Jupiter in Infrared

    This stunning new image of Jupiter in infrared is part of a data set combining measurements from ground- and space-based observatories. The glowing Jovian orb seen here is a composite of some of the sharpest images captured by the Gemini North Telescope’s Near-Infrared Imager from its perch on Mauna Kea. The brightest areas correspond to warmer temperatures over thinner, hazier clouds, whereas the dark areas mark towering, thick clouds.

    The ground-based images — and observations from Hubble — were timed to coincide with passes from the Juno spacecraft. This combination of infrared, visible light, and radio wave observations gives scientists an unprecedented look at Jovian atmospheric processes. It revealed, for example, that lightning measured by Juno deep inside Jupiter’s atmosphere corresponded to convective storm cores visible to the other imagers. The combination of observations allowed the researchers to reconstruct the structure of these Jovian storms in a way that no single instrument could reveal. No doubt planetary scientists will learn lots more about Jovian convection from the data set. (Image credit: Jupiter – International Gemini Observatory/NOIRLab/NSF/AURA, M.H. Wong (UC Berkeley)/Gizmodo, illustration – NASA, ESA, M.H. Wong (UC Berkeley), and A. James and M.W. Carruthers (STScI); research credit: M. Wong et al.; via Gizmodo)

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    Exploring Martian Mud Flows

    When looking at Mars and other parts of our solar system, planetary scientists are faced with a critical question: if what I’m looking at is similar to something on Earth, did it form the same way it does here? In other words, if something on Mars looks like a terrestrial lava flow, is it actually made of igneous rock or something else?

    To tackle this question, a team of researchers explored mud flows in a pressure chamber under both Earth-like and Martian conditions. They found that mud flowed quite freely on Earth, but with Martian temperatures and pressures, the flows resembled lava flows like those found in Hawaii or the Galapagos Islands.

    On Mars, mud begins boiling once it reaches the low pressure of the surface. This boiling cools it, causing the outer layer of the mud to freeze into an increasingly viscous crust, which changes how the mud flows. In this regard, it’s very similar to cooling lava, even though the heat loss mechanisms are different. (Video and research credit: P. Brož et al.; image credit: N. Sharp; see also P. Brož; submitted by Kam-Yung Soh)

  • Martian Landslides

    Martian Landslides

    Sometimes there are advantages to studying planetary physics beyond Earth. Mars does not have plate tectonics, vegetation, or the level of erosion we do, allowing geological features like those left behind by landslides to persist undisturbed for millions of years. And, thanks to a suite of orbiters, we’ve mapped most of Mars at a resolution better than many parts of our own planet. All together, this gives researchers a treasure trove of geological data from our nearest neighbor.

    One peculiar feature of many landslides is their long runout. Even over relatively flat ground, some landslides cover extreme distances from their point of origin. On Earth, we often see this behavior near glaciers, so scientists theorized that the presence of ice was somehow necessary for the landslide to cover such a long distance. But previous laboratory experiments with dry, ice-free grains showed the same behavior: long runouts marked with ridges running parallel to the flow. The mechanism behind the ridges is still somewhat unclear, but it seems to be connected to fluid dynamical instabilities that form between fast-flowing particles of differing density. But such results have been confined to lab-scale experiments and numerical simulations.

    A new report, however, shows that landslides on Mars share the same characteristic spacing and thickness between their ridges. This evidence suggests that the same ice-free mechanism could account for the long run-out of landslides on Mars and other planets. (Image credit: NASA/JPL-Caltech/University of Arizona; research credit: G. Magnarini et al.; via The Conversation; submitted by Kam-Yung Soh)

  • Titan’s Dragonfly

    Titan’s Dragonfly

    Last week, NASA announced its next New Frontiers mission: a nuclear-powered drone named Dragonfly heading to Titan. This astrobiology mission is set to search our solar system’s second largest moon for signs of life. It’s exciting aerodynamically, as well, since Titan’s thick atmosphere makes it uniquely suited for heavier-than-air flight. Therefore, rather than using wheeled rovers like we have on Mars, Dragonfly is a rotorcraft. It will be capable of traveling up to 8km per flight, which will quickly surpass the fewer than 21km the Curiosity Rover has managed on Mars! 

    Like Earth, Titan has rainfall and open liquid bodies on its surface. I, for one, can’t wait to see the alien vistas Dragonfly sends back as it cruises over methane lakes. (Image and video credit: NASA)

  • Pluto’s Subsurface Ocean

    Pluto’s Subsurface Ocean

    Since the New Horizons probe visited Pluto in 2015, scientists have suspected that Sputnik Planitia (a.k.a. Pluto’s Heart), shown above, may hide a subsurface ocean. But it’s tough to explain how that ocean could stay warm enough to be liquid while the surface ice remains cold and viscous enough to support the variations in thickness we see. One theory cites the possibility of ammonia in the ocean, essentially serving as anti-freeze, but that would require much higher concentrations of ammonia than have been observed in comets – which, like Pluto, spend most of their time in the icy, frigid regions of the Kuiper Belt.

    A new study suggests another theory: a layer of gas-trapping hydrates between the liquid ocean and its icy cap. A thin layer of clathrate hydrates, as proposed by the authors, would trap gases like methane and create a thermally-insulating layer between a warm ocean and much colder ice cap. Because heat would struggle to cross the insulation layer, the water beneath would stay above the freezing point without the cold ice above leeching all of its warmth away.

    It would likely require future missions to Pluto or other potential ocean worlds to confirm the presence of such a hydrate layer, but, for now, the theory provides a possible new explanation for how icy objects like Pluto maintain liquids. (Image credit: NASA/JHU Applied Physics Laboratory/SwRI; research credit: S. Kamata et al.; via Gizmodo)

  • Earth, Moon, and Magma Ocean

    Earth, Moon, and Magma Ocean

    Among objects in our solar system, the Moon is rather unusual. It’s the only large moon paired with a rocky planet, and only Pluto’s Charon boasts a larger size relative to its planet. Chemically speaking, the Moon is also extremely similar to the Earth, which is part of why scientists theorized that the moon coalesced after the proto-Earth collided with a Mars-sized object. But lingering questions remained, like why the Moon is rich in iron oxide compared to the Earth.

    A new study tweaks the idea of the giant impactor by adding a magma ocean to the proto-Earth. In the early days of the solar system, collisions were so common that larger bodies (> 2*Mars) probably maintained a molten ocean. By simulating collisions with and without a magma ocean and studying the final composition of these simulated Earth-Moon-systems, the researchers found that a molten ocean not only matches the expected size and orbital characteristics of the two bodies, but the results reflect the actual chemical make-up of the  real Earth and Moon, too! (Image credits: moon – N. Thomas, impact simulation – N. Hosono et al.; research credit: N. Hosono et al.; via Ars Technica; submitted by Kam-Yung Soh)

  • Rays in Craters

    Rays in Craters

    On bodies around the solar system, there are craters marking billions of years’ worth of impacts. Many of these craters have rays–distinctive lines radiating out from the point of impact. But if you drop an object onto a smooth granular surface (upper left), the ejecta form a uniform splash with no rays. The impactor must hit a roughened surface (upper right) in order to leave rays. 

    Through experiment and simulation, researchers found that the rays emanate from valleys in the surface that come in contact with the impactor. Moreover, the number of rays that form depends only on the size of the impactor and the undulations of the surface. That means that, by knowing the topography of a planetary body and counting the number of rays left behind, scientists can now estimate what the size of the object that struck was! (Image, video, and research credit: T. Sabuwala et al.)