Annual Reviews Extra
An Atlas of Phanerozoic Paleogeographic Maps: Phanerozoic Dual Globes
updated
Two planets undergoing a graze-and-merge giant impact: Visualization of two planets undergoing a graze-and-merge style giant impact, based on computer simulation output. This style of collision has been widely theorized for the formation of the Moon. The larger (target) body is one tenth the mass of the Earth and the smaller (impactor) body is 70% the mass of the target. The planets are colliding at 1.10 times their mutual escape velocity, which equates to 3.69 km/s. The collision angle, defined by the angle between the velocity vector at impact and the line of their centers of mass, is 45°.
Variables: The top-left panel shows mantle and core materials as unique colors for the target and impactor. The top-right panel shows the density of material in kilograms per cubic meter. The bottom-left panel shows temperature in thousands of Kelvins. The bottom right panel shows pressure in Pascals.
Software: Simulation run by T.S.J. Gabriel (tgabriel@usgs.gov) using SPLATCH, a planetary Smooth Particle Hydrodynamics code developed at the University of Bern by (Reufer 2011), maintained by A. Emsenhuber (Ludwig Maximillian University of Munich; emsenhuber@usm.lmu.de) and H. Ballantyne (University of Bern; harry.ballantyne@unibe.ch).
Citation: Gabriel & Cambioni (2023). The Role of Giant Impacts in Planet Formation, Annual Reviews.
Two planets undergoing a hit-and-run giant impact: Visualization of two planets undergoing a hit-and-run giant impact, based on computer simulation output. This style of collision comprises around half of the giant impacts expected to occur during the latter stages of Solar System formation. The larger (target) body is one tenth the mass of the Earth and the smaller (impactor) body is 70% the mass of the target. When the impactor survives relatively intact after the collision, it is sometimes referred to as the runner. The planets are colliding at 2.5 times their mutual escape velocity, which equates to 8.40 km/s. The collision angle, defined by the angle between the velocity vector at impact and the line of their centers of mass, is 60°.
Variables: The top-left panel shows mantle and core materials as unique colors for the target and impactor. The top-right panel shows the density of material in kilograms per cubic meter. The bottom-left panel shows temperature in thousands of Kelvins. The bottom right panel shows pressure in Pascals.
Software: Simulation run by T.S.J. Gabriel (tgabriel@usgs.gov) using SPLATCH, a planetary Smooth Particle Hydrodynamics code developed at the University of Bern (Reufer 2011), maintained by A. Emsenhuber (Ludwig Maximillian University of Munich; emsenhuber@usm.lmu.de) and H. Ballantyne (University of Bern; harry.ballantyne@unibe.ch).
Citation: Gabriel & Cambioni (2023). The Role of Giant Impacts in Planet Formation, Annual Reviews.
Erosion of two planets in a giant impact: Visualization of two planets undergoing a giant impact that results in the erosion of the target and impactor, based on computer simulation output. This giant impact outcome is sometimes referred to as an erosive hit-and-run. The larger (target) body is one tenth the mass of the Earth and the smaller (impactor) body is 70% the mass of the target. The planets are colliding at 3.25 times their mutual escape velocity, which equates to 10.92 km/s. The collision angle, defined by the angle between the velocity vector at impact and the line of their centers of mass, is 30°. At greater multiples of the escape velocity, the runner may be entirely disrupted after the collision.
Variables: The top-left panel shows mantle and core materials as unique colors for the target and impactor. The top-right panel shows the density of material in kilograms per cubic meter. The bottom-left panel shows temperature in thousands of Kelvins. The bottom right panel shows pressure in Pascals.
Software: Simulation run by T.S.J. Gabriel (tgabriel@usgs.gov) using SPLATCH, a planetary Smooth Particle Hydrodynamics code developed at the University of Bern (Reufer 2011), maintained by A. Emsenhuber (Ludwig Maximillian University of Munich; emsenhuber@usm.lmu.de) and H. Ballantyne (University of Bern; harry.ballantyne@unibe.ch).
Citation: Gabriel & Cambioni (2023). The Role of Giant Impacts in Planet Formation, Annual Reviews.
The disruption of two planets in a giant impact: Visualization of two planets undergoing a disruptive giant impact, based on computer simulation output. Disruptive collisions are not expected to be common in Solar System formation and due to numerical effects, the amount of disruption shown here is likely overestimated. The larger (target) body is one tenth the mass of the Earth and the smaller (impactor) body is 70% the mass of the target. The planets are colliding at 3.75 times their mutual escape velocity, which equates to 12.60 km/s. The collision angle, defined by the angle between the velocity vector at impact and the line of their centers of mass, is 5°.
Variables: The top-left panel shows mantle and core materials as unique colors for the target and impactor. The top-right panel shows the density of material in kilograms per cubic meter. The bottom-left panel shows temperature in thousands of Kelvins. The bottom right panel shows pressure in Pascals.
Software: Simulation run by T.S.J. Gabriel (tgabriel@usgs.gov) using SPLATCH, a planetary Smooth Particle Hydrodynamics code developed at the University of Bern (Reufer 2011), maintained by A. Emsenhuber (Ludwig Maximillian University of Munich; emsenhuber@usm.lmu.de) and H. Ballantyne (University of Bern; harry.ballantyne@unibe.ch).
Citation: Gabriel & Cambioni (2023). The Role of Giant Impacts in Planet Formation, Annual Reviews.
The merging (accretion) of two planets by giant impact: Visualization of two planets undergoing a giant impact that results in a merger (accretion), based on computer simulation output. The larger (target) body is one tenth the mass of the Earth and the smaller (impactor) body is 70% the mass of the target. The planets are colliding at 1.08 times their mutual escape velocity, which equates to 3.63 km/s. The collision angle, defined by the angle between the velocity vector at impact and the line of their centers of mass, is 30°. Off-axis collisions such as these are more probable than on-axis (head-on) collisions.
Variables: The top-left panel shows mantle and core materials as unique colors for the target and impactor. The top-right panel shows the density of material in kilograms per cubic meter. The bottom-left panel shows temperature in thousands of Kelvins. The bottom right panel shows pressure in Pascals.
Software: Simulation run by T.S.J. Gabriel (tgabriel@usgs.gov) using SPLATCH, a planetary Smooth Particle Hydrodynamics code developed at the University of Bern (Reufer 2011), maintained by A. Emsenhuber (Ludwig Maximillian University of Munich; emsenhuber@usm.lmu.de) and H. Ballantyne (University of Bern; harry.ballantyne@unibe.ch).
Citation: Gabriel & Cambioni (2023). The Role of Giant Impacts in Planet Formation, Annual Reviews.
Micron-scale fluorescent tracer particles (green) injected at the back of the skull are swept along by flowing CSF (blue) and pass through the perivascular space surrounding a surface artery (red). Automated particle tracking measurements of their positions and velocities make it possible to overlay pathlines colored according to the instantaneous velocity of each. Though tracer particles do not enter penetrating PVSs, two-photon microscopy through a cranial window allows quantifying flows in surface PVSs with high fidelity and up to 30 min at a time. Imaging provided by Antonio Ladron-de-Guevara and Maiken Nedergaard.
Shown: Video of the [CII] velocity channel maps of the Orion region. Several distinct kinematic structures are seen, including the expanding Veil shell in the south, the interaction with the molecular ridge (at ), and the expanding shell in the north surrounding NGC1977 ( ). Video from Universität zu Koln/NASA/SOFIA, Pabst et al. (2020) and Higgins et al. (2021).
Conformational cycle of MurJ. The 5 crystal structures of MurJTA were interpolated in the following order: inward open, inward occluded, outward, inward closed, first inward structure, (loop back to inward open). The N-lobe (TMs 1-6) is shown in blue, the C-lobe (TMs 7-12) in green, and TMs 13-14 in brown. Front view of MurJ is shown on top while the corresponding view of the cavity from the cytosol is shown at the bottom. For simplicity, ions captured in the structures were not shown in this animation.
Shown: Pyrococcus furiosus SecYEβ. Note the partially open lateral gate that spans across the entire width of the inner membrane.
Shown: A composite model of BamA constructed by superposition of two alternative structures of the five BamA POTRA domains with the FhaC outer membrane β-barrel protein and its single POTRA domain. The POTRA domains project into the periplasm.
Shown: Animated version of the middle and right panels of Figure 1. The left panels show the time evolution of the osculating ecliptic (black) and free (orange) inclination (top panel) and longitude of ascending node (bottom panel) for TNO 2001 QD298, which has a nearly constant barycentric semimajor axis of 42.6 au, over a 10 Myr numerical integration. The right panel shows the evolution in the same integration of the forced (blue) and free (orange; measured relative to the forced) inclination vectors, in the components (i cos Ω, i sin Ω). The dashed axes in the right panel denote the reference plane (the ecliptic) where the polar distance is iecl (the sum of the orange and blue vectors; shown as a black trace over time) and the osculating ecliptic node Ω (not labelled) is the polar angle measured from the positive x axis.
The free and forced inclination vectors (and thus also the osculating ecliptic inclination) rotate clockwise over time in the right panel, causing a regression of Ω. The path of the forced inclination vector traces a (blue) circle around the Solar System’s invariable pole (the total angular momentum vector); this is largely because Neptune’s inclination varies over time as it interacts with the other giant planets, and Neptune’s orbital plane influences the TNO’s forced inclination. While the time evolution of the ecliptic inclination and node over time is complex, the free inclination remains relatively constant over time and the free node regresses smoothly.
Shown: Animated version of Figure 2, which shows the orbital evolution of TNO 225088=Gonggong=2007 OR10 in Neptune’s 10:3 mean-motion resonance over a 105 year simulation. Left panels: the time evolution of a, e, and the resonant angle ϕ. Right panel: Gonggong’s position projected on a reference x-y plane that rotates around the Solar System’s barycenter at the rate of Neptune’s mean motion; Neptune thus remains nearly fixed along the x-axis (magenta point; the other giant planet paths are shown interior to Neptune).
The first portion of the video shows Gonggong completing three orbits around the Sun (black trace), during which Neptune completes ten orbits. This path creates a three-fold symmetry in the rotating frame. We then speed up the time in the video to show how the locations of Gonggong’s perihelia in the rotating frame librate back and forth over the full resonant cycle described by ϕ. In this portion of the video, each new three-orbit trace for Gonggong is shown in yellow, while the past traces are shown in black, building up a picture of the libration cycle. The Δϕ≈80° libration amplitude corresponds to an angular oscillation of the perihelion location in the rotating frame of Δϕ/3≈27° (labeled in red in the bottom left panel and by the three red arcs in the right panel); the corresponding sinusoidal variations in a and e are apparent in the top left two panels. We note that the majority of TNO detections occur at distances ≲45 au due to the flux bias (see Section 2); for resonant TNOs, this results in detection preferentially at specific longitudes relative to Neptune.
Shown: Computer simulation of the waves, water levels, currents and subsequent breaching of an uninhabited section of the Fire Island barrier island off the coast of Bellport, NY, during hurricane Sandy. During the hurricane event, the water level (shown in blue) increases on the Atlantic Ocean side of the barrier (earth tones) due to the wind blowing over the water surface. At the same time, infragravity or long period waves (shown as ripples on the water surface) increase in intensity. Together, the wind and waves drive an alongshore current (white arrows) to the right (West). The waves erode the dunes on the barrier islands, lowering the dune tops. During the peak of the storm, the dunes have eroded so much, and the water level and waves have increased so much that the island is overtopped, and water can be seen flowing over the island (white arrows). These currents further scour the initial gaps into larger breaches. The eroded sediment is deposited on the landward side (front side of the animation) as so-called overwash fans. As the storm passes the water levels recede and the breaches (one of which is still open today) in the dunes and the flattening of the island is visible. The simulation was made using the open-source model XBeach (xbeach.org). The results presented here have been published by Van Der Lugt et al., 2019.
Shown: Computer simulation of waves, sand transport, and morphology changes during Hurricane Matthew at Matanzas, FL. Cross-shore velocity (red-green colors), pre-storm topography and bathymetry (gray lines), and current topography and bathymetry (black lines) at three cross-barrier transects: northern, breach, and southern. The transects are indicated in white on the map of the pre-storm topography and bathymetry in the top right panel. Time series of the water level gradient across the barrier and of the offshore significant wave height, with the current time marked in red, are on the bottom right. Note that the negative water level gradient indicates that ocean water levels were lower than back-barrier water levels. The water level gradient and the significant wave height (gray line) were filtered to remove infragravity and sea-swell wave group signals.
At the beginning of the storm, typical cross-shore circulation patterns emerged, with onshore currents at the surface and offshore currents (undertow) at the bed. As offshore waves increased, wave action on the beach face and at the dune toe lead to erosion and transport of sediment offshore. At the peak of offshore waves, overwash of the now vulnerable dune crest occurred, with transport of sediment from the dune to the back-barrier. Dunes were lowered further. Transitions from collision to overwash storm regimes (Sallenger, 2000) occurred at different times due to spatial variability in dune crest height and water levels. Water levels increased in the back-barrier due to phase lags between the storm surge in the coastal ocean and in the back-barrier waterway, and due to overwash. Ultimately, the water level gradient across the barrier drove a flow that breached the barrier. Sediment was transported into the coastal ocean, where it formed a small deposit.
Shown: Computer simulations of morphology change on the Bolivar Peninsula, TX during Hurricane Ike. The three animations show the impact of changing bottom roughness in a Delft3D-4 simulation. The upper left model animation uses a low, spatially uniform roughness (Manning's n = 0.02) and shows large morphodynamic changes, including a large breach of the Peninsula. The upper right model animation uses a higher, spatially uniform roughness (Manning's n = 0.03) in which there is less erosion and accretion than the first simulation, but still causes two breaches of the Peninsula. The lower left model animation uses a spatially variable bottom roughness determined from the National Land Cover Database. This model generates greater erosion on the sandy landward (upper) side of the peninsula, but much smaller changes on the ocean (lower) side, where vegetation increased the bottom roughness. A breach did not occur during this variable-roughness simulation.
Shown: Alexander hepatocellular carcinoma (HCC) cells lacking Axin1 have dynamic remodeling and vesicle formation in the apical plasma membrane that is absent from the membranes between neighboring cells. In contrast, HCCs reconstituted with Axin1 have relatively low plasma membrane motility. Cells transfected with membrane-GFP were filmed by live cell microscopy for 30 minutes. Scale bars, 10 μm. Reproduced from Albrecht et al. 2020a, with permission from Cell Press.
Shown: 3D hydrochemical simulation for a binary system containing a mass-losing asymptotic giant branch (AGB) star, showing (a) the total density; (b) CO/H2 number density; and (c) temperature for a binary system model in which the AGB star has a mass of 1 M⊙, effective temperature of 2,900 K, a radius of 0.9 AU, and a pulsation period of 1 year. The companion has a mass of 0.5 M⊙ and resides at a circular orbit with separation of 10 AU. The simulation time runs for 59.3 years. Owing to dust formation occurring in the region where the temperature is lower than 1,500 K, a wind is initiated with mass-loss rate of 4.7 x 10-6 M⊙ year-1. The formation of two types of spiral structures can readily be seen, one structure being caused by the gravity wake near the companion, the other one caused by the reflex motion of the AGB star. Both spiral structures merge at larger distances from the AGB star. The small ripples in the close vicinity of the AGB star are relics of the pulsation pattern. The same setup for the AGB star not having a companion yields a mass-loss rate of 7.6 x 10-7 M⊙ year-1 (J. Bolte, L. Decin, W. Homan, F. De Ceuster, J. Yates, et al., in preparation). For a simulation time of 59.3 years, the hydrodynamical quantities are then displayed for viewing angles of the system ranging between 0 deg (edge-on view) and 90 deg (face-on view). Also shown is the corresponding CO v = 0 J = 1--0 emission map and line profile at t = 59.3 years for three different viewing angles [at 90 deg (d), at 45 deg (e), and at 0 deg (f)] in the observer's frame calculated using the MAGRITTE 3D radiative transfer solver (De Ceuster et al. 2020a,b}. The video slices through the velocity channel map between -20 and +20 km s-1.
Shown: Radiative shock fronts have corrugated and clumpy structure, due to thermal and thin-shell instabilities. This animation shows the complex density structure of the dual shocks created by a head-on collision of two flows (from the left and right, entering with 500 km/s corresponding to a Mach number M = 36 for the adopted temperature floor of 104 K). The colorscale tracks the log of density in units of g/cm3. This animation is from the simulations of Steinberg & Metzger (2018).
Shown: As in Supplemental Video 1, but here the colorscale tracks the log of temperature rather than density. This animation is from the simulations of Steinberg & Metzger (2018).
Shown: Reading with a left homonymous hemianopia and macular sparing