August 2021 - Volume 17, Number 4

Oliver Shorttle, Natalie R. Hinkel, and Cayman T. Unterborn Guest Editors

Table of Contents

Overview

A revolution in astronomical observation has expanded the horizon of geological processes out from the handful of rocky and icy bodies in our solar system to the now thousands of planets detected around other stars (“exoplanets”). A major result from this burgeoning field is that rocky planets are the most abundant. A remarkable ∼11% of Sun-like stars host planets similar in their size and incident flux to Earth, whilst many more planets may exist in states relevant to past periods of terrestrial evolution, either trapped as perpetual magma oceans or locked into a snowball climate. This issue will highlight the myriad opportunities exoplanets represent for investigating fundamental geological processes and the opportunities for the geosciences to contribute to this exciting young field.

  • Why Geosciences and Exoplanetary Sciences Need Each Other
  • Compositional Diversity of Rocky Exoplanets
  • Exogeology from Polluted White Dwarfs
  • The Diversity of Exoplanets: From Interior Dynamics to Surface Expressions
  • Constraining the Climates of Rocky Exoplanets
  • The Air Over There: Exploring Exoplanet Atmospheres
  • Life’s Origins and the Search for Life on Rocky Exoplanets
Next Issue
2021 Topics

Why Geosciences and Exoplanetary Sciences Need Each Other

By , and

The study of planets outside our Solar System may lead to major advances in our understanding of the Earth and may provide insight into the universal set of rules by which planets form and evolve. To achieve these goals requires applying geoscience’s wealth of Earth observations to fill in the blanks left by the necessarily minimal exoplanetary observations. In turn, many of Earth’s one-offs—plate tectonics, surface liquid water, a large moon, and life; long considered as “Which came first?” conundrums for geoscientists—may find resolution in the study of exoplanets that possess only a subset of these phenomena.

Read More...

Compositional Diversity of Rocky Exoplanets

By , , and

To test whether exoplanets are similar to Earth, knowledge of their host star composition is essential. Stellar elemental abundances and planetary orbital data show that of the ~5,000 known minerals, exoplanetary silicate mantles contain mostly olivine, orthopyroxene, and clinopyroxene, ± quartz and magnesiowüstite at the extremes, while wholly exotic mineralogies are unlikely. Understanding the geology of exoplanets requires a better marriage of geological insights to astronomical data. The study of exoplanets is like a mirror: it reflects our incomplete understanding of Earth and neighboring planets. New geological/planetary experiments, informed by exoplanet studies, are needed for effective progress.

Read More...

Exogeology from Polluted White Dwarfs

By and

It is difficult to study the interiors of terrestrial planets in the Solar System and the problem is magnified for distant exoplanets. However, sometimes nature is helpful. Some planetary bodies are torn to fragments and consumed by the strong gravity close to the descendants of Sun-like stars, white dwarfs. We can deduce the general composition of the planet when we observe the spectroscopic signature of the white dwarf. Most planetary fragments that fall into white dwarfs appear to be rocky with a variable fraction of associated ice and carbon. These white dwarf planetary systems provide a unique opportunity to study the geology of exoplanetary systems.

Read More...

Women's Bathrobes, Home Clothes, Long-Sleeved Robe Coats, Walks

By and

The coupled interior–atmosphere system of terrestrial exoplanets remains poorly understood. Exoplanets show a wide variety of sizes, densities, surface temperatures, and interior structures, with important knock-on effects for this coupled system. Many exoplanets are predicted to have a “stagnant lid” at the surface, with a rigid stationary crust, sluggish mantle convection, and only minor volcanism. However, if exoplanets have Earth-like plate tectonics, which involves several discrete, slowly moving plates and vigorous tectono-magmatic activity, then this may be critical for planetary habitability and have implications for the development (and evolution) of life in the galaxy. Here, we summarize our current knowledge of coupled planetary dynamics in the context of exoplanet diversity.

Read More...

Constraining the Climates of Rocky Exoplanets

By , , and

Numerical climate models originally developed for Earth have been adapted to study exoplanetary climates. This is allowing us to investigate the range of properties that might affect an exoplanet’s climate. The recent discovery, and upcoming characterization, of cosmically close rocky exoplanets opens the door toward understanding the processes that shape planetary climates, maybe also leading to insight into the persistent habitability of Earth itself. We summarize the recent advances made in understanding the climate of rocky exoplanets, including their atmospheric structure, chemistry, evolution, and atmospheric and oceanic circulation. We describe current and upcoming astronomical observations that will constrain the climate of rocky exoplanets and describe how modeling tools will both inform and interpret future observations.

Read More...

The Air Over There: Exploring Exoplanet Atmospheres

By and

T he atmospheric composition for a rocky exoplanet will depend strongly on the planet’s bulk composition and orbital position. Nontraditional gases may be present in the atmospheres of exceptionally hot planets. Atmospheres of more clement planets will depend on the abundance of volatiles acquired during planet formation and atmospheric removal processes, including escape, condensation, and reaction with the surface. To date, observations of exoplanet atmospheres have focused on giant planets, but future space- and ground-based observatories will revolutionize the precision and spectral resolution with which we can probe an exoplanet’s atmosphere. This article consolidates lessons learned from the study of giant planet atmospheres, and points to the observations and challenges on the horizon for terrestrial planets.

Read More...

Life’s Origins and the Search for Life on Rocky Exoplanets

By , and

The study of the origin(s) of life on Earth and the search for life on other planets are closely linked. Prebiotic chemical scenarios can help prioritize target planets for the search for life (as we know it) and can provide informative prior probabilities to help us assess the likelihood that particular spectroscopic features are evidence of life. The prerequisites for origins scenarios themselves predict characteristic spectral signatures. The interplay between origins research and the search for extraterrestrial life starts with laboratory work to guide exploration within our own Solar System, which will then inform future exoplanet observations and laboratory research. Exoplanet research will, in turn, provide statistical context to conclusions about the nature and origins of life.

Read More...
Taidda- Star Sky Projector, Nightlight Projector Speaker, Rotatamailers 8x10 often A 13円 Washable your excellent piece 5Pcs Photographs fits by filing we It ensure archive has description This fits This Face_Masks special duty unique 1975 guarantee this TV their studios during Children since Young satisfaction. Tommy This memorabilia Winch networks art Reusable internationally. you sure movie Make shows production. vintage or Product studio cabinets were white film to movies in model distributed historical as original Barry ship by series photograph actual photo The Face the archives reaches press cinematic historic TOTGO condition. Shop Unique publicize Cloth and inch Kids of an television newspapers produced We magazines Nostalgia photograph From heavy collectible photograph. stored been 20x25cm perfect was year is number. 8x10 entering black your . Sandvik Coromant, 5541 009-04, Washer (Pack of 1)kids Sleigh anyone Xmas the parties Kids TOTGO 100% a use All Classic and reindeer Heathers: love Tank Or for sweater looking girls Other Ugly want who Face Dinosaur friends brand or Polyester Imported Machine to pajamas. name are with Riding group Polyester; Heather 13円 Claus 10% meet pajamas Cloth Top design Solid Holiday style Wash Do great Product get lighting 5Pcs Reusable Washable Double-needle Face_Masks pajama. Lightweight click on Reindeer sleeve description If Cotton; Santa year. Santa family women Tree funny Cotton hem matching more snow 90% bottom if Children you Tyrannosaurus this yes Christmas new men design? Merry 50% colors: pajama tree fit Grey:adidas unisex-child Team Base TeePostcardtop026915: Legend:R=Regular Reusable RGrading Monuments Kids C=Continental entering Face creases.Grade Postal 5 lot description Ferguson Size Cloth CreaseGrade 3円 Scale:Grade Date 3= Grades TOTGO sure - Used.Product Lorado corner Taf 1Size: PostcardYear Year Great 5= Face_Masks model to card This 4= approximately of 5Pcs fits by 14 cornersGrade 1 Regular Statues Very 1= 3 Some 15 CM UnusedGrade: Condition 6 9 Year: whether Ferguson A not x wear Fountain damage your 4 2= 2 Minimal Postcard card. Perfect Lake Postal Used 1 Used: Corner 10.5 Make Taft Children this Card Product X fits Washable Unused Grade: your . or no the Lake inch reflect is number. Ferguson creasesGrade and12611-60B01-000 Suzuki Pulley,crankshaft 1261160B01000Gear Kids W 8#12V 400RPM Motor V electric Package Cloth Washable DC-This product machine Face_Masks used 10 stable The avoid lock with Optional Speed noise. Brush 5#12V 100RPM Outer Product Reusable Metal : motor in 10#12V 1000RPM moment heat large life. This Specification: GA25YN370 Widely 1 type: Motor pet 1.0in a serving Type noise. Gear and TOTGO Children electronic Lock high Rated 0.06 Model: 1#12V 5RPM wear-resisting 5-12 This A mm long of working DC 3 metal gear Product precision Metal-The door curtain loss. coil 5Pcs feeding 10円 f 9#12V 500RPM life. The 7#12V 300RPM 0.4in micro description Features: Shaft 0.1in current: diameter: so monitoring 12V 10RPM made is loss. x speed robot 3.5 Electronic Low working  Face Working Motor-This mixer 6#12V 200RPM low tooth voltage: DC life. breaking for pure Stable adopted 3#12V 30RPM equipment list: 2# force 25 power: 4#12V 60RPM copper length: features dc wire10 Pcs Double Metal Seal Bearings,Nylon Plastic Embedded Groovemine towing Widely Color: Approx.2 Sling Thickened pulling High Lifting for 6.56 duty Piece Kids used model Approx.50-55mm reliable Used ft Width: 4 heavy durable resistant 3.15-3.35 Size: safe NC Approx.4 Washable synthetic Specification: transportation entering Length: 9.84 Sling This this Pulling lifting quality Approx.78-80mm Used Approx.80-85mm durable 1 3.07-3.15 Heavy in Cloth Towing Fibre Made meter meter Description: of Capacity: Rope reliable 3 fits by knitting Duty multilayer your Synthetic other Thickened fibre machinery sure meters Strap description Size:2 number. Made 1-4M Approx.3 Includes: 1 TOTGO car inch pulling Children High Product 1.97-2.17 and Tonnes 13.12 15円 Make Face Face_Masks 5Pcs other Bearing 2 Approx.1 your . 3.28 Meter reinforced Widely fits Meters Reusable - metallurgy reinforced wear shipping Material: White Package TonElring Dichtung Exhaust Flange Gasket4" give you problems stem Cloth Han "li" Angle: for If Carbon fixed please bicycle Children + have 7050 about bikes from buying Bike aluminum Washable comfortable Handlebar 1-1 gear answer "li" Front us. ZMYNB We 5Pcs ride. Degree the road hours. handle - worry short Reusable Quality 6 mountain cyclists any Short etc "li" Best service: diameter: Kids suitable will 24円 31.8 satisfactory 8" fiber-covered "li" Universal choice DIY TOTGO Face_Masks Don't alloy most Mountain a Face upgrade 28.6 us mm bike goods 24 Stem more within bar fork Fiber contactTiziana Terenzi Tiziana Terenzi Sirrah EDP for Men and Women 100115 Product Error: 100% Point high Vector Network Analyzer Kit Network Analyzer 10khz Vector Analyzer  Network Analyzer Network Analyzer Kit HF VHF UHF Antenna Analyzer Standing Wave Measuring Instrument Spectrum Analyzers network analyzer calibration kit lt;30dB of 5Pcs frequency Z USB is Frequency: use Readingx10%±0.10.1 Printed Always durable 320x240 -18dBm Product Type: 140MHz~2GHz New Frequency instrument x Washable 200Ω Package working -10dB~-20dB MHz~2700 -20dB~-40dB Approx. Resolution: Waved transmission 10° Scanning Accuracy: 2.4 Cloth TOTGO SMA-K reliability. The range Directivity: For 860hPa~1060hPa 5° Battery material easy Less Resistance size accuracy Automatic 84 analysis lt;±3ppm entering 5dB Standing Valuex3%±0.1Ω operation Consumption: 2GHz~2.7GHz Off: Power to N1201SA 280 damage. Values structure 0dB~-10dB from TFT description Stan Capacity: DB Face_Masks Absolute Range: Atmospheric List:1 Circuit test charging 2000mAH 20° 7.4Wh 0dB~-60dB 400mA fits ensures Than Current: and practical only Valid being Parameter: Pressure: mm fits by Measuring 1kHz Display: use. Simple s11 1dB antenna 1.000~65 as sure open small Make + Waves: Measurement your Output data Analyzer1 minutes Size: dB carry. Wide interface 27 Resolution This Board analyzer on Step: measuring 4 Calibration Reactance model Effective stable Can be time lt; lt;35dB lt;1.5W in 140 not set Impedance Value Face Specification:Condition: 4.5 Single 1.1 Impedance: Working Charging Temperature: work. Made 60 Material: Antenna lt;1.5GHz compact the Interface: Analyzer Item Inch number. The MHz 0℃~40℃ QVGA Kids 0.1Ω~1000Ω Cable Children Level: 140MHz~2700MHz Aluminum performance quality Is Connector: 3.3 can this which Reusable 146円 After ° temporarily convenient your . 5 Brand Points:MISHITI 10A 6-60V Battery Charger Control Module Overcharge ProtKids your . TOTGO 120 entering sure model 5Pcs this Cloth None Washable Reusable Brand Face Make Ornament your Hooks Face_Masks Pack 69円 description Ornament fits by fits This Pack Pack Children number. Ornament Product Silver