Eggshell Planets Have a Thin Brittle Crust and No Mountains or Tectonics

'Eggshell planets’ are rocky worlds that have an ultra-thin outer brittle layer and little to no topography. Here, an artist’s rendition of such an exoplanet. (Image: NASA)

Planets without plate tectonics are unlikely to be habitable. But currently, we’ve never seen the surface of an exoplanet to determine if plate tectonics are active. Scientists piece together their likely surface structures from other evidence. Is there a way to determine what exoplanets might be eggshells, and eliminate them as potentially habitable?

The authors of a newly-published paper say there is.

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LightSail 2 has Been Flying for 30 Months now, Paving the way for Future Solar Sail Missions

LIGHTSAIL 2 IMAGE OF AFGHANISTAN AND PAKISTAN This image taken by The Planetary Society's LightSail 2 spacecraft on May 31, 2021 shows Afghanistan, Pakistan, and the Arabian Sea. The Caspian Sea is at lower left. The shadows of the spacecraft's solar panels can be seen on the sail. North is approximately at the top left. This image has been color-adjusted and some distortion from the camera’s 180-degree fisheye lens has been removed. Credit: The Planetary Society

Even after 30 months in space, The Planetary Society’s LightSail 2 mission continues to successfully “sail on sunbeams” demonstrating solar sail technology in Earth orbit. The mission is providing hard data for future missions that hope to employ solar sails to explore the cosmos.

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Orbital Launch in January? Elon Musk Updates His Vision for SpaceX’s Starship

Launch from Mars
An artist's conception shows a SpaceX rocket lifting off from Mars. (SpaceX Illustration)

SpaceX CEO Elon Musk has laid out a scenario for space travel that calls for his company’s Starship launch system to take on its first orbital test flight as soon as January.

Starship could go through “a dozen launches next year, maybe more,” and be ready to send valuable payloads to the moon, Mars and even the solar system’s outer planets by 2023, Musk said during a Nov. 17 online meeting of the National Academies’ Space Studies Board and Board on Physics and Astronomy.

But he advised against sending anything too valuable on the first flight to Mars. “I would recommend putting the lower-cost scientific mission stuff on the first mission,” he said, half-jokingly.

The National Academies presentation followed up on big-picture talks that Musk delivered in 2016 (when Starship was known as the Interplanetary Transport System), 2017 (when it was known as the BFR or “Big Frickin’ Rocket”) and 2018 (when Musk settled on “Starship”).

Musk’s basic concept is the same: Starship and its giant Super Heavy booster would be a one-size-fits-all system that could be used for point-to-point suborbital travel, orbital space missions and all manner of trips beyond Earth orbit, including moon landings. It’d be capable of lofting more than 100 tons to low Earth orbit (three times as much as the space shuttle), and sending 100 people at a time to Mars.

This week’s presentation provided some new details.

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Maybe There’s No Way to Tell if Habitable Planets Orbit Proxima Centauri… Yet!

This artist’s impression shows the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image between the planet and Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. Credit: ESO/M. Kornmesser

Our closest stellar neighbor is Proxima Centauri, an M-type (red dwarf) star located over 4.24 light-years away (part of the Alpha Centauri trinary system). In 2016, the astronomical community was astounded to learn that an Earth-like planet orbited within this star’s circumsolar habitable zone (HZ). In addition to being the closest exoplanet to Earth, Proxima b was also considered the most promising place to look for extraterrestrial life for a time.

Unfortunately, the scientific community has been divided on whether or not life could even be possible on this planet. All of these studies indicate that this question cannot be answered until astronomers characterize Proxima b’s atmosphere, ideally by observing it as it passes in front (aka. transited) of its host star. But in a new NASA-supported study, a team led by astrophysicists at the University of Chicago determined that this is an unlikely possibility.

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A new Simulation of the Universe Contains 60 Trillion Particles, the Most Ever

Illustris simulation, showing the distribution of dark matter in 350 million by 300,000 light years. Galaxies are shown as high-density white dots (left) and as normal, baryonic matter (right). Credit: Markus Haider/Illustris

Today, the greatest mysteries facing astronomers and cosmologists are the roles gravitational attraction and cosmic expansion play in the evolution of the Universe. To resolve these mysteries, astronomers and cosmologists are taking a two-pronged approach. These consist of directly observing the cosmos to observe these forces at work while attempting to find theoretical resolutions for observed behaviors – such as Dark Matter and Dark Energy.

In between these two approaches, scientists model cosmic evolution with computer simulations to see if observations align with theoretical predictions. The latest of which is AbacusSummit, a simulation suite created by the Flatiron Institute’s Center for Computational Astrophysics (CCA) and the Harvard-Smithsonian Center for Astrophysics (CfA). Capable of processing nearly 60 trillion particles, this suite is the largest cosmological simulation ever produced.

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The Next Generation Very Large Array Would be 263 Radio Telescopes Spread Across North America

Artists's conception of the central portion of the Next Generation Very Large Array. Credit: Sophia Dagnello, NRAO/AUI/NSF

The iconic Very Large Array (VLA) in New Mexico has been at the forefront of astrophysical research since its dedication in 1980. The Y-shaped configuration of 27 radio astronomy dishes have made key discoveries about the cosmos, while becoming a part of pop-culture in several high-profile movies.

But the aging array is due for an upgrade, one that would take advantage of advanced technology. So says the latest Decadal Survey, published by the U.S. National Academy of Sciences, which presents a consensus among researchers on the most important scientific goals and missions for the upcoming decade.

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New Hubble Image Shows Dark Cocoons Where New Stars are Forming

This image shows knots of cold, dense interstellar gas where new stars are forming. These Free-floating Evaporating Gaseous Globules (frEGGs) were first seen in Hubble’s famous 1995 image of the Eagle Nebula. Because these lumps of gas are dark, they are rarely seen by telescopes. Image Credit: NASA, ESA, and R. Sahai (Jet Propulsion Laboratory); Processing: Gladys Kober (NASA/Catholic University of America)

Star formation is a complex process. But in simple terms, a star forms due to clumps and instabilities in a cloud of molecular hydrogen called a Giant Molecular Cloud (GMC). As more and more gas accumulates and collapses inward, the pressure becomes immense, the gas eventually heats up to millions of degrees, and fusion begins.

But what happens to the gas that remains as the young star forms? Some of it can form a type of dark halo called a frEGG—a free-floating Evaporating Gaseous Globule. And, proving that the Universe is indeed strange, the frEGG itself can contain another stellar embryo. The frEGG can be quite opaque, making it difficult to observe the star’s formation process in all its complexity.

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This was Juno’s View on its 37th Flight Past Jupiter

Jupiter, as seen from Juno during its 37th pass over Jupiter. Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

As originally planned, Juno’s 37th close pass by Jupiter – called Perijove 37 – would have been its last. Per the original mission outline, the Juno spacecraft would have been programed to plunge into Jupiter on Perijove 37 as a mission-ending self-sacrifice. Destroying Juno would protect the Jovian moons — especially Europa — from potential future contamination by an unpowered spacecraft wandering adrift through the Jupiter system. As careful as NASA is about taking precautions to limit the amount of Earth-sourced biological material carried by robotic spacecraft, it’s incredibly difficult to ensure that no microbes might have tagged along.

But, back to Juno: as it stands now, the Juno mission is just getting started. With a mission extension granted earlier this year, Juno will continue to operate until at least 2025, with 42 extra orbits added to the mission.

And thank goodness, because the images from Perijove 37 are pretty stunning. The new mission plan put Juno on a relatively close pass to image Jupiter itself, as well as a great view of Jupiter’s moon Europa, see below.

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“Irresponsible” Russian Anti-Satellite Test Creates Orbital Debris Field, Endangering the Space Station and Crew

The International Space Station in orbit round Earth. Credit: NASA

Early Monday, November 15, 2021, the International Space Station Flight Control team in Houston told the crew that due to a to satellite breakup, a debris field was created near the station’s orbital path. The astronauts and cosmonauts were told to “shelter in place” on board the Soyuz and SpaceX capsules attached to the ISS.

What became apparent as the day wore on is that the debris field was the result of a “destructive” test by Russia of an anti-satellite missile system against one of their own satellites. Experts from the US Space Command say the test resulted in “over fifteen hundred pieces of trackable orbital debris” which could stay in orbit for several years.

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