If Earth is Average, We Should Find Extraterrestrial Life Within 60 Light-Years

Illustration: Assortment of exoplanets
Astronomers have detected thousands of planets, including dozens that are potentially habitable. (NASA Illustration)

In 1960, while preparing for the first meeting on the Search for Extraterrestrial Intelligence (SETI), legendary astronomer and SETI pioneer Dr. Frank Drake unveiled his probabilistic equation for estimating the number of possible civilizations in our galaxy – aka. The Drake Equation. A key parameter in this equation was ne, the number of planets in our galaxy capable of supporting life – aka. “habitable.” At the time, astronomers were not yet certain other stars had systems of planets. But thanks to missions like Kepler, 5523 exoplanets have been confirmed, and another 9,867 await confirmation!

Based on this data, astronomers have produced various estimates for the number of habitable planets in our galaxy – at least 100 billion, according to one estimate! In a recent study, Professor Piero Madau introduced a mathematical framework for calculating the population of habitable planets within 100 parsecs (326 light-years) of our Sun. Assuming Earth and the Solar System are representative of the norm, Madau calculated that this volume of space could contain as much as 11,000 Earth-sized terrestrial (aka. rocky) exoplanets that orbit within their stars’ habitable zones (HZs).

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The OSIRIS-REx Capsule Has Landed! Asteroid Samples Returned!

The sample return capsule from NASA’s OSIRIS-REx mission is seen shortly after touching down in the desert, Sunday, Sept. 24, 2023. Credit: NASA

The OSIRIS-REx mission has just completed NASA’s first sample-return mission from a near-Earth asteroid (NEA). The samples arrived at the Utah Test and Training Range (UTTR) near Salt Lake City, where a team of engineers arrived by helicopter to retrieve the sample capsule. The samples will be curated by NASA’s Astromaterials Research and Exploration Science Directorate (ARES) and Japan’s Extraterrestrial Sample Curation Center (ESCuC). Analysis of the rocks and dust obtained from Bennu is expected to provide new insight into the formation and evolution of the Solar System.

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Tiny Swarming Spacecraft Could Establish Communications with Proxima Centauri

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

Achieving interstellar travel has been the dream of countless generations, but the challenges remain monumental. Aside from the vast distances involved, there are also the prohibitive energy requirements and the sheer cost of assembling spacecraft that could survive the trip. Right now, the best bet for achieving an interstellar mission within a reasonable timeframe (i.e., a single person’s lifetime) is to build gram-scale spacecraft paired with lightsails. Using high-power laser arrays, these spacecraft could be accelerated to a fraction of the speed of light (relativistic speeds) and reach nearby stars in a few decades.

There are a handful of major projects, like Breakthrough Starshot, that hope to leverage this technology to create spacecraft that could reach Alpha Centauri in a few decades (instead of centuries). This technology also presents other opportunities, like facilitating communications across interstellar distances. This is the idea recently by a team of researchers led by the Initiative for Interstellar Studies (i4is). In a recent paper, they recommended that a swarm of gram-scale spacecraft could rely on their launch laser to maintain optical communications with Earth.

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Whether Saturn's Rings are Young or Old, its Moons are as Ancient as the Planet Itself

The moons of Saturn, from left to right: Mimas, Enceladus, Tethys, Dione, Rhea; Titan in the background; Iapetus (top) and irregularly shaped Hyperion (bottom). Some small moons are also shown. All to scale. Credit: NASA/JPL/Space Science Institute

Saturn is best known for two things: its iconic ring structures and its large system of natural satellites. Currently, 146 moons and moonlets have been discovered orbiting the ringed giant, 24 of which are regular satellites. These include the seven largest moons, Titan, Rhea, Iapetus, Dione, Tethys, Enceladus, and Mimas, which are icy bodies believed to have interior oceans. In addition, there are unresolved questions about the age of these satellites, with some suspecting that they formed more recently (like Saturn’s rings, which are a few hundred million years old).

To address these questions, an international team of astronomers created a series of high-resolution simulations coupled with improved estimates of Trans-Neptunian Object (TNO) populations. This allowed them to construct a chronology of impacts for Saturn’s most heavily cratered regular satellites – Mimas, Enceladus, Tethys, Dione, and Rhea. This established age limits of 4.1 and 4.4 billion years for all five, with the two innermost moons appearing more youthful than the outer three. These results could have significant implications for our understanding of the formation and tidal evolution of moons in the outer Solar System.

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Some Metal Meteorites Have a Tiny Magnetic Field. But How?

Illustration of the metallic asteroid Psyche. Credit: Peter Rubin/NASA/JPL-Caltech/ASU

One of the striking things about iron meteorites is that they are often magnetic. The magnetism isn’t strong, but it holds information about their origin. This is why astronomers discourage meteorite hunters from using magnets to distinguish meteorites from the surrounding rock, since hand magnets can erase the magnetic history of a meteorite, which is an important scientific record.

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Jupiter’s Moons Get the JWST Treatment

Spectroscopic map of Ganymede (left) obtained from JWST’s Near-Infrared Spectrograph (NIRSpec) instrument displaying light absorption in the polar regions distinctive of the molecule hydrogen peroxide. A JWST NIRSpec infrared image of Io (right) displaying volcanic eruptions at Kanehekili Fluctus (center) and Loki Patera (right) with temperatures up to 1200 Kelvin (926.85 degrees Celsius/1700 degrees Fahrenheit). Circles indicate the surfaces of both moons. (Credit: Ganymede: Cornell/Dr. Samantha Trumbo; Io: UC Berkeley/Dr. Imke de Pater)

A pair of studies published in JGR: Planets and Science Advances discuss new findings from NASA’s James Webb Space Telescope (JWST) regarding Jupiter’s first and third Galilean Moons, Io and Ganymede, and more specifically, how the massive Jupiter is influencing activity on these two small worlds. For Io, whose mass is about 21 percent larger than Earth’s Moon, the researchers made the first discovery of sulfur monoxide (SO) gas on the volcanically active moon. For Ganymede, which is the largest moon in the solar system and boasts twice the mass of the Earth’s Moon, the researchers made the first discovery of hydrogen peroxide, which exists in Ganymede’s polar regions.

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Psyche Mission Passes Independent Review Board with Flying Colors

Image of NASA engineers preparing the Psyche spacecraft for launch within a clean room at the Astrotech Space Operations Facility located near the NASA Kennedy Space Center. Psyche is scheduled to launch in October 2023 on a SpaceX Falcon Heavy rocket from historic Launch Complex 39A at Kennedy. (Credit: NASA/Ben Smegelsky)

An independently appointed review board recently announced that NASA, their Jet Propulsion Laboratory (JPL), and the California Institute of Technology (Caltech) have exceeded expectations in taking steps to ensure the successful launch of the metal-rich-asteroid-hunting Psyche mission this October. This comes after Psyche’s initial launch date was delayed from August 2022 due to late delivery of the spacecraft’s flight software and testing equipment, which prevented engineers from performing the necessary checkouts prior to launch.

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NASA’s HiRISE Camera Recently Imaged a Martian Dust Devil. But Why Study Them?

A recent dust devil on Mars captured by NASA's High Resolution Imaging Experiment (HiRISE) camera. (Credit: NASA/JPL-Caltech/UArizona)

NASA recently used its powerful High Resolution Imaging Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter to take a breathtaking image of a dust devil traversing Syria Planum on Mars. One unique aspect of dust devils is their shadows can be used to estimate their height, which have been estimated to reach 20 km (12 miles) into the Martian sky. Studying dust devils on Mars is a regular occurrence for the scientific community and can help scientists better understand surface processes on other planets. But with the atmospheric pressure on Mars being only a fraction of Earth’s, what processes are responsible for producing dust devils?

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Jupiter’s “Stripes” Change Color. Now We Might Know Why

Infrared images of Jupiter obtained by a ground-based telescope displaying changes in the stripes of Jupiter's clouds between 2001 and 2011 (dashed blue lines). (Credit: Arrate Antuñano/NASA/IRTF/NSFCam/SpeX)

While Jupiter’s Great Red Spot is one of the most well-known spectacles in the solar system, Jupiter’s clouds and stripes that are responsible for the planet’s weather patterns are highly regarded, as well. Though not nearly as visible in an amateur astronomy telescope, Jupiter’s multicolored, rotating, and swirling cloud stripes are a sight to behold for any astronomy fan when seen in up-close images. And, what makes these stripes unique is they have been observed to change color from time to time, but the question of what causes this color change to occur has remained elusive.

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Juice is Fully Deployed. It’s Now in its Final Form, Ready to Meet Jupiter’s Moons in 2031

Still image from a video animation of the European Space Agency’s (ESA) Jupiter Icy Moons Explorer (Juice) spacecraft. (Credit: ESA/ATG Medialab)

Launched on April 14, 2023, the European Space Agency’s (ESA) Jupiter Icy Moons Explorer (Juice; formerly known as JUICE) spacecraft has finally completed the unfurling of its solar panel arrays and plethora of booms, probes, and antennae while en route to the solar system’s largest planet.

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