Featured Archives

September 23, 2023September 23, 2023 by Matt Williams

OSIRIS-REx Returns This Sunday!

An artist's concept of OSIRIS-REx obtaining a sample of asteroid Bennu for return to Earth. Image Credit: NASA/GSFC/UofArizona

On September 8th, 2016, NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission launched from Earth. Its primary mission was to rendezvous with the asteroid Bennu, a carbonaceous Near-Earth Asteroid (NEA), obtain samples from its surface, and return them to Earth for analysis. On December 3rd, 2018, the mission reached Bennu and spent the next two years searching for the optimal place to retrieve these samples. Tomorrow, on Sunday, September 24th, the mission will finally deliver these samples to Earth for analysis.

Last week, on Saturday, September 16th, the OSIRIS-REx mission was spotted by the ESA’s Optical Ground Station (OGS) 1-meter telescope on the island of Tenerife, Spain. The spacecraft was still 4.66 km million (2.9 million mi) from Earth, but well on its way to returning. This will be the last time OSIRIS-REx will be spotted by ground-based telescopes before it reaches Earth to deliver its sample and heads back out into space.

September 20, 2023September 20, 2023 by Matt Williams

We Should Be Looking for Small, Hot Dyson Spheres

A Type II civilization is one that can directly harvest the energy of its star using a Dyson Sphere or something similar. Credit: Fraser Cain (with Midjourney)

In 1960, legendary physicist Freeman Dyson published his seminal paper “Search for Artificial Stellar Sources of Infrared Radiation,” wherein he proposed that there could be extraterrestrial civilizations so advanced that they could build megastructures large enough to enclose their parent star. He also indicated that these “Dyson Spheres,” as they came to be known, could be detected based on the “waste heat” they emitted at mid-infrared wavelengths. To this day, infrared signatures are considered a viable technosignature in the Search for Extraterrestrial Intelligence (SETI).

So far, efforts to detect Dyson Spheres (and variation thereof) by their “waste heat” signatures have come up empty, leading some scientists to recommend tweaking the search parameters. In a new paper, astronomy and astrophysics Professor Jason T. Wright of the Center for Exoplanets and Habitable Worlds and the Penn State Extraterrestrial Intelligence Center (PSTI) recommends that SETI researchers refine the search by looking for indications of activity. In other words, he recommends looking for Dyson Spheres based on what they could be used for rather than just heat signatures.

September 20, 2023September 20, 2023 by David Dickinson

Introducing Magic: Analog Sky’s New 3D Printed Binoculars for Astronomy

A new project promises to ‘bring back the magic’ to night sky observing.

When it comes to deep sky observing versus portability, we’ve all been there. How do you balance the trade-off between big complicated optics, with something basic and simple to use? We’ll make a small confession: while big light bucket optics have their place in astronomy, only binoculars give you a true view of the sky.

September 17, 2023September 18, 2023 by Matt Williams

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.

September 15, 2023September 15, 2023 by Matt Williams

NASA Confirms That 2023 was the Hottest Summer on Record

This map depicts global temperature anomalies for meteorological summer in 2023 (June, July, and August). It shows how much warmer or cooler different regions of Earth were compared to the baseline average from 1951 to 1980. Credit: NASA's Earth Observatory/Lauren Dauphin

Yesterday, NASA’s Goddard Institute of Space Studies (GISS) announced that the summer of 2003 was the hottest on record. This year saw a massive heat wave that swept across much of the world and was felt in South America, Japan, Europe, and the U.S. This exacerbated deadly wildfires in Canada and Hawaii (predominantly on the island of Maui) and are likely to have contributed to severe rainfall in Italy, Greece, and Central Europe. This is the latest in a string of record-setting summers that are the direct result of anthropogenic climate change.

September 14, 2023September 14, 2023 by Matt Williams

The Moon's Southern Ice is Relatively Young

Elevation data of the Moon showing the South Pole-Aitken Basin. Credit: NASA/GSFC/University of Arizona

Around the Moon’s southern polar region lies the South Pole-Aitken Basin, the single-largest impact basin on the lunar surface. Within this basin, there are numerous permanently shadowed regions (PSRs) that are thought to have trapped water ice over time. These deposits are crucial to future missions like the Artemis Program that will lead to the creation of permanent infrastructure. This water ice will supply crews with a steady source of water for drinking and irrigation and the means for chemically producing oxygen gas and rocket fuel.

For scientists, these PSRs are believed to have emerged when the Moon began migrating away from Earth roughly 2.5 billion years ago. Over time, these regions acted as “cold sinks” and trapped water ice that existed on the lunar surface at the time. However, according to a recent study led by the Planetary Science Institute (PSI), the Moon’s permanently shadowed areas arose less than 2.2 billion years ago and trapped ice even more recently than that. These findings could significantly impact future crewed missions as they indicate that the water ice found in lunar craters could be of more recent origin.

September 14, 2023September 17, 2023 by Matt Williams

Some Lunar Regolith is Better for Living Off the Land on the Moon

Artist's impression of astronauts on the lunar surface, as part of the Artemis Program. Credit: NASA

Between now and the mid-2030s, multiple space agencies hope to send crewed missions to the Moon. of These plans all involve establishing bases around the Moon’s southern polar region, including the Artemis Base Camp and the International Lunar Research Station (ILRS). These facilities will enable a “sustained program of lunar exploration and development,” according to the NASA Artemis Program mission statement. In all cases, plans for building facilities on the surface call for a process known as In-Situ Resource Utilization (ISRU), where local resources are used as building materials.

This presents a bit of a problem since not all lunar soil (regolith) is well-suited for construction. Much like engineering and construction projects here on Earth, builders need to know what type of soil they are building on and if it can be used to make concrete. In a recent study, planetary scientist Kevin M. Cannon proposed a lunar soil classification scheme for space resource utilization. This could have significant implications for future missions to the Moon, where it would help inform the construction of bases, habitats, and other facilities based on soil type and location.

September 13, 2023September 13, 2023 by Matt Williams

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.

September 10, 2023September 10, 2023 by Matt Williams

Polaris is the Closest, Brightest Cepheid Variable. Very Recently, Something Changed.

View from within the Polaris triple star system; artist's rendering. The North Star is labeled Polaris A. Credit: NASA/ESA/HST, G. Bacon (STScI)

When you look up in the night sky and find your way to the North Star, you are looking at Polaris. Not only is it the brightest star in the Ursa Minor constellation (the Little Dipper), but its position relative to the north celestial pole (less than 1° away) makes it useful for orienteering and navigation. Since the age of modern astronomy, scientists have understood that the star is a binary system consisting of an F-type yellow supergiant (Polaris Aa) and a smaller main-sequence yellow dwarf (Polaris B). Further observations revealed that Polaris Aa is a classic Cepheid variable, a stellar class that pulses regularly.

For most of the 20th century, records indicate that the pulsation period has been increasing while the pulsation amplitude has been declining. But recently, this changed as the pulsation period started getting shorter while the amplitude of the velocity variations stopped increasing. According to a new study by Guillermo Torres, an astronomer with the Harvard & Smithsonian Center for Astrophysics (CfA), these behaviors could be attributed to long-term changes related to the binary nature of the system, where the two stars get closer to each other, and the secondary perturbs the atmosphere of the primary.

September 9, 2023September 9, 2023 by Matt Williams

Every Night and Every Morning, the Moon Rumbles With Tiny Quakes

Artist's impression of astronauts on the lunar surface, as part of the Artemis Program. How will they store power on the Moon? 3D printed batteries could help. Credit: NASA

The Moon was geologically active between 3.7 and 2.5 billion years ago, experiencing quakes, volcanic eruptions, and outgassing. Thanks to the Moon being an airless body, evidence of this past has been carefully preserved in the form of extinct volcanoes, lava tubes, and other features. While the Moon has been geologically inert for billions of years, it still experiences small seismic events due to tidal flexing (because of Earth’s gravitational pull) and temperature variations. These latter events happen regularly and are known as “moonquakes.”

Thanks to the Apollo missions, scientists have measured this activity using seismometers placed on the surface. In a recent NASA-funded study, a team of researchers from the California Institute of Technology (Caltech) reexamined the seismic data with a machine-learning model. This revealed that moonquakes occur with precise regularity, coinciding with the Sun rising to its peak position in the sky and then slowly setting. In this respect, moonquakes are like a “Lunar Alarm Clock,” which could be useful for future missions and lunar settlers!