Space News & Blog Articles

The cosmic zoo contains objects so bizarre and extreme that they generate gravitational waves. Scorpius X-1 is part of that strange collection. It’s actually a binary pair: a neutron star orbiting with a low-mass stellar companion called V818 Scorpii. The pair provides a prime target for scientists hunting for so-called “continuous” gravitational waves. Those waves should exist, although none have been detected—yet.

“Scorpius X-1 is one of the most promising sources for detecting these continuous gravitational waves,” said Professor John Whelan from Rochester Institute of Technology’s School of Mathematical Sciences. He’s the principal investigator of RIT’s group in the LIGO Scientific Collaboration, part of a group of scientists focused on the direct detection of gravitational waves. LIGO is the Laser Interferometer Gravitational-Wave Observatory, situated in Washington State and Louisiana. Virgo (in Italy) and KAGRA (in Japan) are also searching for gravitational waves, often in conjunction with LIGO.

Hunting for Gravitational Waves at Scorpius X-1

Whelan’s team used data from the third LIGO-Virgo observing run in their search for continuous gravitational waves from Scorpius X-1. “It’s fairly close at only 9,000 light years away,” said Whelan. “We can see it very brightly in x-rays because the gaseous matter from the companion star is pulled onto the neutron star.”

Despite its brightness, the team did not detect a continuous wash of gravitational waves from Scorpius X-1. That doesn’t mean the waves aren’t there. In fact, their data provide important goalposts as they plan more observations of the pair. It helped them improve their search methodology and should eventually result in the detection of these elusive waves.

“This search yielded the best constraint so far on the possible strength of gravitational waves emitted from Scorpius X-1,” said Jared Wofford, an astrophysical sciences and technology Ph.D. candidate. “For the first time, this search is now sensitive to models of the possible torque balance scenario of the system, which states that the torques of the gravitational wave and accretion of matter onto the neutron star are in balance. In the coming years, we expect better sensitivities from more data taken by Advanced LIGO observing runs probing deeper into the torque balance scenario in hopes to make the first continuous wave detection.”

In a recent study published in Science, a team of researchers at Imperial College London examined 18 meteorites containing the volatile element zinc to help determine their origin, as it has been long hypothesized that Earth’s volatiles materials, including water, were derived from asteroids closer to our home planet. However, their results potentially indicate a much different origin story.

“Our data show that about half of Earth’s zinc inventory was delivered by material from the outer Solar System, beyond the orbit of Jupiter,” Dr. Mark Rehkämper, a professor in the Department of Earth Science and Engineering at Imperial, and a co-author on the study, said in a statement. “Based on current models of early Solar System development, this was completely unexpected.” 

Approximately 4.5 billions years ago, our solar system formed from the collapsed cloud of interstellar gas and dust, whose collapse has been hypothesized to come from the supernova explosion of a nearby star. Upon its collapse, the cloud formed a swirling and spinning disk of material, a solar nebula. Over time, the gravity and pressure at the center of the nebula eventually forced hydrogen and helium atoms to fuse, which birthed our Sun. The remaining material in the nebula formed the planets and moons we see today, with the rocky planets comprising the inner part and the much larger gas planets forming in the outer parts.

Since the Earth formed in this inner part of the nebula, the long-standing hypothesis has been the majority of the Earth-forming materials also came from the inner portion, as well, so this most recent research could help reshape our understanding of both the formation and evolution of our own solar system.

“This contribution of outer Solar System material played a vital role in establishing the Earth’s inventory of volatile chemicals.,” Dr. Rehkämper said in a statement. “It looks as though without the contribution of outer Solar System material, the Earth would have a much lower amount of volatiles than we know it today – making it drier and potentially unable to nourish and sustain life.”

In a recent study submitted to the journal Icarus, a team of researchers at the International Research School of Planetary Science (IRSPS) located at the D’Annunzio University of Chieti-Pescara in Italy conducted a geological analysis of a region on Neptune’s largest moon, Triton, known as Monad Regio to ascertain the geological processes responsible for shaping its surface during its history, and possibly today. These include what are known as endogenic and exogenic processes, which constitute geologic processes occurring internally (endo-) and externally (exo-) on a celestial body. So, what new insights into planetary geologic processes can we learn from this examination of Monad Regio?

“Exogenic geological features, such as glaciers, channels, and coastlines, characterize the bodies of the Solar System that possess, or possessed, a dense atmosphere,” Dr. Davide Sulcanese, who is a Junior Scientist within IRSPS and lead author of the study, recently told Universe Today. “The surface of Earth, Mars and Titan contains a large variety of similar features. Surprisingly, we observed that even in one of the farthest and coldest bodies of the Solar System, the icy satellite Triton, the surface can be reshaped by exogenic processes, including deposition and flowing of ice (though in this case we refer to nitrogen ice).

“Such exogenic activity has already been observed on another body of the outer Solar System, Pluto, where the high-resolution images acquired by the New Horizons spacecraft in 2015 revealed for the first time the presence of active glaciers and dendritic channels on its surface,” Dr. Sulcanese continued. “We showed that also the surface of Triton (at least in Monad Regio) could host several ice flow-related features, like glaciers, moraines, ogives, and subglacial channels, that have probably played a fundamental role in the rejuvenation of its surface.”

For the study, the researchers created a geomorphological map at a scale of 1:1,000,000 of an extended area of Monad Regio, meaning the measurement of 1 on their map is equivalent to 1 million of the same measurement on Monad Regio. They then used a combination of images from NASA’s Voyager 2, a roughness map of the study area, and a digital elevation model to conduct their geological analysis of the area. Their findings indicate that an endogenic phase is potentially followed by an exogenic phase, which could help explain the surface features we see today.

“Most of the morphologies we observed on Triton are a consequence of the internal geological activity of the moon, like diapirism, explosive events, faulting, cryovolcanism and consequent flow of cryolava,” Dr. Sulcanese recently told Universe Today. “However, we infer that after this first endogenic phase, some of these landforms in Monad Regio have been further modified by deposition and flow of solid and liquid nitrogen, forming features strikingly similar to terrestrial glaciers, morains, ogives, channels, and even coastlines.” The study notes that while endogenic processes could be responsible for reshaping the surface early in the moon’s evolutionary history, it is the exogenic processes that could be responsible for actively reshaping its surface today.

The frontiers of astronomy are being pushed regularly these days thanks to next-generation telescopes and scientific collaborations. Even so, astronomers are still waiting to peel back the veil of the cosmic “Dark Ages,” which lasted from roughly 370,000 to 1 billion years after the Big Bang, where the Universe was shrouded with light-obscuring neutral hydrogen. The first stars and galaxies formed during this same period (ca. 100 to 500 million years), slowly dispelling the “darkness.” This period is known as the Epoch of Reionization, or as many astronomers call it: Cosmic Dawn.

By probing this period with advanced radio telescopes, astronomers will gain valuable insights into how the first galaxies formed and evolved. This is the purpose of the Hydrogen Epoch of Reionization Array (HERA), a radio telescope dedicated to observing the large-scale structure of the cosmos during and before the Epoch of Reionization located in the Karoo desert in South Africa. In a recent paper, the HERA Collaboration reports how it doubled the array’s sensitivity and how their observations will lead to the first 3D map of Cosmic Dawn.

The HERA Collaboration is an international consortium comprised of astronomers and astrophysicists from South Africa, Australia, the U.S., the U.K., Israel, Italy, and India. The research was led by Joshua Dillon, a research scientist at UC Berkeley’s Department of Astronomy and the lead author of the paper. The paper that describes their research and findings recently appeared online and has been accepted for publication by the Astrophysical Journal. Their results provide new insight into how reionization occurred in the early Universe.

A timeline of the cosmos showing which eras will be observed by the Planck satellite, HERA, and NASA’s JWST. Credit: HERA

From Dark to Dawn

Based on current cosmological models, the Universe began 13.8 billion years ago with the Big Bang, which produced a flurry of energy and elementary particles that slowly cooled to create the first protons and electrons (which combined to form the first hydrogen and helium atoms). The leftover “relic radiation” is observable today in the form of the Cosmic Microwave Background (CMB). Thanks to missions like the COBE, WMAP, and Planck, astronomers have mapped the faint variations in temperature that existed 380,000 years after the Big Bang.

It is an exciting time for astronomers and cosmologists. Since the James Webb Space Telescope (JWST), astronomers have been treated to the most vivid and detailed images of the Universe ever taken. Webb‘s powerful infrared imagers, spectrometers, and coronographs will allow for even more in the near future, including everything from surveys of the early Universe to direct imaging studies of exoplanets. Moreover, several next-generation telescopes will become operational in the coming years with 30-meter (~98.5 feet) primary mirrors, adaptive optics, spectrometers, and coronographs.

Even with these impressive instruments, astronomers and cosmologists look forward to an era when even more sophisticated and powerful telescopes are available. For example, Zachary Cordero 
of the Massachusetts Institute of Technology (MIT) recently proposed a telescope with a 100-meter (328-foot) primary mirror that would be autonomously constructed in space and bent into shape by electrostatic actuators. His proposal was one of several concepts selected this year by the NASA Innovative Advanced Concepts (NIAC) program for Phase I development.

Corder is the Boeing Career Development Professor in Aeronautics and Astronautics at MIT and a member of the Aerospace Materials and Structures Lab (AMSL) and Small Satellite Center. His research integrates his expertise in processing science, mechanics, and design to develop novel materials and structures for emerging aerospace applications. His proposal is the result of a collaboration with Prof. Jeffrey Lang (from MIT’s Electronics and the Microsystems Technology Laboratories) and a team of three students with the AMSL, including Ph.D. student Harsh Girishbhai Bhundiya.

Their proposed telescope addresses a key issue with space telescopes and other large payloads that are packaged for launch and then deployed in orbit. In short, size and surface precision tradeoffs limit the diameter of deployable space telescopes to the 10s of meters. Consider the recently-launched James Webb Space Telescope (JWST), the largest and most powerful telescope ever sent to space. To fit into its payload fairing (atop an Ariane 5 rocket), the telescope was designed so that it could be folded into a more compact form.

This included its primary mirror, secondary mirror, and sunshield, which all unfolded once the space telescope was in orbit. Meanwhile, the primary mirror (the most complex and powerful ever deployed) measures 6.5 meters (21 feet) in diameter. Its successor, the Large UV/Optical/IR Surveyor (LUVOIR), will have a similar folding assembly and a primary mirror measuring 8 to 15 meters (26.5 to 49 feet) in diameter – depending on the selected design (LUVOIR-A or -B). As Bhundiya explained to Universe Today via email:

Before going to the Moon, the Apollo astronauts trained at various sites on Earth that best approximated the lunar surface, such as the volcanic regions Iceland, Hawaii and the US Southwest.  To help prepare for upcoming robotic and human Artemis missions, a newly upgraded “mini-Moon” lunar testbed will allow astronauts and robots to test out realistic conditions on the Moon including rough terrain and unusual sunlight.

The Lunar Lab and Regolith Testbed at the Ames Research Center in California simulates conditions on the Moon in a high-fidelity environment, allowing researchers to test hardware designs intended for the lunar surface. The lab is currently being used as a test environment for the next phases of the Artemis Program, to conduct studies on optical sensing and drill testing, and tests for in-situ resource utilization identification and extraction techniques.

The facility was originally built in 2009 but has now been expanded and upgraded to include a lunar lab with multiple testbeds with a variety of simulated lunar regolith. These large indoor “sandboxes” can be configured and customized to simulate various regions on the Moon. In addition, a special lighting system can re-create realistic lighting conditions on the Moon, such as the darkness of a lunar polar crater, or the glaring rays of the Sun that the Apollo astronauts had to deal with in the lunar mares.

The testbeds aren’t huge, but big enough to provide a variety of conditions. The first original sandbox measures approximately 13 feet by 13 feet by 1.5 feet (4 meters by 4 meters by 0.5 meter) and is filled with eight tons a lunar regolith simulant called Johnson Space Center One simulant (JSC-1A), which makes this the world’s largest collection of the material. The JSC-1A simulant mimics the Moon’s mare basins and is dark grey in color.

The new larger testbed, measures 62 feet by 13 feet by 1 foot (19 meters by 4 meters by 0.3 meter) and is  filled with more than 20 tons of Lunar Highlands Simulant-1 (LHS-1), which is light grey to simulate the lunar highlands. This larger sandbox can be reconfigured if needed to be a smaller, but deeper, testbed.

Astronomers have not yet been able to map large portions of the radio emissions from our universe because of interference from the Earth itself. A team of astronomers hopes to change that, beginning with the LuSEE Night mission to the far side of the Moon. It will launch in 2025 and chart a new pathway to Lunar observatories.

The Earth is really loud in the radio, especially at frequencies below 20 megahertz. The ionosphere of the planet itself crackles at those frequencies, obscuring radio emissions from more distant sources. Plus we use low frequency radio waves for communication and radar searches, swamping cosmic sources.

The only way to mitigate all that terrestrial contamination is to get up and away from it. The best place is the far side of the Moon, so that the bulk of the Moon’s body blocks out radio emissions from the Earth. The Sun itself is also a rather loud emitter of radio signals at those frequencies, so the best time to observe is during the Lunar night, when the far side of the Moon is plunged in darkness.

But building radio observatories on the far side of the Moon is no easy task, so we have to start small. One of the first steps is LuSEE Night, the Lunar Surface Electromagnetic Explorer, a small radio antenna and instrument package that is scheduled to be delivered to the far side of the Lunar surface as early as 2025.

LuSEE Night owes its technological heritage to the Parker Solar Probe, and is in fact nearly an identical copy of one of the instruments onboard that spacecraft. LuSEE Night consists of two 6m long antenna set in a cross-shaped pattern along with a bare bones set of electronics.