SPACE/COSMOS
Alien ocean could hide signs of life from spacecraft
Searching for life in alien oceans may be more difficult than scientists previously thought, even when we can sample these extraterrestrial waters directly.
A new study focusing on Enceladus, a moon of Saturn that sprays its ocean water into space through cracks in its icy surface, shows that the physics of alien oceans could prevent evidence of deep-sea life from reaching places where we can detect it.
Published today (Thursday, 6 February 2025) in Communications Earth and Environment, the study shows how Enceladus's ocean forms distinct layers that dramatically slow the movement of material from the ocean floor to the surface.
Chemical traces, microbes, and organic material - telltale signatures of life that scientists look for - could break down or transform as they travel through the ocean's distinct layers. These biological signatures might become unrecognisable by the time they reach the surface where spacecraft can sample them, even if life thrives in the deep ocean below.
Flynn Ames, lead author at the University of Reading, said: "Imagine trying to detect life at the depths of Earth's oceans by only sampling water from the surface. That's the challenge we face with Enceladus, except we're also dealing with an ocean whose physics we do not fully understand.
“We’ve found that Enceladus’ ocean should behave like oil and water in a jar, with layers that resist vertical mixing. These natural barriers could trap particles and chemical traces of life in the depths below for hundreds to hundreds of thousands of years. Previously, it was thought that these things could make their way efficiently to the ocean top within several months.
"As the search for life continues, future space missions will need to be extra careful when sampling Enceladus’s surface waters."
Using computer models similar to those used to study Earth's oceans, the study has important implications for the search for life in the solar system and beyond. As scientists discover more ice-covered ocean worlds orbiting the outer planets and distant stars, similar ocean dynamics could confine evidence of life and its building blocks to deeper waters, undetectable from the surface. Even on worlds like Enceladus, where ocean material is conveniently sprayed into space for sampling, the long journey from deep ocean to surface could erase crucial evidence.
Journal
Communications Earth & Environment
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
Ocean stratification impedes particulate transport to the plumes of Enceladus'
Article Publication Date
6-Feb-2025
Gemini North teams up with LOFAR to reveal largest radio jet ever seen in the early universe
The monster jet spans at least 200,000 light-years and formed when the Universe was less than 10% of its current age
Association of Universities for Research in Astronomy (AURA)
image:
This artist’s illustration shows the largest radio jet ever found in the early Universe. The jet was first identified using the international Low Frequency Array (LOFAR) Telescope, a network of radio telescopes throughout Europe. Follow-up observations in the near-infrared with the Gemini Near-Infrared Spectrograph (GNIRS), and in the optical with the Hobby Eberly Telescope, were obtained to paint a complete picture of the radio jet and the quasar producing it. GNIRS is mounted on the Gemini North telescope, one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab. Historically, such large radio jets have remained elusive in the distant Universe. With these observations, astronomers have valuable new insights into when the first jets formed in the Universe and how they impacted the evolution of galaxies.
view moreCredit: NOIRLab/NSF/AURA/M. Garlick
From decades of astronomical observations scientists know that most galaxies contain massive black holes at their centers. The gas and dust falling into these black holes liberates an enormous amount of energy as a result of friction, forming luminous galactic cores, called quasars, that expel jets of energetic matter. These jets can be detected with radio telescopes up to large distances. In our local Universe these radio jets are not uncommon, with a small fraction being found in nearby galaxies, but they have remained elusive in the distant, early Universe until now.
Using a combination of telescopes, astronomers have discovered a distant, two-lobed radio jet that spans an astonishing 200,000 light-years at least — twice the width of the Milky Way. This is the largest radio jet ever found this early in the history of the Universe [1]. The jet was first identified using the international Low Frequency Array (LOFAR) Telescope, a network of radio telescopes throughout Europe.
Follow-up observations in the near-infrared with the Gemini Near-Infrared Spectrograph (GNIRS), and in the optical with the Hobby Eberly Telescope, were obtained to paint a complete picture of the radio jet and the quasar producing it. These findings are crucial to gaining more insight into the timing and mechanisms behind the formation of the first large-scale jets in our Universe.
GNIRS is mounted on the Gemini North telescope, one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation (NSF) and operated by NSF NOIRlab.
“We were searching for quasars with strong radio jets in the early Universe, which helps us understand how and when the first jets are formed and how they impact the evolution of galaxies,” says Anniek Gloudemans, postdoctoral research fellow at NOIRLab and lead author of the paper presenting these results in The Astrophysical Journal Letters.
Determining the properties of the quasar, such as its mass and the rate at which it is consuming matter, is necessary for understanding its formation history. To measure these parameters the team looked for a specific wavelength of light emitted by quasars known as the MgII (magnesium) broad emission line. Normally, this signal appears in the ultraviolet wavelength range. However, owing to the expansion of the Universe, which causes the light emitted by the quasar to be ‘stretched’ to longer wavelengths, the magnesium signal arrives at Earth in the near-infrared wavelength range, where it is detectable with GNIRS.
The quasar, named J1601+3102, formed when the Universe was less than 1.2 billion years old — just 9% of its current age. While quasars can have masses billions of times greater than that of our Sun, this one is on the small side, weighing in at 450 million times the mass of the Sun. The double-sided jets are asymmetrical both in brightness and the distance they stretch from the quasar, indicating an extreme environment may be affecting them.
“Interestingly, the quasar powering this massive radio jet does not have an extreme black hole mass compared to other quasars,” says Gloudemans. “This seems to indicate that you don’t necessarily need an exceptionally massive black hole or accretion rate to generate such powerful jets in the early Universe.”
The previous dearth of large radio jets in the early Universe has been attributed to noise from the cosmic microwave background — the ever-present fog of microwave radiation left over from the Big Bang. This persistent background radiation normally diminishes the radio light of such distant objects.
“It’s only because this object is so extreme that we can observe it from Earth, even though it’s really far away,” says Gloudemans. “This object shows what we can discover by combining the power of multiple telescopes that operate at different wavelengths.”
“When we started looking at this object we were expecting the southern jet to just be an unrelated nearby source, and for most of it to be small. That made it quite surprising when the LOFAR image revealed large, detailed radio structures,” says Frits Sweijen, postdoctoral research associate at Durham University and co-author of the paper. “The nature of this distant source makes it difficult to detect at higher radio frequencies, demonstrating the power of LOFAR on its own and its synergies with other instruments.”
Scientists still have a multitude of questions about how radio-bright quasars like J1601+3102 differ from other quasars. It remains unclear what circumstances are necessary to create such powerful radio jets, or when the first radio jets in the Universe formed. Thanks to the collaborative power of Gemini North, LOFAR and the Hobby Eberly Telescope, we are one step closer to understanding the enigmatic early Universe.
Notes
[1] An example of a monster radio jet found in the nearby Universe is the 23 million-light-year-long jet, named Porphyrion, which was observed 6.3 billion years after the Big Bang.
More information
This research was presented in a paper titled “Monster radio jet (>66 kpc) observed in quasar at z ∼ 5” to appear in The Astrophysical Journal Letters. DOI: 10.3847/2041-8213/ad9609
The team is composed of Anniek J. Gloudemans (NSF NOIRLab, International Gemini Observatory), Frits Sweijen (Durham University), Leah K. Morabito (Durham University), Emanuele Paolo Farina (NSF NOIRLab, International Gemini Observatory), Kenneth J. Duncan (Royal Observatory, Edinburgh), Yuichi Harikane (University of Tokyo), Huub J. A. Röttgering (Leiden University), Aayush Saxena (University of Oxford, Durham University), and Jan-Torge Schindler (University of Hamburg).
NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.
The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.
Links
- Read the paper: Monster radio jet (>66 kpc) observed in quasar at z ∼ 5
- Photos of Gemini North
- Videos of Gemini North
- Check out other NOIRLab Science Releases
Journal
The Astrophysical Journal Letters
DOI
New technique to detect dark matter using atomic clocks and lasers
University of Queensland
A team of international researchers has developed an innovative approach to uncover the secrets of dark matter in the cosmos.
University of Queensland PhD student Ashlee Caddell co-led a study in collaboration with Germany's metrology institute Physikalisch-Technische Bundesanstalt (PTB), that searched for dark matter using atomic clocks and cavity-stabilized lasers.
“Despite many theories and experiments scientists are yet to find dark matter, which we think of as the ‘glue’ of the galaxy holding everything together,” Ms Caddell said.
“Our study used a different approach – analysing the data from a network of ultra-stable lasers connected by fibre optic cables, as well as from two atomic clocks aboard GPS satellites.
“Dark matter in this case acts like a wave, because its mass is very very low.
“We use the separated clocks to try to measure changes in the wave, which would look like clocks displaying different times or ticking at different rates, and this effect gets stronger if the clocks are further apart.”
The researchers were able to search for forms of dark matter that have been invisible in previous searches because it emits no light or energy.
“By comparing precision measurements across vast distances, we identified the subtle effects of oscillating dark matter fields that would otherwise cancel themselves out in conventional setups,” Ms Caddell said.
“Excitingly, we were able to search for signals from dark matter models that interact universally with all atoms, something that has eluded traditional experiments.”
UQ physicist and co-author Dr Benjamin Roberts said the study brings researchers closer to understanding one of the universe's most elusive and fundamental components.
“Scientists will now be able to investigate a broader range of dark matter scenarios, and perhaps answer some fundamental questions about the fabric of the universe,” Dr Roberts said.
“This work also highlights the power of international collaboration and cutting-edge technology, using PTB's state-of-the-art atomic clocks and UQ's expertise in combining precision measurements and fundamental physics.”
The research was published in Physical Review Letters.
Journal
Physical Review Letters
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Ultralight Dark Matter Search with Space-Time Separated Atomic Clocks and Cavities
Efforts to find alien life could be boosted by simple test that gets microbes moving
Scientists explored microbial movement as a possible biosignature to detect life on Mars and beyond, cheaper and faster than ever before
Frontiers
Finding life in outer space is one of the great endeavors of humankind. One approach is to find motile microorganisms that can move independently, an ability that is a solid hint for life. If movement is induced by a chemical and an organism moves in response, it is known as chemotaxis.
Now, researchers in Germany have developed a new and simplified method for inducing chemotactic motility in some of Earth’s smallest life forms. They published their results in Frontiers in Astronomy and Space Sciences.
“We tested three types of microbes – two bacteria and one type of archaea – and found that they all moved toward a chemical called L-serine,” said Max Riekeles, a researcher at the Technical University of Berlin. “This movement, known as chemotaxis, could be a strong indicator of life and could guide future space missions looking for living organisms on Mars or other planets.”
Extreme survivors
The species included in the study were chosen due to their ability to survive in extreme environments. The highly motile Bacillus subtilis, in its spore form, can survive extreme conditions and endure temperatures of up to 100°C. Pseudoalteromonas haloplanktis, which is isolated from Antarctic waters, has an aptitude for growing in colder environments, between -2.5° and 29°C. The archaeon Haloferax volcanii (H. volcanii), belongs to a group similar to bacteria but is genetically different. Its natural habitats include the Dead Sea and other highly saline environments, so it, too, is well adapted to tolerate extreme conditions.
“Bacteria and archaea are two of the oldest forms of life on Earth, but they move in different ways and evolved motility systems independently from each other,” Riekeles explained. “By testing both groups, we can make life detection methods more reliable for space missions.”
L-serine, the amino acid the researchers used to get these species moving, has previously been shown to trigger chemotaxis in a wide range of species from all domains of life. It is also believed to exist on Mars. If life on Mars has a similar biochemistry to life on Earth, it is plausible that L-serine could attract potential Martian microbes.
Moving microbes
The results showed that L-serine worked as an attractor for all three species. “Especially the usage of H. volcanii broadens the scope of potential life forms that can be detected using chemotaxis-based methodologies, even when it is known that some archaea possess chemotactic systems,” Riekeles explained. “Since H. volcanii is thriving in extreme salty environments, it could be a good model for the kinds of life we might find on Mars.”
The researchers used a simplified approach, which might make the difference between it being feasible on future space missions or not. Instead of complex equipment, they used a slide with two chambers separated by a thin membrane. Microbes are placed on one side, and the chemical L-serine is added to the other. “If the microbes are alive and able to move, they swim toward the L-serine through the membrane,” Riekeles explained. “This method is easy, affordable, and doesn’t require powerful computers to analyze the results.”
For this method to work on a space mission, however, some adjustments to the process would be needed, the researchers said. Smaller and more robust equipment that can survive the harsh conditions of space travel and a system that can work automatically without human intervention are two of them.
Once these difficulties are overcome, microbial movement could help detect microbes that might exist in outer space, for example, in the ocean of Jupiter’s moon Europa. “This approach could make life detection cheaper and faster, helping future missions achieve more with fewer resources,” concluded Riekeles. “It could be a simple way to look for life on future Mars missions and a useful addition for direct motility observation techniques.”
Journal
Frontiers in Astronomy and Space Sciences
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Application of chemotactic behavior for life detection
Article Publication Date
6-Feb-2025
By studying neutron ‘starquakes’, scientists hope to transform their understanding of nuclear matter
The study of ‘starquakes’ (like earthquakes, but in stars) promises to give us important new insights into the properties of neutron stars, improving our understanding of the universe and advancing the way we live.
University of Bath
The study of ‘starquakes’ (like earthquakes, but in stars) promises to give us important new insights into the properties of neutron stars (the collapsed remnants of massive stars), according to new research led by the University of Bath in the UK.
Such explorations have the potential to challenge our current approaches to studying nuclear matter, with important impacts for the future of both nuclear physics and astronomy. Longer term, there may also be implications in the fields of health, security and energy.
The value of studying asteroseismology – as these vibrations and flares are known – has emerged from research carried out by an international team of physicists that includes Dr David Tsang and Dr Duncan Neill from the Department of Physics at Bath, along with colleagues from Texas A&M and the University of Ohio.
The team’s study, published in the impactful journal Physical Review C, examines how asteroseismology in neutron stars can test predictions about nuclear matter.
The scientists found that measuring these quakes from Earth using powerful telescopes provides detailed information about what is happening inside a neutron star. This helps test and validate a theory called Chiral Effective Field Theory, which in turn is key to improving our understanding of the universe and advancing the way we live on our planet.
A key objective for today’s nuclear scientists is to deepen their understanding of the properties and behaviours of nuclear matter, such as protons and neutrons. This refined understanding is crucial for enhancing their knowledge of the universe's basic building blocks and the forces that govern them.
“Our findings promise to add to, or change, the tools used by nuclear physicists, and bringing astronomy and nuclear physics closer together,” said lead author, postdoctoral researcher Dr Neill. "These results make clear the significance that astronomical observations could have for nuclear physics, helping the connect fields of research that have traditionally been separate."
By aiding the development of nuclear theory, the findings from this study contribute to efforts that may eventually yield benefits for health, security, and energy solutions in the following ways:
- Health: By enhancing techniques like radiation therapy and diagnostic imaging
- National Security: By ensuring the safe and secure maintenance and development of nuclear weapons
- Nuclear Energy: By helping with the development of safe and efficient nuclear energy, leading to improved nuclear reactors and potentially new energy sources
The significance of starquakes in neutron stars
Neutron stars are the dead remnants of massive stars that have burnt through all of their fuel. These objects collapse under their own gravity, becoming compact objects containing the densest matter in the universe.
These extreme conditions mean that the properties of matter inside them may provide key information about the fundamental nature of matter that cannot be obtained by studying matter in Earth-bound experiments.
At present, one of the most popular techniques for modelling nuclear matter in extreme conditions is a method called ‘Chiral Effective Field Theory’. As with any theory, it is important to test its predictions to check that it is consistent with real physics.
However, accurately measuring neutron stars, which are incredibly far away, is very challenging. Because of these challenges, scientists often focus on studying their basic, large-scale characteristics rather than the finer details. As a result, it's hard to thoroughly test specific scientific theories about neutron stars.
“We propose that, in the near future, asteroseismology could be used to obtain granular detail about matter inside neutron stars, and thus test theories like Chiral Effective Field Theory,” said Dr David Tsang, co-author of the study.
Duncan Neill added: “The asteroseismic techniques we propose have the advantage of using instruments already in operation, giving new applications to existing telescopes and expanding the tools of nuclear physics without requiring expensive new developments.
"As this work develops, we may find that we are able to use asteroseismology to pinpoint properties of matter at various densities within neutron stars, allowing astronomy to lead the way in guiding the development of new nuclear physics techniques. We hope to expand our research in asteroseismology at Bath, seeing just how much it could tell us."
The research team for this work included Dr Christian Drischler from Ohio University and FRIB at Michigan State University, Dr Jeremy Holt from Texas A&M University, College Station, and Dr William Newton from Texas A&M University-Commerce.
Journal
Physical Review C
Method of Research
Data/statistical analysis
Subject of Research
Not applicable
Article Title
https://journals.aps.org/prc/abstract/10.1103/PhysRevC.111.015809
