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Bigger antennas are better, at least according to researchers interested in geospatial monitoring. That’s because higher resolution in monitoring applications requires larger apertures. So imagine the excitement in the remote sensing community when a researcher from Leidos, a government consulting firm, developed an idea that dramatically increased the effective aperture size of a remote radio-frequency monitoring system simply by tying a rotating antenna to a flat “sparse” array. That’s exactly what Dr. John Kendra did, and it has garnered him not only two NASA Institute for Advanced Concepts (NIAC) grants to advance the technology but also a prize paper award at a technical conference on remote sensing. In other words, if implemented correctly, the Rotary-Motion Extended Array Synthesis (R-MXAS) technology could be a game changer for remote sensing applications.

To understand why, it is best to understand the underlying concept of synthetic aperture radar (SAR). In a SAR system, multiple images of a single area are collected as a sensor moves past that area. Those images are then combined using a specially designed algorithm to create a single image composition. These images can see through clouds and are commonly used in remote sensing, especially in ground monitoring applications, such as tracking ocean levels.

R-MXAS is an implementation of a synthetic aperture imaging radiometer (SAIR), which combines the movement aspect of a typical SAR system and stitches together data from at least three separate antennas. One antenna is a large, 2-D plane that is, in fact, a 1-D “sparse” antenna. Two antennas are attached to either end of a tether that rotates at a right angle to the flat plane.

Scott Manley explains the basics of Synthetic Aperature Radar (SAR).
Credit – Scott Manley YouTube Channel

Data from those antennas are captured and combined in a specialized signal processing algorithm, some of which would occur in a remote sensing satellite, while some would have to occur on the ground. Those signal-processing algorithms effectively create an aperture area much larger than the sum of the physical components comprising it, which is precisely what remote sensing enthusiasts are looking for.

One particular application of this technology is ground moisture monitoring. Currently, there is a mission known as the Soil Moisture and Ocean Salinity (SMOS) mission, which ESA runs. It does an excellent job of monitoring overall soil moisture content at a resolution of about 35 km per “pixel.” But it does so from a low-Earth orbit, meaning it can only update those estimates once every few days. That update rate is frustrating to end data customers, who would like to see a faster cycle time and a higher resolution to allow for more specific tailoring of responses to conditions on the ground.

R-MXAS can help with both of those desires. First, according to calculations by Dr. Kendra, it can map the same 35 km resolution from geostationary orbit, allowing it to monitor an entire hemisphere simultaneously and continuously. While this particular final report didn’t dive into the detail of how R-MXAS could improve the resolution to 5-10 km rather than 35km, the idea is addressed, at least in theory, to show that the same multi-antenna configuration could be used as a high-gain phased array to increase the resolution even more.

R-MXAS Boom Design depiction
Credit – John Kendra

Given the novel nature of the idea and the enthusiastic acceptance by other researchers in the remote sensing community, R-MXAS was one of the lucky projects selected to receive a NIAC Phase II grant in 2019, immediately after its original Phase I grant in 2018. A brief search shows the most recent paper as being from 2021 and no further adopted plans or missions that implement the concept, but it would seem that a project somewhere would do so. Given the wide variety of use cases for a technology such as R-MXAS, it remains to be seen what that use case might be.

Learn More:
John Kendra – Rotary-Motion-Extended Array Synthesis (R-MXAS) FINAL REPORT
UT – There’s a Cloud of Space Debris Around Earth. Here’s how we Could get a Better Picture of it
UT – How a Single Atomic Sensor Can Help Track Earth’s Glaciers
UT – Astrobiologists Detect a Signature of Life Remotely. Don’t get too Excited, Though, it was With a Helicopter Here on Earth

Lead Image:
Artist’s conception of the R-MXAS system.
Credit – John Kendra

The post A Unique Combination of Antennas Could Revolutionize Remote Sensing appeared first on Universe Today.

Many people enjoy the experience of using AIs like ChatGPT or voice assistants like Alexa to find out information, but it turns out doing so makes it less likely you will spot inaccurate information

Josh Malerman, James S. A. Corey and Neal Asher all have new science fiction novels out in August, making it a bumper month for fans

Opponents of birth control don't object to condoms because they think they don't work, and Dr. Vinay Prasad doesn't object to masks because he thinks they don't work.

The post Dr. Adam Cifu Should Recognize, Dr. Vinay Prasad Will Never Admit Measures to Limit Viruses “Work” first appeared on Science-Based Medicine.

Scientists have made significant strides in understanding the properties of a ferroelectric material under an electric field. This breakthrough holds potential for advances in computer memory, lasers and sensors for ultraprecise measurements.

Scientists have made significant strides in understanding the properties of a ferroelectric material under an electric field. This breakthrough holds potential for advances in computer memory, lasers and sensors for ultraprecise measurements.

Scientists develop next-generation semiconductor technology for high-efficiency, low-power artificial intelligence.

Scientists develop next-generation semiconductor technology for high-efficiency, low-power artificial intelligence.

The temperature of the Sun’s corona is a minimum of 100 times hotter than the Sun’s surface, despite the corona being far less dense and extending millions of miles from the Sun’s surface, as well. But why is this? Now, a recent study published in The Astrophysical Journal could eliminate a longstanding hypothesis regarding the processes responsible for the corona’s extreme heat, which could help them better understand the Sun’s internal processes. This study holds the potential to help scientists gain greater insight into the formation and evolution of our Sun, which could lead to better understanding stars throughout the universe, as well.

For the study, the researchers analyzed data from the first 14 laps conducted by NASA’s Parker Solar Probe around the Sun with the goal of ascertaining how the magnetic field causes S-shaped bends, often called magnetic switchbacks due to their behavior in causing sudden reversals in the magnetic field’s direction. The goal of the study was to determine the source of the switchbacks, which are known to store energy from the magnetic field, to better understand how they could potentially heat the corona and solar wind.

“That energy has to go somewhere, and it could be contributing to heating the corona and accelerating the solar wind,” said Dr. Mojtaba Akhavan-Tafti, who is an assistant research scientist of climate and space sciences and engineering at the University of Michigan and lead author of the study.

The debate regarding the origin of the switchbacks has been disputed for some time within the scientific community, with scientists currently favoring two potential hypotheses: switchbacks originate from the magnetic field bending due to the solar wind’s extreme activity that occurs past the corona, and the other origin being from the surface of the Sun.

The results of the study show switchbacks do not originate from the surface of the Sun, which the researchers attribute to the lack of the number of switchbacks inside the corona. In contrast, if the Sun’s surface was the origin of the switchbacks, it is hypothesized the switchback numbers inside the corona would be far greater. Therefore, the study’s results eliminate one of the two competing hypotheses regarding the origin of switchbacks in the Sun.

“Our theory could fill the gap between the two schools of thought on S-shaped switchback generation mechanisms,” said Dr. Akhavan-Tafti. “While they must be formed outside the corona, there could be a trigger mechanism inside the corona that causes switchbacks to form in the solar wind.”

He follows this with, “The mechanisms that cause the formation of switchbacks, and the switchbacks themselves, could heat both the corona and the solar wind.” 

The study of the Sun’s magnetic field reversal dates to the 1970s when the two German-US Helios spacecraft, dubbed Helios-1 and Helios-2, observed this reversal behavior when Helios-2 traveled just over 43.432 million kilometers (26.99 million miles) from the Sun with Helios-1 being 3 million kilometers (1.9 million miles) behind it. This distance record was broken by the Parker Solar Probe in October 2018 and has since achieved a jaw-dropping distance of 7.26 million kilometers (4.51 million miles) from the Sun, which was accomplished in September 2023.

The Helios missions were followed by the first observations of switchbacks conducted by the NASA/ESA Ulysses probe that studied the Sun’s southern and northern polar regions in 1994 and 1995, respectively. More recently, remnants of switchbacks were observed by the ESA/NASA Solar Orbiter in September 2020 when the spacecraft was just over 146 million kilometers (91 million miles) from the Sun.

As noted, discovering the origin of switchbacks could help scientists better understand the internal processes of the Sun, and specifically the behavior of the solar wind, which contributes to space weather that can cause massive damage to orbiting satellites and electronic ground stations on Earth.

What new discoveries will scientists make about the origins of switchbacks on the Sun in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Why is the Sun’s Corona So Hot? One Hypothesis Down, Many to Go appeared first on Universe Today.

Interest in interstellar objects (ISOs) was ignited in 2017 when ‘Oumuamua flew through our Solar System and made a flyby of Earth. Roughly two years later, another ISO passed through our Solar System – the interstellar comet 2I/Borisov. These encounters confirmed that ISOs are not only very common, but pass through our Solar System regularly – something that astronomers have suspected for a long time. Even more intriguing is that some of these objects are captured and can still be found orbiting our Sun.

In a recent study, a team of researchers described a region in the Solar System where objects can be permanently captured from interstellar space. Their analysis determined that once objects are captured by our Sun’s gravitational pull and fall into this region—which could include comets, asteroids, and even rogue planets—they will remain in orbit around the Sun and not collide with it. These findings could have drastic implications for ISO studies and proposed missions to rendezvous with some of these objects in the near future.

The research was conducted by Edward Belruno, a professor of mathematics with the Katz School of Science and Health at Yeshiva University, New York, and James Green, the Director of the Planetary Science Division at NASA Headquarters. Their findings were presented in a paper titled “Permanent Capture into the Solar System” that appeared online and was recently presented at Heidelberg University and to the trajectory dynamics group at the European Space Agency’s Operations Centre (ESOC).

‘Oumuamua (l) and 2I/Borisov (r) are the only two ISOs we know of for certain. Credit: ESO/M. Kornmesser (left) NASA/ESA/D. Jewitt (right)

As noted, previous research has indicated that ISOs regularly visit our Solar System and could even be responsible for seeding Earth with the building blocks of life. In addition, researchers have attempted to simulate how many of these objects are captured by our Solar System over time, which yielded estimates in the thousands. Last, but not least, the arrival of ‘Oumuamua and 2I/Borisov also led to numerous proposals for spacecraft that could rendezvous with future ISOs and study them up close – such as the Interstellar Object Explorer (IOE) concept – or fly to those that our System has captured.

For their study, Belbrundo and Green performed simulations using a simplified model involving three masses – a captured ISO, the Sun, and the Milky Way – which allowed them to recreate the motion of the captured object. As they describe in their paper, when ISOs get caught by the Sun’s gravitational pull, they can enter a state known as “permanent capture,” where captured objects will remain in orbit around the Sun indefinitely. In addition, these objects will also enter a state known as “weak capture,” where they are slowly drawn into a stable orbit around the Sun but never collide with it.

Their simulations showed that captured objects in this region can exhibit chaotic motion, making their orbits appear highly unpredictable. However, they also noted that the region exhibits a complex, repeating pattern, similar to a fractal (or the patterns seen in the Mandelbrot set in mathematics) that contributes to the stability of the captured object’s orbit. As Belbruno explained to Astrobiology contributor Keith Cowing:

“The combined gravitational forces of the Sun and the Milky Way play a crucial role in this process. The galaxy’s gravitational field, including the effects of dark matter, significantly influences how objects are captured. Previous studies mainly focused on comet captures, which weren’t always permanent. This new research, however, describes a mechanism that ensures a permanent capture.”

Their study also suggests that in addition to asteroids and comets, the Sun could capture rogue planets throughout eons. Recent research has shown that there could be trillions of rogue planets in the Milky Way that were kicked from their solar systems over time. The gravitational influence of captured rogue planets and other objects would cause perturbations in the orbits of other bodies in the Solar System.

Similar to how astronomers have used the orbits of Kuiper Belt Objects to search for evidence of Planet 9 (aka. Planet X), astronomers could use these perturbations to infer the presence of captured bodies. Said Belbruno:

“The discovery not only enhances our understanding of gravitational dynamics but also opens up new possibilities for detecting and studying these fascinating celestial bodies. As we continue to explore the cosmos, who knows what other secrets the universe holds about the objects that have joined our solar family?”

Further Reading: Astrobiology, arXiv

The post A New Study Shows How our Sun Could Permantly Capture Rogue Planets! appeared first on Universe Today.

Space is big, really big! Finding new asteroids which are usually dark against the inky blackness of space is harder than looking for a needle in a cosmic haystack. Back in 1991 an astronomer discovered a kilometre wide asteroid which was subsequently found to have a smaller moon half its size. It was given the snappy name of 1991 VH which , after follow up observations was revealed to have a tumbling, chaotic rotation. This was the first binary asteroid that has been seen to exhibit this behaviour. A paper just published suggests that a close encounter with Earth as recently as 12,000 years ago could have started its tumbling motion. 

Asteroid 1991 VH was discovered by Robert McNaught at the Siding Spring Observatory. The asteroid was subject to high resolution imaging from Goldstone and the Arecibo Observatory in 2008 and showed a roughly spherical object. There is an equatorial ridge which gives the whole thing the appearance of a classical spinning top. It’s shape is not what makes the system unique, instead it is the chaotic tumbling nature of the binary system. 

The Arecibo Radio Telescope Credit: UCF

The satellite of 1991 VH has been dubbed S/2008 (35107) 1 and it was discovered on 27 February 1997 by a team of astronomers at Ondrejov Observatory. It was detected through photometric observations of the system’s dip in brightness caused by the eclipses and occultations as the two components rotate about each other. 

The binary asteroid pair have captured attention of astronomers because it comes from a class of asteroids known as Near Earth Binary Asteroids. Usually they consist of an oblate primary asteroid that is rotating rapidly and around it is a tidally locked elongated secondary asteroid. The tidal locking of the system is the result of tidal forces just like those that have tidally locked the Moon to Earth.  

In a paper published by Alex J Meyer from the University of Colorado Boulder and the team of researchers discuss that a past close encounter with Earth could have provided the necessary gravitational influence to disturb the binary system. It has been known that near-Earth asteroids develop chaotic orbital; properties at some point in their life. This is due to orbital resonances with some of the outermost gas giants and on occasions close passages by terrestrial planets. 

The team theorise that a single close passage by Earth could have been enough to impose a chaotic nature to the asteroids orbit. To facilitate their research, the team undertake a series of Monte-Carlo simulations where a stable binary asteroid is perturbed by a series of different orbital geometries. The resultant orbital parameters from the simulations are then compared with real observations from 1991 VH. 

Their results showed that a close fly-by of Earth by 1991 VH could most definitely alter the state. They propose that the flyby would have occurred within the last 100,000 years, possibly as close as within the last 12,000 years. The new altered chaotic state could remain until current day unless further encounters counteract the perturbations. 

Source : An Earth Encounter As the Cause of Chaotic Dynamics in Binary Asteroid (35107) 1991VH

The post This Binary Asteroid is Messed Up. It’s Probably Earth’s Fault appeared first on Universe Today.

Two studies have linked "problematic smartphone use" to higher rates of anxiety, depression and insomnia among teenagers, but the researchers haven't shown that excessively using such devices directly causes these issues

Being trapped in space sounds like the stuff of nightmares. Astronauts on board the International Space Station have on occasion, had their return delayed by weather or equipment malfunction. We find ourselves again, watching and waiting as two astronauts; Juni Williams and Butch Wilmore have been stuck for months instead of their week long mission. The delays came as the Starliner system required fixes to be implemented. NASA successfully fired up 27 of its 28 thrusters in a hot-firing test and now, ground teams are preparing finally, to bring them home.

The Boeing Starliner spacecraft is officially known as the CST-100 Starliner. It was developed by Boeing as part of NASA’s Commercial Crew Program. Its purpose is to transport astronauts to the International Space Station and other low orbit craft. Starliner hit the headlines with its reusable design aimed at reducing costs and increasing launch frequency. It was first launched on 20 December 2019 as an uncrewed test flight to demonstrate docking capability with ISS. 

Boeing’s CTS-100 Starliner taking off from Cape Canaveral, Florida, on June 5th, 2024. Credit: NASA

Since 2019 Starliner has had issues along the way but has largely seen a successful progression to becoming a key part of NASA’s launch capability. Just recently however there have been issues with the manoeuvring jets used to adjust the attitude. Engineering teams at NASA and Boeing have been working on and running tests with Mexico a new configuration. Part of the thruster system controls the flow of helium, these are the helium manifolds and they were opened to allow engineers to monitor any helium supply issues and leaks. 

The team ran a hot fire test of the reaction control system jets on 27 July to see if there were any problems with the propulsion system. They test fired 27 out of 28 jets while astronauts Wilmore and Williams sat inside the docked Starliner. The tests involved firing the jets for short bursts, one at a time. They revealed that all thrusters were back to performing well and the helium manifolds were within operational margins that were needed for a return trip from ISS. The engineering teams closed the manifolds ahead of undocking and returning the astronauts home. 

The work is not over for the engineering teams however as they are now reviewing data from the tests and from ground based testing at the White Sands Test Facility in New Mexico. Once the review of data is complete, NASA and Boeing will identify a date to return the astronauts. 

Meanwhile back on board the ISS Wilmore and Williams wait. They have been checking other Starliner systems in preparation for return, working with other Boeing teams to prepare and have been undertaking pressure tests of their space suits. They have been working alongside Expedition 71 members and have recently helped setup the BioServe centrifuge in the Harmony Module. The centrifuge supports a wide range of biological, physical and materials science projects. Facilitating the separation of substances with different densities it can work with cell cultures, DNA, protein, blood and sedimentary samples.

Source : NASA, Boeing Complete Second Docked Starliner Hot Fire Test

The post Starliner Successfully Fires its Thrusters, Preparing to Return to Earth appeared first on Universe Today.

An analysis of people who were hospitalised with covid-19 in the first wave of the pandemic has revealed that the ongoing decline in their cognitive abilities is the equivalent to losing 10 IQ points

Fourteen modifiable risk factors are behind nearly half of all dementia cases worldwide, a report claims, but genetics and old age are the main causes of the condition

An artificial intelligence method to detect biomarkers in tumor biopsies promises to cut weeks and thousands of dollars from cancer detection, extending the benefits of precision oncology to underserved and under-resourced patients.

An international research team has succeeded in developing a new version of RNA building blocks with higher chemical reactivity and photosensitivity. This can significantly reduce the production time of RNA chips used in biotechnological and medical research. The chemical synthesis of these chips is now twice as fast and seven times more efficient.

An artificial intelligence program created explanations of heart test results that were in most cases accurate, relevant, and easy to understand by patients.

Calculations show that nerve fibres in the brain could emit pairs of entangled particles, and this quantum phenomenon might explain how different parts of the brain work together

New research led proposes a plan to safeguard Earth's imperiled biodiversity by cryogenically preserving biological material on the moon. The moon's permanently shadowed craters are cold enough for cryogenic preservation without the need for electricity or liquid nitrogen.