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Will future humans use warp drives to explore the cosmos? We’re in no position to eliminate the possibility. But if our distant descendants ever do, it won’t involve dilithium crystals, and Scottish accents will have evaporated into history by then.

Warp drives have their roots in one of the most popular science fiction franchises ever, but they do have a scientific basis. A new paper examines the science behind them and asks if a warp drive containment failure would emit detectable gravitational waves.

The paper is titled “What no one has seen before: gravitational waveforms from warp drive collapse.” The authors are Katy Clough, Tim Dietrich, and Sebastian Khan, physicists from institutions in the UK and Germany.

There’s room for warp drives in General Relativity, and Mexican physicist Miguel Alcubierre described how they could theoretically work in 1994. He’s well-known in space and physics circles for his Alcubierre Drive.

Everyone knows that no object can travel faster than the speed of light. But warp drives may offer a workaround. By warping spacetime itself, a spacecraft with a warp drive wouldn’t be breaking the faster-than-light (FTL) rule.

“Despite originating in science fiction, warp drives have a concrete description in general relativity, with Alcubierre first proposing a spacetime metric that supported faster-than-light travel,” the authors write.

There are clear scientific barriers to actually making a warp drive. But it’s possible to simulate how one would work and how they may be detectable via gravitational waves in the event of a failure. Warp drives distort spacetime itself, just like binary mergers of compact objects like black holes and neutron stars. It’s theoretically possible that they emit a gravitational wave signal in the same vein as mergers. “To search for such signals and to correctly identify them in the measured data, it is important to understand their phenomenology and properties,” the authors explain.

It begins with understanding how warp drives might work, and for that, we have to delve deeply into physics.

“The principle idea behind a warp drive is that instead of exceeding the speed of light directly in a local reference frame, which would violate Lorentz invariance, a “warp bubble” could traverse distances faster than the speed of light (as measured by some distant observer) by contracting spacetime in front of it and expanding spacetime behind it,” the paper states.

The first barrier is that warp drives require a Null Energy Condition (NEC). Physics states that a region of space cannot have a negative energy density. There are theoretical workarounds for that, but for now, none of them are practical.

“Other issues with the warp drive metric include the potential for closed time-like curves and, from a more practical perspective, the difficulties for those in the ship in controlling and deactivating the bubble,” the authors explain. This is because there would be no way for the crew to send signals to the front of the ship. It’s difficult for events inside the bubble to influence events outside the warp bubble, as this paper explains.

“From the perspective of simulating the warp drive dynamically, the key challenge is stability,” the authors explain. Equations show that the Alcubierre Drive can initiate a warp bubble using the Einstein Equation, but no known equations can sustain it. “There is (to our knowledge) no known equation of state that would maintain the warp drive metric in a stable configuration over time. Therefore, whilst one can require that initially, the warp bubble is constant, it will quickly evolve away from that state, and, in most cases, the warp fluid and spacetime deformations will disperse or collapse into a central point.”

Though instability is a prime obstacle to warp drives, it’s also what could make them detectable. If an Alcubierre Drive achieves a constant velocity, it’s not detectable. It generates no gravitational waves and has no ADM mass. ADM stands for Arnowitt–Deser—Misner, named for three physicists. I’ll leave it to curious readers to read more about ADM mass.

But the warp drive is only undetectable if it’s constant and stable. Once it breaks down, accelerates or decelerates, it could be detectable. In their work, the authors allow the warp drive bubble to collapse. “Physically, this could be related to a breakdown in the containment field that the post-warp civilization (presumably) uses to support the warp bubble against collapse,” they write.

In their formulations, the nature of the ship itself isn’t important. Only the warp bubble and the warp fluid inside are significant.

The researchers simulated the breakdown of the warp bubble. They found that the collapse generated gravitational waves with characteristics different from those generated by mergers. “The signal comes as a burst, initially having no gravitational wave content, followed by an oscillatory period with a characteristic frequency of order 1/[R],” they write. “Overall, the signal is very distinct from the typical compact binary coalescences observed by gravitational wave detectors and more similar to events like the collapse of an unstable neutron star or the head-on collision of two black holes.”

The authors point out that though the warp drive creates a GW signal, it’s outside the frequency range of our current ground-based detectors. “Proposals for higher frequency detectors have been made, so in the future, one may be able to put bounds on the existence of such signals,” they write.

The ship itself could also send some type of multimessenger signal, but it’s difficult to know how the ship’s matter would interact with regular matter. “Since we do not know the type of matter used to construct the warp ship, we do not know whether it would interact (apart from gravitationally) with normal matter as it propagates through the Universe,” the researchers explain.

This is a fun thought experiment. It’s possible that some type of workaround to FTL travel will exist one day in the distant future. If it does, it may be related to a better understanding of dark matter and dark energy. If any ETIs exist, they may be in a position to exploit fundamental knowledge of the Universe that we don’t yet possess.

If they’ve figured out how to construct and use a warp drive, even with all of its seeming impossibilities, their activities might create gravitational waves that our future observatories could detect, even in other galaxies. But for now, it’s all theoretical.

“We caution that the waveforms obtained are likely to be highly specific to the model employed, which has several known theoretical problems, as discussed in the Introduction,” the authors write in their conclusion. “Further work would be required to understand how generic the signatures are and properly characterize their detectability.”

Without a doubt, some curious physicists will continue to work on this.

The post Warp Drives Could Generate Gravitational Waves appeared first on Universe Today.

Thanks to readers who sent in their photos. Today we have ecologist Susan Harrison‘s batch of photos of Arctic seabirds. Her captions and IDs are indented, and you can enlarge the photos by clicking on them.

Visit to an Arctic seabird island

On a May trip to the Arctic regions of Finland and Norway, one of the highlights was a visit to the seabird colony on Hornoya, a tiny island in the Barents Sea that is home to something like 80,000 nesting birds.

Hornoya is reached by a 15-minute boat ride from Vardo, a small town where Norwegian dried fish were for many centuries traded for Russian grain, and where an infamous series of 17th-century witch trials took place.  Despite its age, Vardo lacks historic buildings since the retreating Germans leveled it in 1944. Vardo now gets by on fishing, ecotourism, and a radar antenna array that may possibly be listening to Russian submarines in nearby Murmansk.

Vardo with a Yellow-Billed Loon (Gavia adamsii), found only in the high Arctic, floating in the foreground:

Yellow-Billed Loon closeup:

Black-Legged Kittiwake (Rissa tridactyla) nests festooning Vardo buildings:

Common Murres (Uria aalge) on the water, and the Hornoya Island tour boat returning to Vardo:

Common Murres circling Hornoya Island and nesting on its cliffs:

Common Murre closeup:

Razorbills (Alca torda) mating and nesting:

European Shags (Gulosus aristotelis) courting and nesting:

Atlantic Puffins (Fratercula arctica) socializing and nesting:

Birdwatchers waiting for the return boat to Vardo:

The UK’s journey to net zero has stalled – whoever wins the 4 July election will need to get it moving again, but many climate scientists are frustrated with what the main parties are offering

Using the James Webb Space Telescope, astronomers have increased the number of known supernovae in the early universe by a factor of 10 and found the most distant one ever confirmed

Long term space exploration comes with many challenges. Not least is how much toilet paper to take but more worryingly is the impact on human physiology. We have not evolved in a weightless environment, we are not used to floating around for months on end nor are we able to cope with increased levels of radiation. It is likely that organs like the kidneys will become damaged but it make take time for signs to appear. Researchers are developing ways to detect organ issues in the early stages and develop ways to protect them during long duration flights. 

We have known for some years that space flight causes health problems. Reduced muscle and bone density are the more well known but since the 1970’s we have also seen a weakening of the heart, eyesight issues and kidney stone development. The main cause of the problem is thought to be increased exposure to radiation from space. It’s not just the radiation from the Sun but Galactic Cosmic Radiation from deep space also plays a part. Fortunately for us here on Earth, the magnetic field protects us and those in low Earth orbit to a degree too. Those who travel further afield; to the Moon and other planets will be far more at risk. 

ESA astronaut Alexander Gerst gets a workout on the Advanced Resistive Exercise Device (ARED). Credit: NASA

To date, no-one has attempted to study what might be happening inside our organs as a result of long duration space flight, until now. A new study, published in Nature Communications, reports upon the analysis of kidney health in space flight. The study was funded by Wellcome, St Peters Trust and Kidney Research UK and was undertaken by a team of researchers from over 40 groups. 

The research team collected samples from over 40 low Earth orbit missions from humans and mice chiefly from the International Space Station. Using these samples they conducted biomolecular, physiological and anatomical assessments. Using mice, they were able to simulate Galactic Cosmic Radiation doses equivalent to a 1.5 year to 2.5 year Mars mission. 

NASA Image: ISS020E049908 – NASA astronaut Nicole Stott, Expedition 20/21 flight engineer, is pictured near the Mice Drawer System (MDS) in the Kibo laboratory of the International Space Station.

Indications from the study showed that the kidney from both animal and human experienced changes. Parts of the kidney, known as tubules, are responsible for tweaking the calcium and salt balances and these showed signs of shrinkage after less than a month in space. The researchers believe though that this is more likely the result of weightlessness rather than radiation doses. The team did suggest however that further research is appropriate to see if the combination of increased doses of radiation coupled with microgravity had an increasing effect. 

Another finding of the study was the way in which salt is processed by the kidneys. It is now thought that fundamental changes to how this is handled leads to the formation of kidney stones whilst it was originally assumed to be the result solely of microgravity. 

Perhaps the most shocking finding of the study though was that anyone venturing beyond the confines fo the Earth’s protective magnetic field for 2.5 years is likely to experience permanent kidney damage and loss of function. This was demonstrated in the mice samples that had experienced a simulated Galactic Cosmic Radiation dose for that period fo time. The impact of this is quite staggering. Currently any astronaut venturing to Mars is likely to need kidney dialysis on the way back! The race is now on to find new ways to protect astronauts, and organs during long duration spaceflights. 

Source : Would astronauts’ kidneys survive a roundtrip to Mars?

The post An Astronaut Might Need Kidney Dialysis on the Way Home from Mars appeared first on Universe Today.

The search for life has to be one of the most talked about questions in science. The question is, what do you look for? The Odysseus lunar lander has recently detected signs of a technologically advanced civilisation…on Earth! The lander is equipped with an instrument called ROLSES which has probed the radio emissions from Earth as if it was an exoplanet to se if it could detect signs of life! 

Odysseus was launched on 15 February, it was the Intuitive Machines lunar lander and it touched down in the solar polar region of the Moon seven days later. Since then it has been collecting valuable data from the area as a prelude for future human exploration. It was part of the Commercial Lunar Payload Services program which have all been built by private companies. Despite the hiccup of a landing where Odysseus tipped onto its side it has still been performing well.

There have been other challenges along the way. The laser guided navigation system which was supposed to aid the landing over the rocky surface failed. In a nod to Armstrong landing Apollo 11 manually in the last few minutes, the ground crew had to land using the optical camera system alone.  Even the journey to the Moon was not without incident. One of the antennae of the ROLSES system overheated and became dislodged from its housing.  On landing, an image showed the antenna sticking out. 

Neil Armstrong and Buzz Aldrin plant the US flag on the Lunar Surface during 1st human moonwalk in history 45 years ago on July 20, 1969 during Apollo 1l mission. Credit: NASA

On board Odysseus is the Radio wave Observations at the Lunar Surface of the photo Electron Sheath or ROLSES for short. It is a radio experiment designed to explore properties of the Earth’s atmosphere from the surface of the Moon. It was a unique opportunity to observe Earth in a completely different way and, to see if our approach for hunting for technologically capable alien civilisations are correct. 

The instrument was built at NASA’s Goddard Space Flight Center in Maryland and included radio antennae and a device called a radio spectrometer. It’s purpose was to record a wide range of radio emissions from the ‘radio quiet’ locale of the Moon. It turned out to be a bit of a bonus though as the team were able to record radio waves coming from Earth for about an hour and a half. 

NASA has selected three commercial Moon landing service providers that will deliver science and technology payloads under Commercial Lunar Payload Services (CLPS) as part of the Artemis program. Each commercial lander will carry NASA-provided payloads that will conduct science investigations and demonstrate advanced technologies on the lunar surface, paving the way for NASA astronauts to land on the lunar surface by 2024…The selections are:..• Astrobotic of Pittsburgh has been awarded $79.5 million and has proposed to fly as many as 14 payloads to Lacus Mortis, a large crater on the near side of the Moon, by July 2021…• Intuitive Machines of Houston has been awarded $77 million. The company has proposed to fly as many as five payloads to Oceanus Procellarum, a scientifically intriguing dark spot on the Moon, by July 2021…• Orbit Beyond of Edison, New Jersey, has been awarded $97 million and has proposed to fly as many as four payloads to Mare Imbrium, a lava plain in one of the Moon’s craters, by September 2020. ..All three of the lander models were on display for the announcement of the companies selected to provide the first lunar landers for the Artemis program, on Friday, May 31, 2019, at NASA’s Goddard Space Flight Center in Greenbelt, Md. ..Read more: https://go.nasa.gov/2Ki2mJo..Credit: NASA/Goddard/Rebecca Roth

We have known for some time that all the signals from mobile phones and TV/radio  broadcast have been slowly drifting out into space (and have now reached a distance of just over 100 light years.) All of these emissions are potentially detectable but the further away from Earth, the weaker the signal. Within those signals, the team were able to detect signs of an intelligent, technological civilisation. The attention now will of course turn to hunting down the same signals from exoplanets, but perhaps not from ROLSES, something a little larger may be required. 

Source : In new experiment, scientists record Earth’s radio waves from the Moon

The post Moon Lander Detects Technosignatures Coming from Earth appeared first on Universe Today.

A doctor who actually treated COVID patients said at the start of the pandemic, "Just because they are young doesn’t mean they aren’t vulnerable."

The post Dr. Jay Bhattacharya: “An Infection Is A Severe Problem For Older Populations, and Also For People Who Have Certain Chronic Conditions. For Younger Populations Under 70, It’s Much Milder.” first appeared on Science-Based Medicine.

A recent study found that hospitalized patients were 43 percent more likely to have their care escalated and significantly less likely to die if their care team received AI-generated alerts signaling adverse changes in their health.

Researchers have made a significant breakthrough in how to enable and exploit ultra-fast spin behavior in ferromagnets. The research paves the way for ultra-high frequency applications.

Researchers have made a significant breakthrough in how to enable and exploit ultra-fast spin behavior in ferromagnets. The research paves the way for ultra-high frequency applications.

Researchers have developed new chemistry to achieve commercially relevant stability and performance for perovskite solar cells.

In 2021, NASA’s Perseverance rover landed in the Jezero Crater on Mars. For the next three years, this astrobiology mission collected soil and rock samples from the crater floor for eventual return to Earth. The analysis of these samples is expected to reveal much about Mars’ past and how it transitioned from being a warmer, wetter place to the frigid and desiccated place we know today. Unfortunately, budget cuts have placed the future of the proposed NASA-ESA Mars Sample Return (MSR) mission in doubt.

As a result, NASA recently announced that it was seeking proposals for more cost-effective and rapid methods of bringing the samples home. This will consist of three studies by NASA and the Johns Hopkins University Applied Physics Laboratory (JHUAPL). In addition, NASA has selected seven commercial partners for firm-fixed-price contracts for up to $1.5 million to conduct their own 90-day studies. Once complete, NASA will consider which proposals to integrate into the MSR mission architecture.

As Administrator Bill Nelson stated in a NASA press release

“Mars Sample Return will be one of the most complex missions NASA has undertaken, and it is critical that we carry it out more quickly, with less risk, and at a lower cost. I’m excited to see the vision that these companies, centers and partners present as we look for fresh, exciting, and innovative ideas to uncover great cosmic secrets from the Red Planet.”

The MSR mission represents the culmination of decades of efforts to learn more about the early history of Mars. NASA had originally hoped that the first crewed mission (planned for 2033) would retrieve the samples and transport them back to Earth. However, delays and budget concerns have led to growing concerns that a crewed mission will not reach Mars until 2040 (at the earliest). As a result, NASA and the European Space Agency adopted a joint mission architecture consisting of multiple robotic elements that would return the samples by 2031.

This included the Sample Retrieval Lander (SRL), two Sample Recovery Helicopters (SRH), the Mars Ascent Vehicle (MAV), the Earth Return Orbiter (ERO), and the Earth Entry System (EES). However, the current budget environment forced NASA to announce that the 15-year MSR mission architecture (which would cost $11 billion) was too expensive and that waiting until 2040 was impractical. As a result, NASA has adopted a revised plan that leverages current technology and will return the Mars samples by the 2030s. As NASA Administrator Bill Nelson said at the time:

“Mars Sample Return will be one of the most complex missions NASA has ever undertaken. The bottom line is, an $11 billion budget is too expensive, and a 2040 return date is too far away. Safely landing and collecting the samples, launching a rocket with the samples off another planet – which has never been done before – and safely transporting the samples more than 33 million miles back to Earth is no small task. We need to look outside the box to find a way ahead that is both affordable and returns samples in a reasonable timeframe.”

In addition to the NASA-led studies, seven aerospace companies have been selected to develop sample-return concepts. They include NASA’s regular commercial partners, such as Lockheed Martin, SpaceX, Aerojet Rocketdyne, Blue Origin, and Northrop Grumman, as well as relative newcomers Quantum Space and Whittinghill Aerospace. A total of $10 million has been awarded to these companies to develop their concepts, the full list of which can be found here.

Once again, NASA is facing a budget crunch and has reached out to its commercial partners to develop cost-effective alternatives. This is in keeping with NASA’s long history of collaborating with the commercial sector to develop key mission concepts. However, the need to outsource major elements of its Moon to Mars program highlights the agency’s ongoing budget problems. As independent experts have concluded, a budget increase is necessary if NASA is to realize its ambitious goals for the future.

Further Reading: NASA

The post NASA is Considering Other Ways of Getting its Mars Samples Home appeared first on Universe Today.

I walked by this pathetic specimen of a bicycle on my way home today. Note that while it is still locked up with a sturdy lock, most of the rest of it has been stolen. It is an ex-bicycle, singing with the choir invisible. The only thing I wonder is whether it’s possible to lock a bike so it doesn’t get stripped this way.

Researchers detail a new wearable fabric that can help urban residents survive the worst impacts of massive heat caused by global climate change, with applications in clothing, building and car design, and food storage. By addressing both direct solar heating and the thermal radiation emitting from pavement and buildings in urban heat islands, the material kept 2.3 degrees Celsius (4.1 degrees Fahrenheit) cooler than the broadband emitter fabric used for outdoor endurance sports and 8.9 degrees Celsius (16 degrees Fahrenheit) cooler than the commercialized silk commonly used for shirts, dresses and other summer clothing.

Researchers have experimentally generated high-density relativistic electron-positron pair-plasma beams by producing two to three orders of magnitude more pairs than previously reported.

Researchers have experimentally generated high-density relativistic electron-positron pair-plasma beams by producing two to three orders of magnitude more pairs than previously reported.

With their 'T-REX' method, researchers developed a glassy, amber-like polymer that can be used for long-term storage of DNA, such as entire human genomes or digital files such as photos.

With their 'T-REX' method, researchers developed a glassy, amber-like polymer that can be used for long-term storage of DNA, such as entire human genomes or digital files such as photos.

A new type of dart launcher has been developed as a safer and more cost-effective alternative to firearms or air guns to inject animals with drugs or tracking chips.

A suite of three innovations enables high-resolution, high-throughput imaging of human brain tissue at a full range of scales and mapping connectivity of neurons at single cell resolution. To demonstrate the advance, researchers compared a brain region in an Alzheimer's and a control sample.