In a First, an ‘Atomic Fountain’ Has Measured the Curvature of Spacetime - Could provide an alternative to GPS in the future

 

As reported by Scientific American: In 1797, English scientist Henry Cavendish measured the strength of gravity with a contraption made of lead spheres, wooden rods and wire. In the 21st century, scientists are doing something very similar with rather more sophisticated tools: atoms.

Gravity might be an early subject in introductory physics classes, but that doesn’t mean scientists aren’t still trying to measure it with ever-increasing precision. Now, a group of physicists has done it using the effects of time dilation—the slowing of time caused by increased velocity or gravitational force—on atoms. In a paper published online today (Jan. 13) in the journal Science, the researchers announce that they’ve been able to measure the curvature of space-time.

The experiment is part of an area of science called atom interferometry. It takes advantage of a principle of quantum mechanics: just as a light wave can be represented as a particle, a particle (such as an atom) can be represented as a “wave packet.” And just as light waves can overlap and create interference, so too can matter wave packets.

In particular, if an atom’s wave packet is split in two, allowed to do something, and then recombined, the waves might not line up anymore—in other words, their phases have changed.

“One tries to extract useful information from this phase shift,” Albert Roura, a physicist at the Institute of Quantum Technologies in Ulm, Germany, who was not involved in the new study, told Space.com. Roura wrote a “Perspectives” piece about the new research, which was published online in the same issue of Science today.

Gravitational wave detectors work via a similar principle. By studying particles in this way, scientists can fine-tune the numbers behind some of the key workings of the universe, such as how electrons behave and how strong gravity really is—and how it subtly changes over even relatively small distances.

It’s that last effect that Chris Overstreet of Stanford University and his colleagues measured in the new study. To do this, they created an “atomic fountain,” consisting of a vacuum tube 33 feet (10 meters) tall ornamented with a ring around the very top.

The researchers controlled the atomic fountain by shooting laser pulses through it. With one pulse, they launched two atoms up from the bottom. The two atoms reached different heights before a second pulse shot them back down. A third pulse caught the atoms at the bottom, recombining the atoms’ wave packets.

The researchers found that the two wave packets were out of phase—a sign that the gravitational field in the atomic fountain wasn’t completely uniform.

“That … in general relativity, can be understood, actually, as the effect of space-time curvature,” Roura told Space.com, referring to one of Albert Einstein’s most famous theories.

Since the atom that went higher was closer to the ring, it experienced more acceleration thanks to the ring’s gravity. In a perfectly uniform gravitational field, such effects would cancel out. That isn’t what happened here; the atoms’ wave packets were out of phase instead, and thanks to the effects of time dilation, the atom that experienced more acceleration was ever so slightly out of time with its counterpart.

The result is a minuscule change, but atom interferometry is sensitive enough to pick it up. And since the scientists can control the placement and the mass of the ring, Roura told Space.com, “they are able to measure and study these effects.”

Although the technology behind this discovery—atom interferometry—might seem arcane, atom interferometry may one day be used to detect gravitational waves and help us navigate better than GPS, researchers have said. 

Tesla Semi in Limited Production

 As reported by Teslarati: Back in November, PepsiCo CEO Ramon Laguarta remarked that his company was expecting its first Tesla Semi deliveries in the fourth quarter. This was a surprise to electric vehicle enthusiasts, as Tesla CEO Elon Musk noted during the 2021 Annual Shareholder Meeting that the Class 8 all-electric hauler would be hitting volume production in 2023. Yet if recent sightings at the Giga Nevada area are any indication, it appears that the Semi is now in limited production — and Tesla is doing some interesting tests with its freshly made trucks.

The Semi’s new video, which was shared on YouTube by Tesla advocate Sawyer Merritt, was shot last Friday near Gigafactory Nevada. The truck in the footage was reportedly manufactured in a production facility that has been constructed near Tesla’s massive battery plant. While the Semi in the footage looked quite similar to the white painted, updated prototypes that have been spotted several times this year, the new truck reportedly did not have any stickers from the Department of Transportation, nor did it have manufacturer plates. 

Sightings of the Tesla Semi have been going on for some time, but what makes last Friday’s footage quite special was that it showcased a clear tire-shredding acceleration run from the Class 8 all-electric truck. The footage was brief, lasting only two and a half minutes, but it was enough to show just how quick the Semi really is when it accelerates at full speed. Granted, the Semi was not pulling a trailer when it was captured on video, but it’s still remarkable to see such a large all-electric vehicle run like a sports car on the road. 

Also quite interesting was the Semi’s incredibly tight turning radius. After running the length of the production facility near Giga Nevada, the Semi simply took a U-turn to head back. The vehicle then proceeded to showcase its turning circle several more times, and just like its acceleration, the Semi’s turning radius is pretty remarkable. This bodes well for the Semi’s maneuverability, which would likely help it stand apart from its more conventional, more traditional competitors.  

If recent reports are accurate and the Tesla Semi has indeed entered limited production, it would suggest that the company might be working with some of its first customers as part of its efforts to refine and finalize the Class 8 hauler. Considering CEO Laguarta’s statements last November, PepsiCo could very well be one of these first customers. PepsiCo has been dropping hints about its upcoming Tesla Semi fleet as of late, after all. Earlier this year, the company noted that it was expecting to receive 15 units of the Semi by the end of 2021. PepsiCo has also received a permit for a Tesla Megacharger at its Modesto, California facility. 

Russia issues threat to US GPS Satellites

 As reported by GPS World: The Kremlin warned it could blow up 32 GPS satellites with its new anti-satellite technology, ASAT, which it tested Nov. 15 on a retired Soviet Tselina-D satellite, according to numerous news reports.

Russia then claimed on state television that its new ASAT missiles could obliterate NATO satellites and “blind all their missiles, planes and ships, not to mention the ground forces,” said Russian Channel One TV host Dmitry Kiselyov, rendering the West’s GPS-guided missiles useless. “It means that if NATO crosses our red line, it risks losing all 32 of its GPS satellites at once.”

The International Space Station (ISS) Flight Control team was notified of indications of a satellite breakup, causing 1,500 pieces of debris to threaten the station. “Due to the debris generated by the destructive Russian Anti-Satellite (ASAT) test, ISS astronauts and cosmonauts undertook emergency procedures for safety,” said NASA Administrator Bill Nelson.

“With its long and storied history in human spaceflight, it is unthinkable that Russia would endanger not only the American and international partner astronauts on the ISS, but also their own cosmonauts,” Nelson said. “Their actions are reckless and dangerous, threatening as well the Chinese space station and the taikonauts on board. All nations have a responsibility to prevent the purposeful creation of space debris from ASATs and to foster a safe, sustainable space environment.

“Russia has demonstrated a deliberate disregard for the security, safety, stability and long-term sustainability of the space domain for all nations,” Gen. James Dickinson, commander of U.S. Space Command, said. “Russia’s tests of direct-ascent anti-satellite weapons clearly demonstrate that Russia continues to pursue counterspace weapon systems that undermine strategic stability and pose a threat to all nations.”

The Navy is Testing a GPS-like Device That Doesn’t Require Satellites

 As reported by Task & Purpose: The Navy is researching a new technology that could help sailors and Marines navigate in places where the Global Positioning System just doesn’t work.

Unlike GPS signals, cosmic ray muons are a natural source of radiation that can pass through rock, buildings and earth and can be used at high latitudes north of the Arctic Circle, where GPS satellites do not work well due to their orbital constraints, the Office of Naval Research wrote in a press release on Tuesday.

In September, ONR and the U.S. Army Development Command co-funded a group of international researchers who want to show that muons can work as an alternative to GPS and still deliver the same level of precision. They have nine months to show their stuff, and if it works, it could be a game-changer for the military.

“The ability to navigate in polar regions will be of increasing importance in the coming decades as climate change is opening up Arctic waterways to commercial and military activities,” said Dr. Charles Eddy, the lead ONR Global science director for the muon project. “This project, which uses cosmic relativistic particles that continuously impinge on the Earth’s entire surface, offers an innovative approach to the challenge of navigation at high latitudes with little or no GPS service.”

The question of how to preserve navigation capability is a big one these days, especially as countries like the U.S., Russia and China develop new ways of disabling the satellites that GPS is based on.

“The most important thing that the Space Force supports, from the perspective of a civilian, is the fact that we have GPS,” said Capt. Natalia Pinto, a space operations officer, in a Space Force commercial in August. “That is something that is leveraged by an individual, companies, banks, all sorts of financial institutions. So from the outside looking in, that’s probably the most important thing that we rely on.”

The military uses GPS every day for guiding ships, planes, bombs and so many other things where they need to go. But those signals are easily disrupted by jammers, which block GPS signals, and spoofers, which take them over and feed the user false information, National Defense Magazine wrote in February. Enter, spoof-proof muon technology.

If you’re like me and have never heard of muons before now, have no fear. Muons are one of the fundamental subatomic particles, kind of like electrons but much heavier, according to the Department of Energy. Muons on Earth result from particles in the Earth’s atmosphere colliding with cosmic rays, which are high-energy photons and atomic nuclei coming from the sun or other solar systems or galaxies. Muons exist for only 2.2 microseconds, but they are created constantly in the atmosphere, hitting every inch of the Earth’s surface and passing through nearly any substance at almost the speed of light. 

Penetrate nearly any substance you say? Well that’s helpful in case you need to figure out where you are underground or underwater. 

“Cosmic-ray muons (or atmospheric muons) are ubiquitous and universal,” researchers wrote in a study of muons published in the journal Nature in 2020. “[B]y utilizing this universality and relativistic nature, cosmic muons have a potential to be used for positioning the receiver detector located underwater or underground three dimensionally with a great accuracy.”

The same goes for navigating north of the Arctic Circle. The Navy-funded research into the use of muons for navigation is led by Dr. Chris Steer of the British company Geoptic Infrastructure Investigations Limited. Steer explained that “like echolocation, the timing difference between ‘pings’ — the signals from a crossing muon in our detectors — can allow the user to measure the distance from one detector to another with multiple detectors allowing location by triangulation.” 

Researchers have already tested the system in a large water-immersion tank in the United Kingdom. Now the project will move to Finland, specifically into an Arctic lake covered with a meter of ice, the press release said. 

“At these high latitudes, conventional GPS measurements are problematic due to their orbital constraints,” ONR wrote.

To make it work, researchers will need a set of highly-synchronized clocks that can work partially underwater in a freezing Arctic environment. But if it does work, it would be a big step up for military navigation.

“The sea is broadly transparent to cosmic ray muons, so we expect there to be a number of scientific subsea navigation opportunities,” Steer said. “Similarly, as cosmic ray muons are highly penetrating and able to pass through many tens to hundreds of meters of rock, it is possible to see that this technology also has strong opportunities in tunnels and other underground settings.”

Muon tech is not the only alternative to GPS for figuring out where you are in the world. For example, the Navy has started teaching good ol’ celestial navigation using a sextant and the stars again in recent years.

“That’s an oldie but goodie,” said Richard Mason, a senior engineer at the RAND Corporation. The military could also automate systems to keep track of celestial navigation for service members, Mason suggested.

At a higher-tech level, the military may be close to using quantum science as a ‘hacker-proof’ alternative to GPS, Defense One reported earlier this month.

“These inertial sensors can be used wherever there is a need for position or navigational information, and where a GPS outage is unacceptable or GPS is unavailable,” Peter Schwindt, a scientist at Sandia National Labs, which is researching quantum navigation, told Defense One. “Civilian applications such as aviation and autonomous vehicles are areas where momentary outages of the GPS signal is not acceptable. GPS is decidedly not available underground or underwater so inertial navigation is very important for these operational environments.”

Between quantum science and muons, navigation in the military is becoming much more sci-fi than simply reading a map. But as complicated as it sounds, scientists are excited about what might happen next.

“The future is extremely bright for this line of research,” ONR wrote.

‘Tesla Bot’ prototype to arrive in 2022

 
As reported by Teslarati: Tesla will launch the “Tesla Bot” prototype in 2022, Elon Musk announced during the Artificial Intelligence Event the company held today at its Palo Alto headquarters.

After jokingly walking out a human in the Tesla Bot uniform, Musk said “Tesla Bot will be real.” Musk detailed some of the tasks that the robot will be able to complete, including grocery runs, picking up household objects, and other everyday commands.

The robot will be 5 feet 8 inches tall and 125 pounds. It will include a screen on the face of the bot to display useful information. Additionally, it will have human-level hands. The extremities operate using 40 electromechanical actuators, with two feet, and force feedback sensing for balance and agility. Musk joked that it may be able to run up to 5 MPH.

The Tesla Bot will also utilize some of the company’s AI devices that are operational on the company’s vehicles. Autopilot cameras will essentially act as the vision for the Tesla Bot, while a Full Self-Driving computer will function as the internal organs of the robot, helping it to operate and function as a productive member of the household. It will utilize mutli-camera video neural networks, identical to what was detailed during the company’s AI Event. Additionally, Neural Net planning, labeling, simulation and tools will also be used to help the Tesla Bot operate effectively and efficiently, while accurately performing tasks.

“For this robot, we’re trying to be as literal as possible: Can it do boring, dangerous, repetitive jobs that people don’t want to do. You know, once you have it do that, maybe it can do other things too…I mean, maybe it could be your buddy, too. I’m sure people will think of some very creative uses,” Musk joked.

The Tesla Bot won’t be available until next year, Musk said, especially as the robot will utilize the Dojo Supercomputer’s training mechanisms to improve functionality. It seems that Tesla’s idea for the robot is to decrease the need to perform tasks by yourself. There will be “no shortage of labor,” Musk said about the future, but physical work will simply be a choice. The Tesla Bot’s purpose could eliminate the need to perform minimal, mindless tasks around the house. “For the Tesla bot it’s going to start with work that is boring and repetitive Basically work that a person would least like to do,” Musk added.

“Things that I think are very hard about having a useful humanoid robot is ‘Can it navigate through the world without being explicitly trained?’ Without explicit line-by-line instructions,” Musk said. “Can you talk to it and say ‘Pick up that bolt, attach it to the car with that wrench. It should be able to do that.”

The development of the robot seems to be a responsibility of Musk’s, especially as the CEO has been critical of AI’s potential power in the past. On an episode of the Joe Rogan Experience podcast, Musk once warned that AI could become increasingly dangerous if overdeveloped, especially as its mind and memory are terrifically powerful.

Don’t expect to see the Robot on Tesla’s production lines, either. Musk said the parts were there, and Tesla decided to make it. “If we don’t, someone else would, so I guess we should probably make it. And make it safe,” Musk said.

Iconic - SpaceX's Starship Booster Fitup

 

SpaceX's next Starship prototype got the black-and-white treatment in a suave new photo shared by company founder Elon Musk.

The picture appears to show the Starship SN20 ("Serial No. 20") prototype during fit checks on Aug. 4 with the first-stage Super Heavy rocket, when the stacked rocket briefly became the tallest one in the world.

The picture provides a close-up view of the mating procedure between Starship and Super Heavy, with engineers perched underneath. The picture is reminiscent of the famous black-and-white "Lunch Atop a Skyscraper Photograph" taken by Charles Clyde Ebbets on Sept. 20, 1932, during construction of Rockefeller Center in Manhattan.

Watch as Tesla Model S Plaid Hits insane Speeds on Pikes Peak Hill Climb

 

As reported by Electrek: Unplugged Performance has brought its brand-new Tesla Model S Plaid to the Pikes Peak Hill Climb, and the new top-performance electric vehicle is already impressing in the practice round.

After famously crashing their Model 3 and building it back up in record time to compete last year, Unplugged Performance is back at Pikes Peak, but this time with a brand-new Model S Plaid.

It’s going to be the first time Tesla’s new top performance vehicle is being put to the test, and it’s no easy test.

Pikes Peak consists of a 12.4-mile route that starts at just above 9,000 feet and climbs to the summit at 14,115 feet above sea level.

It’s not only extremely dangerous for the driver since the sharp turns mostly open up to the sides of cliffs, but it’s also extremely demanding on the vehicles competing.

As we previously reported, Unplugged Performance, a Tesla tuner and aftermarket accessory maker, managed to get their hands on an early Tesla Model S Plaid, which they modified with a new suspension, brakes, tires, roll cage, and a few aerodynamic changes.

They released a video of the vehicle during the practice runs at the Pikes Peak Hill Climb:

It is leading its division (exhibition) by a decent margin, and it’s getting close to the times of some purpose-built vehicles in the open wheel category:

Those times are only for one section of the route that is open for practice.

While he wasn’t pushing it too hard, he was able to hit 130 mph in some stretches of the climb, which is simply insane:

It’s going to be interesting to see what time Unplugged Performance can get with their modified Tesla Model S Plaid, which stock can accelerate from 0 to 60 mph in less than two seconds.