A new paper proposes a fully physically realized model for warp drive.

This builds on an existing model that requires negative energy—an impossibility.

The new model is exciting, but warp speed is still probably decades or centuries away.

In a surprising new paper, scientists say they’ve nailed down a physical model for a warp drive, which flies in the face of what we’ve long thought about the crazy concept of warp speed travel: that it requires exotic, negative forces.

To best understand what the breakthrough means, you’ll need a quick crash course on the far-out idea of traveling through folded space.

The colloquial term “warp drive” comes from science fiction, most famously Star Trek. The faster-than-light warp drive of the Federation works by colliding matter and antimatter and converting the explosive energy to propulsion. Star Trek suggests that this extraordinary power alone pushes the ship at faster-than-light speeds.

Scientists have been studying and theorizing about faster-than-light space travel for decades. One major reason for our interest is pure pragmatism: without warp drive, we’re probably never making it to a neighboring star system. The closest such trip is still four years long at light speed.

Our current understanding of warp speed dates back to 1994, when a now-iconic theoretical physicist named Miguel Alcubierre first proposed what we’ve called the Alcubierre drive ever since.

The Alcubierre drive conforms to Einstein’s theory of general relativity to achieve superluminal travel. “By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it,” Alcubierre wrote in his paper’s abstract, “motion faster than the speed of light as seen by observers outside the disturbed region is possible.”

Essentially, an Alcubierre drive would expend a tremendous amount of energy—likely more than what’s available within the universe—to contract and twist space-time in front of it and create a bubble. Inside that bubble would be an inertial reference frame where explorers would feel no proper acceleration. The rules of physics would still apply within the bubble, but the ship would be localized outside of space.

It might help to think of an Alcubierre drive like the classic “tablecloth and dishes” party trick: The spaceship sits atop the tablecloth of spacetime, the drive pulls the fabric around it, and the ship is situated in a new place relative to the fabric.

Alcubierre describes spacetime expanding on one side of the ship and contracting on the other, thanks to that enormous amount of energy and a requisite amount of exotic matter—in this case, negative energy.

Is NASA Working On a Warp Drive?

Some scientists have criticized the Alcubierre drive, however, because it requires too much mass and negative energy for humans to ever seriously construct a warp-based propulsion system. NASA has been trying to build a physical warp drive through Eagleworks Laboratories for most of the last decade, but hasn’t yet made any significant strides.

warp propulsion
This brings us to the new study, which scientists in the Advanced Propulsion Laboratory (APL) at Applied Physics just published in the peer-reviewed journal Classical and Quantum Gravity. In the report, the APL team unveils the world’s first model for a physical warp drive—one that doesn’t require negative energy.

The study is understandably pretty thick (read the whole thing here), but here’s the gist of the model: Where the existing paradigm uses negative energy—exotic matter that doesn’t exist and can’t be generated within our current understanding of the universe—this new concept uses floating bubbles of spacetime rather than floating ships in spacetime.

The EmDrive Just Won’t Die
The physical model uses almost none of the negative energy and capitalizes on the idea that spacetime bubbles can behave almost however they like. And, the APL scientists say, this isn’t even the only other way warp speed could work. Making a model that’s at least physically comprehensible is a big step.

Plus, Alcubierre himself has endorsed the new model, which is like having Albert Einstein show up to your introductory physics class.

Of course, there’s one gigantic caveat here: The concept in this paper is still in the “far future” zone of possibility, made of ideas that scientists still don’t know how to construct in any sense.

“While the mass requirements needed for such modifications are still enormous at present,” the APL scientists write, “our work suggests a method of constructing such objects based on fully understood laws of physics.”

But while a physical drive may not be a reality today, tomorrow, or even a century from now—let’s hope it’s not that long—with this exciting new model, warp speed travel is now a lot more likely in a much shorter timespan than we previously thought.

Source: https://www.popularmechanics.com/science/a35718463/scientists-say-physical-warp-drive-is-possible/?source=nl&utm_source=nl_pop&utm_medium=email&date=0

• Experts analyzed a meteorite discovered last year in the Sahara desert
• The rock weighs 70 pounds and is tan in color with green spots throughout
• It consists mostly of volcanic rock, but also silicon dioxide that is found on Earth
• Named EC 002, it is 4.6 billion years old and was once part of an early planet

An ancient, meteorite, or achondrite, was discovered in the Sahara desert last year that has now been identified as chunk from a protoplanet that formed before Earth came into existence.

The space rock, named EC 002, dates back 4.6 billion years and consists mostly of volcanic rock, leading experts to believe it came from the crust of a very early planet.

The team of French and Japanese scientists determined that the rock was once liquid lava, but cooled and solidified over 100,000 years to form the 70-pound piece that eventually made its way to our planet.

Researchers also note that no asteroids have been found with similar properties, which suggests the protoplanet it came from has since disappeared by either becoming parts of larger bodies or ‘were simply destroyed.’

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An ancient achondrite was discovered in the Sahara desert last year that has now been identified as chunk from a protoplanet that formed before Earth came into existence. The stony meteorite, named EC 002, dates back 4.6 billion years

Anchondrites originate from early planetary bodies that have reformed from molten fragments and were flung into space as a result of another collision.

These rocks also resemble those on Earth at first glance, deeming them a rare discovery in the scientific community.

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The latest anchondrite has been named after its landing site in Algeria’s Erg Chech dune sea, which consist of several meteorites that collectively weight some 70 pounds, Motherboard reports.

Only a few thousands of these have been analyzed, most of which are basaltic, but EC 002 is made mostly of volcanic rock – making it rich in sodium, iron and magnesium.

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The rock consists mostly of volcanic rock, leading experts to believe it came from the crust of a very early planet. The team describes EC 002 as ‘relatively coarse grained, tan and beige,’ noting that it was also spotted with yellow and green bits

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The latest anchondrite has been named after its landing site in Algeria’s Erg Chech dune sea, which consist of several meteorites that collectively weight some 70 pounds

With this in mind, the team says EC 002 ‘is also the oldest magnetic rock ever observed.’

Researchers determined its age by studying the rock’s magnesium and aluminum isotopes, which showed it formed about 4.566 billion years ago – while Earth is said to be 4.543 billion years old.

The team describes EC 002 as ‘relatively coarse grained, tan and beige,’ noting that it was also spotted with yellow and green bits.

They also note that when they looked at other celestial bodies, focusing on their wavelengths, they found nothing that matched the wavelength reflected by EC 002.

The meteorite is also 58 percent silicon dioxide, making it even rarer than others previously found on Earth, as this mineral is commonly found in volcanic regions on our planet.

‘Protoplanets covered by andesitic crusts were probably frequent,’ the team wrote in the study published in Proceedings of the National Academy of Sciences.

‘However, no asteroid shares the spectral features of EC 002, indicating that almost all of these bodies have disappeared, either because they went on to form the building blocks of larger bodies or planets or were simply destroyed.’

Source: https://www.dailymail.co.uk/sciencetech/article-9346939/4-6-BILLION-year-old-meteorite-discovered-Sahara-shed-light-early-solar-system.html

Scientists have peered into the heart of Mars for the first time. NASA’s InSight spacecraft, sitting on the Martian surface with the aim of seeing deep inside the planet, has revealed the size of Mars’s core by listening to seismic energy ringing through the planet’s interior.

The measurement suggests that the radius of the Martian core is 1,810 to 1,860 kilometres, roughly half that of Earth’s. That’s larger than some previous estimates, meaning the core is less dense than had been predicted. The finding suggests the core must contain lighter elements, such as oxygen, in addition to the iron and sulfur that constitute much of its make-up. InSight scientists reported their measurements in several presentations this week at the virtual Lunar and Planetary Science Conference, based out of Houston, Texas.

Rocky planets such as Earth and Mars are divided into the fundamental layers of crust, mantle and core. Knowing the size of each of those layers is crucial to understanding how the planet formed and evolved. InSight’s measurements will help scientists to determine how Mars’s dense, metal-rich core separated from the overlying rocky mantle as the planet cooled. The core is probably still molten from Mars’s fiery birth, some 4.5 billion years ago.

Compare and contrast

The only other rocky planetary bodies for which scientists have measured the core are Earth and the Moon. Adding Mars will allow researchers to compare and contrast how the Solar System’s planets evolved. Similar to Earth, Mars once had a strong magnetic field generated by liquid sloshing its core; but that magnetic field dropped dramatically over time, causing Mars’s atmosphere to escape into space and the surface to become cold, barren, and much less hospitable to life than Earth’s.

Simon Stähler, a seismologist at the Swiss Federal Institute of Technology in Zurich, reported the core findings in a pre-recorded 18 March presentation for the virtual conference. Stähler declined an interview request from Nature, saying the team intends to submit the work for publication in a peer-reviewed journal.

First ‘marsquake’ detected on red planet

The work builds on earlier findings from InSight that detected layers in the Martian crust. “Now we start to have that deep structure down to the core,” said geophysicist Philippe Lognonné in another pre-recorded talk. Lognonné, based at the Paris Institute of Earth Physics in France, heads InSight’s seismometer team.

The spacecraft, which cost nearly US$1 billion, landed on Mars in 2018 and is the first mission to study the red planet’s interior. The stationary lander sits near the Martian equator and listens for ‘marsquakes’, the Mars equivalent of earthquakes. So far, InSight has detected around 500 quakes, meaning the planet is less seismically active than Earth but more so than the Moon. Most marsquakes are very small, Lognonné said, but nearly 50 of them have been between magnitude 2 and 4 — strong enough to provide information on the planet’s interior.

Just as seismometers do on Earth, InSight measures the size of the Martian core by studying seismic waves that have bounced off the deep boundary between the mantle and the core. With information from enough of these deep-travelling waves, InSight scientists were able to calculate the depth of the core–mantle boundary and hence the size of the core. The seismic data also suggest that the upper mantle, which extends to around 700 to 800 kilometres below the surface, contains a zone of thickened material in which seismic energy travels more slowly.

In an effort to replicate the conditions inside planetary cores, other researchers have squeezed combinations of different chemical elements at high pressures and temperatures. InSight’s estimate of the Martian core density agrees with many of those laboratory-based estimates, says Edgar Steenstra, a geochemist at the Carnegie Institution for Science in Washington, DC.

Orbital extreme

InSight might be running out of time to make discoveries. Dust has been piling up on its 2-metre-wide solar panels, cutting down on the amount of power the spacecraft can generate. Mars is also moving towards the farthest point from the Sun in its orbit, which will further limit the craft’s opportunity to recharge.

“This is going to cause us to reduce our instrument usage over the next few months,” says Mark Panning, InSight’s project scientist at the Jet Propulsion Laboratory in Pasadena, California.

In January, the team already had to give up on its German-built ‘mole’, a thermal probe that was supposed to bury itself in the soil and measure heat flow, but which encountered problems with friction and couldn’t dig deep.

Drastic temperature changes on Mars that occur when day turns to night and vice versa, create noise in the signals that Insight’s seismometer collects, as the tether connecting it to the lander lays exposed on the planet’s surface. So InSight is now trying to bury the tether by scooping dirt onto it in an attempt to insulate it.

InSight detects marsquakes mostly at night, because daytime winds cause too much shaking and interfere with seismic signals. But the windy season at its landing site recently drew to an end. Team scientists are looking forward to new-found seismic quiet to catch as many marsquakes as they can before the mission has to end.

Source: https://www.nature.com/articles/d41586-021-00696-7?utm_source=Nature+Briefing&utm_campaign=02e41775a1-briefing-dy-20210318&utm_medium=email&utm_term=0_c9dfd39373-02e41775a1-46019854