[I've never heard of anything like this before. I have never yet heard of X-rays emanating from the centre of a planet. Jan]
For the first time ever, Astronomers have detected X-rays from Uranus. It’s unusual but is it good news or bad news?
[I've never heard of anything like this before. I have never yet heard of X-rays emanating from the centre of a planet. Jan]
For the first time ever, Astronomers have detected X-rays from Uranus. It’s unusual but is it good news or bad news?
An asteroid seems to have exploded over Antarctica with a tremendous power.
Hints of a hefty source of gravity beyond Pluto sparked the search for a possible “Planet Nine”. Now, some astronomers think it could instead be a black hole from the big bang, offering a rare glimpse into the early universe
SPACE 31 March 2021
By Stuart Clark
BEYOND the giant planets of the outer solar system lies a vast wilderness. Most astronomers think it is inhabited by a population of small, icy worlds similar to Pluto, and several groups have dedicated themselves to tracking down these dwarf planets. In the process, some have come to suspect that something bigger is lurking out there: a planet several times the mass of Earth.
They believe that this hypothetical world, known as Planet Nine, betrays its presence by the way its gravity has aligned the orbits of a group of these small, icy bodies. The problem is that no one can imagine how a planet big enough to do that could form so far from the sun. “All we know is that there’s an object of a certain mass out there,” says Jakub Scholtz, a theorist at Durham University in the UK. “The observations we have can’t tell us what that object is.”
But if not a planet, then what? Scholtz suspects it could be something even more exotic: a primordial black hole, one forged in the big bang.
If he is right, it would be a stunning discovery. Primordial black holes would give us a new window onto the early universe. They might even comprise dark matter, the mysterious substance that holds galaxies together. All of which explains why cosmologists have been scouring the universe for them. But no one had dared to dream we might find one in our own backyard.
The question now is, how can we determine what the mysterious source of gravity lurking at the fringes of our solar system really is? …
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.
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.
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.
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.
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
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.’
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.
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.
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.
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.
I was looking for video footage of the testing of the Mars Helicopter on Earth to see how it actually performs.
This contains a fascinating discussion about what happens to rockets after they’ve been fired off. I never knew that they end up returning, more or less to where they started from. Also the mention of the pressure of solar radiation on the rocket also surprised me. I was unaware the pressure had such an effect.
SMITHSONIANMAG.COM | Feb. 22, 2021, 8 a.m.
The Perseverance Rover is about to gather a rock collection with no equal. On February 18, the rover landed in Mars’ Jezero Crater to gather rock samples and begin searching for signs of ancient microbial life in visible deltas where water once flowed. The rover is set to fill 38 glass tubes with samples of Mars’ surface, then send them to Earth like pebbly postcards, souvenirs to show scientists where it has been. But the samples will need to travel a complicated delivery route to get to their final destination.
Support the Smithsonian with these exclusive designs celebrating the Red Planet’s latest rover. Available through February 23 only!
The mission, called Mars Sample Return, will require two more rocket launches from Earth, currently slated for 2026 and 2031, and one rocket launch from Mars, which could become the first launch from another planet. If the plan runs smoothly, the mission will provide the first cache of rock samples from another planet—complete with details about when, where and how they were collected. The mission will culminate with the samples crash-landing on the mudflats of the Utah Test and Training Range. Scientists on Earth will then be able to scour the samples for details about the Red Planet’s climate, geological history and even subtle signs of life.
“It’s something that the entire Mars exploration community is really excited about and looking forward to,” says David Spencer, the Mars Sample Return campaign mission manager at NASA’s Jet Propulsion Laboratory. “And Perseverance is that critical first step.”
Perseverance is loaded with scientific equipment to help it hunt for signs of life, like SHERLOC, which uses an ultraviolet laser to observe some details of minerals, and SuperCam, which can spot organic compounds at a distance. But SHERLOC is about the size of a large hardcover book, and SuperCam is the size of two stacked shoeboxes. To study a rock’s age, texture, mineral makeup or the climate that it formed under, scientists need access to equipment that’s closer to the size of a microwave or refrigerator.
“These instruments could not be on a rover, they are too large and too sensitive and too high maintenance,” writes Rutgers University planetary scientist Juliane Gross, now the deputy curator of Apollo moon samples at NASA, in an email. “But we need to use these instruments if we want to understand how these rocks form.”
A tray holding 39 sample tubes is installed into the Perseverance rover. (NASA / JPL-Caltech / KSC)
Over 30 years ago, an international panel of scientists wrote a report that first detailed their interest in a Mars sample return mission. The scientific community knew then that a quick grab-and-go mission for one sample, as has recently been accomplished from asteroids, wouldn’t be worthwhile on Mars, given the cost of an interplanetary mission. (Last July, NASA and the European Space Agency estimated it would cost about $7 billion.)
A useful sample return mission from Mars requires grabbing a bunch of samples from many scientifically interesting locations. “Rocks and minerals record the conditions of these environment from which they crystallized,” says Gross. “So, bringing back these samples that span a range in age and crystallized at different times in Mars history, we can start to answer some of these fundamental questions.”
Perseverance will spend its first Martian year, the equivalent of 687 Earth days, in Jezero crater compacting half-ounce samples of rock and regolith into some of its glass tubes. Most of the samples will be gathered in pairs. At some point during that first year, Perseverance will drop a cache of samples in Jezero crater—while keeping the second set of samples on board.
Perseverance uses its drill to core a rock sample on Mars in this illustration. (NASA / JPL-Caltech)
If the rover is still in good working order after one Martian year, then NASA will have a chance to extend the mission. The rover will roll to the edge of Jezero crater and gather more samples from both inside the crater and along its ridge, also in pairs. Once the rover fills the last of its sample tubes, it will drop a second cache on Mars’ surface—again keeping the second set of samples stowed.
When Perseverance puts sample tubes down, it can’t pick them back up. The rover will drive away, leaving glass tubes of precious geological samples laying around on the surface of a distant planet. That might sound risky, but NASA has a plan.
“Once we place them on the surface, we will thoroughly document every tube, and where it’s located relative to its surroundings,” says Spencer. NASA will use local landmarks for on-the-ground references, as well as orbital measurements, to track the tubes. “So we’ll know, down to the centimeter level, where every tube is on the surface of Mars.”
Perseverance is also responsible for scoping out the landing site for the next phase of the sample return mission, the Sample Retrieval Lander.
The Sample Retrieval Lander is slated to depart from Earth in 2026, and it will be packing the Sample Fetch Rover, which will be designed and built by the European Space Agency. The five-foot-long rover will have four wheels for speed, solar panels for power and one job: gather Perseverance’s samples to send to Earth.
The rover will drive to the coordinates of Perseverance’s caches and use machine vision and artificial intelligence technologies to recognize and collect the sample tubes on Mars’ surface autonomously using a robotic arm—which it can do even if the glass tubes are covered by several years-worth of dust.
A robotic arm transfers samples of Martian rock and soil from a fetch rover onto a lander in this illustration. (NASA / JPL-Caltech)
And if something goes wrong with the Fetch rover, Perseverance has its backup samples.
“The most challenging aspect of Mars Sample Return is just the long chain of events that all need to be successful,” says Spencer. “We’re trying to build in robustness as much as we can. One aspect of that is the Perseverance rover will be capable of delivering samples directly to the SRL [Sample Retrieval Lander].”
Once the sample tubes reach the Sample Retrieval Lander, either from Perseverance or the Fetch rover, they will be packaged into a soccer ball-sized container called the Orbiting Sample Canister. The canister will not be able to hold all of the samples collected; it can only hold one cache. Glass tubes from the second group, which will include rocks from inside and along the edge of Jezero crater, will be first in line to leave Mars because they will have a greater variety of samples and therefore more scientific value, Spencer says.
NASA’s Mars Ascent Vehicle, which will carry tubes containing rock and soil samples, is launched from the surface of Mars in this illustration. (NASA / JPL-Caltech)
The Orbiting Sample Canister will be loaded into the Sample Retrieval Lander’s Mars Ascent Vehicle, which may become the first rocket launched from a planet other than Earth. It will ferry the canister into Mars orbit, where the canister could circle the planet for up to a decade.
To finally deliver the samples to Earth, the European Space Agency plans to launch the Earth Return Orbiter mission in 2031. The agency plans to put a satellite in Mars orbit that can intercept the canister and contain it in another layer of protection, in case it’s covered in Mars dust. Then the satellite will fly back to Earth with its quarry, transfer the canister to an Earth entry capsule and drop it on Utah’s mudflats, where giddy geologists will retrieve it.
The Mars Ascent Vehicle releases a sample container high above the Martian surface. (NASA / JPL-Caltech)
NASA and the European Space Agency haven’t yet decided how they will distribute the Mars samples among the scientific community. When Apollo astronauts brought back samples from the moon, NASA took proposals from scientists around the world for moon rock-based research projects. Those projects have illuminated the life and death of the moon’s magnetic field, the formation of the moon and Earth and the history of space weathering over billions of years.
Perseverance’s primary goal is to search for signs of fossilized life on Mars, but there is a lot to learn about Earth’s planetary neighbor no matter the results. The samples could provide insights into Mars’ history and help scientists predict Earth’s distant future. And any information about the Martian environment could help the astronauts who, someday, take humanity’s first steps on the Red Planet.
“Bringing back samples to be analyzed in Earth based laboratories is crucial for our understanding of planetary processes that have shaped our corner of the universe,” Gross says. By “bringing back these samples that span a range in age and crystallized at different times in Mars history, we can start to answer some of these fundamental questions that ultimately will help us explore Mars safely in person one day.”
The official video of the touchdown on Mars: