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Consumer Reports Misses the Boat on Back Pain

Science-based Medicine Feed - 5 hours 22 min ago
Consumer Reports' recent articles on low back pain address anecdotal customer satisfaction rather than scientific evidence of effectiveness.
Categories: Science

SpaceX Accomplishes Double Headed American Space Spectacular – 2 Launches and 2 Landings in 2 Days from 2 Coasts: Gallery

Universe Today Feed - Mon, 06/26/2017 - 6:31pm

Liftoff of SpaceX Falcon 9 on June 25 at 1:25 p.m. PDT (4:25 p.m. EDT) carrying ten Iridium Next mobile voice and data relay communications satellites to low Earth orbit on the Iridium-2 mission from Vandenberg Air Force Base in California. Credit: SpaceX

KENNEDY SPACE CENTER, FL – With Sunday’s successful Falcon 9 blastoff for Iridium Communications joining rocketry’s history books, Elon Musk’s SpaceX accomplished a double headed American space spectacular this weekend with 2 launches and 2 booster landings in 2 days from 2 coasts for 2 commercial customers – in a remarkably rapid turnaround feat that set a new record for minimum time between launches for SpaceX.

On Sunday, June 25 at 1:25 p.m. PDT (4:25 p.m. EDT; 2025 UTC) a SpaceX Falcon 9 rocket successfully launched a second set of ten Iridium Next mobile voice and data relay communications satellites to low Earth orbit on the Iridium-2 mission from SLC-4E on Vandenberg Air Force Base in California.

“All sats healthy and talking,” tweeted Matt Desch, Iridium Communications CEO, soon after launch and confirmation that all 10 Iridium NEXT satellites were successfully deployed from their second stage satellite dispensers. Iridium is a global leader in mobile voice and data satellite communications.

“It was a great day!”

Following stage separation, the first stage of Falcon 9 successfully landed on the “Just Read the Instructions” droneship stationed in the Pacific Ocean, despite challenging weather conditions, said SpaceX.

Indeed the droneships position was changed in the final minutes before launch due to the poor weather.

“Droneship repositioned due to extreme weather. Will be tight,” tweeted Musk minutes before liftoff.

Liftoff of SpaceX Falcon 9 on June 25 at 1:25 p.m. PDT (4:25 p.m. EDT) carrying ten Iridium Next mobile voice and data relay communications satellites to low Earth orbit on the Iridium-2 mission from Vandenberg Air Force Base in California. Credit: SpaceX

The launch, landing and deployment of the 10 Iridium Next satellites was all broadcast live on a SpaceX webcast.

The US West Coast Falcon 9 liftoff of the Iridium-2 mission from California on Sunday, June 25 took place barely 48 hours after the US East Coast Falcon 9 liftoff of the BulgariaSat-1 mission from Florida on Friday, June 23.

The perfectly executed launch and landing duo clearly demonstrates the daunting capability of SpaceX’s privately owned and operated engineering team to pull off such a remarkable feat in nimble fashion.

The stage was set for the unprecedented Falcon 9 launch doubleheader just a week ago when SpaceX CEO and billionaire founder Elon Musk tweeted out the daring space goal after all went well with the Florida Space Coast’s static hotfire test for the first in line BulgariaSat-1 flight.

Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

Check out the expanding gallery of Bulgariasat-1 eyepopping photos and videos from several space journalist colleagues and friends and myself.

Click back as the gallery grows !

Liftoff of used SpaceX Falcon 9 at 3:10 p.m. EDT on June 23, 2017 delivering BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Dawn Leek Taylor

Sunday’s Iridium 2 flight was Iridium Communications second contracted launch with SpaceX.

“This payload of 10 satellites was deployed into low-Earth orbit, approximately one hour after a SpaceX Falcon 9 rocket lifted off from Vandenberg,” Iridium said in a statement.

The Mini Cooper sized Iridium NEXT satellites each weigh 1,900 pounds, totaling approximately 19,000 pounds placed into space. That is the weight of a semi tractor trailer truck!

The inaugural Iridium 1 launch with the first ten Iridium Next satellites took place successfully at the start of this year on Jan. 14, 2017.

The new set of ten Iridium Next mobile relay satellites were delivered into a circular orbit at an altitude of 625 kilometers (388 miles) above Earth.

They were released one at a time from a pair of specially designed satellite dispensers at approximately 100 second intervals.

“Since the successful January 14, 2017 launch, Iridium NEXT satellites have already been integrated into the operational constellation and are providing service. The first eight operational Iridium NEXT satellites are already providing superior call quality and faster data speeds with increased capacity to Iridium customers. The two additional satellites from the first launch are continuing to drift to their operational orbital plane, where upon arrival they will begin providing service.”

Iridium 2 is the second of eight planned Falcon 9 launches to establish the Iridium NEXT constellation which will eventually consist of 81 advanced satellites.

At least 75 will be launched by SpaceX to low-Earth orbit, with 66 making up the operational constellation.

The inaugural launch of the advanced Iridium NEXT satellites in January 2017 started the process of replacing an aging Iridium fleet in orbit for nearly two decades.

Nine of the 81 will serve as on-orbit spares and six as ground spares.

“Now, and for approximately the next 45 days, these newly launched satellites will undergo a series of testing and validation procedures, ensuring they are ready for integration with the operational constellation,” said Iridium.

“We are thrilled with yesterday’s success. These new satellites are functioning well, and we are pressing forward with the testing process,” said Scott Smith, chief operating officer at Iridium. “Since the last launch, the team at our Satellite Network Operations Center (SNOC) has been anxiously awaiting this new batch of satellites. There is a lot of work to do, and we are up for the challenge.”

Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

BulgariaSat-1 and Iridium-2 count as the eighth and ninth SpaceX launches of 2017.

Liftoff of used SpaceX Falcon 9 at 3:10 p.m. EDT on June 23, 2017 delivering BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Julian Leek

Watch for Ken’s onsite mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.

Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida- as seen from the crawlerway. Credit: Ken Kremer/kenkremer.com

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com

Launch 2nd recycled SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida – as seen from the countdown clock. Credit: Ken Kremer/kenkremer.com

The post SpaceX Accomplishes Double Headed American Space Spectacular – 2 Launches and 2 Landings in 2 Days from 2 Coasts: Gallery appeared first on Universe Today.

Categories: Science

Odd properties of water and ice explained: Water exists as two different liquids

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 4:06pm
Scientists have discovered two phases of liquid water with large differences in structure and density. The results are based on experimental studies using X-rays.
Categories: Science

Could this strategy bring high-speed communications to the deep sea?

Computers and Math from Science Daily Feed - Mon, 06/26/2017 - 3:10pm
A new strategy for sending acoustic waves through water could potentially open up the world of high-speed communications to divers, marine research vessels, remote ocean monitors, deep sea robots, and submarines. By taking advantage of the dynamic rotation generated as the acoustic wave travels, also known as its orbital angular momentum, researchers were able to pack more channels onto a single frequency, effectively increasing the amount of information capable of being transmitted.
Categories: Science

Amazing whale breach

Why Evolution is True Feed - Mon, 06/26/2017 - 2:23pm

by Matthew Cobb

Astonishing – and scary – footage…

Humpback Whale Breaches Near a Boat Off New Jersey – @ollivier_yves @BrendanGodley @JoJoAngelus @les_fees_nature https://t.co/P4GPHQBllx

— Ecojustice Truths (@HCApeggy) June 26, 2017

I have never seen a whale (or indeed any cetacean) outside of a zoo (and I feel bad about seeing them, because they shouldn’t be there). Post your encounters with your favourite cetaceans in the comments!


Categories: Science

Microbe mystery solved: What happened to the Deepwater Horizon oil plume?

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 12:57pm
The Deepwater Horizon oil spill in the Gulf of Mexico in 2010 is one of the most studied spills in history, yet scientists haven't agreed on the role of microbes in eating up the oil. Now a research team has identified all of the principal oil-degrading bacteria as well as their mechanisms for chewing up the many different components that make up the released crude oil.
Categories: Science

Computer model simulates sense of touch from the entire hand

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 12:57pm
Neuroscientists have developed a computer model that can simulate the response of nerves in the hand to any pattern of touch stimulation on the skin. The tool reconstructs the response of more than 12,500 nerve fibers with millisecond precision, taking into account the mechanics of the skin as it presses up against and moves across objects.
Categories: Science

No, NASA (Still) Has Not Discovered Proof of Alien Life

Universe Today Feed - Mon, 06/26/2017 - 12:29pm

It seems that every few months or so, breathless claims surface on the internet that NASA is about to make an Earth-shattering announcement about aliens … or UFOs … or killer asteroids … or some other sensational assertion. Or better yet, NASA is hiding these ‘facts’ from us.

The latest claims says that “NASA Is About to Announce the Discovery of Intelligent Alien Life,” and this one might be receiving more attention and credence than usual because the group making the claim is Anonymous, the notorious hacking and activist group.

However, before we get into their claim, for the record, this morning NASA’s Thomas Zurbuchen, the associate administrator for the Science Mission Directorate, tweeted, “Contrary to some reports, there’s no pending announcement from NASA regarding extraterrestrial life.”

Contrary to some reports, there’s no pending announcement from NASA regarding extraterrestrial life.

— Thomas Zurbuchen (@Dr_ThomasZ) June 26, 2017

Anonymous’ video has been viewed over a million times, and the video’s description claims, “Latest anonymous message in 2017 just arrived with a huge announcement about the Intelligent Alien Life. NASA says aliens are coming!”

The video is a rambling (over 12 minutes), rather incoherent collection of statements and quotes from various people and NASA websites. The main quote that is attributed to the alien life claim is from Zurbuchen, speaking at a House Science Committee hearing in April. The quote, taken a little out of context, is, “Taking into account all of the different activities and missions that are specifically searching for evidence of alien life, we are on the verge of making one of the most profound, unprecedented, discoveries in history.”

If you watch the House Science Committee hearing, Zurbuchen is talking about upcoming missions like the Mars 2020 rover and the Europa Clipper mission — both of which will look for sign of life and conditions suitable for life – as well as current missions like the Kepler telescope that has discovered and confirmed thousands of planets around other stars. Of course, Zurbuchen is talking about these missions in the most exciting way possible to make sure Congress is excited about these missions, too. But he certainly does not say that NASA has found alien life, or that they have evidence they will be revealing soon. He tweeted about that this morning, too.

Are we alone in the universe? While we do not know yet, we have missions moving forward that may help answer that fundamental question.

— Thomas Zurbuchen (@Dr_ThomasZ) June 26, 2017

Another quote in the video is a very old one from former NASA astronaut Dr. Brian O’Leary, who passed away in 2011. He was a planetary scientist who ended up leaving NASA in 1968 and never flew in space. I met O’Leary in the 1990’s and can confirm the statement on the Wikipedia page about him that he “increasingly explored unorthodox ideas.”

The video goes on to talk about the well-known discoveries of the Kepler mission, saying “Twenty-five years ago, we didn’t know that planets existed beyond our solar system. Today we have confirmed the existence of over 3,400 exoplanets that orbit other suns, and we continue to make new discoveries.”

NASA’s Kepler space telescope was the first agency mission capable of detecting Earth-size planets. Credit: NASA/Wendy Stenzel

It also discusses other well-publicized discoveries such as finding the key ingredients for life on Saturn’s moon Enceladus, but offers no sources of facts when the Guy Fawkes look-alike says, “There are many who claim that unofficially, mankind has already made contact with aliens and not just little micro-organisms floating around inside a massive alien ocean, but advanced space-faring civilizations.”

All the claims in the video that “aliens are on the way” are nothing but speculation and the quotes from NASA officials and scientists are all in the public domain, easily found online, so there is nothing being “revealed’ here. I’ve talked to scientists from all around the world, and if NASA or any other space agency had found evidence of alien life, they’d be shouting it from the rooftops, not hiding it.

The post No, NASA (Still) Has Not Discovered Proof of Alien Life appeared first on Universe Today.

Categories: Science

Boomer the skateboarding cat

Why Evolution is True Feed - Mon, 06/26/2017 - 12:00pm

Boomer is the new companion of Didga, an awesome Aussie cat that can skateboard and follow all kinds of commands. Boomer, a Bengal, has learned how to not just ride a skateboard, but to propel it. Here he is:

Here’s a video of Boomer, adorable at 11 weeks old.  By the way, “Didga” is a shortening of “didgeridoo”, and you can guess what Aussie instrument “Boomer” stands for.


Categories: Science

What Caused the Kuiper Belt to Get Warped?

Universe Today Feed - Mon, 06/26/2017 - 11:00am

Astronomers have known about the Kuiper Belt for decades, and were postulating about its existence long before it was even observed. Since that time, many discoveries have been made in this region of space – ranging from numerous minor planets to the fact that the orbital planes of Kuiper Belt Objects (KBOs) are widely dispersed – that have led to new theoretical models of the formation and evolution of the Solar System.

For instance, while conducting measurements of the mean plane of minor planets and KBOs, a team from the Lunar and Planetary Laboratory (LPL) at The University of Arizona discovered a warp in orbits of certain, highly-distant KBOs.  According to their study, this warp could be an indication of a planetary-mass object in the area, one which orbits our Sun even closer than the theoretical “Planet 9“.

The study – “The Curiously Warped Mean Plane of the Kuiper Belt” which is scheduled to be published in the Astronomical Journal – was produced by Kathryn Volk and Renu Malhotra (two astronomers with the LPL). As they stated in their study, the presence of this planet was confirmed by examining the orbits of icy bodies in the very outer reaches of the Solar System.

Artist’s impression of the yet-to-be-discovered “planetary mass object”, who’s existence has been theorized based on the orbital plane of distant Kuiper Belt objects. Credit: Heather Roper/LPL

Whereas most KBOs – which are leftover material from the formation of the Solar System – orbit the Sun close to the mean plane of the Solar System itself, the most distant objects do not. To determine why, the researchers analyzed the tilt angles of the orbital planes of more than 600 KBOs to determine the direction of their precession – i.e. the direction in which these rotating objects experience a change in their orientation.

As Malhotra – a Louise Foucar Marshall Science Research Professor and Regents’ Professor of Planetary Sciences at LPL – illustrated, KBOs operate in a way that is analogous to spinning tops:

“Imagine you have lots and lots of fast-spinning tops, and you give each one a slight nudge. If you then take a snapshot of them, you will find that their spin axes will be at different orientations, but on average, they will be pointing to the local gravitational field of Earth… We expect each of the KBOs’ orbital tilt angle to be at a different orientation, but on average, they will be pointing perpendicular to the plane determined by the Sun and the big planets.”

What they found was that the average plane of these objects was tilted away from the solar plane by about eight degrees, which suggests that a powerful gravitational force in the outer Solar System is tugging on them. “The most likely explanation for our results is that there is some unseen mass,” said Volk in UA News press release. “According to our calculations, something as massive as Mars would be needed to cause the warp that we measured.”

Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign

According to their calculations, this Mars-size body would likely orbit the Sun at a distance of roughly 60 AU, and with an orbital inclination that was tilted eight degrees to the average plane of the known planets (i.e. the same tilt as the “warped” KBOs). Within these parameters, a planet of this size would have sufficient gravitational influence to warp the orbital plane of the distant KBOs to within 10 AU on either side of it.

In other words, a Mars-sized planet in the outer Kuiper Belt would be able to influence the orbital inclination of KBOs that are between 50 and 70 AUs from the Sun. This is certainly consistent with what we know about the Kuiper Belt, who’s orbital inclination appears to be consistently flat (i.e. consistent with the rest of the Solar System) past a distance of about 50 AU – but changes between a distance of 50 and 80 AU.

As Volk indicated, there is a possibility that this warping could be the result of a statistical fluke. But in the end, their calculations indicated that this is highly unlikely, and that the behavior of distant KBOs is consistent with the existence of a as-yet-unseen gravitational influence:

“But going further out from 50 to 80 AU, we found that the average plane actually warps away from the invariable plane. There is a range of uncertainties for the measured warp, but there is not more than 1 or 2 percent chance that this warp is merely a statistical fluke of the limited observational sample of KBOs… The observed distant KBOs are concentrated in a ring about 30 AU wide and would feel the gravity of such a planetary mass object over time, so hypothesizing one planetary mass to cause the observed warp is not unreasonable across that distance.”  

Artist’s impression of Planet Nine, blocking out the Milky Way. The Sun is in the distance, with the orbit of Neptune shown as a ring. Credit: ESO/Tomruen/nagualdesign

Another possibility is that another object entirely could have disturbed the plane of the outer Kuiper Belt – for instance, a star passing through the outer Solar System. But as Malhotra explained, this explanation is also a highly unlikely, as any disturbance caused by a passing star would only be temporary and would have manifested itself differently.

“A passing star would draw all the ‘spinning tops’ in one direction,” he said. “Once the star is gone, all the KBOs will go back to precessing around their previous plane. That would have required an extremely close passage at about 100 AU, and the warp would be erased within 10 million years, so we don’t consider this a likely scenario.”

Moreover, the tilt of these objects could not be attributed to the existence of Planet 9, who’s existence has also been suggested based on the extreme eccentricity of certain populations of KBOs. Compared to this Mars-sized planet that is thought to orbit at 60 AUs from the Sun, Planet 9 is predicted to be much more massive (at around 10 Earth masses) and is believed to orbit at a distance of 500 to 700 AU.

Naturally, one has to ask why this planetary-mass body has not been found yet. According to Volk and Malhotra, the reason has to do with the fact that astronomers have not yet searched the entire sky for distant for Solar System objects. Beyond that, there’s also the likely position of the object (within the galactic plane), which is so densely packed with stars that surveys would have a hard time spotting it.

However, with the construction of instruments like the Large Synoptic Survey Telescope (LSST) in Chile nearly complete, opportunities to spot it may be coming sooner other than later. This wide-field survey reflecting telescope, which is run by a consortium that includes the University of Arizona, is expected to provide some of the deepest and widest views of the Universe to date (which will begin in 2020).

In the meantime, and in response to any possible controversies regarding the so-called “Planet Debate”, it is worth noting that this body (if it exists) is currently being referred to as “planetary-mass object”. This is because, by definition, a body needs to have cleared its orbit in order to be called a planet. What’s more, the study does not rule out the possibility that the warp could be the result of more than one planetary mass object in the area.

Therefore, it would premature to state that astronomers – having not yet even confirmed the existence of Planet 9 – are now talking about the existence of a possible “Planet 10”. In the coming years, more news and information will become available, which will hopefully help us put the debate to rest and agree on just how many planets there are out there!

Further Reading: UA News, Earth and Planetary Astrophysics

The post What Caused the Kuiper Belt to Get Warped? appeared first on Universe Today.

Categories: Science

Air pollution casts shadow over solar energy production

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 10:57am
Global solar energy production is taking a major hit due to air pollution and dust. The first study of its kind shows airborne particles and their accumulation on solar cells is cutting energy output by more than 25 percent in certain parts of the world. The regions hardest hit are also those investing the most in solar energy installations -- China, India and the Arabian Peninsula.
Categories: Science

2-D material's traits could send electronics R&D spinning in new directions

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 10:18am
Researchers created an atomically thin material and used X-rays to measure its exotic and durable properties that make it a promising candidate for a budding branch of electronics known as 'spintronics.'
Categories: Science

Microscope can scan tumors during surgery and examine cancer biopsies in 3-D

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 9:46am
A new microscope could provide accurate real-time results during cancer-removal surgeries, potentially eliminating the 20 to 40 percent of women who have to undergo multiple lumpectomy surgeries because cancerous breast tissue is missed the first time around.
Categories: Science

Cloning thousands of genes for massive protein libraries

Computers and Math from Science Daily Feed - Mon, 06/26/2017 - 9:46am
Discovering the function of a gene requires cloning a DNA sequence and expressing it. Until now, this was performed on a one-gene-at-a-time basis, causing a bottleneck. Scientists have invented a technology to clone thousands of genes simultaneously and create massive libraries of proteins from DNA samples, potentially ushering in a new era of functional genomics.
Categories: Science

New tool to identify and control neurons

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 9:45am
One of the big challenges in the neuroscience field is to understand how connections and communications trigger our behavior. Researchers have now developed a tool to identify and control neurons. The new technique, called Calcium and Light-Induced Gene Handling Toolkit or 'Cal-Light,' allows researchers to observe and manipulate the neural activities underlying behavior with never-before-seen specificity, hopefully allowing researchers to identify causality between neuronal activity and behavior.
Categories: Science

One billion suns: World's brightest laser sparks new behavior in light

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 9:44am
Using the brightest light ever produced on Earth, physicists have changed the way light behaves.
Categories: Science

Peering through opaque brains with new algorithm

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 9:44am
A new algorithm helps scientists record the activity of individual neurons within a volume of brain tissue.
Categories: Science

Microplastics sloughed from synthetic fabrics in the washing machine

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 9:43am
Billions of pieces of plastic are floating in the oceans. Their effects are also sufficiently well-known: marine animals swallow them or get tangled up in them, which can cause them to die in agony. On the other hand, we know less about the consequences of the smallest pieces of plastic, known as microplastics. Researchers have now started to investigate how microplastics are generated and where they actually come from.
Categories: Science

System of quadcopters that fly and drive suggest another approach to developing flying cars

Computers and Math from Science Daily Feed - Mon, 06/26/2017 - 9:43am
Being able to both walk and take flight is typical in nature many birds, insects, and other animals can do both. If we could program robots with similar versatility, it would open up many possibilities: Imagine machines that could fly into construction areas or disaster zones that aren't near roads and then squeeze through tight spaces on the ground to transport objects or rescue people.
Categories: Science

System of quadcopters that fly and drive suggest another approach to developing flying cars

Matter and energy from Science Daily Feed - Mon, 06/26/2017 - 9:43am
Being able to both walk and take flight is typical in nature many birds, insects, and other animals can do both. If we could program robots with similar versatility, it would open up many possibilities: Imagine machines that could fly into construction areas or disaster zones that aren't near roads and then squeeze through tight spaces on the ground to transport objects or rescue people.
Categories: Science

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