This is the most violent object in the solar system


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This is the most violent object in the solar system

Scientists discover largest bacteria-eating virus. It blurs line between living and nonliving.


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Scientists discover largest bacteria-eating virus. It blurs line between living and nonliving.

How Long Can Organs Stay Outside the Body Before Being Transplanted?


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How Long Can Organs Stay Outside the Body Before Being Transplanted?

NASA’s experimental X-59 supersonic jet could be built by the end of 2020


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NASA’s experimental X-59 supersonic jet could be built by the end of 2020

By Chelsea Gohd – Space.com 3 days ago

It’ll test ways to shush sonic booms.

An illustration of the X-59 supersonic plane landing on a runway.

An illustration of the X-59 supersonic plane landing on a runway.
(Image: © Lockheed Martin)

NASA’s new experimental supersonic X-plane is on a fast track to flying.

The plane, officially named X-59 QueSST in 2018 and often referred to as just X-59, was greenlit for final assembly during a critical design review in 2019. With this plane, NASA aims to create an ultraquiet craft that can travel over land faster than the speed of sound.

In 2020, Lockheed Martin, which NASA commissioned to build the plane, plans to mate the aircraft and completely finish the building process by the end of the year, a company  representative told Space.com. “It’s moving very fast on the shop floor in terms of manufacturing and production,” the company said.

Related: Supersonic! The 10 Fastest Military Airplanes

This follows a year of serious progress as the plane’s wings have been assembled at Lockheed Martin Skunk Works in Palmdale, California, and innovative systems for the craft continue to develop.

After the “mating of the aircraft and final assembly,” the representative said, “we’ll take the airframe to do some proof testing and get some other parts installed, do some test runs of the systems, and then roll it out.”

Once the plane is all together, it will take its first flight in 2021, the representative added.

But will a plane that travels at supersonic speeds, or faster than the speed of sound, really be quiet enough to avoid causing a major disturbance? According to the representative, the team behind the plane is confident that the craft will be ultrafast and ultraquiet.

“We’re very confident. All kinds of modeling simulations and predictions align, so we believe, based on these models and simulations we’ve run, that it will achieve that low-boom sound once it reaches supersonic speeds.”

To ensure that this is the case and that the plane not only works correctly and reaches these incredible speeds, but also remains quiet enough to not be a public nuisance, additional testing will follow the completion of the plane in 2020.

As the Lockheed Martin representative explained, building the plane is really only Phase 1 of the entire project. With Phase 2, further testing, certifications and acoustic (or sound) validation will occur. After that, in the third phase, community-response testing will ensure that, with a low-boom (a quiet sonic boom) demonstration, will validate how people respond to the craft flying overhead.

According to a NASA statement, in the community response testing, the team will “fly the X-plane over select U.S. communities to gather data on human responses to the low-boom flights and deliver that dataset to U.S. and international regulators.”

Follow Chelsea Gohd on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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A Mysterious New Form of DNA Was Just Discovered in Human Cells


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A Mysterious New Form of DNA Was Just Discovered in Human Cells

By Yasemin Saplakoglu April 23, 2018

new DNA, i-motif

An artist’s impression of the i-motifs (shown in white and green) with white, Y-shaped antibodies binding to them.
(Image: © Chris Hammang)

When you think of DNA, odds are, you picture the famous double helix, a ladder-like structure elegantly twisted like a corkscrew.

But DNA doesn’t always assume this form. The existence of one shape of DNA in humans, in particular — a four-stranded knot of genetic code — has been controversial among scientists for years. Because this so-called i-motif loves acidic environments (a condition that scientists can create in the lab but doesn’t naturally occur in the body), many scientists thought that it couldn’t possibly exist in human cells.

But in recent years, studies have pointed to the possibility that this bizarre form of DNA could, in fact, exist in living humans. Now, a new study published today (April 23) in the journal Nature Chemistry provides the first direct evidence that it does exist and that it may play an important role in regulating our genes. [Unraveling the Human Genome: 6 Molecular Milestones]

“Before this, it was kind of an academic idea that DNA could [fold like this], but it wasn’t known at all what it meant for biology,” said senior study author Marcel Dinger, head of the Kinghorn Centre for Clinical Genomics at the Garvan Institute of Medical Research in Sydney. Watching these i-motifs appear in living human cells “was pretty spectacular,” he said.

To spot the i-motifs, Dinger and his team designed an antibody — a protein that targets foreign invaders in the body — to specifically find and latch onto i-motifs. They tagged these antibodies with a fluorescent dye and then injected them into human cells in the lab. Using powerful microscopes, they spotted a bunch of tiny, glowing, green dots — colored antibodies holding onto elusive i-motifs.

According to Dinger, the hardest part about publishing this paper was proving that the antibody latched only onto i-motifs and not onto other shapes of DNA. They did this by testing how the antibody interacted with other forms of DNA, such as the classic double helix and a better-studied structure related to the i-motif, called the G4 quadruplex. Sure enough, the antibody proved faithful — it didn’t bind to either of these other forms.

“This is a very exciting discovery,” said Zoe Waller, a senior lecturer in chemical biology at the University of East Anglia in the United Kingdom who was not involved with the study. “This work is the icing on what is now quite a large cake of evidence that these [forms of DNA] do exist in vivo and are worthy of further study.”

A role in regulation

What really fascinated the team, Dinger told Live Science, was not only that these i-motifs existed in living cells but that these green lights twinkled on and off — meaning the i-motifs folded into existence and then unfurled, repeatedly. In particular, the researchers found that the DNA folded into i-motifs at higher rates during a specific stage of transcription — the process that kicks off the translation of genes into proteins — when the DNA was just beginning to actively transcribe. Later, the DNA unfolded back into its usual form, and the i-motifs disappeared. According to Dinger, this probably means the i-motifs play a very specific role in regulating the transcription process.

Indeed, this study supports previous research in lab dishes that these folds occur in areas that regulate genes. These areas include the very ends of chromosomes called “telomeres” that are thought to play a role in aging and regions called promoters which are tasked with turning genes on and off.

But despite knowing some of the regions in which these folds can appear, the researchers don’t yet know which genes the folds control or what happens when you disturb the cell so that it can’t form these structures.

“There’s so much of the genome that we don’t understand, probably like 99 percent of it,” Dinger said.  Seeing DNA folded like this in living cells “makes it possible to decode those parts of the genome and understand what they do.”

Indeed, these weird folds are probably present in every one of our cells, Dinger said. And because the genome has fewer folds like this compared with regularly shaped DNA, drugs that target DNA may be able to bind more specifically, compared with non-folded regions, he said.

These types of drugs could be helpful for cancer treatment, for example. One problem with certain cancer treatments is that they aren’t selective enough in targeting the problematic stretches of DNA, said Laurence Hurley, a professor at the University of Arizona and the chief scientific officer of Reglagene, a company that designs therapeutic molecules to target four-stranded DNA like i-motifs. Instead, cancer drugs may attach to other parts of DNA as well, leading to possibly harmful side effects, said Hurley, who was not part of the new study.

“I’ve been waiting for a paper like this to come out for a long time,” Hurley told Live Science. “This provides a firm foundation for a major therapeutic effort around these new structures, and it takes away the doubt that people have had [about] whether these structures were real and had any biological significance.”

Originally published on Live Science.

The Universe May Be Flooded with a Cobweb Network of Invisible Strings


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The Universe May Be Flooded with a Cobweb Network of Invisible Strings

By Paul Sutter – Astrophysicist January 02, 2020

We may soon find out whether we live in an axiverse.

an abstract image of axion strings

(Image: © Shutterstock)

What if I told you that our universe was flooded with hundreds of kinds of nearly invisible particles and that, long ago, these particles formed a network of universe-spanning strings?

It sounds both trippy and awesome, but it’s actually a prediction of string theory, our best (but frustratingly incomplete) attempt at a theory of everything. These bizarre, albeit hypothetical, little particles are known as axions, and if they can be found, that would mean we all live in a vast “axiverse.”

The best part of this theory is that it’s not just some physicist’s armchair hypothesis, with no possibility of testing. This incomprehensibly huge network of strings may be detectable in the near future with microwave telescopes that are actually being built.

Related: The Biggest Unsolved Mysteries in Physics

If found, the axiverse would give us a major step up in figuring out the puzzle of … well, all of physics.

A symphony of strings

OK, let’s get down to business. First, we need to get to know the axion a little better. The axion, named by physicist (and, later, Nobel laureate) Frank Wilczek in 1978, gets its name because it’s hypothesized to exist from a certain kind of symmetry-breaking. I know, I know — more jargon. Hold on. Physicists love symmetries — when certain patterns appear in mathematics.

There’s one kind of symmetry, called the CP symmetry, that says that matter and antimatter should behave the same when their coordinates are reversed. But this symmetry doesn’t seem to fit naturally into the theory of the strong nuclear force. One solution to this puzzle is to introduce another symmetry in the universe that “corrects” for this misbehavior. However, this new symmetry only appears at extremely high energies. At everyday low energies, this symmetry disappears, and to account for that, and out pops a new particle — the axion.

Now, we need to turn to string theory, which is our attempt (and has been our main attempt for 50-odd years now) to unify all of the forces of nature, especially gravity, in a single theoretical framework. It’s proven to be an especially thorny problem to solve, due to a variety of factors, not the least of which is that, for string theory to work (in other words, for the mathematics to even have a hope of working out), our universe must have more than the usual three dimensions of space and one of time; there have to be extra spatial dimensions.

These spatial dimensions aren’t visible to the naked eye, of course; otherwise, we would’ve noticed that sort of thing. So the extra dimensions have to be teensy-tiny and curled up on themselves at scales so small that they evade normal efforts to spot them.

What makes this hard is that we’re not exactly sure how these extra dimensions curl up on themselves, and there’s somewhere around 10^200 possible ways to do it.

But what these dimensional arrangements appear to have in common is the existence of axions, which, in string theory, are particles that wind themselves around some of the curled-up dimensions and get stuck.

What’s more, string theory doesn’t predict just one axion but potentially hundreds of different kinds, at a variety of masses, including the axion that might appear in the theoretical predictions of the strong nuclear force.

Silly strings

So, we have lots of new kinds of particles with all sorts of masses. Great! Could axions make up dark matter, which seems to be responsible for giving galaxies most of their mass but can’t be detected by ordinary telescopes? Perhaps; it’s an open question. But axions-as-dark-matter have to face some challenging observational tests, so some researchers instead focus on the lighter end of the axion families, exploring ways to find them.

And when those researchers start digging into the predicted behavior of these featherweight axions in the early universe, they find something truly remarkable. In the earliest moments of the history of our cosmos, the universe went through phase transitions, changing its entire character from exotic, high-energy states to regular low-energy states.

During one of these phase transitions (which happened when the universe was less than a second old), the axions of string theory didn’t appear as particles. Instead, they looked like loops and lines — a network of lightweight, nearly invisible strings crisscrossing the cosmos.

This hypothetical axiverse, filled with a variety of lightweight axion strings, is predicted by no other theory of physics but string theory. So, if we determine that we live in an axiverse, it would be a major boon for string theory.

A shift in the light

How can we search for these axion strings? Models predict that axion strings have very low mass, so light won’t bump into an axion and bend, or axions likely wouldn’t mingle with other particles. There could be millions of axion strings floating through the Milky Way right now, and we wouldn’t see them.

But the universe is old and big, and we can use that to our advantage, especially once we recognize that the universe is also backlit.

The cosmic microwave background (CMB) is the oldest light in the universe, emitted when it was just a baby — about 380,000 years old. This light has soaked the universe for all these billions of years, filtering through the cosmos until it finally hits something, like our microwave telescopes.

So, when we look at the CMB, we see it through billions of light-years’ worth of universe. It’s like looking at a flashlight”s glow through a series of cobwebs: If there is a network of axion strings threaded through the cosmos, we could potentially spot them.

In a recent study, published in the arXiv database on Dec. 5, a trio of researchers calculated the effect an axiverse would have on CMB light. They found that, depending on how a bit of light passes near a particular axion string, the polarization of that light could shift. That’s because the CMB light (and all light) is made of waves of electric and magnetic fields, and the polarization of light tells us how the electric fields are oriented — something that changes when the CMB light encounters an axion. We can measure the polarization of the CMB light by passing the signal through specialized filters, allowing us to pick out this effect.

The researchers found that the total effect on the CMB from a universe full of strings introduced a shift in polarization amounting to around 1%, which is right on the verge of what we can detect today. But future CMB mappers, such as the Cosmic Origins Explorer, Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection (LiteBIRD), and the Primordial Inflation Explorer (PIXIE) , are currently being designed. These futuristic telescopes would be capable of sniffing out an axiverse. And once those mappers come online, we’ll either find that we live in an axiverse or rule out this particular prediction of string theory.

Either way, there’s a lot to untangle.

Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and Space Radio, and author of Your Place in the Universe.

Originally published on Live Science.

Amazing Images: The Best Science Photos of the Week


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Amazing Images: The Best Science Photos of the Week

By LiveScience Staff 2 days ago

Each week we find the most interesting and informative articles we can and along the way we uncover amazing and cool images. Here you’ll discover incredible photos and the stories behind them.

Ice cracks

(Image credit: ESA, CC BY-SA 3.0 IGO)

In October 2019, two huge cracks split across the edge of Pine Island Glacier — one of the fastest-shrinking glaciers in Antarctica (seen here). Earlier this week, those cracks finally met. A chunk of ice with twice the area of Washington, D.C., split off of the glacier and spilled into the sea. The city-sized slab won’t raise sea levels (it was already floating in the water to begin with), but it does continue an alarming trend at Pine Island Glacier, which is seeing its edges retreat much faster than fresh ice can form. Scientists worry the whole glacier could collapse, and the neighboring Thwaites glacier could be close behind. The two regions hold enough ice to raise the ocean by 4 feet (1.2 meters).

[Read full story: One of Antarctica’s fastest-shrinking glaciers just lost an iceberg twice the size of Washington, D.C.]

Epic mouse battle

Two mice fight over a scrap of food on a London subway platform

(Image credit: Sam Rowley)

Two mice dance the tango after a romantic night out in London… is what we wish this photo was about. Actually, this incredible action shot taken by UK-based photographer Sam Rowley shows two of the London Underground’s 500,000 resident mice fighting over a scrap of food on a subway platform. Earlier this week, the photo won the people’s choice award for the London Natural History Museum’s Wildlife Photographer of the Year competition. Hopefully that’s just desserts for Rowley; to get the shot, he spent a week’s-worth of nights scouting around various subway platforms — on his stomach.

[Read full story: Epic battle between 2 subway mice takes people’s choice prize at wildlife photography competition]

Bombarding Mars

(Image credit: SwRI/Marchi)

The surreal-looking brown and green spheres flowing around Mars in this image depict particles from a projectile’s core and mantle, respectively. These particles would have assimilated into the Martian mantle.

A new computer simulation suggests that planetesimals (projectiles) likely slammed into Mars as the Red Planet was just forming. These impacts would have carried “iron-loving” elements — such as tungsten, platinum and gold — to Mars, something that would have influenced how fast the planet matured into the chilly, terrestrial orb we know and love today. From this simulation, the researchers at the Southwest Research Institute think Mars formed more slowly than was previously thought.

Jaguar duo snag anaconda

(Image credit: Michel Zoghzoghi)

Lebanon-based photographer Michel Zoghzoghi was filming jaguars in Brazil when he saw an unexpected case of cross-species coordination. Two jaguars — a mother and her baby — stepped out of a nearby river carrying a large, spotted anaconda between their teeth. Because the snake’s pattern closely matched the jaguars’, Zoghzoghi titled this photo “Matching outfits.” The photo was selected as a runner-up in the people’s choice award category of the London Natural History Museum’s Wildlife Photographer of the Year contest.

Enormous turtle

(Image credit: Jaime Chirinos)

The largest complete turtle shell on record belongs to Stupendemys geographicus, a beast that lived 8 million years ago. The shell is nearly 8 feet (2.4 meters) long, meaning its owner weighed an estimated 2,500 lbs. (1,145 kilograms), twice that of the largest living turtle, the marine leatherback (Dermochelys coriacea). A new look at S. geographicus revealed that the males had pointed horns near their necks, which likely helped them in combat.

[Read full story: This may be the biggest turtle that ever lived]

Pollen-coated bee

(Image credit: George Poinar Jr., OSU College of Science.)

A primitive female bee got trapped in sticky resin some 100 million years ago. That resin hardened into an amber tomb that preserved the bee’s last moments as if frozen in time. Several pollen grains are still clinging to the bee’s body, indicating the insect had likely just visited one or more flowers, the researchers who identified the bee said. This mid-Cretaceous fossil, which was discovered in Myanmar, is considered the oldest record of a bee with pollen, said George Poinar Jr. of Oregon State University. Poinar found that the bee fits into a new family, genus and species, he reported in the journal BioOne Complete. Attached to the bee are four beetle parasites, which plague bees to this day

Mucus bombs

(Image credit: Allen Collins and Cheryl Ames)

Scientists finally discovered the source of mysterious “stinging water” that zaps the skin of people swimming in tropical lagoons around the world: A mix of jellyfish mucus and venom-filled “bombs.” The upside-down jellyfish (Cassiopea xamachana) rests top-down on the ocean floor and secretes viscous mucus into the water above. When researchers examined the snot under the microscope, they saw tiny spheres spinning around in the fluid. Stinging cells coat the spheres and deposit venom on creatures that run into them. Unwary swimmers develop an irritating itch after touching the toxin, while tiny animals like brine shrimp perish on contact.

[Read full story: Upside-down jellyfish release venom-filled ‘bombs’ in their snot]

Mating millipedes

Two millipedes are mating under UV light. The millipedes, in the Pseudopolydesmus genus, don’t have an affinity to ultraviolet light.

(Image credit: Stephanie Ware, Field Museum)

At first glance, this image might look more psychedelic than scientific, but take a closer look and you’ll see: Two millipedes are mating under UV light. The millipedes, in the Pseudopolydesmus genus, don’t have an affinity to ultraviolet light. Rather, scientists wanted to understand details of the millipedes’ genitals, which start glowing under black light. With that imaging combined with other techniques such as CT scanning, the researchers were able to see, for the first time, pairs’ sexual organs interact. They described the findings in the journal Arthropod Structure and Development.

[Read full press release on the Field Museum in Chicago site]

Coronavirus images released

 

(Image credit: NIAID-RML)

This is one of the first-ever images of SARS-CoV-2, the coronavirus that has sickened tens of thousands of people and killed over 1,000 in an outbreak that began in Wuhan, China. Researchers at the National Institute of Allergy and Infectious Diseases’s Rocky Mountain Laboratories (RML) imaged samples of the virus and cells taken from a U.S. patient infected with COVID-19, the disease caused by SARS-CoV-2.

[Read full story: Images of new coronavirus just released]

Reaper of death

(Image credit: Julius Csotonyi)

The infamous Tyrannosaurus rex has a new cousin! And this beast may have been just as fierce. Partial skulls and jaws of the 79.5-million-year-old species were discovered in Alberta, Canada. From those bones, paleontologists think the beast would have sported a monstrous face with a mouthful of serrated teeth, each more than 2.7 inches (7 centimeters) long. They named the tyrannosaur Thanatotheristes degrootorum, or “reaper of death” — “Thanatos” is the Greek god of death and “theristes” is Greek for “reaper.” When alive, the dinosaur would have been quite a sight, measuring 26 feet (8 meters) long from snout to tail, the researchers estimated.

[Read full story: ‘Reaper of death,’ newfound cousin of T. rex, discovered in Canada]

Originally published on Live Science.