Invasive Species Could Kill Nearly Half of U.S. Forests

By Roni Dengler | August 13, 2019 10:53 am
Hemlock Forest
Hemlock trees killed by hemlock woolly adelgid in Great Smoky Mountains National Park, North Carolina. (Courtesy Songlin Fei)

With its sparkling green wings, the emerald ash borer, a tiny beetle no longer than a knuckle-length, is almost beautiful. The insect however has been ravaging America’s forests for nearly 20 years. First seen in Michigan in the early 2000s, the invasive pest has killed millions of ash trees in more than 30 states.

The ash borer is not the only species devastating U.S. forests. More than 450 pests have invaded America’s woods. Now researchers find 15 of them threaten more than 40 percent of live forests in the contiguous U.S. Researchers say the discovery calls for better regulations to quarantine goods that the pests travel on.

“The important thing we have to realize is there has to be stronger policy in terms of regulation,” said Purdue University natural resources spatial analyst Songlin Fei, who led the new study.

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CATEGORIZED UNDER: Environment, Living World, top posts

Supernova Dust Found Hidden in Antarctic Snow

By Korey Haynes | August 13, 2019 10:45 am
illustration of cloud of gas with bright star in center
In this artist illustration, the sun (the yellow star at center) moves through a clump of interstellar gas that may still be raining down radioactive iron from a long-ago supernova explosion. (Credit: NASA/Goddard/Adler/U. Chicago/Wesleyan)

Antarctica is one of the most pristine places on the planet. Thanks to its generally inhospitable nature, as well as its natural isolation, it’s a good place for astronomers to search for meteorites and other materials that fall from the sky. They tend to sit undisturbed for long periods of time.

A team of astronomers from Germany and Austria recently made use of that preservation by collecting over 1,000 pounds of snow laid down in the past 20 years. After analyzing all the various dust and grains they found within the snow, they discovered a suspicious amount of iron-60. This particular radioactive strain of iron told astronomers that the dust wasn’t local, but instead came from outer space.

What’s more, they suspect it came from a supernova that exploded sometime in the recent cosmic past.

Our solar system sits in one particular spiral arm of the Milky Way, and it orbits the galactic center every 230 million years or so. Astronomers suspect that as the sun and Earth traversed the local galactic neighborhood, they would have plowed through the cloud of debris that this supernova left behind, causing the materials to rain down on Earth.

The same type of iron has been found buried in deep sea beds and other ancient rocks, but those were laid down millions of years ago. This is the first find of such interstellar iron laid down in recent years, and it could shed more light on exactly where and when the supernova that created the metal occurred.

The researchers published their findings August 12 in the journal Physical Review Letters.

Iron Hunters

To analyze the cosmic dust they were seeking, astronomers melted their 1,000 pounds of Antarctic snow. Then, they ran it through an instrument called a mass spectrometer to determine the precise chemical makeup of any materials caught inside. This told them not only that there was iron and manganese in the sample, but specifically iron-60 and manganese-53. These special isotopes, or varieties, of the elements have different numbers of particles in their nucleus than normal iron or manganese atoms (most iron is iron-56, and most manganese is manganese-55). Both are radioactive, meaning they’re not stable with that number of particles, and will at some point decay into other atoms – though for iron-60, it will take 2.6 million years for half of it to decay into something else, making it fairly long-lived for a radioisotope.

Once astronomers found the iron-60 and manganese-53, they had to figure out where it came from. Space was one option, but it’s actually quite common for that combination of elements to occur when cosmic rays strike the dust that fills the solar system. However, when that happens, there’s a particular ratio of iron to manganese scientists have come to expect, and that wasn’t the ratio researchers saw from the Antarctic snow – instead, they saw an excess of iron-60.

So they next tested to see if the extra iron might come from a more local source – fallout from nuclear weapons or power plants that might have drifted south. But further investigations showed that the amount of iron-60 scientists should expect from such sources is negligible, and can’t explain the amounts researchers measured.

Researchers have seen iron-60 like this before, in older rocks embedded in the seafloor or even on the moon. In those cases, they put it down to a long-ago supernova, a dying star whose explosion would have created all kinds of exotic elements, including iron-60. But knowing that the iron-60 is still falling to Earth today can help astronomers connect the long-ago iron fall to the one that’s probably still happening today, and figure out where and when the supernova occurred that created the iron in the first place.

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: stars

How Cell Membranes May Have Kicked Off the Origin of Life

By Sofie Bates | August 12, 2019 5:20 pm
Early Earth
(Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab)

(Inside Science) — Experts believe the building blocks of life first bumped into each other about 3.5 billion years ago. This serendipitous collision somehow helped form the first rudimentary cell — and the first life on Earth.

At least, that’s been the predominant theory. Now, a team of scientists from the University of Washington is challenging this idea in a paper published in the journal Proceedings of the National Academy of Sciences. They propose that membranes might have been the key component that helped congregate the pieces needed to create the first cell.

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MORE ABOUT: microbes & viruses

Astronomers Catch a Pulsar ‘Glitching,’ Offering Insights Into the Strange Stars

By Korey Haynes | August 12, 2019 11:00 am
jet coming from cloud of gas
The Vela pulsar is known to glitch something like once every three years, when it speeds up for a few seconds. (Credit: X-ray: NASA/CXC/Univ of Toronto/M.Durant et al; Optical: DSS/Davide De Martin)

When a massive star dies, it leaves behind a dense core called a neutron star. Many of these exotic suns spin rapidly, sending out beams of radiation like lighthouses, and these are called pulsars. They can rotate thousands of times a second, and spin so steadily that they can be used as cosmological clocks – except sometimes, when they glitch.

Some five percent of pulsars are known to glitch, when they spin faster for only a few seconds. It’s a puzzling hiccup in their otherwise precise spin rates. One example is the Vela pulsar, which sits roughly 1,000 light-years away from Earth and glitches as much as once every three years. It lurks inside the cloud of gas and dust left over from when its star went supernova more than 10,000 years ago.

In 2016, the Vela pulsar glitched again, and astronomers caught the event with the Mount Pleasant Radio Observatory in Tasmania, Australia. Some of the details of the event helped to back up astronomers theories and models of these stellar hiccups. But the pulsar also revealed a totally new surprise: the neutron star actually slowed down briefly just before the faster rotation kicked in, marking the glitch itself.

Astronomers led by Greg Ashton from Monash University in Australia published their findings in Nature Astronomy on August 12.

Slow Down and Speed Up

It’s not entirely clear what’s making these pulsars glitch. Astronomers’ best understanding is that an inner layer of the star suddenly sloshes outward. When it hits the pulsar’s outer crust, it causes the star to spin faster, though it quickly reverts back to its previous spin rate. The whole event was over in less than 13 seconds.

The 2016 observations of the Vela pulsar glitch are some of the most detailed ever made of such a glitch. In general, their observations matched with what astronomers saw during glitch observations in 2000 and 2004, though those came from a less sensitive telescope. The big surprise for Ashton’s group was the pulsar slowing down in the seconds just before it sped up.

“We actually have no idea why this is, and it’s the first time it’s ever been seen,” Ashton said in a press release. “It could be related to the cause of the glitch, but we’re honestly not sure.”

There’s a lot yet to learn about pulsar glitches in general, but other astronomers will be on the lookout for these slow-down periods as well as any speed-up glitches.

For now, Ashton’s group says they’ll keep studying the Vela pulsar outside of glitches, hoping to better understand the strange star. It’s anyone’s guess as to when the next glitch will happen.

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: stars

This Week in Science News: Maya Warfare, Lucid Dreams, Ancient Galaxies

By Discover Staff | August 9, 2019 4:30 pm
We’ve got: Maya warfare, giant extinct parrots, ancient galaxies, space travel radiation, a pill for lucid dreams, and more.

Maya Warfare

The Maya Classic Period, from 300 to 900 A.D., is seen as a kind of golden age for the ancient Central American civilization.

Populations boomed. Art and science flourished. It was a pretty peaceful time, or so we thought. Archaeologists have now discovered evidence of all-out warfare and near-complete destruction at a Maya city called Witzna. Ash layers and written texts hint that the city was ruined, its temples burned and its people taken away or killed.

It’s a sign that destructive warfare wasn’t just present during the Maya civilization’s collapse. Such violence might have been a part of their lives all along.

Read More: A Burned City, and a New View of Warfare Among the Ancient Maya

A Pill for Lucid Dreams?

If ancient warfare doesn’t give you nightmares, maybe you’d be interested in having a lucid dream. Lucid dreams are when you take control of your own dream narrative, often with thrilling results. Ever wanted to fly? You can lift right off. But only a lucky few actually get to experience this.

Now some people are trying to bring on lucid dreams with chemical shortcuts. That’s despite little research on the safety and efficacy of such pills.

Researchers and dream enthusiasts have been experimenting with everything from dementia pills to over-the-counter supplements to memory tricks that help you notice when you’re dreaming.

Read More: Looking to Have a Lucid Dream? There’s a Pill for That

Heracles the Unexpected

You’d probably think you were dreaming if you came face to face with the ancient and extinct giant parrot scientists recently discovered in New Zealand.

Some are calling it “squawkzilla,” but it’s scientific name is Heracles inexpectatus, after the muscled Greek hero and the surprising nature of the find.

The ancient parrot stood up to three feet tall — as tall as a large dog — and weighed as much as 15 pounds. Its beak alone spanned 4 inches. 

Paleontologists were digging in an eroded riverbed when they found the animals’ fossils. They say it lived roughly 20 million years ago. 

Read More: Heracles the Giant Parrot Stood 3-Feet-Tall

Deep Space Problems

In a recent study, researchers exposed mice to chronic, low-dose radiation for six months. It’s the kind of radiation that future space colonists might experience on a journey to Mars. 

But the results were troubling for the future of spaceflight. The radiation left the mice suffering from both memory and mood problems that the scientists say would likely show up in human subjects as well.

In fact, it hints that one in five astronauts may experience increased anxiety or mood swings on a mission to Mars, while one in three astronauts will have memory problems.

Read More: Long-Term Radiation Exposure From Space Travel Harms Memory, Mood

Ancient Galaxies Revealed

In much, much, much more distant space, astronomers have discovered dozens of massive galaxies that formed just two billion years after the Big Bang. 

Because these galaxies are so far away and so dim, very few have actually been spotted before, and those were usually the brightest kind – not very typical galaxies. The 39 just discovered are special because they actually are of the more normal variety.

The scientists involved were surprised at their own success in finding so many typical, early galaxies. It’s a sign that many more of them likely existed earlier than scientists suspected.  

So, studying these may help explain scientists explain how today’s galaxies began, and also how so many of them came to exist so early in the universe.

Read More: Dozens of Galaxies Discovered From the Early Universe

New SETI Project Will Practice Looking for Alien Life Near Deep-Sea Vents on Earth

By Korey Haynes | August 9, 2019 3:00 pm
deep-sea vent
InVADER will explore deep-sea vents on Earth to prepare future missions to do the same on watery worlds in the solar system like Europa or Enceladus. (Credit: D. Kelley, University of Washington/NSF-OOI/WHOI)

Some of the most intriguing possibilities for finding life outside Earth are on water worlds like Europa or Enceladus — ocean moons orbiting Jupiter and Saturn. However, those worlds are encased in layers of ice, meaning any ocean exploration will take place far beneath the surface.

But on our own planet, these deep-sea zones teem most reliably with life. That life is most often found near hydrothermal vents. These cracks in the seafloor release heat and chemicals that fuel intense biozones far from any sunlight.

Now, the Search for Extraterrestrial Intelligence (SETI) has received a NASA grant to fund a new project called In-situ Vent Analysis Divebot for Exobiology Research (InVADER). It will explore deep-sea vents on Earth in preparation for the day that scientists can send a similar craft out into the solar system to explore alien oceans and their own hydrothermal vents.

Deep Sea Exploration

InVADER aims to explore a hydrothermal vent area called Axial Seamount. This is an active volcano a mile underneath the surface, and the biggest one on the western edge of the Juan de Fuca tectonic plate. InVADER will have three major goals during its mission. The first is to produce actual science near Axial Seamount, to better understand the geology, chemistry, and biology around the vent system. By better understanding deep-sea vents on Earth, scientists hope they’ll be more prepared to understand whatever they find when deep-sea missions to other planets become a reality.

The second goal is to practice their science operations, testing different ways to answer the science questions they want to explore. They’re prepared to use lasers to analyze the different materials they encounter, as well as experiment with different strategies for collecting and analyzing data. That can be tricky when your instrumentation is a mile underwater, much less hundreds of millions of miles away, as it would be on Enceladus or Europa. InVADER can also take pictures and even provide 3-D mapping of its environment so researchers can better understand the other readings the underwater robot sends back.

The last goal is a technology demonstration. The team wants to prove that InVADER can actually perform in its deep-sea environment, both in terms of on-site science, and in its ability to gather samples and bring them back to the lab.

InVADER will remain at its underwater research site for a full year, taking daily measurements and eventually returning with samples from the rocks and water it collects.

While InVADER will remain safely on Earth, the lessons it learns from Earth’s own underwater vents will prepare researchers for the eventual trip to the oceans of watery moons that planetary scientists and astrobiologists alike are keen to explore.

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: space exploration

How These Sharks Glow Neon Green to their Friends

By Rodrigo Pérez Ortega | August 9, 2019 2:13 pm
biofluorescent shark
The biofluorescent shark Scyliorhinus retifer. (Credit: David Gruber)

(Inside Science) — When we look at the seafloor, we might not see the bottom-dwelling sharks that blend in with the rocks and the sand. But to other sharks of the same species, they stand out like green glow sticks. Now scientists know how.

In 2014, marine biologist David Gruber, from the City University of New York, and his team discovered that two species of bottom-dwelling sharks are biofluorescent. The swell shark is native to the Pacific Ocean, and the chain catshark is from the Atlantic Ocean, but both species live in similar habitats and both glow neon green. Under blue light, the lighter, gray-colored areas in the skin of both sharks give out a neon green fluorescent hue, visible to other animals — and with the help of a filter, to humans too.

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CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: animals

Ancient African Ancestors Lived In High Mountains, Ate Rodents of Unusual Size

By Roni Dengler | August 9, 2019 1:58 pm
Ethiopia Bale Mountains
Ethiopia’s Bale Mountains. (Credit: Michele Alfieri/Shutterstock)

High-altitude environments are not exactly welcoming places to call home. It’s hard to breathe, there’s little shelter and being that much closer to the sun means more exposure to UV radiation. The inhospitable conditions are why high mountains and plateaus were some of the last places on Earth humans occupied.

Now researchers find prehistoric humans lived in a high-altitude rocky outcrop in Ethiopia’s Bale Mountains 31,000 to 47,000 years ago. They say the discovery is the earliest evidence for humans taking up residence at high altitude.

Ancient humans inhabited the Tibetan Plateau 30,000 to 40,000 years ago, and our cousins, the Denisovans, were there as long as 160,000 years ago. But this is the first time ancient humans have been found living at high altitude in Africa.

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CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: human origins

Flight of the Midge Larva: How These Tiny Creatures Blast Off

By Nathaniel Scharping | August 8, 2019 7:00 pm

via GIPHY

Imagine trying to bend an inflated bicycle tire tube in half. It’s a bit difficult, though not impossible. When you let go, the pressure inside snaps the tube back to its normal shape, as if spring-loaded.

What you’re doing when you bend the tube is essentially storing energy inside it, to be released all at once when you let go. The trick isn’t very useful when it comes to bike tires, of course, but scientists have found that a species of midge has found a unique way to put this technique to use in nature.

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CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: animals

Hubble Settles an Old Debate About Galaxies with Supermassive Black Holes

By Korey Haynes | August 8, 2019 2:45 pm
jets emerging from a dusty galaxy
Galaxies with central black holes can take various forms depending on the angle at which astronomers see them. (Credit: NASA)

Every large galaxy has a supermassive black hole at its center. And some of those black holes are actively ejecting huge amounts of high-energy light out into the cosmos.

Astronomers divide some of these active galaxies, which otherwise look like normal spirals, into two types, so-called Seyfert 1 and Seyfert 2 galaxies. Seyfert 1 galaxies have distinctive light signatures that emerge from the fast-moving material just outside the black hole. Seyfert 2s lack these signals.

But for three decades now, astronomers have suspected that these two types of galaxies might in fact be the same, we’re just seeing them from different angles. The thought was that a dusty ring around the black hole could hide certain features, making a Seyfert 1 appear like a Seyfert 2.

However, a few stubborn galaxies persisted in hiding those features apparently without any dust ring. That made some astronomers think there might really be a class of “true Seyfert 2 galaxies,” whose features weren’t hidden but genuinely lacking.

Now, astronomers have ruled out one of the last remaining “true Seyfert 2” stragglers, proving it was a Seyfert 1 after all. This means there’s no such thing as a Seyfert 2, just Seyfert 1 galaxies viewed from different angles. Astronomers led by Stefano Bianchi, from the Università degli Studi Roma Tre in Italy, published their results in Monthly Notices of the Royal Astronomical Society July 11.

Hidden Features

Seyfert galaxies look like normal spiral galaxies when viewed in visible light. But when astronomers observe them at high-energy wavelengths like X-rays and ultraviolet light, their cores light up as hotbeds of activity, revealing the energetic black holes powering their centers. And when astronomers peer at the galaxies’ chemical fingerprints in detail, they notice two sub-groups, Seyfert 1 and 2 galaxies.

The idea is that Seyfert 2 galaxies are really Seyfert 1 galaxies, with their cores hidden behind an obscuring wall of dust. This dust only gets in the way from certain angles, since it sits in the plane of the galaxy like a doughnut, with the black hole at center.

But a few galaxies, especially one called NGC 3147 appeared to be missing the signals from the fast-moving material just outside the black hole, while also showing no sign of a dusty doughnut to hide them. That left NGC 3147 as a shining example of a “true” Seyfert type 2 galaxy. And so, the debate has lingered.

But now, using just one hour of time on NASA’s Hubble Space Telescope, astronomers have finally observed the missing signals from NGC 3147. Because it was so dim, the signals coming from that fast-moving material just outside the black hole were masked by brighter starlight nearby. But Hubble’s keen vision spotted them anyway.

The authors point out that since NGC 3147 was the best known example of a true Seyfert 2, this new result quite likely rules out their existence entirely. “What’s most important to astronomers is pruning this dead branch,” study co-author Robert Antonucci in a press release.

The astronomers have been awarded six more hours of time using Hubble to study NGC 3147 in even greater detail, and perhaps unlock any remaining secrets about its central black hole.

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: black holes, galaxies
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