In the 1998 Hollywood blockbuster Armageddon, Bruce Willis and Ben Affleck race to save the Earth from being pulverized by an asteroid. While the Earth faces no such immediate danger, NASA plans to crash a spacecraft traveling at a speed of 15,000 miles per hour (24,000 kph) into an asteroid next year in a test of "planetary defense."

The Double Asteroid Redirection Test (DART) is to determine whether this is an effective way to deflect the course of an asteroid should one threaten the Earth in the future.

NASA provided details of the DART mission, which carries a price tag of $330 million, in a briefing for reporters on Thursday. Lindley Johnson, NASA's Planetary Defense Officer, said:

"Although there isn't a currently known asteroid that's on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there. The key to planetary defence is finding them well before they are an impact threat. We don't want to be in a situation where an asteroid is headed towards Earth and then have to test this capability."

The DART spacecraft is scheduled to be launched aboard a SpaceX Falcon 9 rocket at 10:20 pm Pacific time on November 23 from Vandenberg Space Force Base in California.

Slower ocean circulation as the result of climate change could intensify extreme cold weather in the U.S., according to new UArizona research.

Throughout Earth's oceans runs a conveyor belt of water. Its churning is powered by differences in the water's temperature and saltiness, and weather patterns around the world are regulated by its activity.

A pair of researchers studied the Atlantic portion of this worldwide conveyor belt called the Atlantic Meridional Overturning Circulation, or AMOC, and found that winter weather in the United States critically depends on this conveyor belt-like system. As the AMOC slows because of climate change, the U.S. will experience more extreme cold winter weather.

The study, published in the journal Communications Earth & Environment was led by Jianjun Yin, an associate professor in the University of Arizona Department of Geosciences and co-authored by Ming Zhao, a physical scientist at the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory.

AMOC works like this: Warm water travels north in the upper Atlantic Ocean and releases heat into the atmosphere at high latitudes. As the water cools, it becomes denser, which causes it to sink into the deep ocean where it flows back south.

"This circulation transports an enormous amount of heat northward in the ocean," Yin said. "The magnitude is on the order of 1 petawatts, or 10 to the 15 power watts. Right now, the energy consumption by the entire world is about 20 terawatts, or 10 to the 12 power watts. So, 1 petawatt is enough to run about 50 civilizations."

But as the climate warms, so does the ocean surface. At the same time, the Greenland ice sheet experiences melting, which dumps more freshwater into the ocean. Both warming and freshening of the water can reduce surface water density and inhibit the sinking of the water, slowing the AMOC. If the AMOC slows, so does the northward heat transport.

Heat from a comet exploding just above the ground fused the sandy soil into patches of glass stretching 75 kilometers, a study led by Brown University researchers found.
PROVIDENCE, R.I. — Around 12,000 years ago, something scorched a vast swath of the Atacama Desert in Chile with heat so intense that it turned the sandy soil into widespread slabs of silicate glass. Now, a research team studying the distribution and composition of those glasses has come to a conclusion about what caused the inferno.

In a study published in the journal Geology, researchers show that samples of the desert glass contain tiny fragments with minerals often found in rocks of extraterrestrial origin. Those minerals closely match the composition of material returned to Earth by NASA's Stardust mission, which sampled the particles from a comet called Wild 2. The team concludes that those mineral assemblages are likely the remains of an extraterrestrial object — most likely a comet with a composition similar to Wild 2 — that streamed down after the explosion that melted the sandy surface below.

"This is the first time we have clear evidence of glasses on Earth that were created by the thermal radiation and winds from a fireball exploding just above the surface," said Pete Schultz, a professor emeritus in Brown University's Department of Earth, Environmental and Planetary Sciences. "To have such a dramatic effect on such a large area, this was a truly massive explosion. Lots of us have seen bolide fireballs streaking across the sky, but those are tiny blips compared to this."

Some 9,000 years ago, corn as it is known today did not exist. Ancient peoples in southwestern Mexico encountered a wild grass called teosinte that offered ears smaller than a pinky finger with just a handful of stony kernels. But by stroke of genius or necessity, these Indigenous cultivators saw potential in the grain, adding it to their diets and putting it on a path to become a domesticated crop that now feeds billions.

Despite how vital corn, or maize, is to modern life, holes remain in the understanding of its journey through space and time. Now, a team co-led by Smithsonian researchers have used ancient DNA to fill in a few of those gaps.

A new study, which reveals details of corn's 9,000-year history, is a prime example of the ways that basic research into ancient DNA can yield insights into human history that would otherwise be inaccessible, said co-lead author Logan Kistler, curator of archaeogenomics and archaeobotany at the Smithsonian's National Museum of Natural History.

CBET 5064 & MPEC 2021-V21, issued on 2021, November 02, announce the discovery of a new comet (magnitude ~19) by A. Maury and G. Attard on CCD images taken on October 24.3 UT with the 0.28-m f/2.2 Rowe-Ackermann Schmidt astrograph at San Pedro de Atacama, Chile in the course of the MAP (W94) survey. The new comet has been designated P/2021 U3 (Attard-Maury). This is the 4th amateur comet discovery of 2021. It is also the second comet discovered using the synthetic tracking technique (using TYCHO software).

Stacking of 51 unfiltered exposures, 60 seconds each, obtained remotely on 2021, Oct. 27.3 from X02 (Telescope Live, Chile) through a 0.61-m f/6.5 astrograph + CCD, shows that this object is a comet with a compact coma about 6" arcsecond in diameter and a tail 6" long in PA 275 (Observers E. Guido, M. Rocchetto, E. Bryssinck, M. Fulle, G. Milani, C. Nassef, G. Savini, A. Valvasori).

Stacking of 66 unfiltered exposures, 60 seconds each, obtained remotely on 2021, Oct. 29.9 from G18 (ALMO Observatory, Italy) through a 0.30-m f/4 reflector + CCD, shows that this object is a comet with a compact coma about 5" arcsec in diameter and a tail 6" long in PA 270 (Observers A. Valvasori & E. Guido).

Our confirmation images (click on the images for a bigger version; made with TYCHO software by D. Parrott)

Early-Life Triggers May Prime Cells to Unleash Exaggerated Immune Responses.

The surprise discovery of a new type of cell explains how distress to the skin early in life may prime a person for inflammatory skin disease later, according to a new study by UC San Francisco researchers in the Oct. 27 issue of Nature. Knowledge of this new cell type will likely lead to greater insight on how to reverse autoimmune disorders such as scleroderma, and shed light on the nature of inflammatory disease in general, the researchers said.

"The results reinforce the idea that what you're exposed to initially may have lasting ramifications," said Michael Rosenblum, MD, PhD, principal investigator on the study. "It appears that early exposure to inflammation can, through these cells we discovered, imprint an ability for tissues to develop inflammatory disease later in life."

The team learned about the new type of cell while investigating the effects of a set of actions known to evoke immune response in mice. One of these actions involved knocking out a group of skin cells that suppress the immune system. In the absence of that regulation, Rosenblum said, the researchers saw the presence of a unique cell that seemed to be acting as a shelter for pathogenic immune cells that aren't usually seen in skin tissues.

"We had to knock out one cell population to see that they were controlling the growth and capacity of these other, unknown cells," he said, noting that the new cells became apparent only in the tissue that had been exposed to inflammatory triggers. "What normally would be a deserted island on the skin was now inhabited by all these strangers," he said.

The team dubbed the strangers "TIFFs" (Th2-interacting fascial fibroblasts) after the Th2 immune cells that they help to house. The location of TIFFs in the skin suggests that they belong to a group of cells that make up fascia, the fibrous connective tissue that surrounds and connects organs throughout the body, said lead author Ian Boothby, a graduate student in Rosenblum's lab.

"Because most organs have fascia of some sort, what we're learning about TIFFs in skin may well be widely applicable to the rest of the body, meaning that these cells may play a role in a huge number of inflammatory diseases," he said.

Plants use a variety of mechanisms to communicate with other organisms, including one another. Volatile compounds can signal flowering and attract pollinators, for instance, and mycorrhizal fungal networks can transmit warnings or transfer resources. Small RNAs are on that list of communication molecules, and new findings confirm their potential: according to a paper published October 14 in Nature Plants, the plant Arabidopsis thaliana secretes microRNAs (miRNAs) — a type of small, single-stranded RNAs — into its liquid growth medium. Nearby individuals then take up these RNAs, which alter their gene expression patterns by binding to messenger RNAs and preventing certain genes from being translated into proteins (a process known as RNA interference).

Effective vaccines, without a needle: Since the start of the COVID pandemic, researchers have doubled down on efforts to create patches that deliver life-saving drugs painlessly to the skin, a development that could revolutionize medicine.

The technique could help save children's tears at doctors' offices, and help people who have a phobia of syringes.

Beyond that, skin patches could assist with distribution efforts, because they don't have cold-chain requirements — and might even heighten vaccine efficacy.

A new mouse study in the area, published in the journal Science Advances, showed promising results.

The Australian-US team used patches measuring one square centimeter that were dotted with more than 5,000 microscopic spikes, "so tiny you can't actually see them," David Muller, a virologist at the University of Queensland and co-author of the paper, told AFP.

One of the world's biggest engineering problems is concrete. Critical infrastructure built over the last century — bridges, highways, dams, and buildings — are now crumbling before our eyes. Repairing and rebuilding this decaying infrastructure is estimated to cost trillions of dollars in the United States alone.

When steel reinforcements were introduced to concrete in the 19th century, it was rightfully at the time hailed as a massive step up in innovation. Adding steel bars to concrete speeds up construction time, uses less concrete, and allows the engineering of long, cantilevered structures such as miles-long bridges and tall skyscrapers. These early engineers who introduced these projects thought reinforced concrete structures would last at least 1,000 years. In reality, we now know their lifespan is between 50 and 100 years.

New findings from NASA's Juno probe orbiting Jupiter provide a fuller picture of how the planet's distinctive and colorful atmospheric features offer clues about the unseen processes below its clouds. The results highlight the inner workings of the belts and zones of clouds encircling Jupiter, as well as its polar cyclones and even the Great Red Spot.

Researchers published several papers on Juno's atmospheric discoveries today in the journal Science and the Journal of Geophysical Research: Planets. Additional papers appeared in two recent issues of Geophysical Research Letters.

"These new observations from Juno open up a treasure chest of new information about Jupiter's enigmatic observable features," said Lori Glaze, director of NASA's Planetary Science Division at the agency's headquarters in Washington. "Each paper sheds light on different aspects of the planet's atmospheric processes - a wonderful example of how our internationally-diverse science teams strengthen understanding of our solar system."