Month: July 2023

A stealthy asteroid the size of a 20-story building hid in the sun’s glare before zooming uncomfortably close to Earth on July 13. Scientists didn’t notice until July 15.

An asteroid as large as a 20-story building sailed uncomfortably close to Earth last week, zooming by our planet at roughly a quarter of the distance between Earth and the moon — and astronomers didn’t notice it until two days later.

Now dubbed 2023 NT1, the roughly 200-foot-wide (60 meters) space rock sailed past our planet on July 13, traveling at an estimated 53,000 mph (86,000 km/h), according to NASA. However, because the rock flew toward Earth from the direction of the sun, our star’s glare blinded telescopes to the asteroid’s approach until long after it had passed.

Astronomers didn’t catch wind of the building-size rock until July 15, when a telescope in South Africa — part of the Asteroid Terrestrial-impact Last Alert System (ATLAS), an array of telescopes designed to spot asteroids several days to weeks before any potential impact — caught the rock making its exit from our neighborhood. More than a dozen other telescopes also spotted the rock shortly afterward, according to the International Astronomical Union’s Minor Planet Center.

A diagram of Earth with a gray ring around it showing the moon’s orbit. A green line, representing an asteroid, cuts through the gray circle and approaches Earth

Despite this surprise approach, asteroid 2023 NT1 isn’t large enough to be considered a potentially hazardous object; after calculating the asteroid’s trajectory for the next decade, astronomers say there’s no imminent risk of an impact. In fact, recent research suggests that Earth is safe from asteroids — at least from large, extinction-inducing ones — for the next 1,000 years.

Still, the sun remains a well-known blind spot in the search for near-Earth asteroids — and 2023 NT1 is hardly the first stealthy space rock to slip past our detection. In 2013, a roughly 59-foot-long (18 m) asteroid followed a similar path through the sun’s glare and went undetected before exploding in the sky over Chelyabinsk, Russia. The explosion released a shock wave that damaged buildings and shattered glass for miles around, ultimately injuring nearly 1,500 people (but killing none).

While scientists closely monitor more than 31,000 known near-Earth asteroids, they are well aware of the dangers posed by the solar blind spot. To address this threat, the European Space Agency is hard at work on the NEOMIR mission. The satellite, scheduled to launch around 2030, will orbit between Earth and the sun in an effort to detect large asteroids hidden in our star’s shine.

Source: https://www.livescience.com/space/asteroids/a-skyscraper-size-asteroid-flew-closer-to-earth-than-the-moon-and-scientists-didnt-notice-until-2-days-later

[It is fascinating about the weird past of the earth that scientists have uncovered. When I was younger, scientists used to believe, for a long time, that the earth changed GRADUALLY. But as their knowledge and tools have improved massively, they have instead discovered that lots of weird, nasty events took place in the Earth's history that were unexpected and weird. It turns out that disasters and nasty bizarre, weird things happened a LOT. The Earth is actually a dangerous planet and we are actually a fragile species. This is our only home, but our only home could kill us easily. I will return to this topic. Jan]

Here’s the video: https://www.youtube.com/watch?v=vntVVcazJD4&t=1261s

Here’s the video: https://www.youtube.com/watch?v=CJUVd8SguDw

Here’s the video: https://www.youtube.com/watch?v=CmW-tctT6Y4

The first stars in the cosmos may have topped out at over 10,000 times the mass of the sun, roughly 1,000 times bigger than the biggest stars alive today, a new study has found.

Nowadays, the biggest stars are 100 solar masses. But the early universe was a far more exotic place, filled with mega-giant stars that lived fast and died very, very young, the researchers found.

And once these doomed giants died out, conditions were never right for them to form again.

The cosmic Dark Ages

More than 13 billion years ago, not long after the Big Bang, the universe had no stars. There was nothing more than a warm soup of neutral gas, almost entirely made up of hydrogen and helium. Over hundreds of millions of years, however, that neutral gas began to pile up into increasingly dense balls of matter. This period is known as the cosmic Dark Ages.

In the modern day universe, dense balls of matter quickly collapse to form stars. But that’s because the modern universe has something that the early universe lacked: a lot of elements heavier than hydrogen and helium. These elements are very efficient at radiating energy away. This allows the dense clumps to shrink very rapidly, collapsing to high enough densities to trigger nuclear fusion – the process that powers stars by combining lighter elements into heavier ones.

But the only way to get heavier elements in the first place is through that same nuclear fusion process. Multiple generations of stars forming, fusing, and dying enriched the cosmos to its present state.

Without the ability to rapidly release heat, the first generation of stars had to form under much different, and much more difficult, conditions.

Cold fronts

To understand the puzzle of these first stars, a team of astrophysicists turned to sophisticated computer simulations of the dark ages to understand what was going on back then. They reported their findings in January in a paper published to the preprint database arXiv and submitted for peer review to the Monthly Notices of the Royal Astronomical Society.

The new work features all the usual cosmological ingredients: dark matter to help grow galaxies, the evolution and clumping of neutral gas, and radiation that can cool and sometimes reheat the gas. But their work includes something that others have lacked: cold fronts – fast-moving streams of chilled matter – that slam into already formed structures.

The researchers found that a complex web of interactions preceded the first star formation. Neutral gas began to collect and clump together. Hydrogen and helium released a little bit of heat, which allowed clumps of the neutral gas to slowly reach higher densities.

But high-density clumps became very warm, producing radiation that broke apart the neutral gas and prevented it from fragmenting into many smaller clumps. That means stars made from these clumps can become incredibly large.

Supermassive stars

These back-and-forth interactions between radiation and neutral gas led to massive pools of neutral gas– the beginnings of the first galaxies. The gas deep within these proto-galaxies formed rapidly spinning accretion disks – fast-flowing rings of matter that form around massive objects, including black holes in the modern universe.

Meanwhile, on the outer edges of the proto-galaxies, cold fronts of gas rained down. The coldest, most massive fronts penetrated the proto-galaxies all the way to the accretion disk.

These cold fronts slammed into the disks, rapidly increasing both their mass and density to a critical threshold, thereby allowing the first stars to appear.

Those first stars weren’t just any normal fusion factories. They were gigantic clumps of neutral gas igniting their fusion cores all at once, skipping the stage where they fragment into small pieces. The resulting stellar mass was huge.

Those first stars would have been incredibly bright and would have lived extremely short lives, less than a million years. (Stars in the modern universe can live billions of years). After that, they would have died in furious bursts of supernova explosions.

Those explosions would have carried the products of the internal fusion reactions – elements heavier than hydrogen and helium – that then seeded the next round of star formation. But now contaminated by heavier elements, the process couldn’t repeat itself, and those monsters would never again appear on the cosmic scene.

Source: https://www.livescience.com/the-early-universe-was-crammed-with-stars-10000-times-the-size-of-our-sun-new-study-suggests

NASA’s Perseverance rover has found a diverse menagerie of organic molecules in a Martian crater, a new study reports.

Organic compounds are molecules composed of carbon, and often include other elements such as hydrogen, oxygen, nitrogen, phosphorus and sulfur. Previously, scientists had detected several types of organic molecules of Martian origin — in meteorites blasted off Mars by cosmic impacts that landed on Earth, and in Gale Crater on the Red Planet, which NASA’s Curiosity rover has been exploring since 2012.

"They are an exciting clue for astrobiologists, since they are often thought of as building blocks of life," study lead author Sunanda Sharma, a planetary scientist at the California Institute of Technology in Pasadena, told Space.com.

However, "importantly, they can be created by processes not related to life," Sharma emphasized. As such, investigating what organic molecules exist on the Red Planet and how they were created is key to understanding what may or may not be linked to life on Mars.

Related: ‘Anomalous’ metal spheres unlikely to be alien technology, despite Harvard scientist’s claim

"As planetary scientists and astrobiologists, we are very careful with laying out claims — claiming that life is the source of organics or possible biosignatures is a last-resort hypothesis, meaning we would need to rule out any non-biological source of origin," Sharma said.

In the new study, Sharma and her colleagues analyzed data from Perseverance. In February 2021, the rover landed within Jezero Crater, the site of an ancient lake basin that prior work suggested displayed high potential for past habitability. The crater floor also possesses clays and other minerals that may preserve organic materials.

Specifically, the scientists examined data from the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard Perseverance. SHERLOC is the first tool on Mars capable of conducting fine-scale mapping and analysis of organic molecules.

The researchers focused on SHERLOC data from Máaz and Séítah, two rock formations on the Jezero Crater floor. When ultraviolet light from SHERLOC illuminates organic compounds, they can glow much like material beneath a blacklight. The fingerprint of wavelengths in the glow from a molecule can help identify it.

Sharma and her colleagues found signs of organic molecules in all 10 targets that Perseverance drilled into at Máaz and Séítah, covering a span of time from at least about 2.3 billion to 2.6 billion years ago. These "point to the possibility that building blocks of life could have been present for a long time on the surface of Mars, in more than one place," Sharma said.

Close-up image of a mars rock with green and blue dots superimposed over it to represent chemical composition in different areas.

This annotated image shows a rock target called "Garde," as analyzed by the Mars rover Perseverance’s SHERLOC instrument. This data was taken on Sept. 18, 2021, the 207th Martian day, or sol, of the mission. (Image credit: NASA/JPL-Caltech/MSSS/LANL/PhotonSys)

The scientists discovered evidence of many different classes of organic molecules. These occurred in a variety of patterns in space within Máaz and Séítah, suggesting they might have originated from a number of different minerals and mechanisms of formation. These organic compounds mostly appeared connected to minerals linked to water.

"Seeing that the possible organic signals differ in terms of type, number of detections and distribution between the two units of the crater floor was surprising and exciting," Sharma said. "That opens the possibility of different formation, preservation or transportation mechanisms across the crater and, more broadly, the surface of Mars."

The scientists could not identify specific organic molecules. "To confirm the presence of organics and their specific types, we would need the samples to be returned to Earth," Sharma said. "That’s our goal."

The scientists detailed their findings online today (July 12) in the journal Nature.

Source: https://www.livescience.com/space/mars/building-blocks-of-life-discovered-on-mars-in-10-different-rock-samples

[Our type of solar system and our planet is not normal in the universe. It is very special, and more and more evidence of this is emerging. I will discuss this in more detail later. But be aware of what the science is revealing. Jan]

Here’s the video: https://www.youtube.com/watch?v=_Tju7EaSfmM

The first-ever near-complete sauropod skull found in Australia is remarkably similar to fossils from South America, which suggests that dinosaurs roamed across ice-free Antarctica.

A nearly 100 million-year-old, exceptionally well-preserved sauropod skull discovered in Australia may show that dinosaurs trudged across Antarctica from South America to Australia, researchers have revealed.

The near-complete sauropod skull belongs to a species called Diamantinasaurus matildae. Sauropods are known for their extremely long necks, with one dinosaur’s neck stretching farther than a school bus. D. matildae was also a titanosaur, the only group of sauropod dinosaurs to live right until the end of the Cretaceous (145 million to 66 million years ago) before the nonavian dinosaurs went extinct.

Paleontologists excavated the specimen in 2018 from a sheep ranch northwest of Winton, in Queensland, Australia, and nicknamed it "Ann." D. matildae was as long as a tennis court (78 feet or 23.77 meters) and weighed around 27.5 tons (25 metric tons), three times more than Tyrannosaurus rex. The fossils look strikingly similar to bones unearthed in Argentina, which prompted researchers to think that sauropods journeyed between South America and Australia, via Antarctica.

"In analyzing the remains, we found similarities between the Ann skull and the skull of a titanosaur called Sarmientosaurus musacchioi, which lived in South America at about the same time as Diamantinasaurus lived in Queensland," Stephen Poropat, a paleontologist at Curtin University in Perth, Australia, and lead author of a new study into the fossils, said in a statement. "We suggest that sauropods were traveling between Australia and South America, via Antarctica, during the mid Cretaceous."

In the hothouse world of the Cretaceous, Antarctica was blanketed with lush forests and vegetation. Scientists already knew that sauropods roamed the now-frigid landmass, after the first long-necked-dinosaur fossil in Antarctica was discovered in 2011. Some scientists had already theorized that these behemoths used Antarctica to bridge continents. At the time, Australia, New Zealand, Antarctica and South America were joined and formed the last remnant of the supercontinent Gondwana, according to the Australian Museum.

Now, in a study published Wednesday (April 12) in the journal Royal Society Open Science, researchers compared the best-preserved sauropod skull found to date in Australia with others from across the world.

A photo of the site where paleontologists unearthed the skull shows several cars and a tent set up near a dig site on a vast plain
Paleontologists unearthed the 98 million to 95 million-year-old sauropod skull during a dig organized by the Australian Age of Dinosaurs Museum near Winton, Queensland. (Image credit: Australian Age of Dinosaurs Museum)

Using detailed scans of Ann’s remains, the team detected remarkable similarities with a Sarmientosaurus skull that was discovered in the Chubut province in southern Argentina and described in a 2016 study in the journal PLOS One. "These similarities include details of the braincase, the bones forming the back end of the skull near the jaw joint and the shape of the teeth," Poropat said.

Researchers already suspected that these two dinosaurs were closely related, but until now, they lacked the evidence to back it up. "The new skull shores up the idea in a big way," Poropat wrote in The Conversation. "Bone for bone, the skulls of Diamantinasaurus and Sarmientosaurus are extremely similar."

A photo of scientists arranging the sauropod skull remains on a table set to slide into a CT scanner

Dinosaur skulls are an extremely rare find, according to the study. Aside from a few teeth, Ann’s skull is only the second sauropod skull found in Australia, following the discovery in 2016 of a partial cranium belonging to D. matildae. That’s because the heads of sauropods were small relative to their body size and were made up of tiny, delicate bones and decomposed more rapidly than sturdy limbs, Poropat wrote.

“This is a remarkably detailed and information-packed paper," Matthew Lamanna, a paleontologist at the Carnegie Museum of Natural History and co-author of the 2016 study, told Live Science in an email. "The resemblances between the skulls of Diamantinasaurus and the similarly aged Sarmientosaurus from southern South America are pretty striking, and add further support for the hypothesis that titanosaurs moved between Australia and South America during the mid-Cretaceous, presumably via Antarctica."

Source: https://www.livescience.com/animals/dinosaurs/95-million-year-old-land-bridge-across-antarctica-carried-dinosaurs-between-continents

A new unpublished study is making waves on the internet by claiming that one of the brightest stars in the night sky might die in a spectacular explosion within our lifetime.

The study, currently available on the online pre-print serverarXiv, conjectures that the red giant star Betelgeuse, the left shoulder of the constellation Orion also known as Alpha Orionis, may have less than three hundred years’ worth of fuel left in its core. When the star burns through those last drops, its core will collapse into a black hole and in the process blast out the star’s outer layers at enormous speeds of up to 25,000 miles (40,000 kilometers) per second. This fiery demise is what astronomers call a supernova explosion, and in the case of Betelgeuse, it will be a spectacular sight for observers on Earth. Since the star is only 650 light-years from Earth, those layers of gas and dust will shine as bright as the full moon in our sky for several weeks.

The problem is that most astronomers don’t think that Betelgeuse is ready to go bang just yet. So what makes the researchers behind the new paper think otherwise?

Betelgeuse is undoubtedly a red giant star that has already burned through its primary fuel hydrogen and is now fusing helium in its core into heavier elements. The point at which a star runs out of hydrogen in its lifetime is unmissable. Stars short on hydrogen need to put extra energy into igniting the helium produced during the fusion of hydrogen, which forces them to expand dozens of times beyond their original size. In the process, they also become cooler and redder.

Astronomers know that Betelgeuse is huge. If it were to sit at the center of our solar system, the scorching gas in its outer atmosphere would reach far enough to engulf even the planet Jupiter. However, the exact width of Betelgeuse is hard to measure. That’s because instead of being one rather smooth ball of plasma, Betelgeuse is a lumpy clump of boiling gas bubbles shrouded in burped out dust clouds. To measure its diameter is therefore not easy, yet, the case for determining Betelgeuse’s remaining lifetime rests on the star’s size.

In the new controversial study, a team of astronomers led by Hideyuki Saio from the Tohoku University in Japan suggests that Betelgeuse is larger than what most researchers believe. This could be possible as Betelgeuse is known to pulsate — expand and shrink, dim and brighten up — at regular intervals. Most obviously, Betelgeuse’s brightness swings up and down every 420 days. Astronomers attribute this brightening to the periodical expansion of the star’s envelope, or roughly spherical outer region, in a phenomenon known as the fundamental mode.

A smattering of stars numbers in the thousands across the image, a deep purple background fades to black inconsistently throughout. A small number of exceptionally bright stars shine evident in the bottom corners and just above right center.

There are other quirks in Betelgeuse’s behavior, also appearing on a regular basis, which astronomers attribute to additional turbulent processes taking place inside the dying star. One of those additional variations takes place on a 2,200-day cycle, and astronomers have no explanation for it. The team led by Saio therefore proposed that this 2,200-day oscillation could, in fact, represent Betelgeuse’s main pulsation mode while the 420-day brightness variation could be a secondary quirk.

Such a scenario, however, requires Betelgeuse to be up to one third wider for these models of its evolution to work, Saio told Space.com in an email.

"To explain the 2,200-day period as fundamental mode requires a much larger radius than the case of fitting the 420-day [period] with fundamental mode," Saio wrote in an email. "A larger radius with a range of observed surface temperature means the intrinsic brightness of Betelgeuse to be higher than previously thought."

But for Betelgeuse to be as wide as the models require, it would also have to be in a later stage of its life, already done burning helium and instead running on carbon, which arose from the previous fusion of helium atoms. Whether a red giant star is burning helium or carbon makes a big difference in terms of how much life it has left. The helium-burning phase of a red giant star’s life lasts tens of thousands of years. When carbon-burning switches on, the end is nigh, at least in cosmic terms, and might come within a few thousand years.

"Although we cannot determine exactly how much carbon remains right now, our evolution models suggest that the carbon exhaustion would occur in less than 300 years," Saio wrote. "After the carbon exhaustion, fusions of further heavier elements would occur in probably a few tens of years, and after that the central part would collapse and a supernova explosion would occur."

That would certainly be exciting for skywatchers. The last time a nearby star went supernova was in 1604. Although stars explode somewhere in the universe on a daily basis, most of them are too far away to be visible without powerful telescopes.

But the question remains: What else is there but models to make Saio and his colleagues think that Betelgeuse is larger than what other astronomers think?

An asymmetrical, blurry sphere sits in the center of a black background. Its face is smeared with dull shades of yellow and pale brown.

In their paper, the researchers point out two measurements of Betelgeuse’s size to support their theory. But this is exactly where the paper has drawn criticism from other astronomers.

Miguel Montargès, a postdoctoral fellow at the Laboratory of Space Studies and Instrumentation in Astrophysics at the Paris Observatory who published papers on Betelgeuse based on observations by the Very Large Telescope in Chile, told Space.com in an earlier interview that "of the tens of measurements of Betelgeuse, [Saio and his colleagues] have selected only two."

László Molnár, an astronomy research fellow at the Konkoly Observatory in Budapest, Hungary, who also published several papers on Betelgeuse said that the measurements picked by Saio and his colleagues to support their theory were likely influenced by clouds of dust and gas around the star that make Betelgeuse appear bigger.

"If we look at the sun, we see a well-defined surface with a very crisp edge," Molnár told Space.com in an email. "But Betelgeuse being a red supergiant, is extremely fluffy and puffy, and the photosphere, what we would call its ‘surface,’ is hidden beneath multiple layers of molecular gas and clouds of dust."

Violent expulsions of these materials are typical for red giant stars. In the case of Betelgeuse, astronomers observed one such massive cloud emerge from within the star in 2019, causing the star to temporarily dim.

Molnár and his team made their own measurements of Betelgeuse’s size, which are more aligned with what most scientists think.

The release of Saio’s paper coincides with an unusual brightening of Betelgeuse that led some enthusiasts to speculate that the star might be about to explode. But neither Molnár nor Montargès are convinced. Betelgeuse, Montargès said, is actually too bright to be in its death throes due to the fact that expulsions of material typically make older red giants gradually dim. Betelgeuse, on the contrary, despite its regular pulsations, has been a fixture in the top ten brightest stars of our sky for at least the past 100 years.

The paper has not yet been peer-reviewed and published, so some of its shortcomings might get addressed before it gets officially released.

Source: https://www.space.com/betelgeuse-supernova-in-our-lifetime-study-unsure

[I've known about neutrinos for a very long time. They are totally amazing and weird. And they are passing through your body all the time. Even more bizarre, neutrinos pass through the ENTIRE EARTH. Neutrinos can come at you from above, but also from BELOW! Yes, they can pass through the entire Earth and come out the other side!! As always, these are wonderful European Race discoveries. Jan]

Neutrino map of the galaxy is 1st view of the Milky Way in ‘anything other than light’

By Ben Turner
published 4 days ago

Scientists at the IceCube Neutrino Observatory have used 60,000 neutrinos to create the first map of the Milky Way made with matter and not light.

Scientists have traced the galactic origins of thousands of "ghost particles" known as neutrinos to create the first-ever portrait of the Milky Way made from matter and not light — and it’s given them a brand-new way to study the universe.

The groundbreaking image was snapped by capturing the neutrinos as they fell through the IceCube Neutrino Observatory, a gigantic detector buried deep inside the South Pole’s ice.

Neutrinos earn their spooky nickname because their nonexistent electrical charge and almost-zero mass mean they barely interact with other types of matter. As such, neutrinos fly straight through regular matter at close to the speed of light.

Yet by slowing these neutrinos, physicists have finally traced the particles’ origins billions of light-years away to ancient, cataclysmic stellar explosions and cosmic-ray collisions. The researchers published their findings June 29 in the journal Science.

"The capabilities provided by the highly sensitive IceCube detector, coupled with new data analysis tools, have given us an entirely new view of our galaxy — one that had only been hinted at before," Denise Caldwell, director of the National Science Foundation’s physics division, which funded the research, said in a statement. "As these capabilities continue to be refined, we can look forward to watching this picture emerge with ever-increasing resolution, potentially revealing hidden features of our galaxy never before seen by humanity."

Every second, about 100 billion neutrinos pass through each square centimeter of your body. The tiny particles are everywhere — produced in the nuclear fire of stars, in enormous supernova explosions, by cosmic rays and radioactive decay, and in particle accelerators and nuclear reactors on Earth. In fact, neutrinos, which were first discovered zipping out of a nuclear reactor in 1956, are second only to photons as the most abundant subatomic particles in the universe.

Despite their ubiquity, the chargeless and near-massless particles’ minimal interactions with other matter make neutrinos incredibly difficult to detect. Many famous neutrino-detection experiments have spotted the steady bombardment of neutrinos sent to us from the sun, but this cascade also masks neutrinos from more unusual sources, such as gigantic star explosions called supernovas and particle showers produced by cosmic rays.

To capture the neutrinos, particle physicists turned to IceCube, located at the Amundsen-Scott South Pole Station in Antarctica. The gigantic detector consists of more than 5,000 optical sensors beaded across 86 strings that dangle into holes drilled up to 1.56 miles (2.5 kilometers) into the Antarctic ice.

While many neutrinos pass completely unimpeded through the Earth, they do occasionally interact with water molecules, creating particle byproducts called muons that can be witnessed as flashes of light inside the detector’s sensors. From the patterns these flashes make, scientists can reconstruct the energy, and sometimes the sources, of the neutrinos.

Finding a neutrino’s starting point depends on how clear its direction is recorded in the detector; some have very obvious initial directions, whereas others produce cascading "fuzz balls of light" that obscure their origins, lead author Naoko Kurahashi Neilson, a physicist at Drexel University in Philadelphia, said in the statement.

By feeding more than 60,000 detected neutrino cascades collected over 10 years into a machine-learning algorithm, the physicists built up a stunning picture: an ethereal, blue-tinged image showing the neutrinos’ sources all across our galaxy.

The map showed that the neutrinos were being overwhelmingly produced in regions with previously detected high gamma-ray counts, confirming past suspicions that many ghost particles are summoned as byproducts of cosmic rays smashing into interstellar gas. It also left the physicists awestruck.

"I remember saying, ‘At this point in human history, we’re the first ones to see our galaxy in anything other than light,’" Neilson said.

Just like previous revolutionary advances such as radio astronomy, infrared astronomy and gravitational wave detection, neutrino mapping has given us a completely new way to peer out into the universe. Now, it’s time to see what we find.

Source: https://www.livescience.com/physics-mathematics/particle-physics/ghost-particle-image-is-the-1st-view-of-our-galaxy-in-anything-other-than-light?utm_term=23709803-D360-4259-9C73-BE4FF46B5C71&utm_campaign=368B3745-DDE0-4A69-A2E8-62503D85375D&utm_medium=email&utm_content=2D5C159E-DF3C-4887-B039-4BED38DE05F5&utm_source=SmartBrief