#asteroid

#asteroid

Fossils May Show Us the Day of the Asteroid ImpactAround 66 million years ago, a 12-kilometer-wide asteroid slammed into the earth, causing a massive explosion that sent debris into the atmosphere for years. The impact was felt 3,000 kilometers away, where it caused animals to die instantly. Earth tremors caused waves of water to surge onto land. Particles of molten rock invaded the gills of fish. A turtle was impaled on a piece of wood. A dinosaur had its leg blown off. Some 66 million years later, humans dug up the remains of that devastating event in South Dakota, at an archaeological dig called Tanis. Scientists have been studying the fossils of Tanis for years. They can't definitively say that the chaos at Tanis was left on the exact day of the Chicxulub impact that wiped out the dinosaurs, but the signs are all there. The chemical makeup of the particles found in fish are what one would expect from the impact. The well-preserved dinosaur leg, from a Thescelosaurus, shows no signs of disease, and the rest of it is nowhere nearby. The Tanis fossils will be the subject of a BBC special titled Dinosaurs: The Final Day with Sir David Attenborough, to be broadcast on BBC One on April 15th. It will be aired on the PBS series Nova this fall. Read about the extraordinary finds from Tanis at BBC News. -via Damn Interesting#Chicxulub #fossil #dinosaur #Tanis #asteroid

NASA Practices for ArmageddonIn the 1998 movie Armageddon, astronauts landed on an asteroid and blew it up with nuclear weapons. In another 1998 film, Deep Impact, astronauts do the same to a comet. Both missions were to keep the celestial object from colliding with Earth. The new science fiction comedy Don't Look Up appears to have somewhat the same plot. You may wonder if such a scenario is possible. Yes it is, as we know from the asteroid impact that sent the dinosaurs into oblivion. Is it likely? That depends on what size asteroid, and what size disaster you are willing to endure. But NASA is definitely thinking about contingency plans.  The space agency's Double Asteroid Redirection Test Mission, or DART, is a test to see if we have the know-how to avert an incoming asteroid. The mission lifted off yesterday on a SpaceX Falcon 9 rocket. It will take nearly a year to reach its target, a moon revolving around the asteroid Didymos. The small asteroid is not on a collision course for Earth, but presents a test case for our ability to alter an asteroid's course. Rest assured that the DART spacecraft will not deploy nuclear weapons. The aim is not to obliterate the asteroid, just change its trajectory. While that doesn't make the mission quite as exciting as a movie, it will be much more useful for our ability to save Earth if that ever becomes necessary. Read about the mission at CNN. (Image credit: NASA/Johns Hopkins Applied Physics Lab) #asteroid #asteroiddeflection #NASA #DART

How Did Birds Survive the Asteroid Impact That Killed the Dinosaurs?Around 66 million years ago, the Chicxulub event changed the world when an asteroid slammed into the Yucatan Peninsula and plunged the world into a darkness that killed off 75% of the existing species. The dinosaurs were the best-known of the victims. But not all dinosaurs died out. The few that survived were birds. Even then, the surviving bird species were only a small percentage of the birds that existed before the asteroid impact. Why these these particular species of birds survive? What's the difference between Cretaceous birds and those living today? It appears to be big brains. But it's not just size- new scans of Ichthyornis, a bird that went extinct after the asteroid impact, shows a small forebrain, or cerebrum, like many dinosaurs. Modern birds have much larger forebrains compared to their other brain structures. The forebrain is responsible for many functions, so scientists don't yet know exactly how a larger forebrain aided some birds' survival, but speculate that it might have made them more able to modify their behavior in the face of a new environment. Just don't call them birdbrains. Read more about this research at LiveScience. -via Damn Interesting Image credit: Torres et al/CC BY 4.0)#bird #dinosaur #birdevolution #extinction #asteroid #birdbrain

Dashcam Footage Used to Calculate Trajectory and Track the Location of Meteorite in SloveniaFebruary 28, 2020. People in southern Slovenia were suddenly disturbed with loud explosions and a 3.5-second flash which left a visible trail of dust. A bright ball of light in the sky was also seen in various countries on that day. It was recorded in dashcams, helmets, and security cameras.The ball of light in question was a rock from a distant asteroid. The rock was about one meter across and weighed about four metric tons before entering our atmosphere before it broke down into 17 pieces.But where exactly did these rocks fall? To solve this, scientists have combined observations from cameras to measure the trajectory of the fireball. In doing so, they can determine where in the Solar System it came from, and where it went. This approach proved effective at night. However, because the ball was spotted during the day, scientists needed a different method. They asked local people to take pictures from various locations to help compute the trajectory.See the full story over at the Europlanet Society.(All Videos: Europlanet Society)#Meteorite #TrajectoryCalculation #Asteroid #SpaceRock #Slovenia

Early Earth was Regularly Hit by City-Sized AsteroidsScientists know that early Earth was bombarded by meteor strikes, but new analysis revealed that the number of those impacts were actually much, much higher than originally thought.The size of the meteor was also much larger - some are city-sized asteroid, with estimated size of more than 10-km wide."We have developed a new impact flux model and compared with a statistical analysis of ancient spherule layer data. With this approach, we found that current models of Earth’s early bombardment severely underestimate the number of known impacts, as recorded by spherule layers", said Physicist Simone Marchi of the Southwest Research Institute in Boulder, Colorado."The true impact flux could have been up to a factor of 10 times higher than previously thought in the period between 3.5 and 2.5 billion years ago. This means that in that early period, we were probably being hit by a Chicxulub-sized impact on average every 15 million years. Quite a spectacle!"The Chicxulub impact was caused by a 10 km (6.2 miles) diameter asteroid, and was thought to cause a mass extinction of 75% of plant and animal species on Earth, including all non-avian dinosaurs.Via EurekAlertImage: Meteor Crater in Arizona, which was the result of an impact of a 50 meter (164 feet) meteor, by Dr Dale Nations/AZGS.#meteor #asteroid #massextinction #meteorite #EarlyEarth #ChicxulubImpact

Soil From Ryugu Asteroid has Ingredients for Creating LifeInitial analysis by Eizo Nakamura of Okayama University showed that soil sample from the Ryugu asteroid, brought back to Earth by Hayabusa 2, contains enough hydrogen and molecules of organic substances that can be ingredients of life.From Asahi Shimbun:The Japan Aerospace Exploration Agency announced the discovery on June 17 at a news conference it held prior to starting a full-scale analysis of the soil samples brought back by the space probe.The discovery is expected to assist in investigating the theory that the elements that created life on Earth arrived from space....Nakamura said that a large number of hydrogen atoms, believed to have constituted water molecules, were discovered in soil collected from and below the surface of Ryugu. Hayabusa 2 collected the underground soil samples by blasting an artificial crater on the asteroid.#asteroid #RyuguAsteroid #Hayabusa2 #JAXA