Grmpf... Die aus dem schottischen Recht übernommene Eidesformel lautet natürlich nicht "die schlichte Wahrheit", sondern "the whole truth, and nothing but the truth", die ganze Wahrheit und nichts als die Wahrheit.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat von February 15, 2023The small asteroid that created a light show on February 12-13, 2023, has left meteorites behind on the ground. One lucky searcher – 18-year-old Loïs Leblanc, who was part of a French search team – already found a piece of the asteroid. According to the International Meteor Organization (IMO), the asteroid, first known as Sar2667 and now as 2023 CX1, mostly broke up in our atmosphere. But, IMO has calculated the range where the meteorites would have dropped. The strewn field would be centered on the towns of Angiens and Houdetot. IMO said:
Probably only one large piece, of a mass of about 3 kg, emerged and could have later landed as a ~2 kg meteorite. We guess that an uncertain number of small meteorites of masses up to several tens of grams, which originated in the disruption events, could land as well.
Zitat The ground projection of the trajectory is plotted in Fig. 1. The fireball was first recorded at a height of 89 km. The maximum brightness was reached in a narrow peak at a height of 27.3 km and the fireball disappeared at a height of 20 km. The radiant had an azimuth of 282.3 degrees and zenith distance of 41.4 degrees. The modeling of the light curve suggests that the meteoroid suffered little fragmentation before it reached the height of 29 km. At that height, a fragmentation event occurred, followed by even more destructive fragmentation at 28 km. During these events, most of the meteoroid disrupted into small fragments, which evaporated very quickly. Probably only one large piece, of a mass of about 3 kg, emerged and could have later landed as a ~2 kg meteorite. We guess that an uncertain number of small meteorites of masses up to several tens of grams, which originated in the disruption events, could land as well.
Figure 2 shows the possible meteorite strewn field. The dark flight was computed using the high altitude wind measurements by the radiosonde in Herstmonceux, UK, at 0 UT on Ferbruary 13 (downloaded from the website of the University of Wyoming). The largest meteorite is expected fo fall near the village of Vénestanville. Small meteorites may be located near Houdetot and Angiens. It cannot be excluded that some individual fragments could be found also in between the large and small meteorite areas, especially if the largest piece fragmented additionally at a later stage (possibly even during the dark flight). Also, the small meteorite area may be wider than plotted. The strewn filed calculations can be further improved in the future by using a wind model for the given location and time. The most interesting aspect of 2023 CX1 is that this large meteoroid/small asteroid, which entered the atmosphere at favorably low speed (14 km/s) and moderate entry angle, probably produced only small total mass of meteorites. Note that the masses given here have been computed under the assumption of meteorite density corresponding to ordinary chondrites.
Zitat von ZR, 16.02.23...zwar werden die meisten der gut 6000 Meteoriten, von denen genügend Material bleibt, um den Erdboden zu erreichen nicht vorher aufgefunden. Beim Meteoriten von Tscheljabinsk etwa wäre das auch nicht theoretisch möglich gewesen, das er beinahe „aus der Sonne kam“ und ihr Licht jede Entdeckung unmöglich gemacht hätte. ... Aber bei einer Vorwarnzeit von einigen Tagen oder gar Wochen ließen sich immerhin Evakuierungsmaßnahmen einleiten und die Menschen in den betroffenen Gebieten entsprechend vorwarnen.
Aufs Stichwort:
Zitat ESA@esa Our planned #NEOMIR mission will orbit between Earth and the Sun and will act as an early warning system for #asteroids 20 m and larger that cannot be seen from the ground because they come towards Earth from the direction of the Sun 11:35 AM · Feb 17, 2023
Zitat Space Safety - NEOMIR: finding risky asteroids outshone by Sun
In brief Asteroids, like stars, only come out at night. Hidden in the glare of our Sun are an unknown number of asteroids on paths we cannot track, many of which could be heading for Earth, and we just don’t know it. ESA’s planned NEOMIR mission will be located between Earth and the Sun and will act as an early warning system for asteroids 20 metres and larger that cannot be seen from the ground.
Predicting Chelyabinsk No one saw the Chelyabinsk meteor of 15 February 2013 coming. Just after sunrise on a calm and sunny winter’s day, a 20-metre asteroid struck the atmosphere over the Ural Mountains in Russia, at a speed of more than 18 km/s. The relatively small rock approached Earth from very near the direction of the Sun, exploding in the atmosphere and creating a shockwave that damaged thousands of buildings, breaking windows and injuring roughly 1500 people from flying shards of glass. It was the largest asteroid to strike Earth in over a century.
In fact, we have discovered almost all asteroids larger than 1 km in size. Small and medium-sized asteroids are more common, and can still do great damage, but warning times of a few days can be enough for local authorities to notify the public to keep away from windows or even to evacuate a local area.
Asteroids are visible because they reflect the Sun’s light, which we can detect from Earth. However, the closer they get to the Sun, the harder they are to see. Asteroids crossing the face of the Sun are particularly difficult to detect, but from Earth we are also blind to asteroids near the Sun as they are outshone by its glare.
ESA’s upcoming NEOMIR mission will be launched into orbit around the first Lagrange point (L1) between the Sun and Earth, remaining in the same position relative to the two bodies. This will give the telescope a constant view of asteroids that may come towards the Earth from the direction of the Sun.
Being situated outside of Earth’s distorting atmosphere and with a telescope observing in infrared light, NEOMIR will monitor a close ring around the Sun that is impossible to observe from the ground. The mission will detect asteroids passing between Earth and the Sun – any that pose a threat and that we cannot currently see will have to pass through this ring.
By making observations in the infrared part of the light spectrum, NEOMIR will detect the heat emitted by asteroids themselves, which isn’t drowned out by sunlight. This thermal emission is absorbed by Earth's atmosphere, but from space NEMOIR will be able to see closer to the Sun than we can currently from Earth.
Asteroids 20 metres and larger that are heading toward Earth should be detected by NEOMIR at least three weeks in advance. In the worst-case scenario, in which the asteroid is spotted passing near the spacecraft, we would get a minimum of three days’ warning – the fastest the asteroid could move from L1 to Earth.
Details of the Space Safety Programme's NEOMIR mission are currently being fleshed out and it is planned to be launched around 2030 with an Ariane 6-2 rocket
Zitat ‘Meteorite’ seen speeding over South Texas shakes homes and creates loud 'boom' sound that residents thought was earthquake or gas explosion A fiery object resembling a 'meteorite' was seen flying over Texas on Wednesday Officials have not confirmed the mysterious object but it later crashed Footage revealed homes shaking and a loud explosion when the object hit earth
17:07 GMT, 16 February 2023 | Updated: 18:28 GMT, 16 February 2023
A massive 'meteorite' was seen speeding over South Texas as awestruck residents reported a loud explosion they thought was an earthquake. Officials have yet to confirm the mysterious object that beamed through the sky around 5pm on Wednesday before a boom was heard when the 'meteor' landed near McAllen neighborhoods. Footage of the 'meteor' showed the fiery object shoot through the sky as home surveillance cameras caught the moment it supposedly crashed - creating a loud explosion and shaking homes.
The National Weather Service reported the object and claimed their satellites that detect light from space picked up on the signal. The agency then plotted the occurrence on its Geostationary Lightning Mapper. Houston Air Traffic Control also received reports from two planes about a possible meteorite near the town, according to Hidalgo County Sheriff Eddie Guerra.
Zitat NASA Says 1,000-Pound Meteor Streaked Across South Texas Sky No impact site has been located, though loud booms we reported as a meteor burned through Earth's atmosphere Wednesday By Frank Heinz • Published February 16, 2023 • Updated 11 mins ago
On Thursday, NASA said a half-ton meteoroid broke apart over South Texas Wednesday night and radar showed fragments of it reached the ground.
"Based on analysis of preliminary information from several sources, NASA experts believe the object was a meteoroid about two feet in diameter weighing about 1,000 pounds," a NASA news release said Thursday.
"The angle and speed of entry, along with signatures in weather radar imagery, are consistent with other naturally occurring meteorite falls. Radar and other data indicate that meteorites did reach the ground from this event," the statement continued.
Cesar Torres, Chief of Police in Mission, said 911 dispatchers took calls from panicked residents at about 5:28 p.m. who reported hearing what sounded like explosions. Other callers said the booms left the walls of their homes shaking.
The National Weather Service in Brownsville reported that their Geostationary Lightning Mapper, a satellite that measures lightning, recorded flashes of light in the atmosphere that were bright enough to be detected by their satellites at about 5:23 p.m. though there were no storms in the area at the time.
U.S. Rep. Monica de la Cruz (R-TX, 15th District) said if the meteor made it to the ground they believe it would have come down about 10 miles west of Mission. De la Cruz said she expected to receive a briefing from NASA sometime Thursday.
"We have meteorites that have hit all over," de la Cruz said. "NASA scientists estimate that every single day our planet is hit by over 100 tons of dust and particles from space. So again, while this is not a normal situation here in the Rio Grande Valley, it does occur."
Should anyone find a crater or an object they believe to be a meteorite, Guerra cautioned against touching it with bare hands out of concern the oils from human skin could contaminate the surface of the object and promote rusting. NASA has tips, here, on what to do if you find a meteorite.
Zitat Moment 'beaming bright light' flashes across the sky in Queensland By Allanah Sciberras 9:58pm May 21, 2023
People from across Queensland have reported seeing bright blue and green flashes in the sky, followed by a boom.
In another video shared with 9News, Marcello Avolio captured what he called a "fire ball" in the sky. The still quiet of the night was suddenly disrupted with a blinding flash. Australian National University Astrophysicist Dr Brad Tucker confirmed the item was "definitely" a meteor." "This was a bit of space rock essentially, probably broken off an asteroid in the asteroid belt, the area between Mars and Jupiter," he said.
Tucker said the meteor was travelling anywhere between 100,000 and 150,000 km/h. "The blue-green colour is iron and nickel on the meteor heating up," he said. "It breaks apart and as it breaks apart, that's what gives us that flash and sonic boom that people heard and saw.
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