00:06. Zielerfassung hat Dimorphos erfaßt, aber noch nicht darauf zentriert. Zielumschaltung erfolgt bei 00:26, bei minus 46 Minuten.
00:34. "41 Minuten bis zum Einschlag." Sh. Beitrag. Aktuelle Entfernung von Didymos: 11.807.643 km. 28fache Mondentfernung. Die Sonnenpaneele, die eine Gesamtenergie von 6,6 KW liefern, haben eine Spannweite von jeweils 8,5 Metern. 00:47. Didymos zeigt ganz klar eine Scheibe. Dimorphos als schwächere Scheibe rechts darüber in der 2-Uhr-Position. Zielerfassung auf 30 m zentriert. 00.49. "All systems are GO." 00:55. 20 Minuten bis zum Aufprall. 00:56. "We are precision-locked on Dimorphos." 1:13. 2 Minuten. Zielgenauigkeit 17 Meter. 1:15. Einschlag. (Es war nichts mit einer "Kuppel mit Parabolantenne.")
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat "What happened to the mouse?" occurs when a minor character, action or very minor plotline is suddenly dropped from the story for no apparent reason, without any real explanation about what happened to it, and without a resolution.
Zitat "A German professor, living in the USA, has invented a rocket carrying a mouse, in the hope of reaching the moon. But the spacecraft is attracted by an invisible asteroid peopled with tiny beings who increase the animal's intelligence and send him back on Earth, dressed as Mickey Mouse."
In den 1950er Jahren... Hoch oben in einer kleinen Dachgeschoss-Wohnung lebt ein kleiner Untermieter, eine kleine graue Maus. Eines Tages entdeckt sie das angestaubte Teleskop, das in den Nachthimmel über der Stadt gerichtet ist und beginnt, eine unglaubliche Welt zu erforschen. Wie alle Mäuse ist auch diese Maus seit jeher vom Mond fasziniert, dieser merkwürdigen weiß-gelben Scheibe. Mal steht er dick und rund am Himmel, dann wiederum ist er nur eine dünne Sichel. Was ist er? Mit wissenschaftlichem Eifer und ihrem Teleskop ergründet unsere kleine Maus das Rätsel des Mondes.
Doch die anderen Mäuse hören dem kleinen Astronomen nicht zu. Sie haben sich vor langer Zeit schon entschieden, etwas anderes zu glauben. Der Mond ist Käse! Der größte Käse!
So fasst die Maus eine tollkühne Entscheidung: Sie wird die erste Maus auf dem Mond! Und somit wird sie allen beweisen, was der Mond in Wirklichkeit ist.
Die hier:
Zitat Jonathan McDowell @planet4589 LICIACube has now passed through the Didymos system and is continuing on in solar orbit. Its images of the impact will be downloaded in the coming hours 1:32 AM · Sep 27, 2022·TweetDeck
Zitat Thomas Zurbuchen @Dr_ThomasZ The team will be giving an update on the #DARTMission and its Sept. 26 intentional collision with asteroid Dimorphos on Tuesday, 10/11 at 2pm ET. Learn how to tune in: https://nasa.gov/press-release/nasa-to-p...y-defense-test/
Remember: DART is a test and there are no known asteroid threats to Earth.
Zitat NASA will host a media briefing at 2 p.m. EDT, Tuesday, Oct. 11, to discuss the agency’s Double Asteroid Redirection Test (DART) mission and its intentional collision with its target asteroid, Dimorphos.
The briefing will air on NASA TV, the NASA app, and the agency’s website.
Participants include leaders from NASA, the Italian Space Agency, and the DART mission team.
To attend the briefing in person, or to participate remotely and ask questions, media must RSVP no later than two hours before the start of the briefing to Josh Handal at: joshua.a.handal@nasa.gov. NASA’s media accreditation policy is available online.
The media briefing will take place in the Webb Auditorium of NASA Headquarters Mary W. Jackson building, 300 E. Street, SW in Washington.
On Monday, Sept. 26, DART successfully impacted its asteroid target in the world’s first planetary defense technology demonstration. As a part of NASA’s overall planetary defense strategy, DART’s impact with the asteroid Dimorphos will help to determine whether asteroid deflection using a kinetic impactor spacecraft is a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet, if one were discovered. The Johns Hopkins Applied Physics Laboratory manages the DART mission for NASA's Planetary Defense Coordination Office as a project of the agency's Planetary Missions Program Office. Neither DART’s target asteroid, Dimorphos, nor its larger asteroid parent, Didymos, poses a hazard to Earth.
Zitat Jeff Foust@jeff_foust NASA Administrator Bill Nelson says DART successfully changed the orbit of Dimorphos, decreasing its orbital period around Didymos from 11hrs 55 mins to 11hrs 23mins, a 32-minute change. 8:04 PM · Oct 11, 2022·Tweetbot for Mac
The precision of that orbital change ±2 minutes, says NASa’s Lori Glaze, planetary science division director. The minimal requirement was 73-sec change, but models estimated a change of a few minutes to several tens of minutes, so on the upper end of those models. 8:13 PM · Oct 11, 2022·Tweetbot for Mac
Zitat ESA Operations @esaoperations The results are in. @NASA crashed the #DARTMission into asteroid #Dimorphos. They altered its orbit by 4%.
Orig. orbit around central 🪨: 11hr 55mins Models expected: a few-10 mins difference Post impact: 11hr 23mins. A 32 min orbital change! 8:30 PM · Oct 11, 2022·Twitter Web App
Apropos "Matrix" (weil der Bezug in 2 Tagen nicht mehr herstellbar ist: ich habe vor einer Viertelstunde meinem letzten ZR-Beitrag über "die Entdeckung des Nordpols" verlinkt, in dem die Schlußvolte damit spielt). Kaum verfolgt man mal ein paar Stunden das Weltgeschehen nicht, weil man konzentriert an der Tastatur sitzt, wird einem als erstes das hier eingespielt:
Zitat Tom Williams@tw__astro 🚨ATTENTION! A small asteroid is expected to safely impact the French-English channel in ~4 hours time, 03:00:03 UT tomorrow. Object size is around ~1 meter and should appear as bright as the Moon momentarily as it enters the atmosphere. Approx visibility circle posted below. 1/ 12:08 AM · Feb 13, 2023
Object was discovered by the Konkoly Observatory in Hungary a few hours ago. Temporary designation of the object is Sar2667. It is expected to enter the atmosphere at around a 45° angle, coming from the East. 2/
Impact time of 03:00:03 has an uncertainty of a few minutes as it stands, but should be narrowed down to a few seconds by impact time. I'll keep it updated here in this thread. 3/
Info from respectable comet/asteroid enthusiast, friend and planetary scientist, Sam Deen
New info. Velocity is around 14.2km/s. Duration of atmospheric entry should be on the order of 10-15 seconds. 4/ #Sar2667 #Asteroid
UPDATE: Impact time has been narrowed down to 02:59:17 UT (+/- 30 sec) #Sar2667 #Asteroid
FINAL UPDATE: Atmospheric entry (aka breach of 50km altitude) confirmed to be 02:59:17 UT +/- 1 sec. 1h 10m from now. #Asteroid #Sar2667 is currently ~10,000km away (Diameter of Earth) at the time of this tweet. It will enter Earth's shadow ~5 mins before impact
Now 2:59:16.8 UTC +/- 0.2 sec. Crazy devices we have these days
Zitat von Ulrich Elkmann im Beitrag #8 Was IST eigentlich hier los??
Zitat During a routine search for near-Earth objects with his 0.6 m (2.0 ft) Schmidt telescope,[9] Krisztián Sárneczky first imaged 2023 CX1 on 12 February 2023 at 20:18 UTC, when it was less than 233,000 km (145,000 mi) from Earth and inside the orbit of the Moon at 0.61 lunar distances. ... Sárneczky immediately recognized it was a near-Earth object but did not realize it was on course for impact with Earth until he reobserved it half an hour later. The European Space Agency took notice of the asteroid's impending impact and alerted the public through social media.[9] The asteroid was last observed on 13 February 2023 02:48:01 UTC by Sárneczky, just under 12 minutes before impact and two minutes before it entered Earth's shadow and became invisible at 02:50 UTC.
2023 CX1 is the seventh asteroid discovered before being successfully predicted to impact Earth.[6] It is also Sárneczky's second discovery of an impacting asteroid, after 2022 EB5 which he discovered a year prior in March 2022.
Zitat Scott Manley@DJSnM The measured change in Dimorphos velocity was only 2.7mm/sec That's the equivalent of changing it position by 170km in the last two years (if it wasn't in orbit around Didymos). More than enough to make it miss Earth if it had been a threat to the planet. Last edited 12:10 AM · Sep 27, 2024
Zitat ESA's Hera mission@ESA_Hera Two years ago today, @NASA’s DART spacecraft slammed into asteroid Dimorphos, changing its orbit around the larger object Didymos in the 1st test of asteroid deflection. Here’s 3 things we learned from the impact, and 3 remaining mysteries that @ESA’s #HeraMission will help solve!
1) DART confirmed that a spacecraft can change an asteroid’s trajectory by crashing into it. The impact shortened the orbit of Dimorphos around its parent asteroid Didymos by about 32 minutes, demonstrating that kinetic impact is a possible strategy for planetary defence.
2) DART demonstrated that a spacecraft can autonomously track down and steer into an asteroid while too far from Earth to rely on real-time trajectory corrections from its control team back on the ground. Hera will also test new autonomous navigation technology at Dimorphos
3) The effect of the DART impact was greater than expected. The impact sent more debris hurtling into space than anticipated, suggesting that the asteroid’s surface is more porous or fragile. The escaping debris amplified the force of the impact and the change in the asteroid’s motion.
Three mysteries Hera will help solve: 1) Hera will measure the density and composition of Dimorphos in detail and help scientists determine whether it is a ‘rubble pile’ loosely held together by gravity, or a solid core covered in boulders and gravel.
2) Hera will map the crater created by DART’s impact down to 10 cm resolution to help scientists better understand how the surface material responded to the collision. It’s possible that there is no crater at all, rather the impact reshaped the entire asteroid!
3) ~15% of known asteroids are actually binary systems, but their origins remain mysterious. Hera will determine whether Dimorphos and Didymos are made from the same material, which would hint that the rapidly spinning Didymos once threw off debris into space that later formed Dimorphos.
Hera's investigation of Dimorphos and Didymos will complete the story that DART began two years ago and turn asteroid deflection into a well understood and repeatable technique for protecting Earth from a potential asteroid impact. Stay tuned for launch next month! 3:17 PM · Sep 26, 2024
Da dies in den vergangenen Tagen die Runde machte:
Zitat Asteroid auf Kollisionskurs mit der Erde – NASA verdoppelt Einschlagsrisiko von «2024 YR4»
Letzte Woche vermeldeten diverse Medien, dass der im Dezember 2024 entdeckte Asteroid «2024 YR4» der Erde gefährlich nahe kommen könnte. Die NASA hatte berechnet, dass eine Wahrscheinlichkeit von 1,2 Prozent bestand, dass der Asteroid im Dezember 2032 auf der Erde einschlägt.
Diese Wahrscheinlichkeit wurde inzwischen von der NASA angehoben. Am 22. Dezember 2032 besteht laut aktuellen Berechnungen eine Einschlagswahrscheinlichkeit von rund 2,3 Prozent – das entspricht einer Chance von 1 zu 43, dass der Asteroid auf der Erde einschlägt.
Mit einem geschätzten Durchmesser von etwa 90 Metern ist «2024 YR4» ungefähr so gross wie der Asteroid, der 1908 beim Tunguska-Ereignis rund 2150 Quadratkilometer von sibirischen Wäldern verwüstete. Trotzdem mahnen Astronomen zur Gelassenheit. Schwankungen in der Einschlagswahrscheinlichkeit seien nichts Ungewöhnliches, wenn ein Objekt noch Jahre von der Erde entfernt ist, so die Botschaft. In einem YouTube-Video erklärt die ESA, dass die Wahrscheinlichkeit eines Einschlags von «2024 YR4» auf praktisch null sinken wird, sobald neue Daten zu Geschwindigkeit und Flugbahn in den kommenden Wochen und Monaten vorliegen.
Selbst wenn «2024 YR4» auf Kollisionskurs bleiben sollte, gibt es Grund zur Hoffnung: Die NASA hat 2022 mit der DART-Mission bewiesen, dass ein gezielter Einschlag einer Raumsonde in einen Asteroiden dessen Flugbahn effektiv verändern kann. Dies könnte eine potenzielle Abwehrstrategie sein, falls der Asteroid tatsächlich eine Gefahr darstellen sollte. (ear)
Zitat Scott Manley@DJSnM Let's do some math on how big a spacecraft would be needed to divert 2024 YR4 in 2028 so it would miss in 2032 - according to @astroEdLu the velocity uncertainty is 0.35m/s with a 2.3% chance of impact. That means there's roughly a 0.008m/s range in velocities which lead to an impact in 2032, change it by more than this much and it misses. That's less than a cm/second.
But on a 2028 intercept we'd have half the time, so, double that to 0.016m/s, let's say 0.02m/s just to add some margin.
When 2024YR4 flies past Earth at the closest point it's moving at 13km/sec, let's use that as our impactor velocity.
Slow it down and it arrives early in 2032 so that it passes through the encounter before the Earth arrives there.
Dividing 0.02 by 13,000 gets 1.54E-6 the required mass ratio between impactor and asteroid, that's assuming no beta value enhancement.
Estimates of the asteroid mass range from 25,000t up to over a million. So our spacecraft needs to be anything from 40kg to 1,600kg on impact. These are trivially possible to send out to 0.05 for a 2028 intercept, the hardest part is the high precision terminal guidance, hitting it straight on would be on the dark side of the asteroid. If we come from a different angle then cosine losses increase mass requirement.
But then we need to make sure we don't break the asteroid by hitting it too hard, which makes my recent video at the Ames Vertical Gun Range relevant! 4:18 PM · Feb 8, 2025
https://x.com/DJSnM/status/1888245943545528804
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat ESA Operations@esaoperations Astronomers will turn @ESA_Webb towards asteroid 2024 YR4 next month. The most powerful telescope ever launched into space will provide a more accurate estimate of the size of the asteroid, which has a very small chance of impacting Earth in 2032. https://blogs.esa.int/rocketscience/2025...eroid-2024-yr4/ 12:22 PM · Feb 10, 2025
Zitat Astronomers will use the NASA/ESA/CSA James Webb Space Telescope to improve our understanding of the size and orbit of asteroid 2024 YR4, which has a very small chance of impacting Earth in 2032.
Why is asteroid 2024 YR4 important?
Asteroid 2024 YR4 was discovered on 27 December 2024. As of 10 February 2025, it has an approximately 98% chance of safely passing Earth on 22 December 2032. Astronomers are working to reduce our uncertainty about the asteroid’s orbit and rule out any impact risk, but it will fade from view from Earth in a few months’ time, and a small chance of impact may persist until it becomes visible again in 2028.
The chance of impact is very slim, and the asteroid is small enough that the effects of any potential impact would be on a local scale, but the situation is significant enough to warrant the attention of the global planetary defence community.Astronomers will use the NASA/ESA/CSA James Webb Space Telescope to improve our understanding of the size and orbit of asteroid 2024 YR4, which has a very small chance of impacting Earth in 2032.
To accurately assess the hazard posed by asteroid 2024 YR4, we need a more precise estimate of its size. Our current estimate, 40—90 m, has not changed much since the asteroid was first discovered in December 2024, despite many follow-up observations.
This is because astronomers are currently limited to studying the asteroid via the visible light it reflects from the Sun. In general, the brighter the asteroid, the larger it is, but this relationship strongly depends on how reflective the asteroid’s surface is. 2024 YR4 could be 40 m across and very reflective, or 90 m across and not very reflective.
It is very important that we improve our size estimate for 2024 YR4: the hazard represented by a 40 m asteroid is very different from that of a 90 m asteroid.
Webb is able to study the infrared light (heat) that 2024 YR4 emits, rather than the visible light it reflects. Infrared observations can offer a much better estimate of an asteroid’s size, as explained in an article recently published in the journal Nature, co-authored by members of ESA’s Planetary Defence Office.
Astronomers will use Webb’s MIRI instrument to get a much more precise estimate of the asteroid’s size. This, in turn, will be used by ESA, NASA, and other organisations to more confidently assess the hazard and determine any necessary response.
Observations made using Webb’s NIRCam instrument will complement MIRI’s thermal data and will also provide additional measurements of the asteroid’s position once it is beyond the reach of Earth-based telescopes.
When will the observations of 2024 YR4 take place?
The first round of observations will take place in early March, just as the asteroid becomes observable by Webb and is at its brightest. The second round of observations will take place in May. Astronomers will use these later observations to study how the temperature of 2024 YR4 has changed as it has moved further away from the Sun and to provide the final measurements of the asteroid’s orbit until it returns into view in 2028.
"JWST sighting of decametre main-belt asteroids and view on meteorite sources" Burdanov et al., Nature volume 638, pages 74–78 (2025) (Published: 09 December 2024)
Zitat Abstract
Asteroid discoveries are essential for planetary-defence efforts aiming to prevent impacts with Earth1, including the more frequent2 megaton explosions from decametre impactors 3,4,5,6. Although large asteroids (≥100 kilometres) have remained in the main belt since their formation 7, small asteroids are commonly transported to the near-Earth object (NEO) population 8,9. However, owing to the lack of direct observational constraints, their size–frequency distribution (SFD)—which informs our understanding of the NEOs and the delivery of meteorite samples to Earth—varies substantially among models 10,11,12,13,14. Here we report 138 detections of some of the smallest asteroids (≳10 metres) ever observed in the main belt, which were enabled by JWST’s infrared capabilities covering the emission peaks of the asteroids 15 and synthetic tracking techniques 16,17,18. Despite small orbital arcs, we constrain the distances and phase angles of the objects using known asteroids as proxies, allowing us to derive sizes through radiometric techniques. Their SFD shows a break at about 100 metres (debiased cumulative slopes of q = −2.66 ± 0.60 and −0.97 ± 0.14 for diameters smaller and larger than roughly 100 metres, respectively), suggestive of a population driven by collisional cascade. These asteroids were sampled from several asteroid families—most probably Nysa, Polana and Massalia—according to the geometry of pointings considered here. Through further long-stare infrared observations, JWST is poised to serendipitously detect thousands of decametre-scale asteroids across the sky, examining individual asteroid families 19 and the source regions of meteorites 13,14 ‘in situ’.
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