ESA: Small meteorite will safely impact atmosphere tonight over northern France(twitter.com)
twitter.com
ESA: Small meteorite will safely impact atmosphere tonight over northern France
https://twitter.com/esaoperations/status/1624901825785724929
84 comments
I used to do some astrophotography and I won't ever forget watching one night during the Perseids as a massive fireball streamed across the sky, completely unexpected, the thing was in the sky for a proper 2-3 seconds. I remember being freezing that night, and it was about a 1 hour drive to get to the location, absolutely worth it though!
I still do astrophotography - but nothing will ever top the broad daylight bolide I saw over France 30 years ago aged 10 or so - huge blue fireball labouring its way across the sky before disintegrating in an explosion as bright as the sun. I actually dropped to my knees in awe, the garbage I was carrying utterly forgotten.
Can I recommend:
Desert Fireball Network (Curtin University)
http://fireballsinthesky.com.au/
https://gfo.rocks/blog.html
Desert Fireball Network (Curtin University)
http://fireballsinthesky.com.au/
https://gfo.rocks/blog.html
One way amateurs can help is by setting up a meteor detection system and engaging in a little citizen science. A few years ago this was an expensive task, but now with a Raspberry Pi and some simple electronic parts it’s much easier.
I wonder what percentage of people will go a whole lifetime without seeing a bolide, or even a shooting star. Dark sky areas are harder and harder to come across as well, and I bet looking up at the sky for a few minutes is becoming more of a rarity as well.
Plenty. I live in a very dark sky area - about 2 bortle - and I threw a small star party for some local friends and their friends. They were astonished when I pointed out that you can see satellites, and there was some lively debate over whether the milky way was just a cloud.
It just isn’t important to most people. It’s understandable - our gods used to be in the sky - now they are on the television.
It just isn’t important to most people. It’s understandable - our gods used to be in the sky - now they are on the television.
Even with pure Sky, a lot of people don't look up. I think its more a matter of education. We have to learn to young people to watch the Sky, and how to watch it (being able to identify stars, constellations, the ecliptic plane, ...).
Was that in 2016?
I've been watching meteor showers for about 40 years, but the 2016 Peseids was just amazing. At it's peak, we were getting 2 or 3 large meteors per minute. We couldn't stop saying "wow" about one before another would streak 1/3 across the sky. And I'm sure that we saw over a dozen bolides, at least one or two bright enough to cast shadows on the ground. It was that spectacular. I don't remember when the moon set but I believe that it was gone by the time the show peaked between 1 and 2 am. Truly a night I'll never forget.
I've been watching meteor showers for about 40 years, but the 2016 Peseids was just amazing. At it's peak, we were getting 2 or 3 large meteors per minute. We couldn't stop saying "wow" about one before another would streak 1/3 across the sky. And I'm sure that we saw over a dozen bolides, at least one or two bright enough to cast shadows on the ground. It was that spectacular. I don't remember when the moon set but I believe that it was gone by the time the show peaked between 1 and 2 am. Truly a night I'll never forget.
Probably closer to 2012 or 2013 but I had been watching them almost every year up until 2017 or so. They never disappoint but definitely some years are a different kind of spectacle :)
UKMON has received 40 reports and 4 videos so far, from which they have the meteor coming into Dieppe
http://ukmon.imo.net/members/imo_view/event/2023/937
Thank you for the great video. Works by default on my iPhone 14 in Safari.
> Quite sad it defocused
Look at it from the bright side. You will never forget to manually focus the next time a meteorite passes by. :)
Look at it from the bright side. You will never forget to manually focus the next time a meteorite passes by. :)
It's not that I forgot, actually. I considered using the "pro video" mode on my phone where I can manually set focus to infinity, but decided against it because
- I wouldn't know what shutter time and ISO setting to use, or if it should need to be adjusted during the event when I want to be watching it
- I was already fairly late to the party to start thinking about and configuring this stuff: I didn't know of the +/-1 second window at the time, only saw the 10-minute window (which was a good thing because an adjacent tweet in that thread said it wouldn't be visible even halfway here so I might not have gone out at all!)
- The phone will try to use a broader light range ('HDR') in default mode, which is not something I understand (my confusion about that is a comment in itself), but not in pro mode. It doesn't work for extremes like capturing the sun as part of any picture, but in most cases it will work as though you took two pictures with slightly different shutter times and it'll scale values and stitch the pictures so that the dark areas are not pitch black and the bright areas are not full white. That seems like something I'd not want to disable, as it might make it capture more detail of the bright parts of the event.
... but as I write this, I realize that I can select 'auto' for shutter, ISO, white balance, etc. also in pro mode. Configuring the shutter is the main reason I use pro mode for, so it hadn't occurred to me that there is also a little 'auto' button for that in the corner! Not at the time, and not at the beginning of this comment either ^^'. I can set focus to infinity and only lose "HDR", not automatic selection of other settings. That might actually be worth it, don't know. But that's a good thing to be aware of, so thanks for making me realize this :D
- I wouldn't know what shutter time and ISO setting to use, or if it should need to be adjusted during the event when I want to be watching it
- I was already fairly late to the party to start thinking about and configuring this stuff: I didn't know of the +/-1 second window at the time, only saw the 10-minute window (which was a good thing because an adjacent tweet in that thread said it wouldn't be visible even halfway here so I might not have gone out at all!)
- The phone will try to use a broader light range ('HDR') in default mode, which is not something I understand (my confusion about that is a comment in itself), but not in pro mode. It doesn't work for extremes like capturing the sun as part of any picture, but in most cases it will work as though you took two pictures with slightly different shutter times and it'll scale values and stitch the pictures so that the dark areas are not pitch black and the bright areas are not full white. That seems like something I'd not want to disable, as it might make it capture more detail of the bright parts of the event.
... but as I write this, I realize that I can select 'auto' for shutter, ISO, white balance, etc. also in pro mode. Configuring the shutter is the main reason I use pro mode for, so it hadn't occurred to me that there is also a little 'auto' button for that in the corner! Not at the time, and not at the beginning of this comment either ^^'. I can set focus to infinity and only lose "HDR", not automatic selection of other settings. That might actually be worth it, don't know. But that's a good thing to be aware of, so thanks for making me realize this :D
> that's a good thing to be aware of, so thanks for making me realize this :D
NP :)
NP :)
Great writeup, thanks!
How did you check your phone's time synchronization?
How did you check your phone's time synchronization?
https://time.is
Per this thread https://twitter.com/tw__astro/status/1624908400902504451 it seems my time is a bit off, though. I took the filename and just checked the time offset in the video. Was considering checking metadata but thought 'nah, those few milliseconds difference'. However, exiftool says 2023:02:13 02:59:29, file name is 20230213_035256.mp4. Adding those three seconds to my previous guess comes out to the tweet's time.
As I write this, I'm still... what's the word, excited? Thrilled? Like, I'm still not down to baseline relaxed. It's really just five seconds of light show, but looking at an astronomical event unfolding, knowing this is hundreds of kilometers away in northwestern France, the tiny voice in the back of your head as you see it explode "could they have been wrong about it being just 1 meter?" I wasn't truly scared at any point but the combination of feelings and awe is still a little bit with me.
Per this thread https://twitter.com/tw__astro/status/1624908400902504451 it seems my time is a bit off, though. I took the filename and just checked the time offset in the video. Was considering checking metadata but thought 'nah, those few milliseconds difference'. However, exiftool says 2023:02:13 02:59:29, file name is 20230213_035256.mp4. Adding those three seconds to my previous guess comes out to the tweet's time.
As I write this, I'm still... what's the word, excited? Thrilled? Like, I'm still not down to baseline relaxed. It's really just five seconds of light show, but looking at an astronomical event unfolding, knowing this is hundreds of kilometers away in northwestern France, the tiny voice in the back of your head as you see it explode "could they have been wrong about it being just 1 meter?" I wasn't truly scared at any point but the combination of feelings and awe is still a little bit with me.
> Holy crap that was exhilarating
A perfect occasion to... laachen?
A perfect occasion to... laachen?
> exhilarating - causing strong feelings of happy excitement and elation
TIL that refers specifically to feelings that would cause laughing. Took me a while to get your pun, also because (to this dutchman) aachen is two sounds removed from lachen and not one like it might be for a german (where they hardly differentiate between short a and long aa).
I find it hard to describe feelings (in any language), maybe "shocking" is a better word than exhilarating? But that sounds more negative than I mean it. The german word that comes to mind (I hardly speak german so this might be far off) is aufregend which dict.cc says translates to both shocking and thrilling, maybe that's a better description because it's not specifically about being happy or scared but rather a neutral energetic feeling? "Getting worked up" might be a translation of aufregen but it doesn't sound like what an english speaker would say in this situation due to connotation.
TIL that refers specifically to feelings that would cause laughing. Took me a while to get your pun, also because (to this dutchman) aachen is two sounds removed from lachen and not one like it might be for a german (where they hardly differentiate between short a and long aa).
I find it hard to describe feelings (in any language), maybe "shocking" is a better word than exhilarating? But that sounds more negative than I mean it. The german word that comes to mind (I hardly speak german so this might be far off) is aufregend which dict.cc says translates to both shocking and thrilling, maybe that's a better description because it's not specifically about being happy or scared but rather a neutral energetic feeling? "Getting worked up" might be a translation of aufregen but it doesn't sound like what an english speaker would say in this situation due to connotation.
"Aufregend" sounds fitting to me as a native German speaker. In most contexts I would translate it as "exciting". It can have some more negative connotations, in the "getting worked up" sense, but mostly when used like "sich über etwas aufregen" (so as a verb not an adjective), and when describing your feelings regarding this event it's more on the "exciting/thrilling" side.
I happened to be up watching the Super Bowl in the UK, saw the ESA tweet across my timeline and was able to pop outside to see it at the time they predicted - was also able to grab a video [0].
So cool to see how far our detection of these objects is coming along, especially for something as small as this was.
[0] https://twitter.com/teh_c/status/1624967399131824130
So cool to see how far our detection of these objects is coming along, especially for something as small as this was.
[0] https://twitter.com/teh_c/status/1624967399131824130
Would you be willing to share your exact location, perhaps in an email to [email protected]? From a sibling comment:
> Got so lucky finding that Brighton video as the 2nd result earlier. Spent another 15 minutes looking for a third angle but the "looking east", "looking south" indicated angles are either implausible or too inaccurate to be useful. A Paris video is of such quality that I couldn't for the life of me find out which buildings are in view to map it to an angle.
There is a building visible in your video, so with that info I could figure out the angle to get a third line. I currently have these two: https://snipboard.io/rBNozt.jpg
Or if someone simply knows where to find someone who has a calibrated observation with range finder, I'd also be happy to find the location that way :D somehow I'm having a lot of trouble finding any information about this stone.
> Got so lucky finding that Brighton video as the 2nd result earlier. Spent another 15 minutes looking for a third angle but the "looking east", "looking south" indicated angles are either implausible or too inaccurate to be useful. A Paris video is of such quality that I couldn't for the life of me find out which buildings are in view to map it to an angle.
There is a building visible in your video, so with that info I could figure out the angle to get a third line. I currently have these two: https://snipboard.io/rBNozt.jpg
Or if someone simply knows where to find someone who has a calibrated observation with range finder, I'd also be happy to find the location that way :D somehow I'm having a lot of trouble finding any information about this stone.
https://snipboard.io/4T8Qvf.jpg
Does this help at all? The line on the left is when the object first becomes visible in the video, and the line on the right is when it explodes and disappears from view - it's actually pretty similar to what you had already.
Does this help at all? The line on the left is when the object first becomes visible in the video, and the line on the right is when it explodes and disappears from view - it's actually pretty similar to what you had already.
Yes, thank you! Overlaying the two, that is indeed awfully close to at least one end: https://snipboard.io/ADVdcO.jpg
What puzzles me is that the other end is so far off that it's outside what I had previously screenshotted of the map (so not visible when intersecting the two). From my POV, the angle difference between start and end was close to zero, like it came fairly straight down. That would be in line with yours if it roughly came towards me, as it roughly indeed did afaict, but I don't think the Brighton pier video had that wide a range. (I should re-watch it to be sure, though.)
There are also various reported angles on this event page https://ams.imo.net/members/imo_view/event/2023/937 but half of those honestly look in line with what I previously noticed where a video might have a description "facing east from Jersey" which would mean Paris is in the ~center of their view, not the English channel in front of Dieppe, resulting (because no visible landmarks) in lines like these horizontal/vertical ones <https://snipboard.io/d3rkNI.jpg>. Compared to all that, your report is definitely more useful! It would seem the meteor traveled at least 30 if not 50 km in those ~five seconds!
What puzzles me is that the other end is so far off that it's outside what I had previously screenshotted of the map (so not visible when intersecting the two). From my POV, the angle difference between start and end was close to zero, like it came fairly straight down. That would be in line with yours if it roughly came towards me, as it roughly indeed did afaict, but I don't think the Brighton pier video had that wide a range. (I should re-watch it to be sure, though.)
There are also various reported angles on this event page https://ams.imo.net/members/imo_view/event/2023/937 but half of those honestly look in line with what I previously noticed where a video might have a description "facing east from Jersey" which would mean Paris is in the ~center of their view, not the English channel in front of Dieppe, resulting (because no visible landmarks) in lines like these horizontal/vertical ones <https://snipboard.io/d3rkNI.jpg>. Compared to all that, your report is definitely more useful! It would seem the meteor traveled at least 30 if not 50 km in those ~five seconds!
There's a moon in that video. That'll give you the angle more accurately than a building.
I considered that, but I don't think that works because where the moon appears in the sky also depends on where you are. There are two unknowns (moon and meteor) and one video (one equation), if I understand the math correctly (we didn't have solving multiple unknowns in school but this is the theory I heard in relation to GPS needing 4 sats to solve for x,y,z,time).
It surprised me how many different combinations of meteor-moon constellations I saw in the various videos being posted. For some, the moon was very close; for me, the moon was like 110° removed I think (somewhere over my left shoulder). Maybe, knowing it was in England, it could help me to narrow down the scenarios (perhaps from an area down to a line?), but I don't have the experience to do that in a time-effective manner and I don't know if it would significantly help with the outcome.
It surprised me how many different combinations of meteor-moon constellations I saw in the various videos being posted. For some, the moon was very close; for me, the moon was like 110° removed I think (somewhere over my left shoulder). Maybe, knowing it was in England, it could help me to narrow down the scenarios (perhaps from an area down to a line?), but I don't have the experience to do that in a time-effective manner and I don't know if it would significantly help with the outcome.
The exact location of the moon in the sky depends to a very small extent on your location on the earth's surface. The tweet says near Brighton, and that's already accurate enough to tell the direction of the moon much more accurately than the size of the moon in the sky. At the time of the video (3am UK time), the moon from brighton was at a compass heading of 144 degrees (calculated by Stellarium). The observer location of "near Brighton" is accurate to within a few km.
The moon at that time had a diameter in the sky of 0.5225 degrees (it doesn't change much), so you can also get a reasonably accurate idea of the zoom level of the video, taking the size of the moon in pixels when it is most in-focus (and accounting a bit for glare).
The moon at that time had a diameter in the sky of 0.5225 degrees (it doesn't change much), so you can also get a reasonably accurate idea of the zoom level of the video, taking the size of the moon in pixels when it is most in-focus (and accounting a bit for glare).
How? Everywhere nearby me, the moon is in the same direction, but my building isn't.
ESA's own Twitter stream would be a more direct (and informative, in this case) source:
<https://twitter.com/esaoperations/status/1624901825785724929>
Looks as if the predicted entry point will be over Rouen.
That tweet cites Richard Moissl (also on Twitter):
<https://twitter.com/Richard_M_F/status/1624890692156751872>
<https://twitter.com/esaoperations/status/1624901825785724929>
Looks as if the predicted entry point will be over Rouen.
That tweet cites Richard Moissl (also on Twitter):
<https://twitter.com/Richard_M_F/status/1624890692156751872>
Ok, changed to that from https://twitter.com/disclosetv/status/1624909455325294593. Thanks!
Appreciated.
(For those reading this: I'd of course emailed [email protected], largely with the text in my comment. It's an effective way to get attention / make changes to posts.)
(For those reading this: I'd of course emailed [email protected], largely with the text in my comment. It's an effective way to get attention / make changes to posts.)
[deleted]
Impactor is ~1m in size, and projected impact time is 04:00 +/- 10 minutes CET (03:00 UCT).
That's about three hours from now as I write this.
My very off-the-cuff estimate is that a 1m impactor might mass anything from a few hundred kilos to a few tonnes, depending on composition (less for ice / chondrites, more for a heavy nickel-iron meteorite).
Looking forward to the skycam views.
That's about three hours from now as I write this.
My very off-the-cuff estimate is that a 1m impactor might mass anything from a few hundred kilos to a few tonnes, depending on composition (less for ice / chondrites, more for a heavy nickel-iron meteorite).
Looking forward to the skycam views.
Stupid question: if the impact time is +/- 10 minutes, doesn't that translate into a lot of uncertainty for where it will hit? How do they know it's going to be Rouen?
My (lay, nonexpert) understanding is:
- The centroid of probability is near Rouen.
- Earlier/later impact probability would be along a path along the movement/orbit of the impactor. I'm going to guess that that's largely east-west track, though with a possible orbital inclination.
- The probability distribution across that range is likely far higher near the centre than at the extremes.
- Relative motion of Earth's rotation (~1,600 km/hr at the equator, less than that at the latitude of Rouen) is a much smaller component than the likely relative velocity of the meteorite (~20 km/s).
- 20 km/s +/- 10 minutes ... gives 12,000 km as a possible range around the impact site.
There's also the question of accurately noting the original position of the impactor.
That said: good question and I'd love to hear from someone who knows what they're talking about.
Thought also comes to mind of Aristotle's future contingents, "there will be a sea battle tomorrow" ...
- The centroid of probability is near Rouen.
- Earlier/later impact probability would be along a path along the movement/orbit of the impactor. I'm going to guess that that's largely east-west track, though with a possible orbital inclination.
- The probability distribution across that range is likely far higher near the centre than at the extremes.
- Relative motion of Earth's rotation (~1,600 km/hr at the equator, less than that at the latitude of Rouen) is a much smaller component than the likely relative velocity of the meteorite (~20 km/s).
- 20 km/s +/- 10 minutes ... gives 12,000 km as a possible range around the impact site.
There's also the question of accurately noting the original position of the impactor.
That said: good question and I'd love to hear from someone who knows what they're talking about.
Thought also comes to mind of Aristotle's future contingents, "there will be a sea battle tomorrow" ...
Hmmm, interesting analysis, but 12,000km is 3x wider than continental US. Based on the plot from ESA's projection, the track over the +-10m period is much smaller than France.
I think the issue with your reasoning is that when you are dealing with orbits, you cannot really talk separately about position and (relative) velocity. Instead, for a given orbital trajectory, the position completely defines the speed. Moreover, your estimate might tell us how far _in space_ the impact would be given +/- 10min, but since both earth and asteroid are moving though space that doesn't really tell us much about how far apart it would be in an earthbound reference frame.
In practice, I don't think they can accurately measure the position OR speed of an object like this... Instead, they make multiple observations over time and can fit the "shape" of the orbit, which can be done even with a fair amount of noise since we know all orbits are elliptical. If the object's orbit doesn't intersect Earth's, there's no impact. If the orbits do interest, there _may or may not_ be an impact event. To determine this, you have to figure out if both the object and the earth will be at that intersection point, _at the same time_.
I'm guessing this is why the quoted uncertainty is given in minutes.
I think the issue with your reasoning is that when you are dealing with orbits, you cannot really talk separately about position and (relative) velocity. Instead, for a given orbital trajectory, the position completely defines the speed. Moreover, your estimate might tell us how far _in space_ the impact would be given +/- 10min, but since both earth and asteroid are moving though space that doesn't really tell us much about how far apart it would be in an earthbound reference frame.
In practice, I don't think they can accurately measure the position OR speed of an object like this... Instead, they make multiple observations over time and can fit the "shape" of the orbit, which can be done even with a fair amount of noise since we know all orbits are elliptical. If the object's orbit doesn't intersect Earth's, there's no impact. If the orbits do interest, there _may or may not_ be an impact event. To determine this, you have to figure out if both the object and the earth will be at that intersection point, _at the same time_.
I'm guessing this is why the quoted uncertainty is given in minutes.
The 12,000 km estimate is straight maths assuming a (fairly typical) relative orbital velocity of ~20,000 km/s for the meteroid, and looking at distance travelled in 10 minutes.
Mind that the geometry of the collision might truncate that considerably. Again, I'm not claiming expertise here, and the "straight maths" rubric isn't a justification for correctness so much as explaining how I arrived at the number.
Mind that the geometry of the collision might truncate that considerably. Again, I'm not claiming expertise here, and the "straight maths" rubric isn't a justification for correctness so much as explaining how I arrived at the number.
Understood! My point was that, while dimensional analysis almost always works (including for this problem), you have to make sure you are using the right dimensionful quantities. In this case that there are constraints here due to orbital mechanics that were not respected, and hence the 12,000km is way off.
To successfully apply DA in this problem, we should start by noting that since we are talking about impact, it is a foregone conclusion that the earth and the asteroid will be in the same place at the same time (your application instead was related to figuring out where earth and asteroid would be in relation to each over at a given time).
Once you've specified that they will be at the same place, asking where it lands _on earth_ amounts to asking which part of the earth will be facing the asteroid at that time. Since there is a quoted uncertainty of +- 10min, the range of outcomes is almost entirely defined by the angular distance that the earth with travel in those 20min -- about half a time zone!
This gets us much closer to the actual projection from ESA. The actual central location at the nominal time is defined almost entirely by the direction the asteroid is approaching from -- i.e. the relative inclination and phase anomaly of the orbits. So, the rest of the projected range can be chalked up to uncertainty on the geometric fit of the object's orbit based on astrometric observations. Which we can't apply DA to without further information.
To successfully apply DA in this problem, we should start by noting that since we are talking about impact, it is a foregone conclusion that the earth and the asteroid will be in the same place at the same time (your application instead was related to figuring out where earth and asteroid would be in relation to each over at a given time).
Once you've specified that they will be at the same place, asking where it lands _on earth_ amounts to asking which part of the earth will be facing the asteroid at that time. Since there is a quoted uncertainty of +- 10min, the range of outcomes is almost entirely defined by the angular distance that the earth with travel in those 20min -- about half a time zone!
This gets us much closer to the actual projection from ESA. The actual central location at the nominal time is defined almost entirely by the direction the asteroid is approaching from -- i.e. the relative inclination and phase anomaly of the orbits. So, the rest of the projected range can be chalked up to uncertainty on the geometric fit of the object's orbit based on astrometric observations. Which we can't apply DA to without further information.
Thanks, appreciate the clarifications.
Yes that's exactly right. You can see this information in the plot attached to the linked Twitter post. There is a range of times (indicated by color) and the corresponding projections for impact location. But note that meteors can be seen from quite far away. Large fireballs can be heard for dozens of miles around! Also, they posted a more recent update that the estimate is zeroing in on Rouen.
Think of a bell curve, more or less. It's much, much, much more likely for the asteroid to come down near the center of the predicted range than some place 5 standard deviations away.
Lot of things going on in space lately
Let's take a moment to remember this beautiful story: https://www.smithsonianmag.com/smart-news/reagan-and-gorbach...
Let's take a moment to remember this beautiful story: https://www.smithsonianmag.com/smart-news/reagan-and-gorbach...
Photos?
Apparently, predicting arrival for natural near-earth objects is rare enough we're still in single digits. \
Very cool!
Apparently, predicting arrival for natural near-earth objects is rare enough we're still in single digits. \
Very cool!
Video from multiple locations.[0]
[0] https://www.youtube.com/watch?v=_eJq6DcIEzM
[0] https://www.youtube.com/watch?v=_eJq6DcIEzM
"Safely" because it is expected to burn completely before impact with the surface? If not, then fair to call it a potential hazard, even if a small one?
These things don't even need to impact the surface to cause massive damage. They can disintegrate mid-air or just pass earth closely and the resulting shock wave will already be devastating. Examples: Tunguska explosion and the Chelyabinsk meteor.
At their speeds they're impacting the atmosphere in a similar way a bullet impacts water (it disintegrates and loses speed rapidly, causing a big splash).
At their speeds they're impacting the atmosphere in a similar way a bullet impacts water (it disintegrates and loses speed rapidly, causing a big splash).
Ah yes, the Chelyabinsk meteor:
https://www.youtube.com/watch?v=c9ch5mtxmLk
Also, here's a great recording of the shock wave, illustrating your point:
https://youtu.be/TKXZ5dwwTyc
https://www.youtube.com/watch?v=c9ch5mtxmLk
Also, here's a great recording of the shock wave, illustrating your point:
https://youtu.be/TKXZ5dwwTyc
Could a F-22 shoot it down? /s
The continuous-rod warhead in a Sidewinder will rip the hell out of an aircraft, which is made of tinfoil wrapped around complications. A rock from space, by contrast, is made out of rock wrapped around rock.
Assuming charitably that the missile could generate an intercept, you would probably get some sparks, maybe more or less depending on how much of the rock is actually nickel and iron. But basically, the rock is a rock. An AIR-2 Genie likely wouldn't bother it all that much beyond maybe a surface glazing and some neutron activation. The most a Sidewinder will do is expensively nothing.
Assuming charitably that the missile could generate an intercept, you would probably get some sparks, maybe more or less depending on how much of the rock is actually nickel and iron. But basically, the rock is a rock. An AIR-2 Genie likely wouldn't bother it all that much beyond maybe a surface glazing and some neutron activation. The most a Sidewinder will do is expensively nothing.
There are bunker busters but most of them are conventional bombs, or cruise missiles (with a propeller).
If they can bust few (double digit?) meters of concrete, they could bust a rock. Assuming they dont miss and assuming they dont slip.
https://en.m.wikipedia.org/wiki/Bunker_buster
Obviously it would have to be some combination of an anti sat missile (so it can fly in space) and a bunker buster (so it can crush throigh rock).
If they can bust few (double digit?) meters of concrete, they could bust a rock. Assuming they dont miss and assuming they dont slip.
https://en.m.wikipedia.org/wiki/Bunker_buster
Obviously it would have to be some combination of an anti sat missile (so it can fly in space) and a bunker buster (so it can crush throigh rock).
My physics is a bit rusty. Would that help? There is a rock with huge amounts of kinetic energy and you hit it with a bunker buster, then what? You've then got the same amount of mass (mass being conserved) and the same amount of energy (energy being conserved) on more or less the same trajectory.
I'm not sure that counts as shooting it down. In the context of a celestial object usually "shoot it down" means "deflect it so it misses earth".
I'm not sure that counts as shooting it down. In the context of a celestial object usually "shoot it down" means "deflect it so it misses earth".
If you break it apart then you have more surface area to interact with the atmosphere.
This site truly is where humor goes to die.
I didn't think I was keeping that straight a face. But on the other hand, now I get to check "twit Cegłowski" off my bucket list, and that's worth a joke falling a little bit flat.
I thought it was pretty funny.
CyanBird(1)
Ignoring the sarcasm marker.
F15s could fire anti satelite missiles in early 1980s. Who knows what "toys" are available 40 years later.
https://en.m.wikipedia.org/wiki/ASM-135_ASAT
F15s could fire anti satelite missiles in early 1980s. Who knows what "toys" are available 40 years later.
https://en.m.wikipedia.org/wiki/ASM-135_ASAT
But this isnt an orbiting satellite, it's an object moving at 20 km/s (quoting another post, I dont really know in what direction or relative to what) which is ~Mach 60. I don't know how that compares to satellites - is it close enough we'd expect an anti-satellite missile to work?
I think we might be able to put something in front of it; but at that speed I dont think anything we loft does not do more than begin the party early. All the energy it's going to release pretty much happens in the same path, we might just begin the breakup and distribution a second or two before the air otherwise would have.
Can't speak to the missiles, but objects in low earth orbit travel at around 7km/s relative to the earth.
The benefit of this sort of task is in both cases the target object doesn't move of its own accord, so presumably if you can predict the path of the object with enough precision then it would work. Clearly we can pinpoint a 1m satellite, but no idea on the error bars for a 1m meteoroid.
The benefit of this sort of task is in both cases the target object doesn't move of its own accord, so presumably if you can predict the path of the object with enough precision then it would work. Clearly we can pinpoint a 1m satellite, but no idea on the error bars for a 1m meteoroid.
Depends on what kind of warhead you have on that missile. :)
A small nuke could definitely obliterate a 1-meter rock, if you don't mind contaminating a large part of Europe with radioactive dust.
A small nuke could definitely obliterate a 1-meter rock, if you don't mind contaminating a large part of Europe with radioactive dust.
This isn't fantasy, either. There were plenty of air-to-air and surface-to-air nuclear-tipped missiles. All of the ones mentioned on Wikipedia [0] have officially been decommissioned for 40+ years, a development due both to disarmament agreements and advances in targeting by conventional missiles. But I wouldn't be shocked to learn there are still some deployed.
[0] https://en.m.wikipedia.org/wiki/Category:Nuclear_anti-aircra...
[0] https://en.m.wikipedia.org/wiki/Category:Nuclear_anti-aircra...
Some sort of a bunker buster perhaps? ( https://en.m.wikipedia.org/wiki/Bunker_buster )
Or a tungusten rod with no warhead at all.
Not sure if they arent much bigger than an anti sat missile though.
Not sure if they arent much bigger than an anti sat missile though.
Does an anti-satellite missile work by catching up to a satellite or by intercepting it head on or at a tangent?
it's an ironic sarcasm marker
why are these events always forecasted so late? some hours earlier i could have witnessed it
It's amazing it's forecast at all. As ESA writes:
> This is just the seventh time an #asteroidimpact has ever been predicted before it happens - a sign of the rapid advancements in global asteroid detection capabilities!
> This is just the seventh time an #asteroidimpact has ever been predicted before it happens - a sign of the rapid advancements in global asteroid detection capabilities!
Two related reasons. 1m is quite small, so it needs to be close for us to detect it. Since we don’t have many observations, the error in estimates of its orbital path is high.
In general, it also is extra difficult to calculate the exact last little bit of a trajectory that will impact earth because the force models start getting really wild as something gets very close to earth - approximations stop working.
In general, it also is extra difficult to calculate the exact last little bit of a trajectory that will impact earth because the force models start getting really wild as something gets very close to earth - approximations stop working.
> it also is extra difficult to calculate the exact last little bit of a trajectory that will impact earth because the force models start getting really wild
What kind of forces? I assume you're talking about the space part, before atmosphere, so I would assume it's the same gravity effects that you also get in space, just that gravity is a bit larger value. I wrote a gravity simulator at lgms.nl/p/badgravity so I have a bit of an idea but am definitely no expert (the thing doesn't do any sort of collisions and assumes 2d point masses), so I'm curious what you mean. Especially with the earth dominating the gravity and not needing to use N-body physics anymore, it should get more accurate if anything.
Could you elaborate or do you have a link? Or do you simply mean the compounding effect of having used N-body approximations for the interplanetary space part of the trajectory leading to different starting points for the final approach?
What kind of forces? I assume you're talking about the space part, before atmosphere, so I would assume it's the same gravity effects that you also get in space, just that gravity is a bit larger value. I wrote a gravity simulator at lgms.nl/p/badgravity so I have a bit of an idea but am definitely no expert (the thing doesn't do any sort of collisions and assumes 2d point masses), so I'm curious what you mean. Especially with the earth dominating the gravity and not needing to use N-body physics anymore, it should get more accurate if anything.
Could you elaborate or do you have a link? Or do you simply mean the compounding effect of having used N-body approximations for the interplanetary space part of the trajectory leading to different starting points for the final approach?
I actually do mean atmospheric effects. The strength of atmosphere effects is usually what makes the difference between a mere close approach and a collision. Those effects are hard to model exactly.
Oh, I did not know that this 'last mile' often makes the difference between collisions and close approaches! Interesting. Indeed, I have to remember that atmosphere is a scale and not a hard boundary. Like, I kinda know that, but just how far up there are still particles that are of significance...
My guess is that the uncertainty has little to do with gravity, although there is gravitational variation in both the Moon and Earth depending on what part you are close to but I don't think that comes into play here. The error is likely more to do with the observational data. Try pinpointing the exact distance and trajectory of a 1m rock using ground based telescopes. Hard enough but remember there is also atmospheric distortion and you only get limited time on the scope.
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Or it won’t be a safe impact and the UFOs are here to watch the show.
That's a meteor. Meteorites are different - they're the ones that hit the dirt.
If we're going to be pedantic, it's actually a meteoroid. Meteoroid is the object, meteor is what happens when it hits the atmosphere, and meteorite is when it has hit the ground.
I found Wiktionary the most helpful:
Usage notes Meteor (streak of light in night sky): Not to be confused with meteoroid and meteorite (cause and remains of a meteor), or asteroid and comet (celestial bodies).
Usage notes Meteor (streak of light in night sky): Not to be confused with meteoroid and meteorite (cause and remains of a meteor), or asteroid and comet (celestial bodies).
It confused me as well.
This post is mistitled. The original Tweet is:
A 1-meter meteoroid (small #asteroid) has been detected and is expected to safely strike Earth's atmosphere over northern France between 3:50-4:03 CET.
This post is mistitled. The original Tweet is:
A 1-meter meteoroid (small #asteroid) has been detected and is expected to safely strike Earth's atmosphere over northern France between 3:50-4:03 CET.
Edit: I was expecting that it would be too far away, also with Aachen's city glow and the highway, that nothing would be visible, or at best, a point appearing and disappearing at basically the same location in the haze of city glow. Compared to that, I'm absolutely blown away. Will post a video in a few minutes, just took the 380MB thing off my phone, now cropping to the right ~10 seconds, rotating, that stuff
Edit again: here we are finally https://lgms.nl/files/Sar2667-Aachen.mp4 Quite sad it defocused, and you'll need an x264 decoder in your browser I think (I used `ffmpeg -c:v copy` to avoid losses, so it's whatever encoding my phone uses), should work in a local video player if you download it.
A friend found this one https://www.youtube.com/watch?v=8owpwqzBEPA
Location estimate, based on where I saw it plus this video https://twitter.com/meteordoc/status/1624967987294765059 from Brighton looking over a pier: <https://www.openstreetmap.org/?mlat=50.0761&mlon=0.5335#map=...>. It became visible to me at 03:59:13 GMT+1/CET and exploded 5 seconds later, with my phone's clock sync being ~0.6s behind so it might have been 03:59:14
Got so lucky finding that Brighton video as the 2nd result earlier. Spent another 15 minutes looking for a third angle but the "looking east", "looking south" indicated angles are either implausible or too inaccurate to be useful. A Paris video is of such quality that I couldn't for the life of me find out which buildings are in view to map it to an angle. This location guess is going to be my final estimate.