[HN Gopher] Small Asteroid Impacts Moon
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       Small Asteroid Impacts Moon
        
       Author : perihelions
       Score  : 157 points
       Date   : 2023-03-11 15:50 UTC (1 days ago)
        
 (HTM) web link (twitter.com)
 (TXT) w3m dump (twitter.com)
        
       | Simon_O_Rourke wrote:
       | The late Patrick Moore did a lot of work on what he termed
       | transient lunar phenomena, essentially lights, or "clouds" on the
       | moon, due to some unknown geological process.
       | 
       | https://en.wikipedia.org/wiki/Transient_lunar_phenomenon
        
         | [deleted]
        
       | can16358p wrote:
       | How rare are these impacts? Are they like once in a lifetime
       | observations, about once a year, or what?
        
         | NGC404 wrote:
         | Nasa has a Program called "Lunar Impact Monitoring".
         | 
         | See:
         | 
         | https://link.springer.com/article/10.1007/s11038-007-9184-0
         | 
         | https://ntrs.nasa.gov/api/citations/20150021386/downloads/20...
         | 
         | http://lunarnetworks.blogspot.com/2013/05/brightest-impact-r...
         | 
         | The data collected by the "Lunar Reconnaissance Orbiter" can be
         | used to estimate the frequency of impacts.
         | 
         | https://www.lroc.asu.edu/posts/943
        
         | foobarbecue wrote:
         | This paper found 222 impacts when comparing repeat LRO images
         | (2009-present): https://www.nature.com/articles/nature19829
         | 
         | I'm leading new a citizen science project called MoonDiff,
         | comparing against older images to look further back in time --
         | contact me if interested.
         | 
         | https://moondiff.org
         | 
         | https://trek.nasa.gov/moondiff/static/moondiff_intro.webm
         | 
         | https://github.com/nasa-jpl/moondiff
        
       | pfortuny wrote:
       | Bottom right corner (took me a while to notice it so near the
       | text).
        
         | marcinreal wrote:
         | I was able to click on the video to view it full screen, then
         | there is no text. (Also took me a while to figure this out.)
        
         | codeduck wrote:
         | thank you!
        
       | quercusa wrote:
       | How Are Places on the Moon Named?
       | https://www.smithsonianmag.com/air-space-magazine/how-are-pl...
       | 
       | Planetary Names: How Names Are Approved
       | https://planetarynames.wr.usgs.gov/Page/Approved
        
       | omoikane wrote:
       | Related:
       | 
       | https://twitter.com/oldspica/status/1630425706290360321
       | 
       | """ I magnified the location of lunar surface impact flash
       | observed by Fujii Daichi-san on February 23 with 25cm reflection
       | (telescope). It's near Ideler L crater according to Fujii-san.
       | Unfortunately I was not able to discern anything like a new
       | crater.
       | 
       | I thought I would be able to tell if the diameter was larger than
       | 2km?! ...
       | 
       | I compared with with America's Lunar Reconnaissance Orbiter, but
       | can't really tell.
       | 
       | Even with such a flash, was that impact crater too small to be
       | easily seen by telescope? """
        
       | meindnoch wrote:
       | Now Samsung has to patch their Moon template.
        
         | tsujamin wrote:
         | shit came here to make this joke
        
           | jonas-w wrote:
           | What do you mean with moon template?
        
             | qup wrote:
             | They were caught faking zoomed in photos of the moon on
             | their phones with AI filling in details.
        
             | asddubs wrote:
             | https://old.reddit.com/r/Android/comments/11nzrb0/samsung_s
             | p...
        
               | yonz wrote:
               | Did you see the HN comment? He basically said he was over
               | redditors and loved the Convo on HN.
               | 
               | https://news.ycombinator.com/item?id=35107601 <Insert it
               | is known GIF>
        
           | yonz wrote:
           | Lol me too
        
             | Maxburn wrote:
             | Me x4!
        
               | yonz wrote:
               | Got down voted for my comment, save yourself.
               | 
               | I am still figuring out participating in HN conversations
               | but this downvote seems excessive no?
        
         | yonz wrote:
         | Probably was shot with a Samsung phone
        
           | yonz wrote:
           | This is clearly a joke btw
        
       | [deleted]
        
       | perihelions wrote:
       | AI translation:
       | 
       | - _" I was able to catch the biggest lunar impact flash in my
       | observation history! This is a picture of the lunar impact flash
       | that appeared at 20:14:30.8 on February 23, 2023, taken from my
       | home in Hiratsuka (replayed at actual speed). It was a huge flash
       | that continued to shine for more than 1 second. Since the moon
       | has no atmosphere, meteors and fireballs cannot be seen, and the
       | moment a crater is formed, it glows."_
       | 
       | - _" This is a picture of the lunar impact flash at 20:14:30.8 on
       | February 23, 2023, captured by another telescope (playback at
       | actual speed). At that time, the altitude of the moon was only 7
       | degrees, and I was glad that I could stick to the limit. At the
       | time of observation, there was no satellite passing over the
       | lunar surface, and from the way it shines, it is highly likely
       | that it is a lunar impact flash."_
       | 
       | - _" This is a still image of the lunar impact flash at
       | 20:14:30.8 on February 23, 2023. It seems to have fallen near
       | Ideler L crater, slightly northwest of Pitiscus crater. Because
       | it is so bright, the generated crater is large, and the
       | striations are clearly visible. It seems that the telephoto
       | camera of NASA's lunar probe LRO can detect the fall trace."_
        
       | elihu wrote:
       | I wonder how big it was. Seems like it would have to be pretty
       | big to be that bright, but maybe it's one of those things that
       | defy our regular intuition.
        
         | actually_a_dog wrote:
         | I don't know, but compared to the scale of the gigantic crater
         | that's visible in the image, whatever it was was pretty much
         | nothing in the grand scheme.
        
           | AnimalMuppet wrote:
           | The impact that made that huge crater must have been an
           | _amazing_ light show...
        
         | Timwi wrote:
         | The brightness is a function of momentum, meaning, it could be
         | large or it could just be unfathomably fast.
        
           | hanoz wrote:
           | Why momentum rather than kinetic energy?
        
           | michpoch wrote:
           | What would create the brightness/light on such impact?
        
             | [deleted]
        
             | jacquesm wrote:
             | Energy dissipation. It's enough energy to temporarily heat
             | the rock and the impactor to the point that they start
             | glowing very brightly.
        
         | csomar wrote:
         | Rather than size, I wonder how much energy the impact released.
         | Waiting for the videos that will do a simulation of what would
         | have happened if this have hit earth.
        
         | _joel wrote:
         | Doesn't have to be that big really.
        
       | dm319 wrote:
       | what does the light come from?
        
         | op00to wrote:
         | The flash is the energy (heat, light) generated by the forces
         | of impact. The asteroid has incredible amounts of energy since
         | it was likely moving very fast compared to the Moon, and it's
         | got to go somewhere.
        
           | Eduard wrote:
           | Layman here. Considering there is no atmosphere on the moon,
           | and stone's conduction properties, does that mean the short
           | flash of light (radiation) was most of the heat energy the
           | impact produced?
        
             | varjag wrote:
             | You see the part of the spectrum the camera sensor was able
             | to capture. Most of the energy went into displacing/melting
             | the regolith and the shockwave.
        
               | wheelerof4te wrote:
               | There's no shockwave since there's no air on the Moon.
        
               | [deleted]
        
               | amelius wrote:
               | There can be a shockwave along the surface, I suppose,
               | for example.
        
               | op00to wrote:
               | Could there be a shockwave through the Moon itself?
        
               | wheelerof4te wrote:
               | Possibly, since the regolith is a good conductor.
        
             | wheelerof4te wrote:
             | Yes.
             | 
             | There would be no shockwave, just some light and incredible
             | amounts of very localized heat.
        
           | marginalia_nu wrote:
           | Are we sure it didn't just kick up dust into the sunlight?
           | 
           | Looks like the sun might have been just below the horizon.
        
             | op00to wrote:
             | If it kicked up dust, would the dust keep going, or would
             | the Moon's gravity pull it back to the lunar surface
             | quickly? I have no idea.
        
               | ktm5j wrote:
               | In my layman opinion a dust cloud would at very least
               | stick around for much longer than the duration that we
               | see this glowing last. There has to be something else
               | responsible for the flash imo.
        
               | cornstalks wrote:
               | The moon's escape velocity is 2.38 km/s (5324
               | miles/hour), so it just depends on whether or not the
               | material reached escape velocity or not.
        
             | gibmeat wrote:
             | I thought about this too, but if it were dust, I'm guessing
             | it wouldn't dissipate in 1 second.
        
               | marginalia_nu wrote:
               | Seems like atmospheric intuition.
               | 
               | I'd expect high velocity dust to diffuse rather quickly
               | in near vacuum.
        
               | icehawk wrote:
               | Here's a 2.8km/sec dust cloud from DART for comparison:
               | 
               | https://www.virtualtelescope.eu/wordpress/wp-
               | content/uploads...
        
         | TrapLord_Rhodo wrote:
         | It discusses this in the article. The regolith 'Glows' from the
         | kenetic energy transfer, and heat disipation.
        
         | tanbog5 wrote:
         | The Sun I think.
        
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       (page generated 2023-03-12 23:02 UTC)