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A-L-E-X
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Re: Asteroids, meteors, and meteorites

02 Jun 2023 18:52

The amazing thing is that it actually landed inside a person's house, the odds of that happening must be incredibly low.
Quite low, but more than once. Many meteorites have been documented falling onto structures, cars, and even a mailbox. Meteorites that do this are sometimes called hammerstones. I haven't found a well cited number for how many of these are known, but it's something around a hundred.

One meteorite has even struck a person, Ann Hodges, while she was laying on her couch, after it crashed through her roof and bounced off her radio. It gave her one heck of a bruise. Lucky that it did not hit her directly and lost most of its energy first.
Thanks, Wat, this is absolutely fascinating and I imagine they either kept the object as a keepsake, gave it to a museum or made money by selling it to a collector!
 
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midtskogen
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Re: Asteroids, meteors, and meteorites

03 Jun 2023 03:07

Yes that is what was reported on the news, likely it was just a coincidence that it happened around the time of that meteor shower then?
The amazing thing is that it actually landed inside a person's house, the odds of that happening must be incredibly low.

Originally I thought maybe space junk, but this is the real deal.

Mid how long does it take for an object of this type to get from the top of the atmosphere to the surface and how large do you think it might have been before it entered the earth's atmosphere?
There is at least one active meteor shower at any time of time, and close to the peak of one much of the year, so coincidences are not really "coincidences".  But meteor showers are unlikely meteorite droppers.  Meteor showers are associated with comets, which are rich in ice and small particles which wont survive the atmosphere.  Maybe showers like the Geminids and Taurids can produce meteors.  These appear to have larger, rocky chunks which not infrequently manage to punch through the atmosphere down to 30 or 40 km altitude though their speed at 30 - 35 km/s makes survival unlikely.  I've not heard of any meteorites confirmed to below to these meteor showers, but I wouldn't completely rule out the possibility.

It's not at all common that meteorites hit roofs, though it probably happens every year globally.  The roof area is tiny compared to the total area of the Earth, but meteorites that do hit a roof are likely found and identified, whereas the vast majority of meteorites falling elsewhere will never be found.  In Norway we have 17 known meteorite incidences, two of which involved roofs.  In 2006 a meteorite was found on the roof of an industrial building.  The first find in this fall was a near roof hit.  Some guy was doing his business in an outhouse and a meteorite hit a aluminium sheet on the ground a couple of meters away.  In 2012 a meteorite hit a building again, this time a house, but it was found a bit later because the roof had begun to leak and the meteorite was found lodged in it.

Meteorites first pass through the atmosphere as a fireball typically lasting 5 to 10 seconds.  They appear around 100 km above ground and fade usually at 15 to 30 km altitude when the speed drops below 2 - 3 km/s.  If the entry speed is above 30 km/s, everything is likely to evaporate before reaching the lower atmosphere.  The typical meteorite goes subsonic at around the cruising height of airplanes and quickly goes into regular freefall hitting the ground a minute or two later at perhaps 200-300 km/h.  This can vary a lot, of course.  Large meteorites or iron meteorites can reach the ground much sooner.  The 14 kg iron meteorite which hit Sweden in 2020 appears to have dropped below 2 km/s at around 11 km altitude and gone subsonic at around 3 - 5 km altitude.  It hit the ground around 35 seconds after atmospheric entry and it still had some of the cosmic speed left when it hit the ground, maybe at 600 km/h.

As a rule of thumb, rocky meteorites have lost 90% of the mass it had before atmospheric entry.  This will of course vary.
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Re: Asteroids, meteors, and meteorites

03 Jun 2023 17:33

Yes that is what was reported on the news, likely it was just a coincidence that it happened around the time of that meteor shower then?
The amazing thing is that it actually landed inside a person's house, the odds of that happening must be incredibly low.

Originally I thought maybe space junk, but this is the real deal.

Mid how long does it take for an object of this type to get from the top of the atmosphere to the surface and how large do you think it might have been before it entered the earth's atmosphere?
There is at least one active meteor shower at any time of time, and close to the peak of one much of the year, so coincidences are not really "coincidences".  But meteor showers are unlikely meteorite droppers.  Meteor showers are associated with comets, which are rich in ice and small particles which wont survive the atmosphere.  Maybe showers like the Geminids and Taurids can produce meteors.  These appear to have larger, rocky chunks which not infrequently manage to punch through the atmosphere down to 30 or 40 km altitude though their speed at 30 - 35 km/s makes survival unlikely.  I've not heard of any meteorites confirmed to below to these meteor showers, but I wouldn't completely rule out the possibility.

It's not at all common that meteorites hit roofs, though it probably happens every year globally.  The roof area is tiny compared to the total area of the Earth, but meteorites that do hit a roof are likely found and identified, whereas the vast majority of meteorites falling elsewhere will never be found.  In Norway we have 17 known meteorite incidences, two of which involved roofs.  In 2006 a meteorite was found on the roof of an industrial building.  The first find in this fall was a near roof hit.  Some guy was doing his business in an outhouse and a meteorite hit a aluminium sheet on the ground a couple of meters away.  In 2012 a meteorite hit a building again, this time a house, but it was found a bit later because the roof had begun to leak and the meteorite was found lodged in it.

Meteorites first pass through the atmosphere as a fireball typically lasting 5 to 10 seconds.  They appear around 100 km above ground and fade usually at 15 to 30 km altitude when the speed drops below 2 - 3 km/s.  If the entry speed is above 30 km/s, everything is likely to evaporate before reaching the lower atmosphere.  The typical meteorite goes subsonic at around the cruising height of airplanes and quickly goes into regular freefall hitting the ground a minute or two later at perhaps 200-300 km/h.  This can vary a lot, of course.  Large meteorites or iron meteorites can reach the ground much sooner.  The 14 kg iron meteorite which hit Sweden in 2020 appears to have dropped below 2 km/s at around 11 km altitude and gone subsonic at around 3 - 5 km altitude.  It hit the ground around 35 seconds after atmospheric entry and it still had some of the cosmic speed left when it hit the ground, maybe at 600 km/h.

As a rule of thumb, rocky meteorites have lost 90% of the mass it had before atmospheric entry.  This will of course vary.
Thanks, Mid, I was wondering if some of the other major meteor showers can produce meteors like the Perseids or the Leonids?  During the Perseid meteor shower which I witnessed in the mountains, during the shower I heard unusual sounds that could only be described as small pebbles or gravel hitting a roof.  Could one of these showers also produce meteorites?
 
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Re: Asteroids, meteors, and meteorites

04 Jun 2023 01:19

Could one of these showers also produce meteorites?
Not even a chance. The meteor velocity for both showers is far too high; they burn up completely at very high altitude.
 
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midtskogen
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Re: Asteroids, meteors, and meteorites

04 Jun 2023 03:23

The Perseids hit at 59 km/s, the Leonids at 71 km/s.  This is fast, even for meteors.  These showers produce short-lived meteors, usually a fraction of a second (but when the radiant is low in the sky, long meteors perphaps lasting a second or even more might be seen).  On the other hand, these fast meteors often leave behind a glowing trail which can be visible for a long time (tens of seconds).  These trails are typically around 80 to 120 km above ground, whereas slower meteors (~15 km/s) typically don't light up until they go below 80 km.  The high speeds also mean that even very small particles, mm sized, will produce easily visible streaks.

Very small meteoroids, well below a single mm, on the other hand, have very little momentum will often survive (and not be visible as meteors), even fast ones, usually melted into tiny spheres.  Several tonnes of such dust probably fall to Earth every day.
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A-L-E-X
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Re: Asteroids, meteors, and meteorites

04 Jun 2023 04:29

Could one of these showers also produce meteorites?
Not even a chance. The meteor velocity for both showers is far too high; they burn up completely at very high altitude.
I'm wondering what I heard when I saw the Perseids.  I guess it could be a bolide.  I see a few fireballs almost every year with the Perseids so one of them could have made that noise as they burned up?
 
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Re: Asteroids, meteors, and meteorites

04 Jun 2023 04:33

The Perseids hit at 59 km/s, the Leonids at 71 km/s.  This is fast, even for meteors.  These showers produce short-lived meteors, usually a fraction of a second (but when the radiant is low in the sky, long meteors perphaps lasting a second or even more might be seen).  On the other hand, these fast meteors often leave behind a glowing trail which can be visible for a long time (tens of seconds).  These trails are typically around 80 to 120 km above ground, whereas slower meteors (~15 km/s) typically don't light up until they go below 80 km.  The high speeds also mean that even very small particles, mm sized, will produce easily visible streaks.

Very small meteoroids, well below a single mm, on the other hand, have very little momentum will often survive (and not be visible as meteors), even fast ones, usually melted into tiny spheres.  Several tonnes of such dust probably fall to Earth every day.
One of my favorite memories of the Perseids happened when I was 13 years old, the first year I saw them.  I was up all night in my driveway watching them and somewhere between 5 am and 6 am when the sky started getting brighter I was getting ready to go inside and go to sleep.  The radiant must have been low in the sky by then because I saw what looked like a "low flying fireball" that streaked across the sky and almost looked like a comet because it had a tail behind it.  And it went south of here so I have always wondered if it landed in the ocean because the ocean is 2 miles south of me.  From what I read, I take it that it burned up before it could reach the water.  Still my favorite Perseids memory and the weather was like early Fall that first year of watching the Perseids for me, it was the first and only time it's been that clear and cool in mid August here with morning temps around 50 F / 10 C.  The viewing was exceptional that year, even from near NYC-- you never get skies that deep blue here in the summer, except for that year. 
 
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Watsisname
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Re: Asteroids, meteors, and meteorites

04 Jun 2023 06:19


I'm wondering what I heard when I saw the Perseids.  I guess it could be a bolide.  I see a few fireballs almost every year with the Perseids so one of them could have made that noise as they burned up?
Previous discussion on this subject: UFO Sightings and Possible Explanations - Page 4 - Space Engine

Article published in Nature: Photoacoustic sounds from meteors
 
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midtskogen
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Re: Asteroids, meteors, and meteorites

27 Jul 2023 13:29

Our meteor cameras recorded an extremely fast moving meteor just after midnight last night.  This was in northern Norway with the sun sitting at the horizon at the time, so the sky was bright, but the meteor even brighter.

What's really interesting is that it appears to have been interstellar with an eccentricity of nearly 3 and an entry speed of nearly 90 km/s.  The eccentricity can be really sensitive to errors in the observations, but in this case I find it really hard to find an origin for this meteor inside our solar system even though all the cameras were located in somewhat the same line of sight.

I've never seen a video of a meteor like this.  It goes really, really fast across the sky, and the afterglow is weird.  It seems to slide along the track.  Many people witnessed this meteor and described is a blue, being amazed how fast it was and that it was visible in daylight.

It appeared at 126 km altitude and disappeared at 98 km.  126 km is a pretty impressive altitude considering that it was daylight.  But the speed was equally impressive.  At such speed even the pretty much vacuum above 100 km will instantly vapourise a meteor.  Hard to tell the mass of this rock.  It was pretty bright, but at this speed something just a few cm big will have enormous energy.

Data, pictures and videos: http://norskmeteornettverk.no/meteor/20230726/220253/

Preliminary data as of writing this.
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MrDeltaKappa
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Re: Asteroids, meteors, and meteorites

26 Mar 2025 13:04

All planets spin. That spin force is somehow sucking asteroids up from the bottom of the solar system. You can check out the grace gravity mission and the Mayan calendar to find the important gravity belts. As for the modern science they are called predicted asteroids. Hope that helps
Struck by 1990 non predicted asteroid. asteroids.fyi . It's clearly crossed with the NY Eve ball drop and the 2014 predicted asteroid. easterasteroid.com .
 
MrDeltaKappa
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Re: Asteroids, meteors, and meteorites

26 Mar 2025 13:35

Some have suggested that by pointing a stick with its end pointed into the palm of your hand that you can get yourself zapped by one of these asteroids. Maybe meteorites will work too.
Struck by 1990 non predicted asteroid. asteroids.fyi . It's clearly crossed with the NY Eve ball drop and the 2014 predicted asteroid. easterasteroid.com .
 
TheKotBS
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Re: Asteroids, meteors, and meteorites

13 Apr 2025 19:51

The GRACE mission is about measuring Earth’s gravity field changes, mostly due to water movement, not space debris or asteroid paths. And the Mayan calendar is cultural/astronomical but isn’t used in predicting gravity belts or asteroid trajectories in modern science
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