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Posted

"Rubble pile" sounds sciency, but it's a term of little to no practical scientific value. As fragments are recovered and analyzed in the coming days & weeks we'll get to hear the results and find out what it was made of and per se how it hanged together.

 

 

 

 

Here's an article on Lunar meteorites, i.e. pieces of the Moon splashed off the Moon by impacts and ultimately falling to Earth. :moon: :earth:

 

>> :read: Lunar Meteorites

 

Here's a blip germane to your question:

 

 

Actually turtle, rubble pile is the correct idiom when referring to asteroids that are composed a loosely gravitationally bound rubble, lots of pieces, of various sizes and composition.

 

http://en.wikipedia.org/wiki/Rubble_pile

Posted

I just did a run on a 15m hard-rock at 18000kph on a 15º descent and got results that both agree and differ with what actually happened. Then again, maybe choosing "dense rock" was too dense. :shrug:

 

Your Inputs:

Distance from Impact: 1.61 km ( = 1.00 miles )

Projectile diameter: 15.00 meters ( = 49.20 feet )

Projectile Density: 3000 kg/m3

Impact Velocity: 18000.00 km per second ( = 11200.00 miles per second ) (Your chosen velocity is higher than the maximum for an object orbiting the sun)

Impact Angle: 15 degrees

Target Density: 2500 kg/m3

Target Type: Sedimentary Rock

 

 

Energy:

Energy before atmospheric entry: 8.59 x 1020 Joules = 2.05 x 105 MegaTons TNT

The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.4 x 106years

Major Global Changes:

The Earth is not strongly disturbed by the impact and loses negligible mass.

The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree).

The impact does not shift the Earth's orbit noticeably.

Atmospheric Entry:

The projectile begins to breakup at an altitude of 165000 meters = 543000 ft

The projectile bursts into a cloud of fragments at an altitude of 43700 meters = 143000 ft

The residual velocity of the projectile fragments after the burst is 16100 km/s = 10000 miles/s

The energy of the airburst is 1.69 x 1020 Joules = 4.03 x 104 MegaTons.

No crater is formed, although large fragments may strike the surface.

Air Blast:

What does this mean?

 

 

The air blast will arrive approximately 2.21 minutes after impact.

Peak Overpressure: 1.02e+06 Pa = 10.2 bars = 144 psi

Max wind velocity: 769 m/s = 1720 mph

Sound Intensity: 120 dB (Dangerously Loud)

Damage Description:

 

 

Multistory wall-bearing buildings will collapse.

 

Wood frame buildings will almost completely collapse.

 

Multistory steel-framed office-type buildings will suffer extreme frame distortion, incipient collapse.

 

Highway truss bridges will collapse.

 

Highway girder bridges will collapse.

 

Glass windows will shatter.

 

Cars and trucks will be largely displaced and grossly distorted and will require rebuilding before use.

 

Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

 

 

 

ooopppssss!!!! :loser: I put in 18000km/s and it should be 18km/s. What a maroon!. :lol:

 

Try this. I went with "rubble pile" [porous rock] and put in the correct [measured] speed of 18 km/s. Results.....

 

Your Inputs:

Distance from Impact: 1000.00 meters ( = 3280.00 feet )

Projectile diameter: 15.00 meters ( = 49.20 feet )

Projectile Density: 1500 kg/m3

Impact Velocity: 18.00 km per second ( = 11.20 miles per second )

Impact Angle: 15 degrees

Target Density: 2500 kg/m3

Target Type: Sedimentary Rock

Energy:

Energy before atmospheric entry: 4.29 x 1014 Joules = 102.58 KiloTons TNT

The average interval between impacts of this size somewhere on Earth is 19.1 years

Major Global Changes:

The Earth is not strongly disturbed by the impact and loses negligible mass.

The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree).

The impact does not shift the Earth's orbit noticeably.

Atmospheric Entry:

The projectile begins to breakup at an altitude of 73400 meters = 241000 ft

The projectile bursts into a cloud of fragments at an altitude of 46100 meters = 151000 ft

The residual velocity of the projectile fragments after the burst is 15.6 km/s = 9.7 miles/s

The energy of the airburst is 1.06 x 1014 Joules = 0.25 x 10-1 MegaTons.

No crater is formed, although large fragments may strike the surface.

Air Blast:

What does this mean?

 

 

The air blast will arrive approximately 2.33 minutes after impact.

Peak Overpressure: 3.89 Pa = 0 bars = 0.000552 psi

Max wind velocity: 0.00917 m/s = 0.0205 mph

Sound Intensity: 12 dB (Barely Audible)

 

This now seems to underestimate the effects. :reallyconfused: Anyone else using this tool? :coffee_n_pc:

Posted

Actually turtle, rubble pile is the correct idiom when referring to asteroids that are composed a loosely gravitationally bound rubble, lots of pieces, of various sizes and composition.

 

http://en.wikipedia.org/wiki/Rubble_pile

 

Perfect then! I stand corrected. Nevertheless, "rubble pile" is not a material choice on the calculator. Have you actually used it yet? Intend to? Or not? :shrug:

 

Again, the speculation in whatever terms is just that...speculation. Damn waste of time in my view. What if this and what if that but maybe if... .ppppphhhh!!! Get over it people. :rolleyes:

 

Anyways, it is the analysis of fragments that will determine the facts of the matter. I'll be watching for that. :clue:

Posted

The last one came over where I live West to East less than 12 hours ago when DA14 was supposed to pass by.

 

http://thelatestworldwidemeteorreports.blogspot.com.au/

 

Report them if you see them.

 

It's unseasonably warm tonight so I'll open the window and set up my all-night-part-of-the-southern-sky cam. I will be shooting straight South at ~20º from ~ the 45th parallel N. If I get a fireball you -Laurie- may see the video for 1/2 of what I will be charging everyone else. say what!! :photos: :lol:

Posted

It's unseasonably warm tonight so I'll open the window and set up my all-night-part-of-the-southern-sky cam. I will be shooting straight South at ~20º from ~ the 45th parallel N. If I get a fireball you -Laurie- may see the video for 1/2 of what I will be charging everyone else. say what!! :photos: :lol:

 

Thanks Turtle :D

Posted

Thanks Turtle :D

 

My pleasure. The model camera I am using I chose specifically for its ability to record continuously over-night. You see, I have a serious interest in this myself. Shall I use Infrared mode, or no?

 

Camera is set up and running as described, except the inclination is more like 30º. It will be tomorrow afternoon before I can review the recording and report back.

 

I accept American currency and gold only. :P

Posted

Funny?

 

Funny alright, I'm with that ultra right wing Russian pol that said it was a secret US weapon. My guess it's from the Kennedy or Nixon era. To be sure Mothea Ruussa should contact Castro and put him on high alert.

Posted (edited)

Russian Meteor Blast Bigger Than Thought, NASA says

Well....? Turtle did you get footage of fire balls?

 

Not this time.

 

PS Estimates of the size & mass of the rock have been increased. :read:

Russian Meteor Blast Bigger Than Thought, NASA says

...

But late Friday, NASA revised its estimates on the size and power of the devastating meteor explosion. The meteor's size is now thought to be slightly larger — about 55 feet (17 m) wide — with the power of the blast estimate of about 500 kilotons, 30 kilotons higher than before, NASA officials said in a statement. [see video of the intense meteor explosion]

 

The meteor was also substantially more massive than thought as well. Initial estimated pegged the space rock's mass at about 7,000 tons. Scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., now say the meteor weighed about 10,000 tons and was travelling 40,000 mph (64,373 km/h) when it exploded.

 

"These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world - the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk," JPL officials explained in the statement. The infrasound stations detect low-frequency sound waves that accompany exploding meteors, known as bolides.

 

...

Edited by Turtle
Posted (edited)

New data in hand, another run with the Impact Calculator seems fitting.

 

Estimated diameter = 17 meters

I calculate a 17 meter ball has a volume of 2572.44 m^3

 

Estimated mass = 10000 metric tons = 10,000,000 kilograms

 

I calculate the density at 3888 kg/m^3

 

The Impact calculator allows any density entry or a choice of 4 presets:

1000 kg/m^3 ice

1500 kg/m^3 porous rock

3000 kg/m^3 dense rock

8000 kg/m^3 iron

 

Shall we say very dense rock? I'll enter the calculated value now that I have one of course. I have not seen a calculated angle of entry yet, and my 15º is an estimate based on what I saw in the videos. Duck & cover!!

 

Earth Impact Effects Calculator

Your Inputs:

Distance from Impact: 1000.00 meters ( = 3280.00 feet )

Projectile diameter: 17.00 meters ( = 55.80 feet )

Projectile Density: 3888 kg/m3

Impact Velocity: 18.00 km per second ( = 11.20 miles per second )

Impact Angle: 15 degrees

Target Density: 2500 kg/m3

Target Type: Sedimentary Rock

 

Energy:

Energy before atmospheric entry: 1.62 x 1015 Joules = 387.07 KiloTons TNT

The average interval between impacts of this size somewhere on Earth is 55.3 years

 

Major Global Changes:

The Earth is not strongly disturbed by the impact and loses negligible mass.

The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree).

The impact does not shift the Earth's orbit noticeably.

 

Atmospheric Entry:

The projectile begins to breakup at an altitude of 46200 meters = 152000 ft

The projectile bursts into a cloud of fragments at an altitude of 31500 meters = 103000 ft

The residual velocity of the projectile fragments after the burst is 14.2 km/s = 8.82 miles/s

The energy of the airburst is 6.13 x 1014 Joules = 0.15 x 100 MegaTons.

No crater is formed, although large fragments may strike the surface.

 

Air Blast:

The air blast will arrive approximately 1.59 minutes after impact.

Peak Overpressure: 47.6 Pa = 0.000476 bars = 0.00676 psi

Max wind velocity: 0.112 m/s = 0.251 mph

Sound Intensity: 34 dB (Easily Heard)

 

All sounds in line with the ground effects in evidence, except the Sound Intensity seems way low. Rather than (Easily Heard) it should output (Impossible to Ignore).

 

Starting to hear reports of small suspected fragment recovery, however nothing big and nothing analyzed yet. :sherlock:

Edited by Turtle
Posted

How are you guys going over there? This is a real worlwide swarm.

 

There's 7 recent hits from Florida to Canada and it looks like its starting in Western Australia. That means it will be here in about 2 hours.

 

http://thelatestworldwidemeteorreports.blogspot.com.au/

 

We're fine. I see nothing to conclude this is a "swarm" and certainly these events are nothing out of the ordinary in the big scheme of things. The Russia event has more people looking up -always a good thing- and more look uppers means more sightings and more reports.

 

Yes the sky is falling, but then it's always falling. Nothing to get your loin cloths in a knot over. :whew: :night_moon:

Posted (edited)

We're fine. I see nothing to conclude this is a "swarm" and certainly these events are nothing out of the ordinary in the big scheme of things. The Russia event has more people looking up -always a good thing- and more look uppers means more sightings and more reports.

 

Yes the sky is falling, but then it's always falling. Nothing to get your loin cloths in a knot over. :whew: :night_moon:

Hi Turtle,

 

BTW, did you capture anything? It's been raining on and off over here.

Edited by LaurieAG
Posted

Hi Turtle,

 

The page is recording hits all over the place atm. It looks like northern hemisphere goes from east to west while southern hemisphere goes from west to east. Look at the world wide swarm map on the right in the middle.

 

Most burn up or go into the ocean but it's much more than normal.

 

BTW, did you capture anything? It's been raining on and off over here.

 

Yes I visisted the page. I have been visiting Spaceweather.com almost daily for more than 6 years and from that view I see nothing out of the ordinary here in astronomical terms. All that's going on is that the Russia event happened over a populated area and people being people have got their interests aroused. :o Add to that all the news stories the week before on the close-approach asteroid and go from aroused to engorged. ;)

 

Rest assured I've got my eye on it. :cyclops:

 

I did not capture any meteors. :( I had Jupiter mid frame when I started and once it moved out of the frame the only lights were a couple of airplanes. I have captured maybe 5 or 6 meteors over the years and I can direct you to the videos if you like. The best fireball I have seen naked eye had a green & yellow "sparkling" tail and I saw it out the window I was recording from. Damn if it wasn't left of the frame & I didn't get a recording!!! :doh: :rant: :lol:

 

Light rain & clouds tonight & 42ºF No dance tonight. :throwtomatoes:

Posted

http://www.space.com/19833-russia-meteor-asteroid-threat.html

 

Rep. Rohrabacher promises a hearing from the science and space committee. Though it was acknowledged that the object was too small to be detected with the current technology we use. At least some in government are getting the wake up call.

 

Always a good thing to have our representatives promoting science at work. However, someone is misinformed about what can/may be detected. Remembering a story of a few years past, I found it out again. Note that the meteroid in question was considerably smaller and less massive than the Russia stone. :read:

 

>> :read: Meteorites Found in Africa From First Predicted Asteroid Hit

...Remember in October 2008 when Asteroid 2008 TC3 hit the scene – literally? This was the first asteroid that was predicted –and predicted correctly — to impact the Earth. Luckily, it wasn’t big enough to cause any problems, and its path was over a remote area in Africa. It streaked into the skies over northern Sudan in the early morning of October 7, 2008, and then exploded at a high 37 km above the Nubian Desert, before the atmosphere could slow it down. It was believed that the asteroid likely had completely disintegrated into dust. But meteor astronomer Peter Jenniskens thought there might be a chance to recover some of the remains of this truck-sized asteroid. And he was right.

...

Picked up by Arizona’s Catalina Sky Survey telescope on 6 October, 2008, Asteroid 2008 TC3 abruptly ended its 4.5 billion year solar-system odyssey only 20 hours after discovery, when it broke apart in the African skies. The incoming asteroid was tracked by several groups of astronomers, including a team at the La Palma Observatory in the Canary Islands that was able to measure sunlight reflected by the object.

...

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