Meteoroid explosion in Russia

[C3PO]

And how rough those calculations would be can be illustrated with Orbiter.


This is from a Deltaglider at 1 lunar distance. (Rad is equal to the Moon's SMa)
You can see that less than 1/3 of the gravitational force is provided by Earth.

 

[Thunder Chicken]

This is from a Deltaglider at 1 lunar distance. (Rad is equal to the Moon's SMa)
You can see that less than 1/3 of the gravitational force is provided by Earth.

Correct; but the point was that the gravitational acceleration due to the proximity of earth is small but not zero, and it acts for months/years. Pull any mass with any force for long enough and you will get dV (i.e. change in orbital parameters).

 

[RGClark]

That the meteor and asteroid were both large and got so close was what was so notable about them. That they both occurred within the same 24 hour period make them extraordinarily unlikely.

These scientists both came to highly unlikely probabilities for this occurrence:

[FONT=Courier, Monospaced]A meteor and asteroid: 1 in 100 million odds.
By Meg Urry, Special to CNN
updated 8:16 PM EST, Mon February 18, 2013
http://www.cnn.com/2013/02/16/opinion/urry-meteor-asteroid/index.html
[/FONT]
Meteor over Russia causes shock waves that injure at least 950 Posted by: Dr. Jeff Masters, 3:12 PM GMT on February 15, 2013
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2350

Smaller fireballs were also seen over Florida and San Francisco:

Florida fireballs? Experts say Florida fireball was a small meteorite
FLORIDA FIREBALLS FEBRUARY 19, 2013 BY: ED WALSH
http://www.examiner.com/article/florida-fireballs-experts-say-florida-fireball-was-a-small-meteorite

Francisco Bay area residents report fireball sighting
By Associated Press,February 16, 2013
http://articles.washingtonpost.com/...merican-meteor-society-large-meteor-fireballs

The Air Force has infrasound detectors that can measure atmospheric explosions. The size of these fireballs needs to be determined to find out how rare they are. In those articles they say both that they occur everyday and also they occur at the rate of 5 to 10 a year. If their size is such they occur even ten times a year, then the probability of one of these meteors of this size occurring on one day is 1 in 36. Now the probability of all three events happening on the same day jumps to 1 in several billion.

The 2029 close approach of the near Earth asteroid Apophis means this is a question that needs to be determined definitively. It also like 2012 DA14 is expected to come so close as to get inside the ring of geosynchronous satellites, but not impact. Apophis is so large though that, unlike 2012 DA14 , on closest approach it will even be visible to the naked eye. If it is the case that it can be accompanied by fragments that do impact then that is potentially very serious because its larger size means it would likely be accompanied by larger fragments.

To answer this question a statistical study needs to be made both of the Air Force infrasound detectors and the space radar detections to find whether on the 2012 DA14 close approach or on other previous close approaches whether there was an increase in meteor hits.


Bob Clark

---------- Post added at 05:49 PM ---------- Previous post was at 11:35 AM ----------

...The 2029 close approach of the near Earth asteroid Apophis means this is a question that needs to be determined definitively. It also like 2012 DA14 is expected to come so close as to get inside the ring of geosynchronous satellites, but not impact. Apophis is so large though that, unlike 2012 DA14 , on closest approach it will even be visible to the naked eye. If it is the case that it can be accompanied by fragments that do impact then that is potentially very serious because its larger size means it would likely be accompanied by larger fragments.
To answer this question a statistical study needs to be made both of the Air Force infrasound detectors and the space radar detections to find whether on the 2012 DA14 close approach or on other previous close approaches whether there was an increase in meteor hits.

Meteor expert Clark Chapman and former astronaut Rusty Schweickart urge U.S. military to re-initiate sharing of satellite detections of meteor impacts:

Russian Meteor Fallout: Military Satellite Data Should Be Shared.
by Leonard David, SPACE.com’s Space Insider Columnist
Date: 18 February 2013 Time: 09:03 AM ET
http://www.space.com/19846-russian-meteor-fallout-military-satellites.html

From links in the article, the military formerly did share this information but the policy was changed in 2009. This is important because the satellites reportedly have the capability to detect meteors down to 1 meter wide and below. This would well have the capability to determine if close asteroid flybys result in increased meteor impacts.


Bob Clark

 

[garyw]

Once again, the two rocks were in DIFFERENT ORBITS. I'm not sure how else to explain it but different orbits means that there is no possibility that these two rocks were related. Different orbits mean that the arrival time was different - one in the morning and a flypast from the other direction in the evening. Different orbits. not related.

Now, here is a seriously impressive sonic boom from the Russian meteorite:

 

[Screamer7]

I feel sorry for all the dogs. They don't have a clue what happened.
And of course for all the injured people.
Here we have another example how tiny we are in comparison to nature's fury.
I think we are lucky this time.
Next time it can be worse than this.
That is quite an impressive audio recording....thanks garyw for sharing it with us.

I saw something similar like this way back in 1986 when Halley was on it's brightest.
I was serving my time in the South African Defense Force somewhere in the north of Nanimbie.
It was already dark, about 21:00.
The object also made a similar streak like this meteor over Russia, and burst into 2 or 3 pieces that quickly fade away.
It was very far from me, almost on the horizon, and I heard nothing afterwards.
But that sight would stay with me for the rest of my life.

---------- Post added at 11:56 PM ---------- Previous post was at 11:36 PM ----------

And Robert, aka RGCLARK, just check the You Tube video in post 200 in this thread.
Afterwards bent down, grab your ankles and kiss you're ass good bye.
Just joking.
There are so many rocks out there........

 

[Athena]

 

[Mister Mxyzptlk]

Read this carefully RGClark:

Hi all,

I still see suggestions popping up on this list about a possible link between
2012 DA14 and the Russian meteor.

I want to point out that even without an accurate trajectory for the Russian
bolide, a link with 2012 DA14 can be 100% rejected. The orbital geometry of 2012

DA14 and the latitude of 55 N for the Russian bolide make this impossible.

2012 DA14 and any fragments in a swarm in similar orbit, would approach the
earth from deep south. The geocentric radiant for the orbit of 2012 DA14 is at
declination -81 degrees. This means 2012 DA14 fragments approach earth almost
parallel to the earth polar axis, coming from the south. I.e. they approach
towards the south pole and the southern hemisphere.

This means fragments can impact on the southern hemisphere, but not on the
northern hemisphere (except very low latitudes north if we take earth
gravitational curvature of the final trajectory in account). Because the
northern hemisphere, and certainly a place as far north as 55 N, is at the "far
side" of the earth globe as seen from the 2012 DA14 entry direction.

Compare it with a car. A bird coming in frontal will always hit the front of the

car - it cannot hit the back of the car. Chelyabinsk at 55 North latitude is
"the back of the car" in this comparison, given the approach direction of 2012
DA 14 and any fragments of it.

- Marco


----
Dr Marco (asteroid 183294) Langbroek
asteroids at langbroek.org
http://www.marcolangbroek.nl
http://asteroids.marcolangbroek.nl

 

[RGClark]

Once again, the two rocks were in DIFFERENT ORBITS. I'm not sure how else to explain it but different orbits means that there is no possibility that these two rocks were related. Different orbits mean that the arrival time was different - one in the morning and a flypast from the other direction in the evening. Different orbits. not related.

The description "the other direction" or as it's been called the "opposite direction" is misleading. It's more similar to an airline flight that goes from Minnesota to NYC compared to one that goes from Louisiana to NYC.

What I was also wondering about is whether the calculated trajectory for the Russian meteor was including the effects of Earth's gravity. I'm inclined to think it should not be included. To give the best view of what the true orbit of the meteor was, you should give it as if the Earth was not there to interrupt it and change its trajectory with its gravity.

On the other hand I was able to show using a Hohmann orbit calculator that using the delta-V you get from a close in Earth encounter, up to 11.2 km/s, can change a 2012 DA14 type orbit into the one claimed for the Russian meteor, with one big caveat. The Hohmann calculator assumes you get the delta-V boost all at once. So it's not precisely correct to apply it to a case when you get it from a gravitating body where it's applied over time.

Here's the calculator:

Simple Hohmann Transfer Orbit Calculator.
http://web.archive.org/web/20100128043604/http://home.att.net/~ntdoug/smplhmn.html

Select the orbit around the Sun and input a little less than 1 AU, say, 135,000,000 km, for the beginning orbit radius, which is that of 2012 DA14, and 2.5 AU, about 375,000,000 for the ending orbit radius, the aphelion for the Russian meteor. You'll see the delta-v needed to change the smaller orbit into an elliptical one with the larger, ending radius as its aphelion is well within that which can be delivered by the Earth's gravity. (Hohmann orbit changes use two delta-v burns. The first changes the original smaller, circular orbit into a larger elliptical one. The second circularizes this into one with that larger radius. For this application we only need it to have the elliptical shape of the Russian meteor's orbit so that first delta-v of the calculator is the only one I'm using.)

Bob Clark

---------- Post added at 07:17 AM ---------- Previous post was at 02:39 AM ----------

And Robert, aka RGCLARK, just check the You Tube video in post 200 in this thread.
Afterwards bent down, grab your ankles and kiss you're ass good bye.
Just joking.
There are so many rocks out there........

Yes, that is a great video. Check out also the one linked in post #201.

Bob Clark

 

[orb]

Universe Today: Astronomers Calculate Orbit and Origins of Russian Fireball

Reconstructed orbits for the Chelyabinsk meteoroid. Credit: Jorge Zuluaga and Ignacio Ferrin, University of Antioquia in Medellin, Colombia​

Jorge Zuluaga:

arXiv:1302.5377: A preliminary reconstruction of the orbit of the Chelyabinsk Meteoroid

Group of Computational Physics and Astrophysics: The Chelyabinsk Meteoroid - Reconstructing the Orbit

Additionally with orbit of 2012DA14 (cyan):

 

[statickid]

those orbits are pretty much the same

 

[Thunder Chicken]

Universe Today: Astronomers Calculate Orbit and Origins of Russian Fireball

I pulled the following elements from this paper, but I am a little confused by the notation. Can anyone give me a lead?

q 0.82 periapsis? <----no units provided
OMEGA 326.70 I think this is the lon of ascending node
omega 120.62 I think this is the argument of periapsis
i 3.45 inclination
e 0.51 eccentricity
a 1.73 semi-major axis <----no units provided

I was hoping to put these into a scenario so we could ride the meteor in.

 

[Cosmic Penguin]

I pulled the following elements from this paper, but I am a little confused by the notation. Can anyone give me a lead?

q 0.82 periapsis? <----no units provided
OMEGA 326.70 I think this is the lon of ascending node
omega 120.62 I think this is the argument of periapsis
i 3.45 inclination
e 0.51 eccentricity
a 1.73 semi-major axis <----no units provided

I was hoping to put these into a scenario so we could ride the meteor in.

I think that is correct, with the periapsis and the semi-major axis expressed in terms of astronomical units (AU), a.k.a. Earth orbit radius.

 

[Thunder Chicken]

Actually a must be the anomaly? I'm not sure how to enter that in Orbiter. All of the other elements are available in the scenario editor.

 

[MaverickSawyer]

Fixed.

 

[Thunder Chicken]

Why the double post, Thunder Chicken?

I was trying to type ALT codes on a laptop without a numpad - I hit Fn Alt and started typing and all sorts of wackiness ensued .

 

[RisingFury]

That buries the last doubts of the connection to 2012 DA14.

 

[Thunder Chicken]

q 0.82 periapsis? <----no units provided
OMEGA 326.70 I think this is the lon of ascending node
omega 120.62 I think this is the argument of periapsis
i 3.45 inclination
e 0.51 eccentricity
a 1.73 semi-major axis <----no units provided

OK, if this is correct the Orbiter element line should look like this:

ELEMENTS 258804316311. 0.51 3.45 326.70 120.62 (mean anomaly) (epoch)

Any chance q actually represents mean anomaly? Given the other parameters something is needed to locate the object in the orbit, right? But if it is in degrees that would mean it was close to perihelion

I'm not sure what to use for epoch. My guess would be the MJD of the impact time? February 15th 2013 at 3:20 UTC = 56338.13888888888?

---------- Post added at 03:50 AM ---------- Previous post was at 03:10 AM ----------

I tried the above with q = 0.82 representing mean anomaly, it isn't correct.

 

[Linguofreak]

The description "the other direction" or as it's been called the "opposite direction" is misleading. It's more similar to an airline flight that goes from Minnesota to NYC compared to one that goes from Louisiana to NYC.

Well, it depends on whether you're taking the Sun-relative or Earth-relative velocities of the objects involved. Both objects were certainly in prograde orbits around the sun. But DA14 was near aphelion when it encountered Earth, whereas the Chelyabinsk impactor was near perihelion. So from Earth's perspective, they came from very nearly opposite directions.

 

[orb]

I tried the above with q = 0.82 representing mean anomaly, it isn't correct.

It's periapsis in AU (you can check that in the top-down view in graphics editor - I got about 100 pixels to green / 121 pixels to blue = 0.826 there).

 

[Scorpius]

Also tried simulate meteoroid in Orbiter, but with numbers above, it is always falling from west to east, which is incorrect. So I took this data: http://www.webalice.it/mizar02/articoli/Meteorb.dat

It gives: aphelion 2.33 AU, perihelion 0.768 AU, semi-major axis 1.55 AU, eccentricity 0.5, inclination 3.6 deg, LAN 326.41, argument of perihelion 109.7

Orbiter scenario editor required Longitude of Periapsis, it can be calculated as LAN + argument of perihelion = 326.41+109.7 = 436.11 - 360 = 76.11 deg

Unfortunately the Mean anomaly is unknown, so ​​I determined Mean longitude experimentally as about 100 deg.

Best result, I can get with such parameters, in this scenario (3.5 hours before impact). There DeltaGlider (in the role of meteoroid) enters the atmosphere at 3:20 UTC, in point with coordinates 60.3E 55N (not far from Chelyabinsk), entry angle ~25 degrees, azimuth 285 deg (from east to west), speed ~15 km/s (which odd, because the reported speed was 17.8 km/s).

BEGIN_DESC
Contains the latest simulation state.
END_DESC

BEGIN_ENVIRONMENT
System Sol
Date MJD 56337.9951500884
END_ENVIRONMENT

BEGIN_FOCUS
Ship GL-01
END_FOCUS

BEGIN_CAMERA
TARGET GL-01
MODE Extern
POS 7.90 52.33 -14.58
TRACKMODE GlobalFrame
FOV 40.00
END_CAMERA

BEGIN_MFD Left
TYPE Orbit
PROJ Ship
FRAME Equator
ALT
REF Earth
END_MFD

BEGIN_MFD Right
TYPE Orbit
PROJ Frame
FRAME Ecliptic
REF Sun
END_MFD

BEGIN_SHIPS
GL-01eltaGlider
STATUS Orbiting Earth
RPOS 113842059.18 24142157.20 -62559734.52
RVEL -8735.479 -1172.577 4622.038
AROT 92.14 -39.86 -7.70
AFCMODE 7
PRPLEVEL 0:1.000000 1:1.000000
NAVFREQ 482 540 84 114
XPDR 0
AAP 0:0 0:0 0:0
END
END_SHIPS

View attachment Meteoroid.scn