INCOMING!, Detection and observation of Earth-approaching asteroids. Options

[scalbers]

I think I've seen this pattern before where the probability goes up to a peak, then goes down to zero. We'll see if this plays out and what the peak is.

[AndyG]

As long as the moving probability peak itself peaks before 2032, we'll be fine!

This time.

Andy

[nprev]

Yeah. I'm definitely not gonna buy my Wile E. Coyote little 1890s parasol just yet...

[Explorer1]

Yep, here's a picture from Wikipedia's Apophis page showing what's (hopefully) going on: http://en.wikipedia.org/wiki/File:Apophis_ellipse.svg
We're not in the bulls-eye I trust....

[dilo]

I think I've seen this pattern before where the probability goes up to a peak, then goes down to zero. We'll see if this plays out and what the peak is.

Indeed, I recall that, 9 years ago, Apophis chances for 2029 impact rised to a scaring 2.7% in few hours before to drop to "0" thanks to recovery of older observations... in this case, we probably should go back to images collected to last 2013 TV135 close approach, dated 1990...

UPDATE: now probability is decreasing in both sources (1:19000 for JPL and 1:8400 for NEODys)

[Gerald]

What you never wanted to know: How to calculate impact probabilities. May be with the exception of the first few pages .

[dilo]

Thanks Gerald, very interesting article!
PS: meanwhile, impact chances are going to "stabilize" around 1:16000 (JPL) and 1:8000 (NEODys)

[Mongo]

Current estimated odds:
NEODyS 1:5076 on 220 optical observations
NASA/JPL 1:10000 on 220 optical observations

The probability of impact is still increasing (although it is still quite low). Both calculations indicate a closest approach of 65% of the Earth's radius ( ), but I assume with a much larger error ellipse.

[Gerald]

... a closest approach of 65% of the Earth's radius ...

... to the geocenter, means the LOV intersects with Earth, with a 66%-error below 0.1 Earth radii.
Excerpt of the NASA/JPL legend:

Distance
The minimum distance on the target plane (scaled b-plane) from the LOV to the geocenter ...

So it looks to me like a matter of timing.
The amount of the sigma value is again below 1, that's a bit surprising after it had been above 1.

Edit: Timing uncertainty (1 sigma) adds up to about 24.6 days, at the moment, from now to end of august, 2032 (18.8 years). Calculated from orbital data:
24.6 days = 18.8 years * 5 days uncertainty / 3.82 years

[Mongo]

Current estimated odds:
NEODyS 1:6173 on 259 optical observations, calculated distance from geocenter is 0.74 REarth
NASA/JPL 1:10638 on 259 optical observations, calculated distance from geocenter is 0.71 REarth

If it does impact the Earth, NASA/JPL estimates the impact energy at 3170 MT.

[Gerald]

Based on 304 optical observations (of 307) NEODyS calculates the risk to about 11% of the background risk.
(The current value of -0.95 on the Palermo scale (PS) means 10^-0.95 = 0.112 of the background risk.)

[dilo]

(The current value of -0.95 on the Palermo scale (PS) means 10^-0.95 = 0.112 of the background risk.)

I would like to add that background probability refers to the 19 years time frame from now to the potential impact; in other words, until 2032, we should have 0.09% chance that an asteroid with same impact energy potential will actually hit the Earth; now, if we divide the estimated 2013 TV135 impact probability by this number, we obtain the "relative risk" factor discussed by Gerald (I know, it's a bit complicated... this is the reason why they created also a "Torino scale" for large audience!).

PS: meanwhile, the JPL impact probability has halved to 1:21000 and the asteroid isn't the highest in the Palermo scale anymore!

[ChrisC]

Hello all -

As I'm sure many of you all know, back in April 2013 the third annual Planetary Defense Conference was held in Flagstaff AZ. After the conference ended I watched ALL the session videos (some 20 hours) that they'd put up on Livestream. The presentations were fantastic! I'll link to them here:

All 15 videos:
http://www.livestream.com/pdc2013/folder

Example direct link to an individual video:
http://www.livestream.com/pdc2013/video?cl...21-384cb8db9ac1

Also, some public events occurred as part of the conference:
http://www.youtube.com/results?search_quer...ense+conference


Three weeks ago, NASA held a multi-day "Asteroid Initiative Workshop". The sessions from the first day appeared on Youtube:

http://www.youtube.com/watch?v=UJRJyljzwTA
http://www.youtube.com/watch?v=INBt1iLJk_Q
http://www.youtube.com/watch?v=tGhXcGztpI8 *
http://www.youtube.com/watch?v=Xoqesv4Cm68

* my personal favorite presentation is in this one, at the 27m30s point

So, my question is this ... The four Youtube links immediately above are just from the FIRST DAY of the conference. Nothing further has been posted. Where is the rest of the workshop? It was supposed to last 3-4 days.

As I was collecting links together for purposes of this post, I went to the NASA AIW website:

http://www.nasa.gov/content/asteroid-initi...thesis-workshop

... and found that the workshop actually had to shut down after the first day due to ... the federal government shutdown! Riiiight, of course, the first day was on Sept 30th, just before the shutdown. The workshop has now been rescheduled for Nov 20-22.

I came in here to ask if anyone knew about the remaining session videos, and in the process of writing this I've answered my own question. So, I'll let this post stand as a recommendation. If you are really interested in this topic, then watch the above videos! The first set of videos in particular, from PDC 2013, represent an EXCELLENT overview of asteroid science and technology, from detection to characterization to mitigation.

[dilo]

Going back a moment to 2013 TV135, I made a set of plots showing evolution of risk indicators and other useful reported figures, included 1-sigma uncertain of some orbital coefficients:

Last update: Oct,29 - 13.30 UT

Edit: in the "Palermo scale" plot I added 2007 VK184 level (it's the other asteroid now classified 1 in the Torino scale)
Note: on Oct,29 the Palermo classification from NEODys is back above -1 (impact probability 1:10600)

[Mongo]

Note: on Oct,29 the Palermo classification from NEODys is back above -1 (impact probability 1:10600)

I was not expecting that. I had thought that the impact probability would continue to decline toward zero as the error ellipse shrinks. I assume that its calculated time of closest approach to the geocenter continues to approach the time that the Earth occupies that point in the geocenter.