Showing posts with label Commentary. Show all posts
Showing posts with label Commentary. Show all posts

Jun 19, 2020

A Foofaraw Over a NEO Designated 2018 VP1

Artist's concept of a near-Earth object. ImageCourtesy NASA/JPL-Caltech
Over the years, the tabloids as shown a propensity for raising a foofaraw over Near-Earth Objects. The Close-Approach of 2018 VP1 is only about four months away, and an internet search will reveal several clickbait stories. Many times it appears that tabloid writers pick a random asteroid and writes a "story" about it. At times one must have some background or do some research to see what the more accurate story is.

There is a low probability, 1 in 240, that the two-meter 2018 VP1 will strike the Earth's atmosphere and create spectacular fireballs on 2020-11-02. A test with the Imperial College London's Earth Impact Effects Program reports, "The average interval between impacts of this size somewhere on Earth is 0.2 years". In other words, it would be safe to assume objects the size of 2018 VP1 has impacted Earth's atmosphere since 2018-Nov-03, the date of discovery. The Earth Impact Effects Program also suggests that the fireball is unlikely to do any significant damage. NASA JPL list kinetic energy at impact from 2018 VP1[IF ANY] as ~ 0.00042 MegaTons of TNT. The Chelyabinsk event was 0.4 to 0.5 MegaTons of TNT.

Four times in the past, NEOs were observed by observers of asteroids before impact. These four asteroids(2008 TC3,2014 AA, 2018 LA, and 2019 MO) all were on the safe side when it comes to size.

 Object Date of discovery Date of Impact Size(M)
 2008 TC32008-10-06 2008-10-07 4.1
 2014 AA2014-01-01 2014-01-02 2–4
 2018 LA2018-06-02 2018-06-02 2.6–3.8
 2019 MO2019-06-22 2019-06-22 3–10

One of the programs available to the amateur observers of asteroids and comets is Find_Orb.[By Bill Gray] It is useful for calculating approximate ephemeris, determining approximate orbits, generating virtual asteroids, virtual impactors, predicting impact locations, and many other things. It should be noted IF one uses the wrong setting, one gets an incorrect solution. Find_Orb can generate an "asteroid risk corridor" with the help of Guide 9.1.[By Bill Gray]

Find_orb computing  Monte Carlo variant orbits  for the NEO 2018 VP1. One can use Monte Carlo method to  create virtual asteroids. By using orbits of  the virtual asteroids one can can see where the "real" asteroid could go. If any of virtual asteroids impact the Earth they become  known as  virtual impactors and the is 'Non-Zero' probability of  the real  asteroid hitting the Earth 

My Find_orb Setting

 Selecting perturbers All
 Epoch 2020-11-01.051
 Monte Carlo noise 2
 Physical model Include  SRP
 Filler out 3 worst observations

As a test of concept, I obtained the observations of 2018 VP1 for the Minor Planet Center. I loaded the observations into Find_Orb and had it run the Monte Carlo method all night. Find_orb generated the following files MPCOrb.datstate.txt, and  virtual.txt. These files had orbits for 129,659 virtual asteroids 200 were virtual impactors( about 0.15%). I place a copy of the virtual.txt file in the Guide directory along with a copy of impact.tdf.(Project Pluto) Then Guide could generate a map of an asteroid risk corridor.

An asteroid (fireball) risk corridor of potential impact for the NEO 2018 VP1, the orange dots is where 200 virtual impactors strike the Earth's atmosphere.

Note: Because there were more than 9 observations, I had to edited virtual.txt to do a workaround. I replace "18 of 21" with "U of O" see edited virtual.txt; this keeps the columns in the right place. I also edited impact.tdf(My) file where I can have more than one risk corridor.

Peter Thomas @ptastro1 also  this path of risk for 2018 VP1 on Twitter


(as of 2020-06-13 )

Also see

Note this has been edit to fix links and know typos.

Jun 14, 2020

2018 VP1 Information Sheet-- "1 in 240" Odds of a Fireball on 2020-11-02 or ."99.59% chance the asteroid will MISS the Earth"

2018 VP1 Information Sheet-- "1 in 240"  Odds of a Fireball on 2020-11-02 or ."99.59% chance the asteroid will MISS the Earth"

This artist's concept shows a broken-up asteroid. Image: Courtesy NASA/JPL-Caltech
This artist's concept shows a broken-up asteroid.
ImageCourtesy NASA/JPL-Caltech

Throughout the year, very small rocks strick the Earth's atmosphere and creating spectacular fireballs.  Most of these rocks travel through space unknown to habitats of Earth until they strick the atmosphere.   If we are lucky, the fireball will be seen and reported.  If we are really lucky, the fireballs will be capture on film.  The most vast majority of fireballs are of no danger what so ever. Most fireballs are like rainbows in that they are cool.  Four times in the past, these rocks travel through the field of vision of an asteroid observer before impact. Observation was taken. The rocks were given designations, like 2014 AA( i.e., the first discovery of the first half of January in 2014), and the rocks "became" asteroids.  These four asteroids were on the safe side when it comes to size.

In the first half of November 2018, an asteroid was discovered and give the designation 2018 VP1.  This asteroid is very small[1.8 m - 3.9 m ( 5.90551 to 12.79528 feet) ]. This asteroid was only observed 21 times over 13 days. 

In orbit determination, one calculation what orbit will place the object in the sky where it was seen. If one knows an object's orbit, it knows where it is going and where it will be in the sky.  All observations are "imperfect," so there will be many similar orbits.  If one were to create virtual asteroids for each of the similar orbits and did a simulation, one would see over time. The virtual asteroids move apart from each other to create an uncertainty region.  The real asteroid is somewhere within the uncertainty region. When doing the simulation, if any of the virtual asteroids impact the Earth, they become virtual impactors, and there is 'Non-Zero' probability of the real asteroid hitting the Earth.  By calculating the percentage of virtual impactors to virtual asteroids, one can calculate the risk of impact.

There is a very low-risk impact 2018 VP1 will on 2020-11-02. However, it must be restarted this asteroid is very small[1.8 m - 3.9 m ( 5.90551 to 12.79528 feet) ]. We have a fireball this size about two times a year.

Find_orb computing  Monte Carlo variant orbits for the NEO 2018 VP1
Find_orb computing  Monte Carlo variant orbits  for the NEO 2018 VP1. One can use Monte Carlo method to  create virtual asteroids. By using orbits of  the virtual asteroids one can can see where the "real" asteroid could go. If any of virtual asteroids impact the Earth they become  known as  virtual impactors and the is 'Non-Zero' probability of  the real  asteroid hitting the Earth


(as of 2020-06-13 )

Note: this was edited  to add links missing data formatting,  typos, replace, the image of Find_orb computing, fixing bad links .

Oct 28, 2019

The 2019 UB8 2019-10-29 Flyby! How Close? Is Close?

(2019 UB8) approximate (0.50 LD) flyby distance from Earth
This image adapted by Steven M Tilley from the image the original
Earth-Moon.png by Nickshanks
 under licensed under the
Creative Commons Attribution 2.5 Generic license
Tonight(2019-Oct-28/29) the NEO 2019 UB8 (4.4 m - 9.7 m) will do a flyby(A.K.A NEO Earth Close Approaches) of a Nominal Distance of 0.50 LD (0.00127 AU) ~191,000 KM (~ 119,000 miles). Sorting by nominal distance, this close approach is listed in the top 270 of 22,500+ entries in JPL's close approach database. (As of 2019-Oct-28) Flybys within one LD are quite common from what we "know" NEOs flybys within one LD a few times every week or so.

If  the Earth was the size of a basketball  how far would the Moon be?
What is Close

Close is a relative term. "Close" to a major sports venue is not the same as "close" to the ER. If one were to think of a basketball-size Earth, it may in understanding what is "close" and what is "far." In this, basketball-size Earth system, the ISS would be at ~0.76 CM (0.3 inches); we had NEO Flybys at 10.35 CM (4.1 inches) [ 2011 CQ1 on 2011-Feb-04] before. The Moon would range from ~673.41 CM (~22.0 Ft) to ~753.81 CM (~24.7 Ft). 2019 UB8 will be ~347.62 CM (~11.4 Ft) from the basketball. To see 2019 UB8 tonight, check out the Virtual Telescope Project.

Sep 25, 2016

An Asteroid as Entered the Blogosphere… Should I Be Worried?

A commentary by Steven M. Tilley

The Asteroid to Earth "Say out my Way!!!!"
Earth to the Asteroid "Watch where you're going ... fool!!!"
 Image edited by Steven M. Tilley
(Disclaimer --  Earth and
asteroids CAN NOT talk)
 see the original (public domain) image
Planetoid crashing into primordial Earth  at
 Donald Davis' official site
About every few month or so an asteroid makes waves online.  This lead some people to panic. Before anyone panics and does something dumb. One should remember one of the secrets to life, breathe, in and out. Then remember anyone can post anything online. Some sources are better than others when it comes to asteroid information. Sources range from very useful to worse than useless.

First check for reliable information from some of the reliable sources such as the Minor Planet Center, NASA NEO Program Office at JPL, ESA's NEODyS (Near Earth Objects Dynamic Site), or The Tracking News.  The writer of this blog post is aware that are many people in the blogosphere who distrusts one or more of the name reliable sources.  The author suggests that they reexamine their stand. A significant number of individuals and organizations from around the world observe asteroids; these observations serve as a cross check. If someone or a group makes an error, the error would soon come to light with more observations. If there is nothing about the asteroid  from the name from reliable sources most likely, the story probably is wrong. 

Another thing to remember as a story moves through the blogosphere it changes like the "telephone game." The original story is misread, poorly translated, misunderstood, etc. then rewritten by other writers with the wrong information.  Then other writers then use the revised story as a source for new stories adding to the madness. One should seek out the original story(and see if it is reliable).

When reading up ( and writing) about asteroids one should know the limits of one's knowledge base.  Some of bloggers and youtbers out there go way outside of their knowledge base; they think they "know" when they don't  "know."  The problem is many people mistakenly repost "wrong" blog posts(and videos) adding to the madness. Just because something has been shared, many times does not make it true.

It should be stated that no post is complete without a "good" headline and an image to hook readers. Many times the picture is wrong, and the headline is highly misleading.  It takes lots of time to find a picture of the asteroid or use a telescope to image the asteroid in question.  This requirement of time will lead many writers to find any old image of any old asteroid. Many times if the author used a real picture of the asteroid internet users would not click.

Finally one should keep studying about asteroid there so much to know. One should not be afraid seeking good answers to questions. Just look for good sources of information.