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Squeeky-bum-time now less squeeky...

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Squeeky-bum-time now less squeeky... was created by dmcdona

Oct. 7, 2009

Dwayne Brown
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DC Agle
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RELEASE: 09-232

NASA REFINES ASTEROID APOPHIS' PATH TOWARD EARTH

PASADENA, Calif. -- Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.

The Apophis asteroid is approximately the size of two-and-a-half football fields. The new data were documented by near-Earth object scientists Steve Chesley and Paul Chodas at NASA's Jet Propulsion Laboratory in Pasadena, Calif. They will present their updated findings at a meeting of the American Astronomical Society's Division for Planetary Sciences in Puerto Rico on Oct. 8.

"Apophis has been one of those celestial bodies that has captured the public's interest since it was discovered in 2004," said Chesley.
"Updated computational techniques and newly available data indicate the probability of an Earth encounter on April 13, 2036, for Apophis has dropped from one-in-45,000 to about four-in-a million."

A majority of the data that enabled the updated orbit of Apophis came from observations Dave Tholen and collaborators at the University of Hawaii's Institute for Astronomy in Manoa made. Tholen pored over hundreds of previously unreleased images of the night sky made with the University of Hawaii's 88-inch telescope, located near the summit of Mauna Kea.

Tholen made improved measurements of the asteroid's position in the images, enabling him to provide Chesley and Chodas with new data sets more precise than previous measures for Apophis. Measurements from the Steward Observatory's 90-inch Bok telescope on Kitt Peak in Arizona and the Arecibo Observatory on the island of Puerto Rico also were used in Chesley's calculations.

The information provided a more accurate glimpse of Apophis' orbit well into the latter part of this century. Among the findings is another close encounter by the asteroid with Earth in 2068 with chance of impact currently at approximately three-in-a-million. As with earlier orbital estimates where Earth impacts in 2029 and 2036 could not initially be ruled out due to the need for additional data, it is expected that the 2068 encounter will diminish in probability as more information about Apophis is acquired.

Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteroid ruled out any possibility of an impact in 2029. However, the asteroid is expected to make a record-setting -- but harmless -- close approach to Earth on Friday, April 13, 2029, when it comes no closer than 18,300 miles above Earth's surface.

"The refined orbital determination further reinforces that Apophis is an asteroid we can look to as an opportunity for exciting science and not something that should be feared," said Don Yeomans, manager of the Near-Earth Object Program Office at JPL. "The public can follow along as we continue to study Apophis and other near-Earth objects by visiting us on our AsteroidWatch Web site and by following us on the @AsteroidWatch Twitter feed."

The science of predicting asteroid orbits is based on a physical model of the solar system which includes the gravitational influence of the sun, moon, other planets and the three largest asteroids.

NASA detects and tracks asteroids and comets passing close to Earth using both ground and space-based telescopes. The Near Earth-Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. Cornell University operates the Arecibo Observatory under a cooperative agreement with the National Science Foundation in Arlington, Va.
13 years 3 months ago #81557

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Replied by mjc on topic Re:Squeeky-bum-time now less squeeky...

Very good.

Bit unfortunate that closest approach is on a "Fri 13th".
18,300 miles distant - two and half football fields - I assume that's American football - don't know how big they are.

Anyone got a ballpark angular size at closest approach?

I think I'll be too old to set-up a scope when that arrives.
Still could have been worse - closest approach could have been such that I would feel the heat on my cheeks as I hold out my hand to ward of the glare...

Mark
13 years 3 months ago #81560

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  • michaeloconnell
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Replied by michaeloconnell on topic Re:Squeeky-bum-time now less squeeky...

Good to hear that the asteroid is less of a threat.

On a separate note:

Squeeky-bum-time now less squeeky...

Your personal hygiene is your own business Dave....:ohmy:
Last edit: 13 years 3 months ago by michaeloconnell.
13 years 3 months ago #81565

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Replied by dmcdona on topic Re:Squeeky-bum-time now less squeeky...

And with Mark mentioning "cheeks"... This could go downhill rapidly... Mods!
13 years 3 months ago #81568

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Replied by mjc on topic Re:Squeeky-bum-time now less squeeky...

If I could piggy back a question here re asteroid work.
Is there an online resource where one can set a celestial coordinate, UTC time, and maybe field of view and determine what known solar system objects are known to be within the field of view - or maybe a list of closest objects.

For you asteroid hunters - how do you know that a suspected object is new or not?

And - no - I haven't got any faint spot on any image that I'm curious about - but maybe something for the future.

Mark
13 years 3 months ago #81570

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Replied by dmcdona on topic Re:Squeeky-bum-time now less squeeky...

Mark - I'm not sure if there's an online resource but it seems most "asteroid hunters" use astrometrica (shareware but a lenghty 180 days before you get a nag screen. But its only €25 to buy).

Its takes a wee bit of time to set up the configuration file for your particular imaging setup (focal length, pixel size etc) but once done, you can open an image, specify the time/date if necessary (it'll take the time/date from a FITS header if theose fields are completed) and ask it to check for known objects. If your little dot doesn't show up as a known object, you have a potential candidate...

You just need to make sure to download the latest MPC catalogue of known objects. Astrometrica can be set to use the online USNO-B1.0 catalogue (for comparison star fields)so you don't even need to download that.

www.astrometrica.at/

If you need any help, just shout.
Dave
13 years 3 months ago #81571

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Replied by phoenix on topic Re:Squeeky-bum-time now less squeeky...

You got to love statistics, why instead of say 4 in 1 million did they not state 1 in 250,000. Maybe the difference would not have been so obvious for us pure mortals outside NASA.

You can download MPCOrb for some sky atlas software from the MPC site which will plot all known asteroids. I use the Sky 6 and update it at least once a week or before I go out at night imaging.

or maybe a list of closest objects


I have been chatting to Neill about doing a NEO list for the monthly sky guide. Spaceweather will give you a list as will some of the Nasa sites but they include southern hemisphere objects plus those in excess of mag 20. If we get it together we will try and get a list of objects only in the northern hemisphere and below mag 17.5. All you J squad with 14" scopes can make your own list.:kiss:
We may do the same for comets?? Any interest in this sort of data being included in the sky guide?
Kieran
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ancarraigobservatory.co.uk/
13 years 3 months ago #81573

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Replied by Seanie_Morris on topic Re:Squeeky-bum-time now less squeeky...

Well, is this a good or bad thing? Good that the asteroid is going to significantly miss Earth, or a bad thing that they had to essetially go over their calculations almost 2 years later and 'adjust' things? :P

Seanie.
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13 years 3 months ago #81574

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Replied by mjc on topic Re:Squeeky-bum-time now less squeeky...

Thanks Dave et al.

Its in my mind that there are thousands of known objects - and being updated all the time. It would be really great if a difinitive reference site was available. There are some wonderful resources out there with public access and I would have thought that this would be - well - essential.

We need a mechanism that allows amateurs to submit quality observations to the professional comunity and to filter out known objects so that the process is more useful than irksome to the professional community (through false alarms because we don't know that this "new" object is in fact well documented).

Dave - I will think about what you said and will get back to you.

I'm in a position where I want to do something other than "mucking about". But there are some key skills that I need to cross the rubikon of before I can engage in a meaningful way.

I still want to get a few pretty pictures - call it outreach if you will...

Mark
13 years 3 months ago #81576

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Replied by philiplardner on topic Re:Squeeky-bum-time now less squeeky...

mjc wrote:

Anyone got a ballpark angular size at closest approach?

Mark


Based on the size (210m to 330m diameter) and closest approach ("no closer than 29,470km" ) numbers given in neo.jpl.nasa.gov/apophis/, Apophis should appear between 2.94" and 4.62" in the sky...

Of course if Apophis keeps getting bigger and bigger and bigger until it fills your eyepiece, then there's an even chance that NASA fluffed their calculations... and you might want to duck! :dry:

Phil.
Last edit: 13 years 3 months ago by philiplardner.
13 years 3 months ago #81580

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Replied by dmcdona on topic Re:Squeeky-bum-time now less squeeky...

phoenix wrote:

All you J squad with 14" scopes can make your own list.:kiss:


I'll just use the MPC NEO Conf page... :kiss:
13 years 3 months ago #81589

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Replied by dmcdona on topic Re:Squeeky-bum-time now less squeeky...

mjc wrote:

It would be really great if a difinitive reference site was available. There are some wonderful resources out there with public access and I would have thought that this would be - well - essential.

We need a mechanism that allows amateurs to submit quality observations to the professional comunity and to filter out known objects so that the process is more useful than irksome to the professional community (through false alarms because we don't know that this "new" object is in fact well documented).


Mark - the MPC have a very good web page with up-to-the-minute ephemerides for all known asteroids plus a whole heap of other really good info. www.cfa.harvard.edu/iau/mpc.html

The MPC *is* the clearing house for all observations - and they really don;t mind if you submit data for existing objects with well determined orbits. Of course, they *really* appreciate data for objects with poorly known orbits or wholly new objects. Of course, your data has to be of good quality - but that's a whole other question...

When you're ready to cross the rubikon, the J club will help ye out :)

Dave
13 years 3 months ago #81592

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Replied by Frank Ryan on topic Re:Squeeky-bum-time now less squeeky...

What was all that about a gravitational 'eddy' created by the Moon that if
it entered it would sufficiently alter it's orbit so as to create a real headache for the next pass?
Other than that..
in all 'probability' ya we are fine.
But statistics, odds and probabilities are all - well - relative.
Odds don't mean crap to the guy getting hit by lightning or
maybe they do for the guy getting the 6 numbers but
as a poker player....I always remind people...
yeah sure the odds of x y z happening are - whatever - millions to one.
Someone has to win therefore we all have the same chance of winning,
odds are negated.
Same go's for NASA telling us....ah... we'll be grand...
so....they can tell me with 100% certainty that an rogue comet entering the
solar system is not going to edge the orbit of this back on track to Earth!
Nope...
all odds..
If I bet you last week another ring around Saturn was to be
found you would have probably taken me up on it...
I ain't second guessing this but odds are...
we will all be out on the night of the closest pass going ooohh...ahhh...
instead of ahhhhh! oooohhh!!!
:laugh:
My Astrophotography
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13 years 3 months ago #81595

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Replied by mjc on topic Re:Squeeky-bum-time now less squeeky...

Dave I appreciate the link to astrometrica it looks very good and I see it helps identify moving objects.

It appears that the MPC provide a mechanism for determing what known minor planets are in a given FOV that might be of interest.

See scully.cfa.harvard.edu/~cgi/CheckMP

Mark
13 years 3 months ago #81627

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