Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math

Topic: Coincidence of meteor strike and close asteroid approach at same time.
Replies: 36   Last Post: Oct 4, 2013 6:26 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Robert Clark

Posts: 68
Registered: 12/13/04
Re: Coincidence of meteor strike and close asteroid approach at same time.
Posted: Feb 22, 2013 1:09 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Feb 20, 5:38 pm, will...@cfa.harvard.edu (Steve Willner) wrote:
> In article <3246ca96-d581-45bc-b8b5-25d4ebd07...@j9g2000vbz.googlegroups.com>,
>  Robert Clark <rgregorycl...@yahoo.com> writes:
>

> >  First though, note there are many ways a fragment could be separated
> > from the main asteroid.

>
> As I understand it, about 1/3 of near-Earth asteroids have moons.
>

> > depending on the direction the fragment is sent, once the asteroid
> > comes around to the Earth or Moon or other planet on a close approach,
> > that fragment could be much closer to that large gravitating body than
> > the asteroid and therefore be sent on a different orbit.

>
> In which case it's an independent object following its own orbit, no
> longer a companion of the first object.
>

> >  Then on subsequent orbits it could impact the gravitating body.
>
> Yes, it would on average have just as much or as little chance of
> impacting as any other NEO.  For a specific object, one would have to
> know the orbit.
>

> > Indeed it could even be captured by the gravitating body, such as the
> > Earth,

>
> Only if it comes close enough to lose energy in the atmosphere.
> That's a tiny probability but not zero.
>

> >  For instance asteroid 2012 DA14 was traveling at 18,641 mph,
> > about 8.3 km/s on closest approach. At the distance it passed the
> > Earth at 17,000 miles this is greater than escape velocity. But it's
> > less than escape velocity at the Earth's surface.

>
> If it had come closer to Earth, it would have been going faster
> because Earth's gravity would have accelerated it more.
>
> --


Thanks for the info. On this page it says the orbits "cross" at two
locations, or more precisely, which
body is on the outside orbit changes twice per orbit:

La Sagra Observatory discovers very near-Earth asteroid 2012 DA14.
Posted By Jaime Nomen
2012/03/27 05:20 CDT
"The preliminary orbit shows that 2012 DA14 has a very Earth-Like
orbit with a period of 366.24 days, just one more day than our
terrestrial year. The orbit is nearly circular but just elliptical
enough to jump inside and outside of the path of Earth two times per
year. Because objects move faster when they are closer to the Sun, the
relative motion is similar to some sports races: when the Earth is on
the outer track, it is overtaken by 2012 DA14, but when the asteroid
crosses Earth's orbit, Earth overtakes it and passes by. It is during
the orbit crossings when the closest encounters occur, and when there
is potential for a future impact."
http://www.planetary.org/blogs/guest-blogs/3418.html

Does this mean there are two close approaches per orbit? It doesn't
necessarily have to be since where the two orbits "cross" does not
mean the two bodies have to be there at the same time. On the other
hand because they have similar orbits and therefor similar speeds, if
they are close at one "crossing" point, they should be relatively
close at the other.


Bob Clark


Date Subject Author
2/19/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/20/13
Read Re: Coincidence of meteor strike and close asteroid approach at same
time.
David Bernier
2/20/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Richard Tobin
2/20/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Jeff Findley
2/20/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/20/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/23/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/23/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/27/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/28/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/28/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
bradguth@gmail.com
10/3/13
Read Re: Coincidence of meteor strike and close asteroid approach at same
time.
David Staup
10/3/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Mike Collins
10/4/13
Read Re: Coincidence of meteor strike and close asteroid approach at same
time.
David Staup
10/4/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Mike Collins
2/28/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Davoud
2/28/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
2/28/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Greg \(Strider\) Moore
3/6/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
3/6/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
bradguth@gmail.com
3/9/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
bradguth@gmail.com
3/7/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
3/11/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
3/11/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Fred J. McCall
3/12/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Fred J. McCall
3/12/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark
3/12/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Jeff Findley
3/15/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
bradguth@gmail.com
2/23/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
bradguth@gmail.com
2/22/13
Read Re: Coincidence of meteor strike and close asteroid approach at same time.
Robert Clark

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.