A long-lived horseshoe companion to the Earth

**Mods i understand that this isnt the title of the article i have initially referenced but rather the title of the research presented by the individuals involved and i felt it was more important.

I read today an intersting article, It was written by these two guys who work up in Nothern Ireland at the Armagh Observatory(lots of little goodies at this site too)

You can tell by all the information there they are pretty serious about what they do. If you click on the link on the left "Latest news" you will find this intersting article. The article is titled "Astronomers Find Newly Discovered Asteroid is Earth's Companion It is not the article i first read but a better version of it....
The article i am talking about is titled
Earth-Companion Asteroid Discovered in Horseshoe-Shaped Orbit this article was published by MIT and written by an individual who seems to go by the name KFC. according to this page they can be reached at KentuckyFC @ arxivblog.com if needed.



Right off the bat my eyes opened and thought i was gettin into some juicy info when i read the first scentence..

In the 1969 film Doppelganger, scientists discover and then visit an Earth-like planet sharing our orbit but on exactly the other side of the Sun.

My first though was that this some new doom and gloom story that i hadnt heard yet, sadly as i continued to read my hopes were dashed.

Since then, astronomers have ruled out the possibility of such a planet on the grounds that its gravitational effects on other planets and spacecraft would be easy to see.
But that doesn't rule out the possibility of smaller objects sharing Earth's orbit and today, Apostolos Christou and David Asher at the Armagh Observatory in Northern Ireland say they've found one--an asteroid called 2010 SO16.
Near-Earth asteroids are common but SO16 is in a category of its own. First and foremost, it has an exotic horseshoe-shaped orbit (see diagram above) which astronomers believe to be very rare.

But i kept reading anyways, i was wondering what the heck a "horshoe orbit" was?

Its worth taking a few moments to think about horseshoe orbits. Two points are worth bearing in mind. First, objects further from the Sun than Earth, orbit more slowly. Second, objects that are closer to the Sun orbit more quickly than Earth.
So imagine an asteroid with an orbit around the Sun that is just a little bit smaller than Earth's. Because it is orbiting more quickly, this asteroid will gradually catch up with Earth.

What?, its gonna catch up with earth? you mean there is doom and gloom after all

When it approaches Earth, the larger planet's gravity will tend to pull the asteroid towards it and away from the Sun. This makes the asteroid orbit more slowly and if the asteroid ends up in a orbit that is slightly bigger than Earth's, it will orbit the Sun more slowly than Earth and fall behind.
After that, the Earth will catch up with the slower asteroid in the bigger orbit, pulling it back into the small faster orbit and process begins again.
So from the point of view of the Earth, the asteroid has a horseshoe-shaped orbit, constantly moving towards and away from the Earth without ever passing it. (However, from the asteroid's point of view, it orbits the Sun continuously in the same direction, sometimes more quickly in smaller orbits and sometimes more slowly in bigger orbits.)
For SO16, the period of this effect is about 350 years

"OHHhhhh so much for the doom and gloom" i though...but i stuck now i had already read half the article and i figured i might as well finish it....

Horseshoe orbits are thought to be very unstable, since any small gravitational tug can destroy the fragile resonance that has been set up. However, SO16's orbit is surprisingly robust.
Christou and Asher simulated its orbit with slightly different values for parameters such as its semi-major axis. In these simulations, SO16 remained in a horseshoe-shaped orbit for at least 120,000 years and sometimes for more than a million years.

Hmmm kinda intersting really this tiny thing out in space only comes along about 350 years, and these two guys Apostolos Christou and David Asher happen to pick it out of all the stars in the sky. I thought it was somethin special and these guys have found a one of a kind object, i had to keep reading.

Astronomers know of three other horseshoe companions for Earth but these are all much smaller (SO16 is a few hundred meters across) and none have orbits that are likely to survive for more than a few thousands years.

GRRrrrrrr its not even unique. It seems these "Horseshoe Orbit" objects(which really arent) are rather common but all the others ones we know about are tiny (ranging from 0.01km to 5km) and this thing is a "FEW HUNDRED!!! and eventually thier orbits fail so maybe there is still hope for doom and gloom yet

That makes SO16 kind of special. For anybody willing and able to look, it is currently near one of its points of closest approach, with an absolute magnitude of about 20, lagging the Earth by 0.13 AU, like a stray puppy.
And it will be there for some time, say Christou and Asher. "It will remain as an evening object in the sky for several decades to come."

"Decades to come" OMG its too good to be true, NOW im sure this isnt the last post you will read about this sucker

Ok, im sorry for the dramitic was just trying make the reading a bit more intersting
Not that this isnt intersting in itself. The idea that this giant rock in space is gonna make our sky home for the next...generation or two, is fantastic. Now..granted it is still expected to be about 715,044,671.31 miles from earth (half the distance of Elenin) and you will probably need some sort of telescope to see it ( i could be wrong), there is plenty of time to view and im sure there will be plenty of pics.
Here is the Research Paper that the two gentlemen wrote about thier observations for those who are that interested in it(i hope you are).

I also urge you all to explore the site of the Armagh Observatory if your interested in astronomy you will find much to keep you interested and if your not maybe this will the spark to get you interested.

Hope you all enjoy what you find here.

Hi. Interesting thread.

I was thinking of starting one myself about this kind of thing, but you beat me to it.

Is this asteroid the same one as this one en.wikipedia.org... ?

There was another thread on this (Cruithne) in about 2005, but it seemed to generate little interest.

Hopefully yours will remedy this.

Thanks.

Originally posted by Illegal Alien
Hi. Interesting thread.

I was thinking of starting one myself about this kind of thing, but you beat me to it.

Is this asteroid the same one as this one en.wikipedia.org... ?

There was another thread on this (Cruithne) in about 2005, but it seemed to generate little interest.

Hopefully yours will remedy this.

Thanks.

Nope thats a different object the one i reference in this artilce is called 2010 SO16
i tried to find the JPL trajectory for the one mention but the link doesnt want load for me right ow for some reason...maybe it will for you
3753 Cruithne

The one i spoke of doesnt have a listing in JPL yet, or at least i couldnt find it.

reply to post by RadicalRebel


The link took me to a page which gave me an alternative link to ssd.jpl.nasa.gov...

I'm not too good with numbers and stuff, so maybe you'll make more sense of this than I can.

I find it really strange that something so interesting doesn't get mentioned more often.

If scientists wanted to study an asteroid, some of these NEOs would be ideal candidates I would think, rather than zooming off to the asteroid belt, but then again, I suppose there would be more other objects to study there.

reply to post by Illegal Alien


yeah sorry, i dont do so well with numbers, and im still learning what all the measurments mean so im really of no use in that dept, thats why i leave it to others.
As for it being reported more, i have a feeling more people on this site will pay attention to it than most places(except perhaps sites dedicated to astronomy and such). In the first article i linked too they talk a bit about the hopes of sending a probe to help them figure out where it came from. Right now it seems they are not 100% sure about it.
"Astronomers Find Newly Discovered Asteroid is Earth's Companion

Ultimately, Christou and Asher would like to know where it came from, and they have already thought of several possibilities. It could be an ordinary asteroid coming from the Main Belt between Mars and Jupiter. In that case, the random gravitational pull of the different planets would be responsible for its present orbit, something that Tolis and David think is an unlikely proposition. It could also be a piece of the Moon that escaped the gravity of the Earth-Moon system and went into an independent orbit around the Sun. However, the very stability of its orbit means that there is currently no way to transport it from the Moon to where it is now. Finally, 2010 SO16 could represent leakage from a population of objects near the so-called triangular equilibrium points 60 degrees ahead of and behind the Earth in its orbit. Such a population has been postulated in the past but never observed as such objects are always near the Sun in the sky. If they do exist, they may represent relic material from the formation of Earth, Moon and the other inner planets 4.5 billion years ago.

For the time being, the astronomers would like to see the physical properties of the object studied from the ground, especially its colour. "Colour, a measure of an asteroid's reflectivity across the electromagnetic spectrum, can tell you a lot about its origin", they explain. "With this information we can start testing possible origin scenarios with hard data. If it proves to be unique in some way, it may be worth sending a probe to study it up close, and perhaps bring back a sample for laboratory scrutiny."

seems like a lot of money would be needed to make something like that happen, maybe there hasnt been enough "buzz" about these objects in the past to induce that kind of funding, maybe there will be now, they should send out a probe to check them all out, but i think this is the first one that they could realistically take a sample from?

S & F good find buddy, just goes to show you the universe is full of cool and interesting things