Roll to observe Elenin – STEREO BEHIND looks at a hot topic

Story submitted by Robert Bateman

In just a few hours from now, NASA rolls the STEREO BEHIND solar satellite to have a look at Comet Elenin (P/2010 X1), and if you haven’t been paying attention, it is one red hot topic topped with wilder imaginations, dooms, hypotheticals and omens than previously imagined.

From being on a par with/substitute for Niburu to a first ever hyperbolic (>1) cometary orbit, you’d be hard pressed to make the relevant data up.  Perihelion somewhat around Sept 11, 2011 (maybe they changed it, maybe not) and origin from the Oort Cloud to an interstellar rogue object.  Composition unknown.

Trajectory of comet Elenin. Trajectory of comet Elenin. Image credit: NASA/JPL-Caltech

So, stay tuned: NASA is about to roll the cameras. Ready or not, here comes P/2010 X1 – yELEveN INe


See more at NASA JPL here

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July 31, 2011 9:59 pm

Add to this story: Elenin, STEREO BEHIND/AHEAD, Earth, Sun, etc. in a JAVA applet

Dan in California
July 31, 2011 10:27 pm

On one hand, I believe that nothing on a hyperbolic trajectory has ever been observed. On the other hand, a comet dropping in from the Oort cloud would like a hyperbola. Let’s keep our copies of Rendezvous With Rama handy.

July 31, 2011 10:33 pm

Earth will bath in the Elenin’s tail.

Jason Joice M.D.
July 31, 2011 10:34 pm

While the coincidences of some of the alignment dates with earthquakes have been interesting, some of these Elenin/Nibiru/TEOTWAWKI people are complete kooks.

Dan in California
July 31, 2011 10:38 pm

Thanks for the link to the app, rbateman. I had lots of fun with the scroll bars. Anything that close to the ecliptic is almost certainly a comet.

July 31, 2011 10:40 pm

Sweet. This is going to be interesting.

July 31, 2011 10:48 pm

I’ve seem mention that this thing either has no coma/tail, or a very diminutive one. If so, that would put it into a Damocloid type object.
I didn’t even know about that class until I started fiddling around with Amors, Apollos and Atens.
“Damocloid are asteroids such as 5335 Damocles and 1996 PW that have Halley family or long-period highly eccentric orbits typical of periodic comets such as Comet Halley, but without showing a cometary coma or tail.”

July 31, 2011 11:31 pm

I’m not worried about Earth getting hit, on this pass. It’s been a long time since I did orbital calculations for a comet, but my worry is that both Earth and Jupiter, based on visual inspection, will slow Elenin down, drawing it into an elliptical orbit. In other words, there’s a possibility Elenin will be coming back again and again, with an orbit that crosses well inside Earth’s orbit. Anybody have any idea of the size?

Molon Labe
July 31, 2011 11:41 pm

Maybe a glancing blow at Washington, DC. Good thing no buildings allowed higher than the Capitol.

July 31, 2011 11:56 pm

Kahoutek was hyperbolic as I recall.

August 1, 2011 12:09 am

There’s so much Internet crap on Elenin, it’s hard to find anything credible on a typical search. Apparently Elenin is about 3 miles in diameter, mostly ice, and has a long tail. Closest approach is currently calculated at 22 million miles. Comet Honda will be 5.5 million miles out at closest approach. Not very close. Either one could ruin your day on impact. We should be studying these NEO objects, which are real, instead of global warming, which is socialist science fiction.

Jean Meeus
August 1, 2011 12:53 am

Hoser : It’s Kohoutek, not Kahoutek.
Many more comets with (slightly) hyperbolic orbits are known, for instance :
comet C/2011 G1 (McNaught), e = 1.00116
comet C/2011 K1 (Schwarz-Holvorgem), e = 1.00091
comet C/2011 L2 (McNaught), e = 1.00173

August 1, 2011 1:08 am

jorgekafkazar says:
August 1, 2011 at 12:09 am
Yes, that’s about what I found, a veritable sea of conflicting information. That is why I posted this story.
NASA is rolling right now, and putting some of it’s heavy space instrumentation to a very close approach.
Now we’ll see what this thing is made of.

August 1, 2011 3:18 am

soooo, what time exactly is the image gonna be available? im counting the minutes…
by the way, thought i had, remember earth has had three green comets pass by in the last decade or so? well i read up on it, a green comet means that comet has never come this close to the sun before and is brand new to this location of the solar system, because green is caused by gasses being burned off the comet by the sun gases which will be long gone after its first fly by of the sun,
so we have had a few green comets lately, could they be sent here by the same thing which is sending elenin? if it or honda is green im gonna get more nervous about this whole thing,
oddly enough, i researched green comets because i had a dream about them, woke up the next day and googled it right away.

August 1, 2011 3:37 am

things will get really interesting when it starts braking 🙂

Ulrich Elkmann
August 1, 2011 4:32 am

Who on Earth (sit venia verbo) names an asteroid “Damocles”? That’s like calling a space shuttle “Atlantis”…

August 1, 2011 5:03 am

I wonder how close it will pass to Mercury?

August 1, 2011 5:19 am

Does anyone know what the eccentricity is off hand? I checked in at and they didn’t mention it in their articles, so I assume it’s barely greater than 1. A real out-of-solar-system comet would have a much greater eccentricity, I’d expect.
One sensible thing worth reading is which says in part:

So-So Prospects for Comet Elenin
Last December, comet-lovers got a bit of an adrenaline rush when they learned that a new object, Comet Elenin (C/2010 X1), might reach naked-eye brightness a week or so after it reaches perihelion on September 10th.
For now, who can or can’t see it doesn’t matter much, as the interloper is still heading inward and won’t get seriously worked up for several months [this was written in April]. But the comet cognoscenti have already started calling it “intrinsically faint,” and it’s becoming clear that hopes for a nice eyeball-easy showing have dimmed considerably.
Best guesstimates now suggest that Comet Elenin’s total brightness might peak near magnitude 6 in mid-September – a nice binocular object – presuming that it survives its dash through perihelion just 45 million miles (0.48 astronomical unit) from the Sun.
Meanwhile, you have my permission to ignore or refute any of the wacky postings about the supposed danger posed by Comet Elenin. All this nonsense seems to have started back in January, when edge-of-reality blogger Laura Knight Jadczyk made provocative warnings – all based on information from a member of her research team who’s “an astronomer at a large observatory”. (Yea, right.) It’s not even worth giving you a link to her ramblings.

Some of the comments provide the links, as does one from her husband who left a typo in his personal URL,
As for what Comet Elenin is, it seems to be just a comet, but one worth a little extra study.

August 1, 2011 5:24 am

What is the difference between P/2010 X1 and C/2010 X1? The text has P twice, but the picture and the wiki link both have C. Is this an odd typo, or is there really a difference? — John M Reynolds

August 1, 2011 5:30 am

Leonid Elenin’s website for observations.

August 1, 2011 5:41 am

Oh, the Wikipedia page has the eccentricity, 1.0000606. It also says “Aphelion distance: ~1034 AU.” How can it have an aphelion? They also have a handy graph showing the eccentricity waffling around 1, so sometimes it hasn’t been hyperbolic. Wiki also notes “Before entering the planetary region (epoch 1950), Elenin had a calculated barycentric orbital period of ~4.4 million years with an apoapsis (aphelion) distance of about 54,300 AU (0.85 light-years).[4] Elenin was probably in the outer Oort cloud with a loosely bound chaotic orbit that was easily perturbed by passing stars.”
The sun’s gravitational field is so weak in the Oort cloud that it doesn’t take much of a delta-V to eject or bring in an object. Looks like closer in bodies will bring it down to 0.9991, so it might be back, but not for a long time.

August 1, 2011 5:47 am

jorgekafkazar says:
“global warming, … is socialist science fiction.”
I like that phrase!

August 1, 2011 5:50 am

I wonder how close it will go to Mercury?

August 1, 2011 5:51 am

Regarding research of solar activities:

August 1, 2011 6:13 am

tobyglyn, funny!

August 1, 2011 6:39 am

tobyglyn: LOL.

Bill Marsh
August 1, 2011 6:45 am

We better get those pesky Triffids under control before then…

Bill Marsh
August 1, 2011 6:48 am

I just ‘briefly’ read a couple of the conspiracy theory sites about Comet Elenin — LOL, one says its really a neutron star and it will destroy most of the earth when it is on its path out, all but the underground city secretly built under the Denver airport. Another says it is shielding an alien invasion fleet in its tail…
Good stuff.

Bill Illis
August 1, 2011 6:57 am

Earth has never been hit, at least in 4.0 billion years, by a big comet, which can be over 100 kms across and carry more speed and, hence energy, than an asteroid or meteorite. We’ve been lucky because an impact of a comet that big would have likely destroyed all life.
The biggest impact that we can find evidence for was Vredefort, a chondrite asteroid, 10 to 15 kms across, 2.0 billion years ago.

August 1, 2011 7:05 am

looks a bit close to Mercury in some of its travels?
doesnt have to Hit us to manage some nasty upsets does it.

John Whitman
August 1, 2011 7:11 am

roll it . . . . cosmic dice?

August 1, 2011 7:29 am

No images between 08UT to 10UT released yet, and this might have something to do with it:
T Aug 04 (216) Behind: 480 kbps downlink on station 14
But then images of the Sun are currently downloading, so I hope they got something for the roll.

Robert of Ottawa
August 1, 2011 8:01 am

Stereo is still pointed at the Sun.
BTW, for the first time, we can see the whole Sun at the same time (except the poles).

August 1, 2011 8:09 am

“Earth has never been hit, at least in 4.0 billion years, by a big comet”
We don’t know that. It’s quite possible that an object that large hit Earth long enough ago that the damage has been covered up by subsequent changes to the surface. What if an impact occurred over deep ocean, and any crust deformation was subducted when that ocean closed?

August 1, 2011 8:33 am

Jean Meeus says:
August 1, 2011 at 12:53 am
Thanks for the additional info. My memory isn’t perfect. I haven’t thought about it much since Hale-Bopp and Hyakutake.
Bill Marsh says:
August 1, 2011 at 6:48 am
Let’s hope there aren’t more Applewhites and Heaven’s Gate types out there.

August 1, 2011 8:36 am

Thanks Robert, awesome story.
Perhaps the arrival of Elenin explains the sudden upswing of sunspots over the past few days? 🙂

Gary Pearse
August 1, 2011 8:36 am

Surely a hyperbolic trajectory could be altered in the course of passage through the solar system?

Darren Parker
August 1, 2011 8:37 am

Nebiru , aka Nemesis is now called Tyche

August 1, 2011 9:03 am

August 1, 2011 at 12:09 am
” … instead of global warming, which is socialist science fiction.”
Your confusing Science Fantasy with Science Fiction. In Science Fiction, the science comes first. There are rules to this genre. In Science Fantasy, any thing goes.

August 1, 2011 9:03 am

More justification for me to get a new telescope.

August 1, 2011 9:04 am

In reference to the posts regading age of last large strikes: Does anyone have updated info regarding the theory of a large planetoid striking Earth and in the disruption having a proto-lunar flung into orbit?

August 1, 2011 9:05 am

Iam, August 1, 2011 at 3:18 am
Let’s hope you have a dream about proper punctuation.

August 1, 2011 9:27 am

Be kind—Iam’s keyboard is truncated, and his three character rows don’t extend past “p”, “l” and “m”.

August 1, 2011 10:42 am

There is a lot of paranoid buzz on the internet and it is scaring a lot of people who follow pseudo-science and conspiracy websites. The latest being that Elenin has charged itself with an overdose of electrons gathered from deep space and with discharge them into the Sun (or to Earth) causing havoc!
However, all may not be plain saling ahead. Bill Illis….you say its millions of years since Earth has had a significant hit……not necessarily so, there is strong (and disputed) geological evidence of a dust-ball comet impact about 13,000 years ago with huge damage to the northern hemisphere – with massive forest fires and tidal inundation.
I don’t understand how trajectories can be computed so accurately before the object has been properly observed – presumably the mass has been worked out?

Kevin Kilty
August 1, 2011 12:38 pm

Jean Meeus says:
August 1, 2011 at 12:53 am
Hoser : It’s Kohoutek, not Kahoutek.
Many more comets with (slightly) hyperbolic orbits are known, for instance :
comet C/2011 G1 (McNaught), e = 1.00116
comet C/2011 K1 (Schwarz-Holvorgem), e = 1.00091
comet C/2011 L2 (McNaught), e = 1.00173

Ric Werme says:
August 1, 2011 at 5:19 am
Does anyone know what the eccentricity is off hand? I checked in at and they didn’t mention it in their articles, so I assume it’s barely greater than 1. A real out-of-solar-system comet would have a much greater eccentricity, I’d expect.

What is the uncertainty in eccentricity for these objects?

August 1, 2011 1:03 pm

Peter Taylor says:”I don’t understand how trajectories can be computed so accurately before the object has been properly observed – presumably the mass has been worked out?”
They can’t. IIRC from my determination of orbits class, a hyperbolic orbit is so close to linear on a star plate that determination of the orbital elements (a, e, i, node, omega and t) is tricky until you get a longer look, which I believe is now the case. The BEHIND fly-by should give even better elements. Be sure to read Ric Werme’s comment, above.
alan says: “I like that phrase!” (global warming is socialist science fiction)
Thanks, Alan:
DesertYote says: “[You’re] confusing Science Fantasy with Science Fiction.”
I’ve written in both genres, they overlap, and, yes, AGW could be considered either one. It’s fiction.
Ulrich Elkmann says: “Who on Earth (sit venia verbo) names an asteroid “Damocles”?”
You know the answer. Someone with a classical background like you, who remembers that Damocles was the ancient king with a heavy object dangling over his head by a hair. Most appropriate if you’re living at the bottom of a big gravity well with stuff flying overhead, not even a hair to hold it.

August 1, 2011 2:19 pm

Geoff Sharp says:
August 1, 2011 at 8:36 am
Perhaps it is a rogue object (a possibliity) from another star system, composition unknown.
If it is something like a chunk of neutron star or small singularity it could have an effect on close passage, but then it should also exhibit gravity lensing to a small degree. I’m not qualified to state that a chunk of neutron star or small singularity is even possible. Anyway, I would think that such determination would require HST.
First, we need to see some data from BEHIND.
Anybody have an idea of when NASA will release images?

August 1, 2011 2:25 pm

Robert of Ottawa says:
August 1, 2011 at 8:01 am
The spacecraft was presumably rolled back just before 10:00 UT.
Examine the images for 08/01/2011 here:
Select all the BEHIND instruments, put in 20110801 for the Start Date, select 512×512 res., check list on Display and hit the Search Button.
You will see a gap in the lists for 08:00 to 10:00 UT.

August 1, 2011 2:49 pm

Johndoe says:
August 1, 2011 at 5:03 am
I wonder how close it will pass to Mercury?

Run the applet here:
50 million miles, roughly, with Mercury mostly on the opposite side of the Sun in it’s orbit.

Ulrich Elkmann
August 1, 2011 4:44 pm

jorgekafkazar: “someone with a classical background…” Indeed, but since the Damocloids do not seem to include any Apollo objects (i.e. crossing Earth’s orbit), the name still seems somewhat misapplied.
Dan in California: “Let’s keep our copies of Rendezvous With Rama handy”. You mean there will be sequels, but conceived by Gentry Lee, not Sir Arthur? An unsettling prospect.
As for rules to the game of SF: not very often (“playing with the net up”, as Gregory Benford put it, limits the gamut of exicting storytelling nastily), but if they are used, they are applied to astronomy and physics, less to sociology, never to economics. Sometimes this results in SF writers censoring other writers for astronomical illiteracy. There have been some green comets in SF (Wells’ ‘In the Days of the Comet’, 1906; Jack Williamson’s ‘The Cometeers’, 1936, etc.), and those have been singled out as glaring examples, since NOTHING in space is green. Cue comet McNaught 2007

August 1, 2011 5:38 pm

While Bill Illis is probably correct concerning “big” impacts, I would think that the Tunguska event, in 1908 along with the similar explosion in South america in 1932 would show that the hits mor common than thought and certainly big enough.
Similarly the Burckle Crater, some 36 kilometres wide at a 3 mile depth under the Indian Ocean, dating from circa 2900 BC would show that even if not huge, a good impact can do a lot of damage.

Barry Day
August 1, 2011 7:12 pm

Bernhard’s_Comet_Project with top quality links all here;.
Which includes;
The latest IAU telegrams or the latest CBET’s. IAUC Astronomical Headlines.
Minor planet center’s orbital elements and Ephemeris,
the comet on Seiichi Yoshida’s Homepage,, actual observations by Russian amateurs
Light curves on Cometas Obs,
JPL Small body database

Barry Day
August 1, 2011 7:41 pm

For those wanting to keep up with any seismic effects Comet Elenin may have.
Almost Real Time Image System (ARTIS)
A Space obs commenter Nick sums up the difference of this comet to others fairly well.
“Because only comets with extremely long orbit, the ones who leave the solar system are electrified because of a different charge of the vast deep space…
And long orbit comets that pass near earth as elenin are very rare. And even rare are comets which passes between us and the sun
homever you can find the Wal Thornhill (… )work here: and here is what they say about electric comets :
and what electrified debris may produce
you can watch also their interesting video documentary :… that i found illuminating”

August 1, 2011 9:14 pm

Come to think of it, STEREO BEHIND is looking right at the face of the Sun that Elenin is currently facing.
The activity is primarily on the side opposite. The comet has been approaching slightly south of the ecliptic.
One might consider making a movie of the last month of AHEAD & BEHIND one image/day and see what turns up.
i.e – what does the data say about Elenin and the Sun interacting?

stephen parker
August 1, 2011 10:35 pm

Brilliant post robert and anthony, lets see how nasa tries to spin this one

August 2, 2011 1:56 am

@Jeff Alberts @bubbagyro it seems to me that the type of person who bothers to criticize random anonymous individuals over the internet for punctuation is not only fighting an endless battle but also must have no life to even bother giving a second thought to such matters let alone trying to make a mocking joke out of it,
get a life, grow up.
hows the punctuation there?

Brian H
August 2, 2011 4:35 am

Iam says:
August 2, 2011 at 1:56 am
@Jeff Alberts @bubbagyro it seems to me that the type of person who bothers to criticize random anonymous individuals over the internet for punctuation ….

It’s a measure of how interested (and competent) the poster is in communicating clearly, and without making the readers do too much of the heavy lifting of making sense out of the word stream. Arrogant and ignorant posters sneer at those who try to get it right.
Hello, there!

August 2, 2011 9:23 am

Ulrich Elkmann says: “…Indeed, but since the Damocloids do not seem to include any Apollo objects (i.e. crossing Earth’s orbit), the name still seems somewhat misapplied.”
Somewhat, yes. But it’s as they said back in the 50’s regarding a quack patent medicine: Q: “Why do they call it Hadacol?” A: They hadda call it something.”

August 2, 2011 1:03 pm

@Brian H you consider it heavy lifting to try and read a short paragraph with not so perfect punctuation? you compare grammar with someones level of interest? i think the two have nothing to do with each other, it is delusional to think that someone has lesser interest simply because their grammar doesn’t meet YOUR standards.
and who is that you think is sneering here? i am the one trying to defend myself from insult, my post was entirely on topic to this article, it was the replies to my post which focused on negativity, everything following from me is simply defending myself,
if you consider it sneering to be offended that i am being criticized for using less then perfect grammar on a website titled then you are way off base.
didnt realize i was in english class with a group of mid 40’s english teacher who carry long rulers for knuckle busting if the period is misplaced.
like i said….get a life

August 2, 2011 1:06 pm

btw english is not my first/native language.
you should go visit another country and mock them for not speaking your language, it would be well on par with this whole ridiculous exchange ive just had with the three of you, all because of….punctuation.

August 2, 2011 3:58 pm

I have written to Joseph Gurman,
(Dr.) Joseph B. Gurman
STEREO Project Scientist
, and he replied with these links:
A very short movie:
And an explanation of current and upcoming observations:
There you go.

Barry Day
August 5, 2011 2:38 am

rbateman says:
August 2, 2011 at 3:58 pm
There you go.????
Half truth’s from NASA ……AGAIN!!! = lie’s through omission.
Here is where there may be a big BIG problem,There are

E L E N I N ~ Catastrophic events CONFIRMED – Dr Omerbashich research papers.

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