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Planets, Comets & Footballs

I remember talking to the exuberant astrophysics professor Sheridan Simon about a football-shaped planet he had created one Super Bowl eve. This was at a science fiction convention and it must have been fifteen years ago. Simon frequented such venues because he had built a cottage industry around creating planets for various science fictional settings. As a lark, he had run the numbers on what would happen to the atmosphere of a world shaped like a pigskin and wound up announcing the result: “It’s plaid! That’s what you would see. A plaid football!”

I think he was pulling my leg, and that wouldn’t have been out of character either for this generous, gregarious man who died all too young. But Mike Brown’s new paper in Nature brought back memories of that conversation with Sheridan Simon in spades. Brown (California Institute of Technology), who specializes in the exotica at the fringes of our Solar System, has been examining an object his team originally found. 2003 EL61 is also shaped like a football, though having no atmosphere, it doesn’t offer as many opportunities for fun as Simon’s planet did.

Brown now believes this Kuiper Belt object was the result of a catastrophic collision sometime around the time Earth was born. The original KBO was doubtless spherical and of roughly Pluto size until it was rammed by a body not much smaller than itself. The rapdily spinning (every four hours) football shape we see today is the result, along with two moons and many other fragments that have long since dispersed.

2003 EL61 plays interestingly into our understanding of how the Solar System evolved. For the area of space we’re talking about isn’t very stable. Here’s Brown on the matter:

“In most places, things go around the sun minding their own business for 4.5 billion years and nothing happens. But in a few places, though, orbits go crazy and change and eventually objects can find themselves on a trajectory into the inner solar system, where they would be what we would then call comets.”

So many of the shattered pieces of 2003 EL61 doubtless made their way in close to the Sun, and Brown believes some have probably hit the Earth at one time or another. And 2003 EL61 itself may become what Brown calls ‘…the largest comet in eons,’ although this won’t happen for a billion years. How big? Brown figures the incoming football will shine about 6000 times brighter than the Hale-Bopp comet did just a few years ago. If Sheridan Simon were still around, he could have some fun with that.

The paper is Brown et al., “A collisional family of icy objects in the Kuiper belt,” Nature 446 (15 March 2007), 294-296. Abstract here.

Comments on this entry are closed.

  • ljk March 14, 2007, 14:53

    Mike Brown discusses this on his Web site here:


  • Eric James March 18, 2007, 23:27

    Didn’t Larry Niven write about a football shaped planet? As I recall, humans could only live in narrow bands of atmosphere in either the northern or southern hemisphere, the atmosphere became too dense for humans at the equator and two thin at the poles. In fact, the poles extended beyond the atmosphere. I’m pretty sure it was Larry Niven. I think it’s where the giant slug-like beings with the big brains lived that were genetically engineered, living remnants of the old Slaver Empire.

  • Administrator March 19, 2007, 7:54

    Boy does that ring a bell. Can anyone else help? I think Eric is right that this was a Niven story, but memory is muddled.

  • ljk March 19, 2007, 10:28

    It was the planet Mesklin from Hal Clement’s 1954 SF novel
    Mission of Gravity. The planet was a superjovian world 16 times
    more massive than Jupiter orbiting the very real nearby star
    61 Cygni.

    The gravity at its equator was 3 Gs, while at the poles it was
    over 700 Gs. Mesklin rotated on its axis once every 17.75
    minutes, making the planet seriously flattened at its poles.

    The native intelligences of Mesklin resembled centipedes with
    seriously powerful and sharp pincers. One notable feature is
    that they are terrified of heights as a fall from even a small
    distance would kill them on such a massive world.

    Mission of Gravity is notable for the author’s attention to
    scientific detail and accuracy. And considering the types
    of wild exoworlds we have been finding since 1995, it would
    not surprise me if a real Mesklin or two is out there somewhere
    in our galaxy or others.

  • Administrator March 19, 2007, 12:46

    Well done Larry! Now it all comes back. Thank goodness for the encyclopedic minds of Centauri Dreams readers…

  • Eric James March 20, 2007, 0:32

    Naw, that isn’t the one to which I was referring. I’m pretty sure it was featured in a Beuwolf Schaeffer (sp?) story of Niven’s. I’ll have to dig through the ol’ sci-fi archive I guess (boxes in my garage).

  • ljk May 14, 2007, 11:32

    Star Trek: Voyager had their version of Mesklin, too:


  • Adam May 15, 2007, 6:01

    Hi Guys

    You’re talking about Jinx, which was a football shaped moon, larger than Earth, of a super-Jovian in orbit around Sirius. Featured in many Known Space stories, usually only peripherally. Jinxian colonists adapted to its ~ 178% gravity by becoming short and incredibly strong. Jinx’s pointed ends project about 600 miles out of its atmosphere, while its equatorial ocean is at high pressure and very hot. The Frumious Bandersnatchi – “Whitefoods” to a thrint – are the intelligent, gigantic and single-celled creatures living on the shores of the ocean. They entered into a covenant with the human colonists to control their population through periodic hunting – usually with the humans winning about 2/3s of the time i.e. it’s an EXTREMELY dangerous sport.

    As Beowulf Schaeffer was a Crashlander – he grew up in 60% gravity – he disliked Jinx intensely, except for the hotel (the Tannhauser?) with artificial gravity. Jinx became incredibly wealthy by inventing the life-extension drug “booster spice”, which allowed Louis Wu, Schaeffer’s non-genetic son, to live to over 200 years.

    All this and I didn’t have to visit the Known Space encyclopedia online [look it up, it’s worth a browse.] I read and re-read “Neutron Star” and other Known Space collections when I was a teen.

  • Adam May 15, 2007, 6:16

    Ah… of course Wikipedia has a pretty comprehensive entry (and a link to the Known Space encyclopedia) – which I had to check. A few things I got wrong – it was the Camelot Hotel, boosterspice is spelt without a space, and Bandersnatchi are unable to mutate because their genetic material is gigantic – thus they have remained as they are since the Slaver-tnuctipun War some 2 billion years ago.

    Oh and the mortality rate for Bandersnatchi hunters is one human per Bandersnatch.

  • ljk January 29, 2008, 17:01

    High Precision Photometry of Extreme KBO 2003 EL61

    Authors: Pedro Lacerda, David Jewitt, Nuno Peixinho

    (Submitted on 27 Jan 2008)

    Abstract: We present high precision, time-resolved visible and near infrared photometry of the large (diameter ~ 2500 km) Kuiper belt object (136108) 2003 EL61. The new data confirm rapid rotation at period P = 3.9155+/-0.0001 hr with a peak-to-peak photometric range (Delta m_R) = 0.29+/-0.02 mag and further show subtle but reproducible color variations with rotation. Rotational deformation of 2003 EL61 alone would give rise to a symmetric lightcurve free of color variations. The observed photometric deviations from the best-fit equilibrium model show the existence of a large surface region with an albedo and color different from the mean surface of 2003 EL61. We explore constraints on the nature of this anomalous region set by the existing data.

    Comments: 9 pages, 8 figures, 5 tables. Accepted for publication in The Astronomical Journal on 2008/01/25

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0801.4124v1 [astro-ph]

    Submission history

    From: Pedro Lacerda [view email]

    [v1] Sun, 27 Jan 2008 11:01:10 GMT (154kb)


  • ljk March 9, 2008, 23:46

    Study of the Surface of 2003 EL61: the largest carbon-depleted object in the trans-neptunian belt

    Authors: N. Pinilla-ALonso, R. Brunetto, J. Licandro, R. Gil-Hutton, T.L. Roush, G. Strazzulla

    (Submitted on 7 Mar 2008)

    Abstract: 2003 EL61 is the largest member of a group of TNOs with similar orbits and ‘unique’ spectra (neutral slope in the visible and the deepest water ice absorption bands ever observed in the TNb). Studying the composition of the surface of 2003 EL61 provides useful constrains on the origin of this particular group of TNOs and on the outer Solar system’s history.

    We present visible and near-infrared spectra of 2003 EL61 obtained with the 4.2m WHT and the 3.6m TNG at the Roque de los Muchachos Observatory (Canary Islands, Spain). Near infrared spectra were obtained at different rotational phases covering almost one complete rotational period. Spectra are fitted using Hapke scattering models and constraints on the surface composition are derived.

    No significant variations in the spectral slope and in the depth of the water ice absorption bands at different rotational phases are evident, suggesting that the surface of 2003 EL61 is homogeneous. The scattering models show that a 1:1 intimate mixture of crystalline and amorphous water ice is the most probable composition for the surface of this TNO, and constrain the presence of other minor constituents to a maximum of 8%

    The derived composition suggests that: a) cryovolcanism is unlikely to be the main resurfacing process responsible for the high presence of water ice on the surface of these bodies; b) the surface is older than 10^8 yr. Any catastrophic event, like the collision suggested to be the origin of this population, had to happen at least 10^8 yr ago; c) the surface of 2003 EL61 is depleted of carbon chains. According to the orbital parameters of this population, this makes it a possible source of carbon-depleted Jupiter family comets.

    Comments: 9 pages, 7 graphs. Keywords: water ice, carbon-depleted, Kuiper Belt, astrochemistry, spectroscopy

    Subjects: Astrophysics (astro-ph)

    Cite as: arXiv:0803.1080v1 [astro-ph]

    Submission history

    From: Noemi Pinilla-Alonso [view email]

    [v1] Fri, 7 Mar 2008 13:13:56 GMT (244kb)


  • ljk April 26, 2008, 19:37

    Caltech Today Alerts for April 26, 2008

    News and Information from Caltech Today – http://today.caltech.edu


    At 5:15 p.m. on April 28, in Beckman Institute auditorium, CPET is
    sponsoring a seminar called “Teaching: How Not to Suck,” featuring
    Mike Brown, Caltech’s Rosenberg Professor and professor of planetary
    astronomy. Brown, who is well known for discovering Eris, which
    resulted in the demotion of Pluto, was the winner of the 2007
    Feynman Award and has been recognized for building hands-on courses
    and engaging students in the research process. Refreshments will be
    served beforehand.

  • ljk October 12, 2010, 23:57

    Mike Brown is finally scanning the southern hemisphere skies:


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