Are We Alone Skeptic Check: Tyche, or not Tyche?

By Phil Plait | March 1, 2011 10:30 am

This month’s "Are We Alone" podcast segment Skeptic Check is now online, where astronomer Seth Shostak and I talk about the purported jovian planet that might or might not exist in the cold depths of the solar system out past Neptune. We talk about the science of such a world, and how the media perhaps puffed this piece past a proportionate planetary propriety.

Probably.

Comments (26)

  1. tmac57

    What did you think about their handling of the homeopathy segment Phil? I thought it was a bit too neutral.

  2. perhaps puffed this piece past a proportionate planetary propriety

    Precisely!

  3. Quiet Desperation

    What did you think about their handling of the homeopathy segment Phil? I thought it was a bit too neutral.

    So you thought their skepticism on the topic was a bit…

    (removes sunglasses)

    …diluted?

    YEEEEEEAH!

  4. Carey

    QD: Well played. Well played.

  5. Ophu

    Since binary star systems seem to be the rule, rather than the exception, it actually seems likely that the sun has a failed brown dwarf companion.

  6. Yoweigh

    What does “jovian” mean in this context? I always thought the word meant “part of Jupiter’s system.” Does it really just mean “similar to Jupiter?”

  7. Ophy, from memory, I believe the minimum cut off for nuclear fusion is around 75 Jupiter masses. And I think “brown dwarfs” have a cutoff around 25 times the mass of Jupiter. (Edit to add: This of course begs the question as to what exactly a browndwarf is and exactly what is going on there. Beyond what I recall at the moment.) So 4 times Jupiter mass is nowhere close to a brown dwarf.

    This is all from memory, so I am sure someone will correct me if I am wrong.

  8. Michael Swanson

    Joe from http://ultoday.com/ interviewed Whitmire and Matese. He posted the link in the last Tyche post, but it was buried pretty deep. It’s nice to hear it straight from them and not the “GIANT PLANET OF DOOM FOUND!” media.

    http://ultoday.com/node/3076

  9. Ophu

    It could have been on it’s way to BEING a brown dwarf before it ran out of material to absorb. Look, it’s basically a large ball of gas if it’s out there at all, right? So we’re talking about a difference of degree. The sun just happened to be in the right place to accumulate the most material. Tyche came in second, assuming it exists, then Jupiter, Saturn, Uranus, and finally Neptune. It’s all determined by gravitational waves anyway.

  10. Quiet Desperation

    @Carey

    Thank you. My first time using that meme. :-)

  11. Nemesis is not amused at being called a planet.

  12. Ray

    Why has it been so hard to find? Neptune and Pluto were both discovered based on their predicted gravitational influence. How far out (and how big is) the other planet if we can’t find it the same way?

  13. Awesome alliterative acumen, Astronomer!

    Seriously, though, your snappy writing is what makes this my all time favorite blog.
    That is all. Carry on.
    -RW

  14. andy

    @Larian LeQuella:
    At the moment there is no universal agreement on how to distinguish brown dwarfs and giant planets. One suggestion is to use fusion as the criterion: in this view planets do not undergo fusion reactions in their interior, while brown dwarfs undergo deuterium fusion (and high-mass brown dwarfs will also fuse lithium) during the early stages of their evolution. This sets the boundary at about 13 Jupiter masses for solar abundances of elements – change the amount of metals or the helium fraction, etc. and the limit will change.

    Unfortunately while this is a nice definition the universe does not appear to play along. There are now several known examples of objects which have masses above the deuterium fusion limit being present as members of multi-planet systems. Furthermore there are observations of star clusters where objects with masses too low to fuse deuterium appear to have been formed via the stellar formation processes. This leads to the other way to define the distinction: brown dwarfs are formed low-mass stars, while planets form out of circumstellar discs. This results in an overlap in mass range (some planets are massive enough to undergo internal fusion reactions, some stars aren’t), in which case we cannot define Tyche (if it exists) as a brown dwarf or a planet based solely on its mass.

    The location would be something of a giveaway though: no way could a 4 Jupiter masses planet form in the Oort cloud. You might be able to form such a planet closer to the Sun and scatter it outwards, but to do that you tend to need an even more massive planet to do the scattering (which typically gets left in a highly eccentric inner orbit… such a scenario does not match our own solar system very well!). Thus if it does exist, it may be that it formed as a binary companion to the Sun, in which case it could be regarded as a brown dwarf, or it may be a captured object.

  15. Larry

    @Ray 12: Let us remember that Pluto was found only serendipitously by its “gravitational” influences. Percival Lovell’s calculations were precise but inaccurate; he predicted the location of the-object-that-would-be-Pluto based on inaccurate data.

    Tyche’s brightness in both the infra-red and the visible is close to , or below, detectability limits. The previous Tyche post on BA discussed this nicely, and a good discussion of the limits is available on http://www.nasa.gov/mission_pages/WISE/news/wise20110218.html.

    Tyche is border-line non-science: the hypothesis is essentially non-testable.

  16. KC

    @Yoweigh

    Gas giants in general are often called jovian.

  17. KC

    @Ophu

    That I think is a poor conclusion. Many stars are multiple but that doesn’t mean *all* of them are.

  18. The Conundrum

    @andy

    Your lengthy explanation was, to me, a very interesting read. I am just wondering, if Tyche is ultimately an accepted fact and is mapped, what would it take to explain how it got there in the first place? Is astronomy to a point where we can take the surrounding neighborhood ‘back in time’ to a possible point where the body may have been either dilosdged or as it were ‘stolen’ from another system?

    I ask this because, while astronomy is a fairly new field of interest for me, my logical thinking says that if it was merely a ‘wanderer’ then the probability of it glancing the solar system at just the right angle to remain in a ‘locked’ orbit and not actually penetrate the solar system would have to be phenomenally slim wouldn’t it? I mean, if it wasn’t formed here, then what is ‘just the right angle, and just the right speed’ for it to be where it is?

    I am eager to explore the question of how it is that it is here if it wasn’t formed here?

  19. Nigel Depledge

    The BA said:

    perhaps puffed this piece past a proportionate planetary propriety

    Alright, alright, don’t go practising your alliteration on me.*

    * OK, I admit it – this is a very obscure reference.

  20. tmac57

    @Quiet Desperation-

    So you thought their skepticism on the topic was a bit…

    (removes sunglasses)

    …diluted?

    YEEEEEEAH!

    While I appreciated the attempt by the ‘Are We Alone’ team to address the problem of the popularity of homeopathy,I thought that their solution was too weak. ;)

  21. mike burkhart

    A little off topic but related : the UFO crowed heald a big convention in Arizona last week. Fox news covered it , it had a woman claiming to be a Human Alien Hybrid (I’ll bet she stays aways form DNA testing and the mental health system) and a call form a UFO researcher for scientists like Phil who are Skeptical to come and look at his evidence of Alien visitors. Maybe Phil should take him up on this and go to the next convention and put a word on this blog if he has changed his mind after viewing the “evidence”. At lest there will be one rational mind there if Phil goes.

  22. Ophu

    @KC: I never said they all were.

  23. @5. Ophu :

    Since binary star systems seem to be the rule, rather than the exception, it actually seems likely that the sun has a failed brown dwarf companion.

    Failed brown dwarf or just *really* successful superjovian planet? ;-)

    @6. Yoweigh asked :

    What does “jovian” mean in this context? I always thought the word meant “part of Jupiter’s system.” Does it really just mean “similar to Jupiter?”

    Yes – to *both* usages there, by Jove! ;-)

    “Jovian” is pertaining to Jupiter system – Joves moons, Jupiter’s rings and its magnetosphere plus more.

    But the term is also used to refer to planets like Jupiter – gas giants composed of Hydrogen and helium of about Jupiter’s size and mass.

    A Jovian planet (exoplanet) is esentially a Jupiter-like planet as opposed to one like Neptune (an “ice giant” or “exo-Neptune”) or a superjovian (“much more massive”) type planet or one like Earth (terrestrial, earth-like) or Pluto (ice dwarf) and so on. Hope that clarifie sit for you.

    @19. Nigel Depledge : Okay, I give up what’s that reference from? Too obscure for me. ;-)

  24. The Conundrum

    Can anyone enlighten me on how they can estimate the mass within a given star system (our Solar system for example) to then say that there is definitely another planet out there or definitely there is not?

    It can’t surely be based on gravitational effects if gravitational effects are so diluted at such distances. What is the margin for error in the estimation of mass of a body they are looking for, yet not really found yet?

    This is something I’ve never fully understood… to be able to account for the total mass within a system

  25. TEDDY

    Larian LeQuella Says:

    So 4 times Jupiter mass is nowhere close to a brown dwarf.
    This is all from memory, so I am sure someone will correct me if I am wrong.
    ====================================================
    The lower mass limit is somewhat arbitrary as there is no obvious point of transition between a high-mass planet and a low-mass brown dwarf. They are the “missing links” between gas giants, such as Jupiter, and red dwarfs, which are the smallest, lowest-mass true stars. One way to distinguish low-mass brown dwarfs from gas giant planets is by their density, which is higher. This may well be a new category of a brown dwarf.

  26. Isaac

    @Messier Tidy Upper: It appears to be from Monty Python’s “Bells”.
    http://www.ibras.dk/montypython/finalripoff.htm#Bells

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