Planets with No Orbit: Fascinating News

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Discussion Overview

The discussion revolves around the concept of planets that do not have a defined orbit, exploring their implications for dark matter, their potential classification, and their effects on the solar system. The conversation includes theoretical considerations, speculative ideas, and references to astronomical observations.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that planets without orbits could have enough mass to account for dark matter.
  • Others argue that there are not enough microlensing events to support the idea that massive compact halo objects (MACHOs) could constitute more than a small fraction of dark matter.
  • One participant notes that big bang nucleosynthesis (BBN) indicates that dark matter is primarily non-baryonic.
  • A viewpoint is presented that these wandering bodies might be failed brown dwarf stars that did not gain sufficient mass for nuclear fusion, potentially outnumbering typical stars.
  • Concerns are raised about the stability of the solar system due to these wandering bodies, referencing a historical flyby of Kapteyn's Star.
  • Another participant mentions a future flyby of Gliese 710 that could disturb the Oort Cloud and affect comet trajectories.
  • A speculative idea is proposed that some of these wandering objects could be micro black holes.
  • There is a suggestion that the definition of a planet may need to be revised in light of these findings.

Areas of Agreement / Disagreement

Participants express a variety of views on the nature and implications of planets without orbits, with no clear consensus reached on their classification or their role in dark matter. Multiple competing hypotheses are presented, and the discussion remains unresolved.

Contextual Notes

Limitations include the dependence on observational data and the need for further clarification on the definitions of celestial bodies involved in the discussion.

Tanelorn
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Interesting news about planets with no orbit:


http://news.yahoo.com/s/ap/20110518/ap_on_sc/us_sci_wandering_planets


Perhaps enough mass to explain dark matter?
 
Last edited by a moderator:
Astronomy news on Phys.org
Tanelorn said:
Interesting news about planets with no orbit:


http://news.yahoo.com/s/ap/20110518/ap_on_sc/us_sci_wandering_planets


Perhaps enough mass to explain dark matter?
Probably not, there's not enough microlensing events for MACHOs to be responsible for more than about 5% of dark matter IIRC.
 
Last edited by a moderator:
And BBN tells us dark matter is mostly non-baryonic.
 
My view is that these could be failed brown dwarf stars which couldn't acquire enough mass to start nuclear reactions. It makes sense to me that there could be a lot more of these "Jupiters" floating around on their own than stars like our own.

Such bodies could also threaten the stability of our solar system. This isn't Sci-Fi, there was a star which 10000 years ago passed within 7 light years of us and is now 13 light years from us. It travels retrograde from us in orbit around the galaxy. I think it is called Kapteyn's Star:

http://en.wikipedia.org/wiki/Kapteyn's_Star



Thanks Vanadium. Here is a BBN article:

http://blogs.discovermagazine.com/cosmicvariance/2007/11/01/dark-matter-still-existing/
 
From current data, there'll be a ~1 LY fly-by in a million years or so...
http://en.wikipedia.org/wiki/Gliese_710

It could seriously perturb the Oort Cloud, scattering umpteen potential comets. The good news is those headed our way may take several million years to reach inner solar system...

Of course, the current infrared surveys could yet find several hyper-dim 'brown dwarf' candidates in our neighbourhood. Problem then is to determine if they are orbiting the Sun, have 'Common Proper Motion' or are merely 'passing through'...
 
Could at least some of these 'wanderers' be micro black holes? If so, I hope one isn't headed our way!
 
Looks like they will once again have to redefine what a planet is.
 

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