Skip to comments.How Many Loose Planets in the Milky Way?
Posted on 03/10/2012 11:28:34 AM PST by SunkenCiv
Researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University estimate that "nomad" planets, ejected from their home stellar system and now free-floating through the Milky Way, could outnumber stars by as many as 100,000 to 1. Earlier estimates were more like a handful to 1, though previous studies have only counted unbound planets more massive than Jupiter.
To estimate the number of unbound planets as small as Pluto that could be roaming the galaxy, Louis Strigari (KIPAC), lead author of the study, began with a basic rule of nature: where a few big objects are found, there are many more small, just like a few boulders may be surrounded by thousands of pebbles. Strigari and colleagues calculated the number of unbound planets by extrapolating from the small number detected so far by direct imaging and by gravitational microlensing.
Direct imaging has severe limits because planets are so faint. Microlensing offers more promise. It looks for the characteristic brightening and fading of a background star when an object, even one as wimpy as Pluto, passes nearly in front of it and bends its light slightly by gravity. So far, 24 planet-mass objects have been detected by microlensing -- 14 bound to their parent stars, 10 apparently not. Microlensing offers hope for detection of loose objects large and small even if they are completely dark, and even at great distances across the galaxy.
(Excerpt) Read more at skyandtelescope.com ...
The Milky Way likely hosts billions, and possibly trillions, of unbound planets, some of which may have atmospheres thick enough to support bacterial life. Loose planets may even outnumber stars in the galaxy, but a more precise count awaits future telescopes such as WFIRST and LSST. [Caltech / NASA]
an ‘extra, extra’ ping to the APoD members.
Sky & Telescope: All 70 Years
March 1, 2011
by the Editors of Sky & Telescope
"...all 818 monthly issues, covering 70 years of astronomy from November 1941 through December 2009..."
How likely is a loose planet to have any atmosphere?
It’s pretty cold in interstellar space...
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To us accretionist’s the concept of a loose planet is heresy.
All planets are accreted.
The concept of a Fluke (loose) planet is however interesting
As likely as it is anywhere, but I take your point, if it’s cold enough, the atmosphere would condense and freeze, as on Pluto — depending on what the atmosphere is made of in the first place, and how much of it is there.
If you continue to post great articles, my cost is 0
What if it was a gas giant like Jupiter? What do you think the shrinkage would be?
Has the vast expanse between Pelosi’s ears been explored?
I wonder if the mass relative to “loose” planets - whose travels do not seem to be (yet) among the calculated mass of the star systems, or the calculted gravitational forces affecting star systems’ travels in their own galaxies - could actually be part of the hypothetical “dark matter” needed to explain current accepted theories of the universe.
Frozen solid, I imagine.
Based on her background, I would say it was more like a planet of the loose women!
Well you have to remember that Jupiter and Saturn create their own heat. Most large gas giants probably would.
A rocky planet like Mars or Earth the atmosphere would probably be frozen with nothing except maybe ethane or methane
It would be measured in Costanzas — with the shrinkage quantification for Jupiter being a 1.
These planets could loosely be termed homeless planets.
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