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.
;’) I’m an accretion denialist.
Quotation is from "Darwin's Ghost" by Steve Jones, page 195
“To us accretionists the concept of a loose planet is heresy.
All planets are accreted.
The concept of a Fluke (loose) planet is however interesting”
Yes, the concept of a Fluke planet is interesting. The theoretical danger of such “loose” planets cannot be overestimated. Are these Fluke planets given free contraceptives to keep them from multiplying? Or would that only reward these loose planets?
The ratio of 100,000:1 (rogues to orbiting) would be a tiny fraction of what is needed, but you may have struck on the reason for this hypothesis. :’)
Yes, the concept of a Fluke planet is interesting. The theoretical danger of such loose planets cannot be overestimated. Are these Fluke planets given free contraceptives to keep them from multiplying? Or would that only reward these loose planets?
Only if someone calls them sluts ...
Might be a good idea to get re-started on some spaceships. Just in case.
I realized long ago that the issue of dark matter is a hypothesis needed to explain the reigning hypothesis of the begining and structure of the universe, unless some as-yet-unidentified phsysicist (or patent clerk with a penchant for math) is going to “solve” the issue by revising the math that demands the existence of dark matter.
Thanks, could make a nice topic as well!
What is the definition of a planet?
I don’t think an object just out there somewhere qualifies.
So I propose “loose planets” be called Vagi.
I’d always assumed there would be plenty of nomads. It may even explain retrograde orbits of some planets.
Interstellar space is about 3 Kelvin, right?
Radiant energy from a nomad planet’s interior would be quite small.
On Earth, for instance, I think it’s less than 1% of what the sun delivers.
I doubt the number is that high.
To start with, while there can be a multitude of reasons that a planet went rogue, once they are out of the powerful gravity of a star, most people would assume Newton’s first law would apply, and the rogue would continue in a straight line in whatever its last vector was when it left orbit.
If that was the case, indeed there would be a lot of rogue planets.
However, Newton’s first law would indeed apply, in that, while it was no longer under the control of its star, it would still be under the control of the forces of the galaxy itself.
These forces are formidable in their own right. They have to be to keep the galaxy from flying off in all directions.
This means that in whatever direction the rogue planet was hurled, it would not be in a straight line, but a gradual arc, over time becoming more and more influenced by this continual force.
So the question becomes one of different effects in different directions. That is, is the rogue heading with or opposed to the flow of the galaxy, toward its edge or center, or its “top” or “bottom”, or a vast number of possible vectors between some of these. Also, where in the galaxy it started from.
This gets even more complicated because while, for example, our Sun takes 250 million years to rotate the galaxy, there is also the density wave theory, that the galaxy also has sections of the galactic disk that have a 10-20% greater mass density, which would strongly affect the arc change of a rogue planet when it passed through them.
Eventually, in most cases, the vast majority of rogues would be slung around until they were captured and destroyed, the vast majority in the center of the galaxy. And while it might take a billion years, it would still cull most of them.
Earth generates tremendous amounts of heat internally. It is largely composed of a very hot liquid magma beneath a thin crust. Magma (lava) spews forth anywhere the crust is thin enough to permit it.
That is true but in outer space, with no sun to heat it, that wouldn’t be enough to keep the atmosphere from freezing.
I was taught there were only 9 planets and that one found in another solar system would be called something else besides a planet. A planet used to be a large body orbiting around our sun. Who changed the rules?
Loose women on loose planets? Ask Laz.
And that’s another thing. 400 billion stars in the galaxy times 100,000 means that commute is going to be a BITCH.
That is a number so big it doesn’t have a name?
I realize the issue itself results from a statistical hypothesis which relies on a hypothesis - as yet unproven by empirical evidence, that presumes a material similarity (on average statisically) in the formation of solar systems.
I am frankly concerned that as much as I think there is room for federal funding of basic science (scientific questions far from deriving a profitable enterprise therefrom) that there is an excess of funding of the purely speculative science that is not only far distant from any pracitcal application or use but just as far distant from any practical, empirical proof (”string theory” for instance).
I think true scientific breakthroughs that have served humanity were at the time actual baby steps built on questions posed by previous steps that had already obtained proof, even though to most people at the time the result seemed like a great leap. But now, in my humble opinion, we have many public and privately funded scientists paid for pursing not “next steps” in science, but great leaps of imagination. Just my humble opinion.
Word is Venus is one "Slutty Ho'" and is always trying to hook-up with Uranus...
KIPAC? Is that near K-PAX?
I also wondered of the “loose planets” where another means of accounting for dark matter, and that’s why they came up with the 100,000:1 ratio.
I’ve never been comfortable with the theory of “Dark Matter.” I have a nagging suspicion that it’s a hypothesis created to patch a hole in a flawed underlying theory.
But, I’m not an astrophysicist, so I can nurse my ignorant prejudices all I want.
Why hasn't the asteroid belt accreted into a planet yet? I've been puzzling over that since I was a kid.
Not having studied it (at all), my working theory is that it once was a planet that was busted up by impact. The accretion process should be ongoing now.
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