View Full Version : Orphan Planets

2005-Feb-25, 04:12 AM
According to this article there could be more plants not orbiting stars in the galaxy, then stars!!

http://www.space.com/searchforlife/seti_or...ets_050224.html (http://www.space.com/searchforlife/seti_orphan_planets_050224.html)

2005-Feb-28, 11:54 PM
How many there really are will probably remain an open question for some time. With concentrated effort, we could nail the local frequency pretty close, but conditions here are not like conditions elsewhere-- both formation of planetary systems and their evolution will be different. For distant systems, we will only see them if they are 1) New, and therefore still hot 2) Traveling rapidly thru gas or dust, creating a bow shock, or 3) Both.

The problem with evolved rogue planets is that, due to their small angular size and coldness, we can't see them at any appreciable distance with today's equipment. Best regards-- Steve

2005-Mar-04, 02:12 AM
If you think about the solar system formation process from start to finish, it's not surprising. Some planets and protoplanets are bound to have unstable orbits - especially in the early formation stages. Just think about how "just right" a planet's orbit has to be in order to not be slung out of the solar system and at the same time avoid falling into the firery oblivion that is it's parent star.

2005-Mar-05, 02:49 AM
I have read that the early solar system may have had as many as 300 planets forming and the gas giants culled the herd by changing their orbits. Some went into the Sun, some absorbed by the giants themselves and others flung out into the deep.

During the life of our galaxy billions of stars have passed close to others billions of times. Their gravities affecting each other and their families of planets.

Large planets (almost-stars failing to ignite after running out of their discs of dust and gas) and their moons roam the the void between the stars as cold dark stealth systems.

There are many other possible mechanisms that can give birth to or evict large and small planetary bodies into interstellar darkness ( and albeit inter-galaxial space too ).

In the vast volumes of black nothingness between suns are probably more large rocks and balls of frozen gas that are orphans, black sheep and lost tribes than are lit by the warm light of stars.

This could be part of that "Dark Matter" that was just given that name.

2005-Mar-05, 06:51 PM
It would be very interesting, to the scientists especially, if we could discover "rogue" planets travelling amongst the stars but not "tied" to any one in particular.

Perhaps they could tell us more about how planets are formed & perhaps why they got "flung out" of the solar system where they originated.

2005-Mar-07, 07:14 AM
However, such planets will be very difficult to detect since they give off no light of their own, nor detectable quanities of heat or other energy.

2005-Mar-07, 12:12 PM
Originally posted by Planetwatcher@Mar 7 2005, 07:14 AM
However, such planets will be very difficult to detect since they give off no light of their own, nor detectable quanities of heat or other energy.
Agreed, this is why we don't have a complete catalog of Kuiper belt and Oort cloud objects. They are cold and dim. We can possibly detect some small number of such objects through surveys such as OGLE, which look for eclipses and gravitational micro-lens events against backgrounds of millions of stars. While such surveys will never turn up exhaustive lists of these objects, they may eventually be able to give us good numbers for haw many such objects there are in parts of our galaxy.

Cave Man
2005-Mar-07, 01:20 PM
We can at least set an upper limit on rogue planets visiting our solar system.
Parameters would include the amount of space we have gone through during the lifetime of our solar system, the probability of a rogue planet interacting with one of the other planets, and the number of possible rogue planets we have captured: at least 1, Pluto. :o

Unless, of course, you want to believe Velikovsky! :unsure:

2005-Mar-07, 02:03 PM
Originally posted by Cave Man@Mar 7 2005, 01:20 PM
we have captured: at least 1, Pluto.
We don't know for certain that Pluto was captured, and current thinking is that it wasn't captured. However, you're general idea that the small number (zero) of these rogue planets that we have seen sets an upper limit is a good one. It is worth noting that we can probably only say that the evidence covers a few centuries as most passing plantes would not change the orbits of our planets in much of an obvious way.