Planets whithout star

[masbtt]

Why nobody speaks about the posibility of lonely independent planets whithout star? I think they could be very numerous and account for at least a small part of the dark matter. They could have formed by the same process that formed the stars and have many moons and even harbour life near volcanic heat. Living creatures in this places could have hight sensitive visual system to work just whith the background light of the galaxy.

 

[MeteorWayne]

Welcome to Space.com!<br /><br />I think the reason they are not spoken about much is that they are very hard to detect, hence we haven't found many (I think only a few, and even those are iffy)<br /><br />When we see more, the conversation will get quite lively methinks <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[mithridates]

I've seen a few articles on them before; they're officially called rogue planets or interstellar planets if you haven't encountered the term before.<br /><br />http://en.wikipedia.org/wiki/Interstellar_planet <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[jaxtraw]

Well, because by the IAU definition, they wouldn't be planets.<br /><br />A body is a planet only if it orbits our own star The Sun, in an almost circular path, without any nearby planet candidates. Anything else in the wrong place is officially known as a "Big Round Thing", or a "Dwarf Big Round Thing".

 

[dragon04]

No, I don't think that the definition of a planet requires it to orbit a star for its entire lifetime.<br /><br />Should a sufficiently massive interloper yank a planet out of its orbit around its host star does not declassify it as a planet.<br /><br />Obviously, a planet would have to form within a stellar system, but that doesn't mean it has to forever remain in it.<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[derekmcd]

Rogue planets have been discussed here.<br /><br />Planet sized objects being formed independant of a star system I would find highly unlikely. Any dust clouds large enough to form an object of any significant size would most certainly be part of something larger.<br /><br />As for life on such objects, I'm not even going to venture to guess how small that possibility is. Infinitesimally small comes to mind <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[weeman]

I would have to agree. Any life would have to be deep down in the planet's core, this would also have to mean that the planet is even volcanically active in the first place. <br /><br />I think our best shot at finding life on extrasolar planets is searching planetary systems similar to our own. <br /><br />If an interstellar planet has no star, and it sits in interstellar space, it would be very, very cold, far colder than Pluto.<br /><br />Now, someone correct me if I'm wrong. The CMB has a temperature of about 2.7K (-454.81 degree Fahrenheit). So, if a rogue planet has no nearby star, and no internal heat (volcanic activity), could we argue that the surface temperature of this planet might be close to that of the CMB? <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

 

[kelvinzero]

Rogue planets are considered as a subset of "Massive Compact Halo Objects", in turn a subset of baryonic dark matter, which is the normal-matter subset of dark matter.<br /><br />http://en.wikipedia.org/wiki/MACHO<br /><br />Black holes are also considered MACHOs but Im not sure if they are considered a subset of baryonic (normal) matter.

 

[pyoko]

Does anyone know the smallest size of a body before it turns into a sun? Like how much larger would Jupiter have to be before it collapses in on itself? <div class="Discussion_UserSignature"> <p> </p><p> </p><p><span style="color:#ff9900" class="Apple-style-span">-pyoko</span> <span style="color:#333333" class="Apple-style-span">the</span> <span style="color:#339966" class="Apple-style-span">duck </span></p><p><span style="color:#339966" class="Apple-style-span"><span style="color:#808080;font-style:italic" class="Apple-style-span">It is by will alone I set my mind in motion.</span></span></p> </div>

 

[weeman]

Here is a chart that I found. I can't say for sure how accurate it is. <br /><br />http://www.uni.edu/morgans/astro/course/Notes/section2/fusion.html<br /><br />According to the chart, the simplest of fusion (hydrogen to helium) occurs at .08 solar masses. This would mean that anything with a smaller mass simply doesn't have the core temperature to achieve nuclear fusion. <br /><br />The only think that I don't understand about this chart, is how a stellar mass can be 0.5 that of the Sun's, and have a core temperature of 100 million K. The Sun's core temperature is only about 15 million K. <br /><br />Now I need help <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

 

[derekmcd]

The way I interperet that chart is the minimum size for the type of fusion taking place... not the ratio of size to temp. A star of 8 solar masses can still be fusing hydrogen at a cooler temperature than a star of 4 solar masses fusing helium. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[MeteorWayne]

IIRC, about 80 Jupiter masses is when normal Hyrogen fusion starts. However that's from memory, I'll have to check that number. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[alokmohan]

10 to the power 37 atoms of hydrogen ,I read long back.

 

[robnissen]

In case you don't have enough to worry about, there is a non-zero possibility that a passing star could interact with the sun and throw the earth out of the solar system. The good news is that there are no stars anytime soon that will be wandering by to cause this.

 

[MeteorWayne]

Here's a somwhat related story about stars forming outside a galaxy in it's tail.<br /><br />"Astronomers have found evidence that stars have been forming in a long tail of gas that extends well outside its parent galaxy. This discovery suggests that such "orphan" stars may be much more prevalent than previously thought. <br /><br />The comet-like tail was observed in X-ray light with NASA's Chandra X-ray Observatory and in optical light with the Southern Astrophysical Research (SOAR) telescope in Chile. The feature extends for more than 200,000 light years and was created as gas was stripped from a galaxy called ESO 137-001 that is plunging toward the center of Abell 3627, a giant cluster of galaxies. <br /><br />"This is one of the longest tails like this we have ever seen," said Ming Sun of Michigan State University, who led the study. "And, it turns out that this is a giant wake of creation, not of destruction." <br /><br />The observations indicate that the gas in the tail has formed millions of stars. Because the large amounts of gas and dust needed to form stars are typically found only within galaxies, astronomers have previously thought it unlikely that large numbers of stars would form outside a galaxy. "<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[qso1]

As you have no doubt seen by now...people have talked about rogue planets as they are known. Planets not orbiting parent stars. They are maybe not as numerous as one might imagine when compared to planets orbiting stars. For now, they are simply too difficult to detect so they are discussed in terms of theoretical possibilities. We have to learn how to detect and measure planets around nearby stars with reasonable precision before we can address planets not orbiting stars.<br /><br />Where would you even begin to look for such a planet? <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[nexium]

If the rough planet was formed less than a billion years ago it might still be warm enough that an infrared telescope would detect it. If it was moving fast, we might assume it was an asteroid or comet, much closer than it's real distance. Attempting to plot it's orbit should reveal it's real idenity. Neil

 

[dragon04]

I wonder how many (if any) stellar systems there are wandering through intergalactic space that we're currently unaware of.<br /><br />I'm trying to imagine a stellar nursery that forms a few dozens of stars in intergalactic space.<br /><br />It might certainly lead any intelligent civilization to a very odd cosmology. If few or no stars were visible in the night sky, would they even have astronomy? <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>