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Lonely ‘homeless’ planet found for the first time

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Re: Lonely ‘homeless’ planet found for the first time

#21

Post by scrumper »

pavel_lishin wrote: post #20
scrumper wrote: post #15

Earlier quoted context omitted.

> hideaway for a fleeing civilization Larry Niven's Known Space books deal with this. They put a civilization of herbivorous creatures called Puppeteers on a group of sunless planets accelerating away from a catastrophe in the galactic center. One enjoyable aspect comes from the creatures' herd-like, risk-averse nature, a hold over from their distant past as prey animals. They dream of fleeing forever, enjoying a nom…

Actually, I think their plan is to go to the Magellanic clouds, following the rest of the Known Space species who would get there before them via Hyperdrive. It's been awhile since I've read the series, the Ringworld novels bored me.

That was the direction they were heading in, but a pretty decent chunk of them didn't ever want to go back to living inside a galaxy.

Re: Lonely ‘homeless’ planet found for the first time

#22

Post by k3n »

btilly wrote: post #17
k3n wrote: post #12

Earlier quoted context omitted.

I'm most of the way through reading Neil deGrasse Tyson's book "Origins", and I just finished chapter 24 last night, which deals with this exact subject. By the way, it looks like the entire book is available online; this[1] is a link to the section of ch. 24 that talks about these star-less planets and the possibility that they contain life. First, he points out the "extremophiles" that exist on earth -- for example…

The core of planets do not remain hot for billions of years based on their formation. They remain hot because they have radioactive material that continues to generate heat. Before the discovery of radioactivity invalidated the calculation, the fact that the Earth's interior is still hot was used by Lord Kelvin to set an upper limit of 40 million years for the Earth's age.

That's not the case for Earth though, is it? I had thought it was the tremendous pressures that kept the internal core molten. If it was radiation wouldn't it be enough to destroy us living in such close proximity?

I am barely qualified to call myself even an amateur astronomer, so sorry if I've misinterpreted anything.

edit: re-reading the passage, it sounds like it's a combination of both (bottom of p.245, 246).

Re: Lonely ‘homeless’ planet found for the first time

#23

Post by schiffern »

ichabodcole wrote: post #8

Would anyone like to explain why this planet would have a temperature of 400C (I was picturing it being really cold)? Is this because of its mass/size, more related to its gaseous composition or both?

Compressive heating when gas collapsed into the planet.

Re: Lonely ‘homeless’ planet found for the first time

#24

Post by jws »

doctorpangloss wrote: post #3

These planetars stoke the scifi imagination. They are the perfect hideaway for a fleeing civilization... or deadly weapon. What kind of life could exist on a planet without a star? Even when the scientific payoff is limited, the payoff to the imagination is immense.

In Passages in the Void[1], these planets are the only places the machines were willing to reincarnate humanity after deciding that stars were too dangerous, having suffered the anguish of their humans being extinguished by our own Sun.

[1] A series of short stories by a Roger Williams, tagged localroger on kuro5hin, wrote back in the day. I gathered the parts together into an ePub suitable for iBooks. I'm checking with the author now to see if I can make it available. You can always read it on the kuro5hin site, linked from http://localroger.com/ (The Metamorphosis of Prime Intellect is something else entirely.)

Re: Lonely ‘homeless’ planet found for the first time

#25

Post by InclinedPlane »

btilly wrote: post #17
k3n wrote: post #12

Earlier quoted context omitted.

I'm most of the way through reading Neil deGrasse Tyson's book "Origins", and I just finished chapter 24 last night, which deals with this exact subject. By the way, it looks like the entire book is available online; this[1] is a link to the section of ch. 24 that talks about these star-less planets and the possibility that they contain life. First, he points out the "extremophiles" that exist on earth -- for example…

The core of planets do not remain hot for billions of years based on their formation. They remain hot because they have radioactive material that continues to generate heat. Before the discovery of radioactivity invalidated the calculation, the fact that the Earth's interior is still hot was used by Lord Kelvin to set an upper limit of 40 million years for the Earth's age.

Things are not the same for all kinds of planets. A rocky planet the size of Mercury is going to cool off much faster than one the size of Earth. This is largely due to the difference in volume to surface area ratios and related effects. A more massive planet will have a much higher amount of heat left over from formation, and it will lose that heat slower. Plus, it will have a higher quantity of radioactive elements relative to its surface area. This is why the Moon is geologically inactive while the Earth still is, despite being made of mostly the same stuff.

Once you scale up to gas giants these factors become even more important. Those planets retain a crap ton of heat from their initial formation and are comparatively inefficient at radiating it away into space. More so, they continue to generate heat through ongoing settling (raining of Helium down to lower levels of the atmosphere, for example).

Re: Lonely ‘homeless’ planet found for the first time

#26

Post by kalms »

MrMember wrote: post #11
GotAnyMegadeth wrote: post #4

Earlier quoted context omitted.

I read this brilliant short story once where the Earth had been 'stolen' by a massive rogue planet (the earth started to orbit it instead of the sun). A family had survived by building a air tight shelter and having a constant fire burning. They had to go out to fill up buckets with frozen oxygen to bring back and defrost.

A Pail of Air http://www.baenebooks.com/chapters/0743498747/0743498747___6...

That was amazing.

Re: Lonely ‘homeless’ planet found for the first time

#27

Post by ImprovedSilence »

kibwen wrote: post #6
doctorpangloss wrote: post #3

These planetars stoke the scifi imagination. They are the perfect hideaway for a fleeing civilization... or deadly weapon. What kind of life could exist on a planet without a star? Even when the scientific payoff is limited, the payoff to the imagination is immense.

The planet was found to be between 50 and 120 millions years old, with a temperature of approximately 400 degrees Celsius, and a mass four to seven times that of Jupiter. Not exactly sure what "temperature" refers to there, but Wikipedia tells me that Jupiter itself has a surface temperature of less than -100 degrees C. So even without a star, it's rather substantially warm. However, at Jupiter's distance, the solar…

Perhaps it is on it's way to becoming a star? If only it could gather up more mass.

Re: Lonely ‘homeless’ planet found for the first time

#28

Post by scottscanlon »

rpm4321 wrote: post #10
ichabodcole wrote: post #8

Would anyone like to explain why this planet would have a temperature of 400C (I was picturing it being really cold)? Is this because of its mass/size, more related to its gaseous composition or both?

It's a brown dwarf: http://en.wikipedia.org/wiki/CFBDSIR2149-0403

ah, thanks for that.

Re: Lonely ‘homeless’ planet found for the first time

#30

Post by kinkora »

If you read the article all the way towards the end, you will see that it's not exactly "lonely". From the article:

The planet is in fact called CFBDSIR2149 and appears to be part of a group of very young stars known as the AB Doradus Moving Group. “This group is unique in that it is made up of around thirty stars that all have the same age, have the same composition and that move together through space. It’s the link between the planet and AB Doradus that enabled us to deduce its age and classify it as a planet,” researcher Lison Malo explained.

I find it fascinating that we have identified a group of stars that are (i'm assuming) moving in synchronous towards a general direction. I can only theorize that it was caused by perhaps a giant supernova that flung all of these stars/planets outwards but it does make you wonder what caused it exactly.

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