Can Living Planets Exist Around Dead Stars?

originally posted by: MKMoniker
a reply to: mcx1942

I am bringing this thread forward, with new and relevant information:

www.scienceworldreport.com...
DYING STARS REVEAL THE CLUE TO EXTRATERRESTRIAL LIFE: EARTH-LIKE PLANETS UNMASKED

The idea is that white dwarfs are dying stars, that have already gone thru a red expanding stage, engulfing and destroying nearby planets. But a recent survey of the closest 500 white dwarfs to Earth, found that most have one or more habitable Earth-like planets currently orbiting them close-in.

Where did they come from, if the original close planets had been engulfed and burned up? Nomad planets that wander the galaxy?

The original planets never were completely consumed. The present ones may be the burnt up cores of what were once larger planets. It will be interesting to study their atmospheres with the James Webb Space Telescope. I have doubts whether these planets would be habitable despite being in habitable zones.

a reply to: JadeStari recall reading about at least one such burnt out star that had a latter day proto-planetary disk going on around it.

EDIT: I did a quick search for "dead Star has Disk" and found several articles

such as this one: science.nasa.gov...

Any planets around the stars that gave rise to pulsars would have been incinerated when the stars blew up. The pulsar disk discovered by Spitzer might represent the first step in the formation of a new, more exotic type of planetary system, similar to the one found by Wolszczan in 1992.
"I find it very exciting to see direct evidence that the debris around a pulsar is capable of forming itself into a disk. This might be the beginning of a second generation of planets," Wolszczan says.

originally posted by: stormbringer1701
a reply to: JadeStari recall reading about at least one such burnt out star that had a latter day proto-planetary disk going on around it.

EDIT: I did a quick search for "dead Star has Disk" and found several articles

such as this one: science.nasa.gov...

Any planets around the stars that gave rise to pulsars would have been incinerated when the stars blew up. The pulsar disk discovered by Spitzer might represent the first step in the formation of a new, more exotic type of planetary system, similar to the one found by Wolszczan in 1992.
"I find it very exciting to see direct evidence that the debris around a pulsar is capable of forming itself into a disk. This might be the beginning of a second generation of planets," Wolszczan says.

Yes! That's amazing and it is possible that perhaps there could be some sort of accretion of gas/dust which did not fully escape the explosion or more likely was gathered during the pulsar's journey around the galaxy after some period of time.

Perhaps white dwarfs also gather planet forming material as well? It's fascinating to think what a habitable white dwarf planet would be like. They would have to orbit insanely close to the star to be in it's habitable zone.

For instance, nearby white dwarf Sirius B only has a luminosity of only 0.026 that of the Sun!!!

So where would a white dwarf planet be considered habitable? Try 0.01 AU!



Such a would need a thick atmosphere and or seas to distribute heat to the other side of the almost certain to be tidally locked planet.


And at that distance the sky on the day side of the planet would be dominated by the white dwarf which would have about the same radius as the Earth!!!!



Of course a habitable earth around a white dwarf would need to have a VERY thick atmosphere and layer like our ozone layer because white dwarfs give off a LOT of UV radiation and this would be exacerbated by how close the planet would have to orbit the star to be warmed to Earthlike-temperatures (SPF 10,000 anyone?)

Of course all that might mean is that life would have to live and evolve underground or deep in seas/oceans. Who knows if evolution would eventually allow life to take the land with armadillo like protection from the harsh UV rays? And all that assumes that the water didn't break down from the UV in the first place. (perhaps due to having a much thicker atmosphere than Earth, idk?)

Here's a good paper on looking for habitable planets around white dwarf stars: Habitable Planets Around White Dwarfs: an Alternate Mission for the Kepler Spacecraft

Of course I am skeptical of habitable worlds around White Dwarfs,this is largely why:

White or Brown Dwarf Planets Not Likely to Host Life
By Charles Q. Choi, Astrobiology Magazine Contributor - May 30, 2013

The dead and failed stars known as white dwarfs and brown dwarfs can give off heat that can warm up worlds, but their cooling natures and harsh light makes it unlikely they can host life, researchers say.

Stars generally burn hydrogen to give off light and heat up nearby worlds. However, there are other bodies in space that can shine light as well, such as the failed stars known as brown dwarfs and the dead stars known as white dwarfs.

White dwarfs are remnants of normal stars that have burned all the hydrogen in their cores. Still, they can remain hot enough to warm nearby planets for billions of years. Planets around white dwarfs might include the rocky cores of worlds that were in orbit before the star that became the white dwarf perished; new planets might also emerge from envelopes of gas and dust around white dwarfs.

Brown dwarfs are gaseous bodies that are larger than the heaviest planets but smaller than the lightest stars. This means they are too low in mass for their cores to squeeze hydrogen with enough pressure to support nuclear fusion like regular stars. Still, the gravitational energy from their contractions do get converted to heat, meaning they can warm their surroundings. NASA’s WISE spacecraft and other telescopes have recently discovered hundreds of brown dwarfs, raising the possibility of detecting exoplanets circling them; scientists have already observed protoplanetary disks around a few of them.

White dwarfs and brown dwarfs are bright enough to support habitable zones — regions around them warm enough for planets to sustain liquid water on their surfaces. As such, worlds orbiting them might be able support alien life as we know it, as there is life virtually everywhere there is water on Earth.

"These planets could be like the Earth, but they are relatively unstudied," said study lead author Rory Barnes, a planetary scientist and astrobiologist at the University of Washington at Seattle.

An added benefit of looking for exoplanets around these dwarfs is that they might be easier to detect than ones around regular stars. These dwarfs are relatively small and faint, meaning any worlds that pass in front of them would dim them more noticeably than planets crossing in front of normal stars.

However, unlike regular stars, white dwarfs and brown dwarfs cool as they age, meaning their habitable zones will move inward over time. Barnes and his colleague René Heller at the Leibniz Institute for Astrophysics Potsdam in Germany were curious as to whether this complicated the habitability of planets there.

The most obvious peril of a shifting habitable zone is that it could result in a planet getting so cold all the liquid water on its surface freezes solid. There are other dangers however — as white dwarfs and brown dwarfs cool, the light they give off would change as well, possibly meaning they would end up sterilizing worlds with dangerous, high-energy radiation.

To be specific, extreme ultraviolet rays would break a planet’s water apart into hydrogen and oxygen. The hydrogen can escape into space, and without hydrogen to bond with oxygen, the world has no water and is not habitable. Such exoplanets would resemble Venus, with dry atmospheres dominated by carbon dioxide. Young white dwarf stars would especially bathe nearby planets in extreme ultraviolet radiation; the situation is less clear with brown dwarfs, Barnes and Heller said.

- See more at: www.astrobio.net...

Still it's a fascinating possibility if a planet somehow retained it's atmosphere. By the way both the paper by Eric Agol proposing the Kepler search as well as the work by Rory Barnes pouring cold water on habitable white dwarf planets linked above are from researchers at my university: UW (Go Dawgs!)

Sounds bad. but if the "Life is easy to create" (anti-anthropomorphic principle) idea is taken to it's logical extreme such a place might be considered ideal. lots of energy. lots of chemicals being stirred around. The life would be very different because only genetic data that coded for survival value features for that environment would survive to replicate among the primitive self organizing pre "RNA" ringlets or strands. maybe silicon of boron based.

originally posted by: stormbringer1701
Sounds bad. but if the "Life is easy to create" (anti-anthropomorphic principle) idea is taken to it's logical extreme such a place might be considered ideal. lots of energy. lots of chemicals being stirred around. The life would be very different because only genetic data that coded for survival value features for that environment would survive to replicate among the primitive self organizing pre "RNA" ringlets or strands. maybe silicon of boron based.

Yeah but if the water is electolyzed from the planet it would be pretty hard to imagine life. What would the soluble substance be?

originally posted by: JadeStar

originally posted by: stormbringer1701
Sounds bad. but if the "Life is easy to create" (anti-anthropomorphic principle) idea is taken to it's logical extreme such a place might be considered ideal. lots of energy. lots of chemicals being stirred around. The life would be very different because only genetic data that coded for survival value features for that environment would survive to replicate among the primitive self organizing pre "RNA" ringlets or strands. maybe silicon of boron based.

Yeah but if the water is electolyzed from the planet it would be pretty hard to imagine life. What would the soluble substance be?

perhaps in deeply trapped water or ammonia or maybe pockets of some easily melted metal. borene would (probably) easily survive such an environment and could be tossed around like hair or dandelion fluff on air currents.

the thing about alien life is it might until proven otherwise be very alien indeed. we have very little basis for evaluating whether other potential abiogenesis processes could work. we have no basis for excluding almost any environment if we posit a priori that life is natural result of the existence of the universe. the habitable zone is a human concept for humans and earth like carbon based life forms and even then what about gas ballasted floaters in gas giants? they could be carbon based and even then they wouldn't give a darn what we think of the chance of their existence or where they should reside.

Gotta love these serious sciency discussions (even though a lot of it goes over my head).

Makes a nice difference from the usual doomporn and conspiracy nonsence.

a reply to: wildespace

its exciting to think about all those places in Space to explore !

the younger guys today (and gals of course) have unlimited potential just like us "old" guys do

we've already got pics from the Moon and Mars, just need to get the public interested and "open" to the idea of funding projects

a reply to: stormbringer1701

originally posted by: stormbringer1701


the thing about alien life is it might until proven otherwise be very alien indeed. we have very little basis for evaluating whether other potential abiogenesis processes could work. we have no basis for excluding almost any environment if we posit a priori that life is natural result of the existence of the universe. the habitable zone is a human concept for humans and earth like carbon based life forms and even then what about gas ballasted floaters in gas giants? they could be carbon based and even then they wouldn't give a darn what we think of the chance of their existence or where they should reside.

A human concept for humans. So True!

I feel that is a big factor we often overlook when discussing the cosmos. Our perspective is extremely limited compared to the Universe as a whole. Just the fact that we can start to even comprehend all this science amazes me still. If you consider modern western culture has really just been around for a blink in human history.

Our view of what may be life is really limited to what we see. I too feel that when we finally do find extraterrestrial life out there, it most likely will not even closely resemble what we think it may look like.

a reply to: mcx1942

Interesting thoughts. On the other hand, as I am personally sure, laws or physics are the same everywhere (except, perhaps in black holes). That translates to molecular biology and interactions between chemicals. This makes me believe that life anywhere in the universe obeys the same basic laws, and develops and evolves along the same general paths. Other planets and systems might host lifeforms completely different to what we've seen on Earth, but I'm sure they would be similar biologically and in other aspects, such as having some sort of DNA or RNA, eating, growing, "breathing", multiplying, affecting the environment around them.

I don't expect we would ever encounter a living rock, some disembodied ghostly intelligence, or a whole living planet (like in Solaris).

But then, these are my views, and I may be very, very wrong.

[Edit] A hive-mind colony is quite possible. If you think about it, our own bodies are effectively a huge colony of single-celled organisms highly specialised to exist and function together.

originally posted by: wildespace
a reply to: mcx1942

Interesting thoughts. On the other hand, as I am personally sure, laws or physics are the same everywhere (except, perhaps in black holes). That translates to molecular biology and interactions between chemicals. This makes me believe that life anywhere in the universe obeys the same basic laws, and develops and evolves along the same general paths. Other planets and systems might host lifeforms completely different to what we've seen on Earth, but I'm sure they would be similar biologically and in other aspects, such as having some sort of DNA or RNA, eating, growing, "breathing", multiplying, affecting the environment around them.

I don't expect we would ever encounter a living rock, some disembodied ghostly intelligence, or a whole living planet (like in Solaris).

But then, these are my views, and I may be very, very wrong.

This is about where I am. As far as anyone can tell there is nothing else like water with its properties which helps form organic chemistry.

Could there be other, non-organic, non-carbon based life? I suppose but its proponents always have a hard time finding a substance which works as well and is as plentiful as water.

That's why we talk about water a lot in our search for life. Nearly everywhere we find water on Earth we find life. And just about everywhere we look in space we're now finding water.

Nature tends to use what is easy. So far as we can tell carbon organic chemistry is far easier in most of the universe than life based on say, silicon. We have detected amino acids in interstellar dust clouds as well as on comets so they are common.

So there is every reason to believe "life as we know it" based on carbon, hydrogen, oxygen and nitrogen will be the most common form of life because those atoms are some of the most common elements in the universe and like to hook up and form more complex molecules.

So it just makes sense to look for "life as we know" it because it is likely to be the most common form of life and because we kinda know what to look for

I'm all for looking for other more exotic forms of life of course but no one has ever made a compelling case for its existence.

We know we exist.

i posted a article about science rethinking tidal locking. In it's own thread now that i think about it. so long as the planet has an atmosphere or even better an atmosphere and an ocean it is harder for close in planets to get tidally locked than was generally thought.

interweb had a seizure.