Are Planets With Oceans Common In the Galaxy? It's Likely, NASA Scientists Find (theverge.com) 55
Planetary scientist Lynnae Quick decided to explore whether -- hypothetically -- ocean planets, similar to Saturn's moon Enceladus and Jupiter's moon Europa, are common in the Milky Way galaxy. "Through a mathematical analysis of several dozen exoplanets, including planets in the nearby TRAPPIST-1 system, Quick and her colleagues learned something significant: More than a quarter of the exoplanets they studied could be ocean worlds, with a majority possibly harboring oceans beneath layers of surface ice, similar to Europa and Enceladus," reports Phys.Org. "Additionally, many of these planets could be releasing more energy than Europa and Enceladus." From the report: To look for possible ocean worlds, Quick's team selected 53 exoplanets with sizes most similar to Earth, though they could have up to eight times more mass. Scientists assume planets of this size are more solid than gaseous and, thus, more likely to support liquid water on or below their surfaces. At least 30 more planets that fit these parameters have been discovered since Quick and her colleagues began their study in 2017, but they were not included in the analysis, which was published on June 18 in the journal Publications of the Astronomical Society of the Pacific. With their Earth-size planets identified, Quick and her team sought to determine how much energy each one could be generating and releasing as heat. The team considered two primary sources of heat. The first, radiogenic heat, is generated over billions of years by the slow decay of radioactive materials in a planet's mantle and crust. That rate of decay depends on a planet's age and the mass of its mantle. Other scientists already had determined these relationships for Earth-size planets. So, Quick and her team applied the decay rate to their list of 53 planets, assuming each one is the same age as its star and that its mantle takes up the same proportion of the planet's volume as Earth's mantle does.
Next, the researchers calculated heat produced by something else: tidal force, which is energy generated from the gravitational tugging when one object orbits another. Planets in stretched out, or elliptical, orbits shift the distance between themselves and their stars as they circle them. This leads to changes in the gravitational force between the two objects and causes the planet to stretch, thereby generating heat. Eventually, the heat is lost to space through the surface. One exit route for the heat is through volcanoes or cryovolcanoes. Another route is through tectonics, which is a geological process responsible for the movement of the outermost rocky or icy layer of a planet or moon. Whichever way the heat is discharged, knowing how much of it a planet pushes out is important because it could make or break habitability. For instance, too much volcanic activity can turn a livable world into a molten nightmare. But too little activity can shut down the release of gases that make up an atmosphere, leaving a cold, barren surface. Just the right amount supports a livable, wet planet like Earth, or a possibly livable moon like Europa.
Some have suggested that some of these planets could be watery, and Quick's estimates support this idea. According to her team's calculations, TRAPPIST-1 e, f, g and h could be ocean worlds, which would put them among the 14 ocean worlds the scientists identified in this study. The researchers predicted that these exoplanets have oceans by considering the surface temperatures of each one. This information is revealed by the amount of stellar radiation each planet reflects into space. Quick's team also took into account each planet's density and the estimated amount of internal heating it generates compared to Earth.
Next, the researchers calculated heat produced by something else: tidal force, which is energy generated from the gravitational tugging when one object orbits another. Planets in stretched out, or elliptical, orbits shift the distance between themselves and their stars as they circle them. This leads to changes in the gravitational force between the two objects and causes the planet to stretch, thereby generating heat. Eventually, the heat is lost to space through the surface. One exit route for the heat is through volcanoes or cryovolcanoes. Another route is through tectonics, which is a geological process responsible for the movement of the outermost rocky or icy layer of a planet or moon. Whichever way the heat is discharged, knowing how much of it a planet pushes out is important because it could make or break habitability. For instance, too much volcanic activity can turn a livable world into a molten nightmare. But too little activity can shut down the release of gases that make up an atmosphere, leaving a cold, barren surface. Just the right amount supports a livable, wet planet like Earth, or a possibly livable moon like Europa.
Some have suggested that some of these planets could be watery, and Quick's estimates support this idea. According to her team's calculations, TRAPPIST-1 e, f, g and h could be ocean worlds, which would put them among the 14 ocean worlds the scientists identified in this study. The researchers predicted that these exoplanets have oceans by considering the surface temperatures of each one. This information is revealed by the amount of stellar radiation each planet reflects into space. Quick's team also took into account each planet's density and the estimated amount of internal heating it generates compared to Earth.
The more you know (Score:5, Interesting)
The more we learn, the more baffling the Fermi Paradox becomes. It now seems like a planet with water is to be expected in any non-binary* star system old enough to have finished planet formation, and some of the binary systems. We don't know yet how many are Earth-sized, not gas giants, but they seem common.
The basic ingredients of life are everywhere, even the interstellar medium. Planets like Pluto that are brown have that color because they're covered with amino acids. Given how early life began on Earth, there's no scientific reason to expect life to be rare. intelligent life still has a lot of unknowns, but how rare can it be?
*Insert joke here
Re: (Score:2, Interesting)
how rare can it be?
If we find the planet of Beef steaks it may even be medium rare, possibly even well done, depending on how close it is to it's star.
Re: The more you know (Score:2)
They are just Entrecotes that rejected the philosophy of deliciousness and refused to bathe in butter "to not wash the seasoning of God off of you". They aren't rare, as can be told from their greeting "Fry long and proper".
Re: The more you know (Score:2)
Lol
Re: (Score:2)
Given how early life began on Earth, there's no scientific reason to expect life to be rare. intelligent life still has a lot of unknowns, but how rare can it be?
Well, the current prevailing scientific view is that abiogenesis happened once on Earth, hence "Common Ancestry".
"Once" seems like a nice religious number for science to go with. No real scientific rationale, given the vastness of the oceans and the amount of time even on Earth alone, as you've noted.
But we can't break Common Ancestry, now can we?
Re: (Score:2)
So, you're asserting Common Ancestry is false. Apart from the unknowns of it happening multiple times in the oceans, we know a subset of life does not occur as a simple matter of descent, because in your last case, we did the design ourselves.
Works for me, given it represents actual reality, and I always found it an arbitrary assertion anyway.
Re: (Score:3)
More to come, undoubtedly. [scientificamerican.com]
No, not that Kingdom, that other Kingdom, per the hierarchy defined by that theist Linnaeus.
Complex, isn't it?
Re:The more you know (Score:4, Interesting)
Re: (Score:2)
Re:The more you know (Score:4, Informative)
>So, you're asserting Common Ancestry is false.
I don't see how you get that they're asserting that. (aside from fully synthetic made-from-scratch life which obviously wouldn't share a common ancestor)
Common Ancestry says everything currently alive shares a common ancestor (strongly suggested by the fact that all life on Earth uses the same kind of RNA and DNA instead of some other kind of information-carrying molecules), it says absolutely nothing about how many times abiogenesis occurred.
Think of it like the concept of "Genetic Adam" - DNA analysis suggests there was some guy alive somewhere between 160,000 to 300,000 years ago who is the common ancestor of every human being alive today. Doesn't mean he was the first man to ever exist, or that no other men existed at the time, or even that no other men alive at the time contributed to your genetic makeup today. All it means is that his genes were useful enough to spread throughout the entire population, making him the common ancestor of every human being alive today.
Consider - if abiogenesis occurred once every million years, then the first time it occurred the resulting life would have a million years (and perhaps billions of generations) to evolve and colonize the entire planet before the next new kind of life emerged. Which means the original life would almost certainly be far more advanced than the new life, and quite likely literally eat it for breakfast before it had even evolved a rapid means of reproduction.
That's not the only option though. Maybe the new life is initially unpalatable to the old, (which might still all be chemovores) and is based on dramatically faster or more efficient chemistry so that it manages to hold its own against the original forms even in its protolife stage. If it has an inherent advantage right out of the gate that's strong enough to let it hold its own against life with a million year evolutionary head start, then its a fair bet that after it's had a few million years to evolve itself it will have managed to completely displace the original lifeforms. Then it becomes the common ancestor of all future life.
There's also the more remote possibility that new life and old would somehow merge into something new and more adaptable than either alone. Then that new hybrid form could displace both predecessor forms of life and itself become the common ancestor. Or if one of the predecessor lines managed to survive, that would become the common ancestor when the other predecessor line died out.
E.g.: Perhaps cytoplasm and RNA/DNA originated independently and later established a symbiosis that allowed for much more sophisticated cells than either could achieve alone? Viruses might be descended directly from the original DNA ancestor, while cellular life descended from the DNA/cytoplasm hybrid, and none of the cytoplasm-only life survived since it couldn't compete with its DNA-enhanced cousins. When the last cytoplasm-only organism died out, the original DNA organism became the common ancestor that all remaining life is descended from.
Of course, if something like my virus idea actually happened, and some of the cytoplasm-only organisms also still survive, then there would NOT be a common ancestor for all life, since viruses and cytoplasmoids would have no shared ancestor.
Re: (Score:2)
Another mod planning on waiting to turn into hydrocarbons for being on fire.
If that way makes you feel better about the outcome, feel free.
Re: (Score:1)
Just a thought, what if Earth was seeded with the building blocks of life multiple times (amino acids, etc) over the 100s of millions or billions of years, but only one "set" actually became life, and it created conditions which prevent other types of building blocks from growing / evolving?
For all we know yesterday we might have had a faint dusting of some other type of amino acids, etc, but since we are already here, they will have no chance.
Snark, snark, snark (Score:2)
AC dude listed some plausible explanations for Common Ancestry.
Re: (Score:2)
Well, the current prevailing scientific view is that abiogenesis happened once on Earth, hence "Common Ancestry".
Is that still the prevailing belief? I mean, sure, for everything found in "normal" environments, since "normal" environments are the result of catastrophic changes to the early environment, but some of the extremophiles are very odd, and very old.
Re: (Score:2)
Intelligent life is simply a competitive evolution thing. Intellectual adaptability must out perform physical evolution. In our case regular ice ages, cycle measured in tens of thousands of year, pushed mental adaptability past physical evolution. Rock throwing monkeys, simply found they could remain in rapidly cooling locales by starting fires and wearing the skins of the animals they killed and thus dominate that locale prior to physically evolving animals being able to do so. Wait two million years and y
Re:The more you know (Score:4, Insightful)
The more we learn, the more baffling the Fermi Paradox becomes.
The entire universe only seems to be 13.8 billion years old and it took Earth nearly 4.6 billion years just to produce (questionably) intelligent life. We've only just started broadcasting radio signals on Earth and they are still weak. Additionally, there are good betting odds for humanity wiping itself out. The Fermi Paradox is no paradox when you realize that it takes a long time for a planet to produce a proper environment for life to arise and it takes even longer for multicellular life to arise. Then on the off chance that life isn't obliterated by a mass extinction event they might become smart enough to discover radio waves and be able to generate an enormous amount of energy to send a signal (or themselves) into space.
With all these requirements in a very tight windows of time and you are surprised that in our brief period of listening and looking at the sky hasn't yielded obvious results? It's no wonder we haven't discovered extrasolar life because of the constraints of our search.
Re: (Score:2)
There's that, and the consideration that the 'radio broadcast' period of civilization seems to be very short. In barely a century and a half we're moving from high-powered broadcast signals to low-power directed signals. That's only 1.5% of the length of our technological civilization. Sure, we're detectable in a sphere 100+ light years wide, but in another decade or two that signal will fade out as broadcast technologies are abandoned for more efficient directed communications. If a high-tech civilizat
Re: (Score:2)
The Fermi Paradox is no paradox when you realize that it takes a long time for a planet to produce a proper environment for life to arise and it takes even longer for multicellular life to arise. Then on the off chance that life isn't obliterated by a mass extinction event they might become smart enough to discover radio waves and be able to generate an enormous amount of energy to send a signal (or themselves) into space.
It's not about radio waves. It's about Kardashev scale class II civilizations, which should be visible even in Andromeda, and Andromeda has about a trillion stars. Even if intelligent life is rare, say 1 in a million, that's still a million intelligent civilizations, half of which should already have done their thing. It only takes one of that million to build Dyson swarms and we'd see that, even millions of years later.
Fundamentally, either there's some new SciFi physics that makes FTL travel possible,
Re: (Score:2)
It's not about radio waves. It's about Kardashev scale class II civilizations
Who is to say such a thing is even possible much less probable? There are no known examples of such a civilization.
Even if intelligent life is rare, say 1 in a million, that's still a million intelligent civilizations,
One in a million? Pff! It's distinctly possible it's one in trillions and that it doesn't last very long. You are failing to take into account the time scales in play.
Re: (Score:2)
Every known species expands into all easily available habitat space. A Kardashev scale class II civilization is merely the inevitable product of that behavior, if you don't go extinct first. There's no new science or unobtainium required, just continued expansion into what will become new territory (and not that far in the future either).
There's simply no good argument for extinction that would apply to a vast majority of possible alien species, so some of them would certainly continue to expand.
As for in
Re: (Score:2)
Every known species expands into all easily available habitat space. A Kardashev scale class II civilization is merely the inevitable product of that behavior
Space is the very definition of uninhabitable. Why expend so many resources encircling a star when it's far easier to modify a planet, a moon, construct a planetoid or just go to somewhere there are more planets? Megastructures like a Dyson sphere make no sense if it's not for utility.
However, You missed the most important point: time. All these things take time to develop and frankly the universe isn't just young, it was practically born yesterday.
Re: (Score:2)
Why expend so many resources encircling a star when it's far easier to modify a planet, a moon,
A Dyson swarm is just a bunch of (large) space stations orbiting the Sun. With a station, and only with a station, you can get the gravity, length of day, atmosphere, temperature, greenery and every other aspect down to what some group finds ideal. People will go because it's better. Different stations for different ideas of "better". And, crucially, it's incremental, starting with stations orbiting Earth, and then near Earth. If the first station isn't very appealing to someone (or some group), there
Re: (Score:2)
There are significant engineering and ecological challenges to keeping people on a space station longterm. This means they are complex machines which need to be maintained and have delicate balances. Things tends to follow the path of least resistance and this is a high level of resistance compared to planetary living. You also seem to be dismissing the idea of war which would quickly destroy such structures. I'm not saying it's an impossible feat, I'm saying it's highly problematic which makes it an hi
Re: (Score:2)
There are significant engineering and ecological challenges to keeping people on a space station longterm.
The challenges of living in the woods in the winter in the 1700s are more difficult, but people did it. People do difficult things in order to have their own place to live. There's a whole history of that. And the ecological problems are just easier at large scale. A small station has all the problems of an aquarium. A station with 1000 sq km of forest can self-correct from the small things.
As for "ancient structures," it seems more likely that they would be repeatedly impacted and destroyed in the span of a few million years. Nothing is forever which is part of my argument about timescales.
You won't get very far without fully automated defenses against such things. Oh, sure, entropy wins in the end,
Re: (Score:2)
The challenges of living in the woods in the winter in the 1700s are more difficult, but people did it. People do difficult things in order to have their own place to live. There's a whole history of that.
I agree. However, when the challenge is persistent, you are going to have very few people actually attempting it when there are perfectly good planets to settle on.
You won't get very far without fully automated defenses against such things.
You cannot stop everything. A simple dust cloud moving at high speed would be unstoppable. You aren't would need significant external defenses that would need regular maintenance. Planetary living has waaay too many perks compared to living on a large space station. You would be better off just constructing a planet to your own specification
Re: (Score:2)
I agree. However, when the challenge is persistent, you are going to have very few people actually attempting it when there are perfectly good planets to settle on.
That's the flaw in your reasoning. Planets suck. Bad gravity. Bad length of day. Bad lighting. Very expensive to get onto and off of. But more importantly, any sort of habitat you can build and lug to Mars, you can just build and leave in orbit. You want soil you can grow plants in? You can haul it to Mars, or just have it in obit. You want to build stuff on Mars? Still easier to build the tool chain in orbit, then build stuff in orbit, then haul the tool chain to Mars, and build stuff on Mars.
You
Re: (Score:2)
It now seems like a planet with water is to be expected in any non-binary* star system old enough to have finished planet formation, and some of the binary systems. We don't know yet how many are Earth-sized, not gas giants, but they seem common.
The basic ingredients of life are everywhere,...
My view of Fermi's paradox is that no species intelligent enough to be aware of these facts is going to want to reveal itself.
Re: (Score:2)
That makes no sense at all, sorry. Any Class II civilization already knows. At the population scale of Dyson swarms, you have more astronomers than Earth does for every star in the galaxy (with astronomy being no more popular). And if you're xenophobic, there's no need to wait for intelligent life to show itself: you can purge every planet in the Galaxy with signs of life with weapons built in the home system. Only way to be sure.
Where are they? (Score:2)
Intelligence might well be rare - life existed here for at least 3,500 million years before the multicellular cacophany of the Cambrian explosion a scant 340 million years ago. Life may be nigh inevitable - some evidence suggests it started here about as soon as it was physically possible, but it seems that in our case at least, that first step to forming complex organisms was a doozy. So it seems was the first steps into advanced toolmaking, and then to technological civilization. It's hard to say wheth
Re: (Score:2)
As I posted upthread: it's not about radio waves, it's about Kardashev scale class II civilizations. They'd be visible even in Andromeda. Heck, if there was a Dyson swarm in this galaxy, we'd probably hear it's traffic control/GPS system (SPS?), as that would by nature be omnidirectional, loud, and obviously a signal.
Re: (Score:2)
Why would you assume a class II civilization wouldn't care about efficiency anymore? The more raw power you have at your disposal, the more raw potential any incremental increase in efficiency delivers.
There's absolutely no reason to waste energy broadcasting a "loud" signal when sensitive receivers can hear a soft whisper from the other side of the solar system. In fact, if you have any interest in what's going on outside your solar system you want to *avoid* being loud, because your loud nearby signal w
Re: (Score:2)
There's absolutely no reason to waste energy broadcasting a "loud" signal when sensitive receivers can hear a soft whisper from the other side of the solar system.
Think about a system with a count of stations in the high billions, and inter-station traffic, the equivalent of airliners, of over a trillion vessels. There's going to be a lot of background noise, and much like current airport and GPS systems, we're not talking about wastefully loud (although power is simply not a concern at some point), but loud enough to be clear at the needed distance. Each of 10^11 to 10^12 signals doesn't need to be high wattage, but it can't scale down too far and still work. So,
Nasa thought the moon once had an ocean (Score:4, Funny)
Re: (Score:2)
There was also a restaurant. Researchers determined that it failed because it had no atmosphere.
Latin superhero? (Score:2)
That name sounds like sombody with a huge fetish for snobish deliberately obsucre and hard to pronounce words from dead languages wanted to create a female The Flash knock-off. :)
Better than Sozialisma Bort Nahassapimapetilan da Silva da Costa de la Hoya Cardinal, I guess. :D
It doesnt just have to be water (Score:2)
Titan has ethane lakes. Theres no reason a larger equally cold body couldn't have entire oceans of the stuff with it's own unique biochemistry.
Re: (Score:2)
Its own very SLLLOOOWWW biochemistry. Intelligent life, if it exists on Titan, may require a century to form a thought.
The objection that interstellar travel is impossible because it takes too long has always seemed short sighted to me. Nothing but the bible says that an intelligent species necessarily has to have a lifespan under a century. If a creature lives for 10,000 years then a trip to Alpha Centauri might be well within the realm of reasonable to it. Additionally, colony organisms such as ants c
Planets in the nearby TRAPPIST-1 system (Score:3)
I expect the oceans to be made up of beer - in which case, I'm all for space travel!
Re: (Score:2)
Re: (Score:2)
Water is insanely common (Score:5, Insightful)
Every time I see articles like this, or those that are amazed to have found water on Mars, or even the Moon, I just shake my head.
Water is one of, if not the most common molecule in the known universe. It's a product of the top 2 most common reactive elements in the universe - hydrogen and oxygen so of course we should expect to find it everywhere, it's prolific. It's certainly not some super rare compound unique to earth. This should be news to no one, especially the scientists who conducted the study.
Re: (Score:2)
Water being commonplace in the universe is a necessary, but not sufficient condition for oceans to be common.
Look around our solar system. We have one planet that has oceans and two that probably had oceans in the past but no longer do. There was enough water to have oceans on Venus and Mars, but the conditions weren't right.
So it's not a stupid question at all to ask whether oceans are commonplace. It *would* be a stupid question if water were rare.
Re: (Score:2)
Then too, water is not necessarily the only substance that can form an ocean. As a poster higher in the thread pointed out Titan has seas of ethane, if lead were common enough on Venus you could see lead lakes forming.
But not ncessarily H2O oceans (Score:2)
Methane and lots of other liquids...
More importantly, was Star Wars right?!?!! (Score:2)
Only a matter of time now... (Score:2)
Maybe? (Score:1)
Step 1) get contacted by journalist
Step 2) speculate on data
Step 3) profit
No, planets with oceans aren't common. (Score:1)
And how can I say that with absolute certainty?
Because the idiotic IAU definition explicitly requires that a planet orbit the Sun. Not just any star, but specifically the Sun.
So we know exactly how many planets in the entire universe have oceans.
One.
That's it.
Re: (Score:2)
Even assuming you accept the IAU definition as being the ultimate authority on the definition of a word whose widespread use dramatically predates their existence, there's still all the gas giants that might have oceans.
intelligent != technological (Score:2)