NASA's Hubble observations suggest underground ocean on Jupiter's largest moon

From NASA/Goddard Space Flight Center – NASA’s Hubble Space Telescope has the best evidence yet for an underground saltwater ocean on Ganymede, Jupiter’s largest moon. The subterranean ocean is thought to have more water than all the water on Earth’s surface.

Ganymede
In this artist’s concept, the moon Ganymede orbits the giant planet Jupiter. NASA’s Hubble Space Telescope observed aurorae on the moon generated by Ganymede’s magnetic fields. A saline ocean under the moon’s icy crust best explains shifting in the auroral belts measured by Hubble. Credit NASA/ESA

Identifying liquid water is crucial in the search for habitable worlds beyond Earth and for the search of life as we know it.

“This discovery marks a significant milestone, highlighting what only Hubble can accomplish,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at NASA Headquarters, Washington. “In its 25 years in orbit, Hubble has made many scientific discoveries in our own solar system. A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth.”

Ganymede is the largest moon in our solar system and the only moon with its own magnetic field. The magnetic field causes aurorae, which are ribbons of glowing, hot electrified gas, in regions circling the north and south poles of the moon. Because Ganymede is close to Jupiter, it is also embedded in Jupiter’s magnetic field. When Jupiter’s magnetic field changes, the aurorae on Ganymede also change, “rocking” back and forth.

By watching the rocking motion of the two aurorae, scientists were able to determine that a large amount of saltwater exists beneath Ganymede’s crust affecting its magnetic field.

A team of scientists led by Joachim Saur of the University of Cologne in Germany came up with the idea of using Hubble to learn more about the inside of the moon.

“I was always brainstorming how we could use a telescope in other ways,” said Saur. “Is there a way you could use a telescope to look inside a planetary body? Then I thought, the aurorae! Because aurorae are controlled by the magnetic field, if you observe the aurorae in an appropriate way, you learn something about the magnetic field. If you know the magnetic field, then you know something about the moon’s interior.”

If a saltwater ocean were present, Jupiter’s magnetic field would create a secondary magnetic field in the ocean that would counter Jupiter’s field. This “magnetic friction” would suppress the rocking of the aurorae. This ocean fights Jupiter’s magnetic field so strongly that it reduces the rocking of the aurorae to 2 degrees, instead of the 6 degrees, if the ocean was not present.

Scientists estimate the ocean is 60 miles (100 kilometers) thick – 10 times deeper than Earth’s oceans – and is buried under a 95-mile (150-kilometer) crust of mostly ice.

Scientists first suspected an ocean in Ganymede in the 1970s, based on models of the large moon. NASA’s Galileo mission measured Ganymede’s magnetic field in 2002, providing the first evidence supporting those suspicions. The Galileo spacecraft took brief “snapshot” measurements of the magnetic field in 20-minute intervals, but its observations were too brief to distinctly catch the cyclical rocking of the ocean’s secondary magnetic field.

The new observations were done in ultraviolet light and could only be accomplished with a space telescope high above the Earth’s atmosphere, which blocks most ultraviolet light.

###

0 0 votes
Article Rating
84 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
GeeJam
March 13, 2015 12:13 am

The “Yes, I already knew that” award goes posthumously to Arthur C Clarke. Next week, NASA will discover those black rectangular metallic slabs on either Io, Europa or Callisto.

asybot
Reply to  GeeJam
March 14, 2015 12:44 am

@ GeeJam,? Was it not Heinlein that had a great (aimed at the then younger ” kind of boy scout” readers now a little greyer crowd ) story that played out on Ganymede, sorry I just cannot come up with the title. Young families and settlers with domes and apple seeds, ” moon” quakes, etc (just give me time I am a little slower these days i’ll come up with it, I have it somewhere in my library).

asybot
Reply to  asybot
March 14, 2015 12:49 am

Farmer in the Sky, I think

Reply to  GeeJam
March 14, 2015 8:54 am

Clarke put the “It’s full of Stars” monolith on Saturn’s Iapetus. The moon’s albedo variation of 6:1 trailing:leading, and Saturn’s Ring system, were two convenient mysteries. Cassini: Iapetus: PIA18436: Color Maps of Iapetus – 2014 That’s one big black spot !
Kubrick put the monolith in Jupiter orbit to simplify the movie. Saturn was a planet too far.

Reply to  Stephen Rasey
March 14, 2015 8:56 am

Made a mistake in the hyperlink:
Cassini: Color maps of Iapetus — 2014
http://photojournal.jpl.nasa.gov/catalog/PIA18436

Annie
March 13, 2015 12:26 am

It really does sound like a thrilling place to live if the earth becomes overcrowded.

Reply to  Annie
March 13, 2015 7:12 am

Unfortunately, Ganymede (as well as Europa) is within Jupiter’s radiation belts so the surface is quite uninhabitable.
However, Callisto is outside Jupiter’s radiation belts so we could always move there. It doesn’t have an ocean but it does have plenty of ice

PeterinMD
Reply to  qam1
March 13, 2015 10:09 am

Well, lets send up a bunch of SUV’s so we can increase the CO2, thereby increasing the warmth and melt the ice!
I hope I don’t need the /sarc tag

Jay Hope
Reply to  qam1
March 13, 2015 3:18 pm

Plenty of ice……it will be a home from home.

Goldie
March 13, 2015 12:49 am

Finding liquid water under 95 kilometres of ice/crust is hardly a harbinger of finding life – the pressure would be phenomenal.

Admin
Reply to  Goldie
March 13, 2015 2:49 am

Not necessarily a problem. And remember Ganymede’s gravity is weaker than Earth.

garymount
Reply to  Eric Worrall
March 13, 2015 3:03 am

Ganymede gravity
1.43 m/s²
– – –
Earth gravity
9.78 m/s²
6.84 times difference, making 95 Km equivalent at being at a depth of nearly 14Km on earth.

beng1
Reply to  Goldie
March 13, 2015 8:00 am

Goldie, true, but some life-forms do fine at the deepest ocean-trenches on earth. I don’t think pressure itself is a problem per-say. If you’re made out of water, you’re pretty much incompressible.

milodonharlani
Reply to  beng1
March 13, 2015 9:48 am

The Challenger Deep of the Marianas Trench lies over 11 km below the surface of the Pacific, plus there is atmospheric pressure, albeit arguably negligible.

TomR,Worc,Ma,USA
March 13, 2015 1:21 am

Not life as it is here, but life.

milodonharlani
Reply to  TomR,Worc,Ma,USA
March 13, 2015 9:55 am

And now for something completely different:
https://cosmosmagazine.com/space/could-there-be-life-titans-methane-sea
Or rather the plausible possibility thereof, complete with potential evidentiary support.

Catherine Ronconi
Reply to  milodonharlani
March 13, 2015 5:52 pm
John Silver
March 13, 2015 1:34 am

“A saline ocean under the moon’s icy crust best explains shifting in the auroral belts measured by Hubble.”
Nope.
“which are ribbons of glowing, hot electrified gas”
Silly, it’s called plasma and they know it. The “ribbons” are Birkeland currents.
The Standard Model is dying and they know it. Just observe the fiasco of Rosetta.

Reply to  John Silver
March 13, 2015 7:57 am

John, they sure do bend over backwards to avoid saying “plasma” and “Birkeland currents”, don’t they. Once one becomes aware of this, their antics with language become comical (if not annoying).
It’s bizarre that electricity is so taboo.
Personally, my favorite is “magnetic reconnection.” Double layers breaking down and short-circuiting, resulting in the magnetic energy of the circuit expressing at the short makes a hell of a lot more sense … to me at least.
But what can you say about an agency that had Hansen at the head?

Bob Boder
Reply to  John Silver
March 13, 2015 11:12 am

Out of the loop, please explain more.

Reply to  Bob Boder
March 13, 2015 5:14 pm

Bob, please see:
Double Layers in Astrophysics
NASA Conference Publication #2469
1986
You might also search Wikipedia for:
— Double layers (plasma)
— Hannes Alfvens

Bob Boder
Reply to  Bob Boder
March 13, 2015 5:30 pm

Max
thanx

Reply to  Bob Boder
March 13, 2015 6:01 pm

You are most welcome. It’s an incredibly interesting topic!

Reply to  John Silver
March 14, 2015 7:49 pm

Now NASA is trying to go green with “magnetic reconnection.”
NASA’s Magnetic Field Mission Looking For Green Energy
http://stgist.com/2015/03/nasa-magentic-reconnection-mms-mission-1818
Magnetic reconnection is a made-up concept.
Exploding double-layers is a real, observable phenomenon.

MCourtney
March 13, 2015 1:41 am

Worth noting the exceptional creativity that was used to find this water.
The idea of observing aurorae in order to do an MRI on a planet is quite delightful.

Bloke down the pub
March 13, 2015 2:56 am

It’s life Jim, but not as we know it. Not that we’d have the means to drill down through 95km to find it in the first place.

Catherine Ronconi
Reply to  Bloke down the pub
March 13, 2015 6:11 am

Europa’s a better bet, both for life being there and for ease of finding it.
Dyches, Preston; Brown, Dwayne; Buckley, Michael (8 September 2014). “Scientists Find Evidence of ‘Diving’ Tectonic Plates on Europa”. NASA.

Editor
Reply to  Bloke down the pub
March 13, 2015 6:24 am

Perhaps not, there could be fracture zones, convective plumes, etc that provide shortcuts.
OTOH, http://www.geol.umd.edu/~jmerck/geol212/lectures/12a.html calls Ganymede afossilized version of Europa. I also claims “this ocean is separated from the surface by a thick icy lithosphere”:

3. Ganymede: Density and moment of inertia indicate roughly equal amounts of ice and heavier stuff (silicates and metals). Thus, Ganymede has:
Core: made of iron sulfide and iron
An Inner mantle made of silicates
An Outer mantle made of ices
Magnetic surprise: The Galileo spacecraft determined that Ganymede’s magnetic field is roughly three times that of Mercury. That’s much stronger than expected. It seems to be generated by electrical currents in a Europa-style sub-surface ocean of salt water. In Ganymede’s case, this ocean is separated from the surface by a thick icy lithosphere.
Lithosphere tectonics: We have mentioned the dichotomy of its surface between ancient crater-saturated terrain, and slightly younger grooved terrain reminiscent of Europa’s surface. Tectonically, Ganymede seems to be a large fossilized version of Europa. Ganymede apparently experienced greater tidal heating in the distant past than it does now, due to changes in its orbital eccentricity, such that for an interval, it experienced enough tidal heating to power the formation of grooved terrain and occasional cryovolcanoes, but this did not last long enough for Ganymede’s entire surface to be remodeled, as Europa’s has. Ganymede’s wild time is long past and both the ancient dark terrain and the grooved terrain are quite ancient.

Frodo
Reply to  Ric Werme
March 13, 2015 7:48 am

I’m somewhat ambivalent – but basically skeptical- whether life (capable of reproducing itself, of course) is found elsewhere in the universe or not – but I find it curious how seemingly desperate the scientific world is to find ANYTHING that might – maybe, point to it. I thought practical science was supposed to be mainly a discipline of skepticism. Yes, maybe there is life that is either carbon-based, like here, or even not carbon-based like life here (I guess) but if that life is anything like what we have here on Earth, it is NOT simple – even the so-called “simplest” bacteria capable of reproducing itself is ridiculously complex, and with each passing decade science is finding “simple” life capable of reproducing itself to be anything but. Look at the video below, where the probabilities of “simple” life coming into existence here on earth by chance is talked about. And I’m not saying it didn’t happen (somehow) – full disclosure – I am a Christian myself and I believe God can bring about things any way He wants – including by supposed “random” chance – both here on earth and elsewhere in the universe. But the video below is at least some food for thought. But there really isn’t any such thing as “simple” life – on this planet anyway. In my opinion, there is too much hand-waving and wishful thinking going on in much of science nowadays, the main focus of this site – the scientifically bogus AGW movement – being a prime example.
I understand this site is science based, so please look at this video from a merely scientific perspective – seriously, what REALLY are the chances that reproducible life exists elsewhere, at least life that is anything like what we have here on earth?
[youtube http://www.youtube.com/watch?v=1–tP49mOoE?feature=player_detailpage&w=640&h=360%5D

Catherine Ronconi
Reply to  Ric Werme
March 13, 2015 8:19 am

Frodo,
Meyer’s spew is not science but a pack of ludicrous lies. It is tendentiously anti-scientific, religious indoctrination.
He obviously either knows absolutely nothing at all about biochemistry or is intentionally lying. I suspect the latter.
Proteins do not form “randomly” as the ignoramus imagines or the shameless liar would have his gullible audience believe. Their synthesis occurs via enzymes. Transcription, translation and replication nowadays require whole arrays of enzymes in eukaryotes, but are simpler processes in bacteria and archaea.
Meyer either is abysmally ignorant or ignores the fact that RNA is capable of both replication and synthesis of proteins. The basic building blocks of life, such as amino acids, are abundant in the universe, as are PAHs, which self-assemble into stacks. When nucleobases attach also spontaneously to such a stack, their separation distance just happens to the same 0.34 nm separation as found between adjacent nucleotides of RNA and DNA.
http://upload.wikimedia.org/wikipedia/commons/d/d1/PAHWorld.png
Not only are the chemical reactions within modern cells controlled by enzymes, but so were those which led to the development of living things. These biochemical syntheses didn’t happen “randomly” but were facilitated by naturally occurring organic compounds. Life is thus likely, or guaranteed, to arise wherever and whenever environmental conditions permit.
You have been lied to by professional liars.

Louis
Reply to  Ric Werme
March 13, 2015 10:11 am

“Life is thus likely, or guaranteed, to arise wherever and whenever environmental conditions permit.”
Catherine, if that’s the case, why not create those environmental conditions in a lab and see what happens? It may take millions of years to get the right conditions to randomly occur in nature, but once you have the right conditions, life should be “likely, or guaranteed,” to arise, right? So what’s the problem?

Frodo
Reply to  Ric Werme
March 13, 2015 10:46 am

Louis Said…
“Louis says:
March 13, 2015 at 10:11 am
“Life is thus likely, or guaranteed, to arise wherever and whenever environmental conditions permit.”
Catherine, if that’s the case, why not create those environmental conditions in a lab and see what happens? It may take millions of years to get the right conditions to randomly occur in nature, but once you have the right conditions, life should be “likely, or guaranteed,” to arise, right? So what’s the problem?”
Here is a good rule of thumb, Louis – the nastier, the more contemptuous, more arrogant and hateful the response, the more you know you’ve hit a chord right where that person lives. Compare a few of the responses here to those of the CAGW crowd to the assertion that CAGW isn’t scientific – sound familiar?
50 years ago, scientists were quite certain they would soon unlock the secret of life. With every passing decade, that hope has faded. For a brief synopsis, read the Wiki entry on the beginning of life and prepare for some entertainment. A real grab-bag, they even put out the ”Infinite number of universes, so of course it could happen” argument when the stats just don’t add up.
I’m sure those in opposition to Meyer (and scientists like him) and are not stupid, but he isn’t either. Calling someone stupid is not the way to win arguments.

tomkob
Reply to  Ric Werme
March 13, 2015 12:00 pm

Catherine said…
March 13, 2015 at 8:19am
“Proteins do not form “randomly” as the ignoramus imagines or the shameless liar would have his gullible audience believe. Their synthesis occurs via enzymes. ”
I believe that enzymes are proteins. The procedure that you described seems, to me at least, to be a mechanism for the random assembly of amino acids. IIRC, the speaker in the video doens’t have a problem with the mechanism, rather the randomness part. If I am misunderstanding it, please let me know. Thanks.

Bob Boder
Reply to  Ric Werme
March 13, 2015 12:24 pm

Frodo;
Question, even if unintelligent design is true, why would a God only do it here?

Frodo
Reply to  Ric Werme
March 13, 2015 1:47 pm

Bob Boder said:
“Frodo;
Question, even if unintelligent design is true, why would a God only do it here?”
I ain’t saying He didn’t – just that I doubt He did. Dunno why He would. The Universe is incredibly fined tuned for us – humans and hobbits, and other rational creatures – right here on earth. But, Shoot, C.S. Lewis wrote a space trilogy. The Big Kahuna can do whatever He wants. I just don’t think He did.
Also see my reply to you below
Fine tuning of the Universe:
http://www.reasons.org/articles/anthropic-principle-a-precise-plan-for-humanity

Bob Boder
Reply to  Ric Werme
March 13, 2015 1:56 pm

Frodo;
seems like an awful waist of Space if you are right.

Catherine Ronconi
Reply to  Ric Werme
March 13, 2015 2:33 pm

Louis,
That has been done on a small scale to achieve first steps in the abiogenesis of lifeforms from complex organic chemicals. To take but one of many examples, RNA has been found to assemble spontaneously from its naturally occurring constituent parts in remarkably short time within the little pockets of liquid water in ice.
We may never know the precise steps in the abiogenesis process as it actually occurred in space or on earth, but there is no insurmountable chemical or physical obstacle to the development of life. Indeed it solves certain energetic problems.
Frodo March 13, 2015 at 10:46 am
You got off easy for polluting this blog with the kind of anti-scientific gibbberish which Warmunistas love to point to in disparaging skeptics. Meyer is not a scientist. He’s a professional liar who has made a shameful career out of duping the uneducated.
Please show me these scientists from 50 years ago who were certain we were about “to unlock the secret of life” then. To be a Christian it isn’t necessary to be a liar, but it appears required for Creationists.
Now how about responding to the science I showed you instead of making false accusations?
tomkob March 13, 2015 at 12:00 pm
Apparently you didn’t read what I wrote.
Not all enzymes are proteins. As I noted, RNA synthesizes and catalyzes reactions, such as assembling polypeptides, as well as replicating itself. In the well-supported, ie not yet shown false, RNA World hypothesis, life arose as RNA organisms before DNA took over the genetic function and RNA concentrated on transcription and translation. As you may know, there are purely RNA viruses even now.
More importantly, it is obvious to anyone who knows anything about biochemistry that Meyer the Liar’s fantasy of how proteins are built is so wrong that it has to be intentionally deceptive.

Bob Weber
March 13, 2015 7:08 am

Paper abstract is here http://onlinelibrary.wiley.com/doi/10.1002/jgra.50122/abstract.
Since the Earth’s aurora location and intensity is directly controlled by the ever-varying solar wind interaction with our magnetosphere, why should Ganymede’s aurora be any different? Did this study attempt to parse out the solar signal? What evidence is there that the Earth’s ocean has any influence on our aurora?
I’m dubious so far about the conclusions drawn from this study. If the rocking motion of the aurora is shown to be out of phase with the solar wind at Ganymede, then I can see their point.

whiten
Reply to  Bob Weber
March 13, 2015 5:53 pm

hello Bob
I am dubious too in this one.
I think the problem is that this study draws to such a conclusion because as in your case relies in a Earth like system to actually estimate the expected aurora rocking motion.
Is an estimate I think derived by comparision and adjustment.
If that done then the main problem is that apart from the gravity and atmospheric parameters to adjust they have to adjust for the salt water oceans.
That adjustment sends the oceans of Ganymede very deep indeed below the crust, where these oceans mean nothing really is a sense of offering the friction supposed to be there as an explanation.
The behavior and the rocking motion of auroras in a case like the Jupiter,s impact will depend in the reaction and response of the planets surface.
If a Earth like planet subjected to such a condition the supposed friction will be due to the atmosphere and much much more due to oceans, because these are the main components that play in the surface energy behavior of an Earth like system.
As in the case of a Earth like system these guys assume that the friction, on the estimated expected auroras rocking motion of Ganymede should be due to atmosphere and salt water oceans.
As there very little atmosphere and very little adjustment there, then the size the depth and the mass of supposed oceans is calculated in the angle of adjustment for the gravity and size of Ganymede.
And according to the calculated mass depth and gravity these oceans end up buried very deep indeed.
As far as I can tell these oceans on Ganymede would offer the supposed friction to the supposed expected auroras rocking motion only if these oceans were on the surface not kilometers deep.
Only six feet under the surface these oceans would lose most of their supposed power of friction.
All this said I have to say that the possibility of me being wrong with this is very very high, lots of assumptions there, and especially while I have not even checked the study in question.
The main point in this originates from the concept that if is not in the surface, it has no much saying in such a case as this.
Again is a concept of mine reached that it still has a very high probability to be wrong….but anyway for what it could be worth..
cheers

Bob Weber
Reply to  Bob Weber
March 13, 2015 7:22 pm

Thanks for your comment whiten. The trouble with a study like this, other than the fact that the important details are pay-walled and not discussed here in the press release article, is that we’ll probably never know for sure if there really is a 90 mile deep ocean under 150 miles of crustal ice, so they can say anything, right or wrong …
http://upload.wikimedia.org/wikipedia/commons/c/c7/Ganymed_Earth_Moon_Comparison.png
Even wikipedia says there’s water there: http://en.wikipedia.org/wiki/Ganymede_(moon)
“Ganymede… is the largest moon of Jupiter and in the Solar System, and the only moon known to have a magnetosphere. … It also has the highest mass of all planetary satellites, with 2.02 times the mass of the Moon. …is composed of approximately equal amounts of silicate rock and water ice… It is a fully differentiated body with an iron-rich, liquid core, and an internal ocean. Ganymede’s magnetosphere was probably created through convection within its liquid iron core… The meager magnetosphere is buried within Jupiter’s much larger magnetic field and would show only as a local perturbation of the field lines. The satellite has a thin oxygen atmosphere that includes O, O2, and possibly O3 (ozone)… Like most known moons, Ganymede is tidally locked, with one side always facing toward the planet.”
“HST observed two bright spots located in the northern and southern hemispheres, near ± 50° latitude, which is exactly the boundary between the open and closed field lines of the Ganymedian magnetosphere (see below). The bright spots are probably polar auroras, caused by plasma precipitation along the open field lines. … The existence of a neutral atmosphere implies that an ionosphere should exist, because oxygen molecules are ionized by the impacts of the energetic electrons coming from the magnetosphere and by solar EUV radiation. However, the nature of the Ganymedian ionosphere is as controversial as the nature of the atmosphere.”
“The Ganymedian magnetosphere has a region of closed field lines located below 30° latitude, where charged particles (electrons and ions) are trapped, creating a kind of radiation belt. The main ion species in the magnetosphere is single ionized oxygen—O which fits well with Ganymede’s tenuous oxygen atmosphere. In the polar cap regions, at latitudes higher than 30°, magnetic field lines are open, connecting Ganymede with Jupiter’s ionosphere. In these areas, the energetic (tens and hundreds of kiloelectronvolt) electrons and ions have been detected, which may cause the auroras observed around the Ganymedian poles. In addition, heavy ions continuously precipitate on Ganymede’s polar surface, sputtering and darkening the ice.”
The interaction between the Ganymedian magnetosphere and Jovian plasma is in many respects similar to that of the solar wind and Earth’s magnetosphere. The plasma co-rotating with Jupiter impinges on the trailing side of the Ganymedian magnetosphere much like the solar wind impinges on the Earth’s magnetosphere. The main difference is the speed of plasma flow—supersonic in the case of Earth and subsonic in the case of Ganymede. Because of the subsonic flow, there is no bow shock off the trailing hemisphere of Ganymede.”
Probable ocean discussed here “The Permanent and Inductive Magnetic Moments of Ganymede” http://www.igpp.ucla.edu/people/mkivelson/Publications/ICRUS1572507.pdf
Abstract:
“Data acquired by the Galileo magnetometer on five passes by
Ganymede have been used to characterize Ganymede’s internal
magnetic moments. Three of the five passes were useful for determination
of the internal moments through quadrupole order. Models
representing the internal field as the sum of dipole and quadrupole
terms or as the sum of a permanent dipole field upon which is superimposed
an induced magnetic dipole driven by the time varying
component of the externally imposed magnetic field of Jupiter’s
magnetosphere give equally satisfactory fits to the data. The permanent
dipole moment has an equatorial field magnitude 719 nT.
It is tilted by 176◦ from the spin axis with the pole in the southern
hemisphere rotated by 24◦ from the Jupiter-facing meridian plane
toward the trailing hemisphere. The data are consistent with an
inductive response of a good electrical conductor of radius approximately
1 Ganymede radius. Although the data do not enable us to
establish the presence of an inductive response beyond doubt, we
favor the inductive response model because it gives a good fit to
the data using only four parameters to describe the internal sources
of fields, whereas the equally good dipole plus quadrupole fit requires
eight parameters. An inductive response is consistent with a
buried conducting shell, probably liquid water with dissolved electrolytes,
somewhere in the first few hundred km below Ganymede’s
surface. The depth at which the ocean is buried beneath the surface
is somewhat uncertain, but our favored model suggests a depth of
the order of 150 km. As both temperature and pressure increase
with depth and the melting temperature of pure ice decreases to
a minimum at ∼170 km depth, it seems possible that near this
location, a layer of water would be sandwiched between layers
of ice.”
Now we know more than evah about that!

whiten
Reply to  Bob Weber
March 13, 2015 8:42 pm

Thank you for your reply and the info Bob.
Very kind of you..:-)
cheers

Frodo
March 13, 2015 7:52 am

Oops sorry, I put in both the embed and the link above, and it ended up being embedded twice – no need to listen to both 🙂

milodonharlani
Reply to  Frodo
March 13, 2015 9:36 am

Once was too much for the anti-scientific drivel.
If life has been designed by a designer, he, she or it is far from intelligent. Rather it is grossly incompetent, intensely stupid and cruelly sadistic.

TC in the OC
Reply to  milodonharlani
March 13, 2015 10:43 am

Lighten up a little…none of us have all the answers…
Get Your Own Dirt
One day a group of scientists got together and decided that man had come a long way and no longer needed God. So they picked one scientist to go and tell Him that they were done with Him. The scientist walked up to God and said, “God, we’ve decided that we no longer need you. We’re to the point that we can clone people and do many miraculous things, so why don’t you just go on and mind your own business?”
God listened very patiently and kindly to the man. After the scientist was done talking, God said, “Very well, how about this? Let’s say we have a man-making contest.” To which the scientist replied, “Okay, we can handle that!”
“But,” God added, “we’re going to do this just like I did back in the old days with Adam.”
The scientist said, “Sure, no problem” and bent down and grabbed himself a handful of dirt.
God looked at him and said, “No, no, no. You go get your own dirt.”
Moral: It isn’t enough just to be able to explain the origin of life, if you cannot explain the raw materials and fine-tuned parameters of chemistry and physics. As Carl Sagan said in Cosmos, “To really make an apple pie from scratch, you must begin by inventing the universe.”

Bob Boder
Reply to  milodonharlani
March 13, 2015 11:52 am

What’s wrong with a Cruelly Sadistic deity? If that’s why we are here it explains a lot.

Bob Boder
Reply to  milodonharlani
March 13, 2015 11:54 am

TC;
One question, what do you use to make a god with?

Catherine Ronconi
Reply to  milodonharlani
March 13, 2015 2:44 pm

It’s not necessary to explain the constituent parts of living things supernaturally. They occur naturally in great abundance in space.
If your “moral” is that the universe itself may have been designed to allow the development of complex organic chemical compounds, indeed of carbon itself, that’s an entirely different proposition from imagining that a designer has intervened in abiogenesis and evolution, for which supernatural activity there is not a shred of evidence. Both processes work just fine without invoking an inept designer.
There is no evidence for design in the universe, either, but it can’t be ruled out. Changing its parameters slightly leads to lack of elements heavier than hydrogen, for instance.
The bootless quest to find “proof” of God in life or the universe is fundamentally, if I may use that term, wrong in Christian theology, or at least Protestant. The whole point is faith. Looking for evidence means you don’t have the faith which saves you. That’s why God remains hidden and mysterious.
Even an Early Church Father said, “I believe (the Christ story) precisely because it is absurd”. Luther similarly observed that “To be a Christian, you must tear the eyes out of your reason”. Creationists and ID spewers don’t even understand their own religions, let alone science.

whiten
Reply to  milodonharlani
March 13, 2015 6:06 pm

Bob Boder
March 13, 2015 at 11:54 am
TC;
One question, what do you use to make a god with?
———————
That is one of the first questions actually there was an answer to before even modern science arrived to prove it.
It takes a man, a completely insane man to make a god out of himself….:-)
And there is proof offered by the modern science on this one….. the Mann himself..:-)
cheers

March 13, 2015 8:40 am

Water on Ganymede? No problem, there seems to be plenty of it on Earth.
Life that we can recognize as such? Mars may have had it.
Date: Tue, 6 Aug 1996 16:50:22 -0400
From: NASANews@luna.osf.hq.nasa.gov (NASA HQ Public Affairs Office)
To: press-release-net@venus.hq.nasa.gov
Subject: Statement from Daniel S. Goldin, NASA Administrator
Sender: owner-press-release@venus.hq.nasa.gov
August 6, 1996
Laurie Boeder
Headquarters, Washington, DC
Release: 96-159
Statement from Daniel S. Goldin, NASA Administrator
NASA has made a startling discovery that points to the possibility that a primitive form of microscopic life may have existed on Mars more than three billion years ago. The research is based on a sophisticated examination of an ancient Martian meteorite that landed on Earth some 13,000 years ago.
The evidence is exciting, even compelling, but not conclusive. It is a discovery that demands further scientific investigation. NASA is ready to assist the process of rigorous scientific investigation and lively scientific debate that will follow this discovery.

Catherine Ronconi
Reply to  Andres Valencia
March 13, 2015 8:51 am

IMO, the Allan Hills meteorite does not contain good evidence for life, which of course doesn’t mean that Mars never had life or even that it’s not there now.
http://en.wikipedia.org/wiki/Martian_meteorite#Possible_evidence_of_life

Reply to  Catherine Ronconi
March 13, 2015 9:28 am

I see Barber and Scott (PNAS 2002) do not agree with NASA on this matter:
Origin of supposedly biogenic magnetite in the Martian meteorite Allan Hills 84001
Abstract:
Crystals of magnetite (Fe3O4) and periclase (MgO) in Fe-Mg-Ca carbonate in the Martian meteorite Allan Hills 84001 were studied by using transmission electron microscopy to understand their origin and evaluate claims that the magnetites were made by Martian microorganisms. In magnesian carbonate, periclase occurs as aggregates of crystals (grain size ≈3 nm) that are preferentially oriented with respect to the carbonate lattice. Larger periclase crystals ≈50 nm in size are commonly associated with voids of similar size. Periclase clearly formed by precipitation from carbonate as a result of partial decomposition and loss of CO2. Magnetite occurs in more ferroan carbonate, and, like periclase, it is associated with voids and microfractures and the two oxides may be intermixed. Magnetite nanocrystals that are commonly euhedral and entirely embedded in carbonate are topotactically oriented with respect to the carbonate lattice, showing that they formed as solid-state precipitates. Magnetites in Fe-rich carbonate rims are not well oriented. These magnetites are generally more irregular in shape and diverse in size than the euhedral variety. All occurrences of magnetite and periclase are entirely consistent with in situ growth by solid-state diffusion as a result of carbonate decomposition during impact heating. Biogenic sources should not be invoked for any magnetites.

Catherine Ronconi
Reply to  Catherine Ronconi
March 13, 2015 9:30 am

Other evidence also weakens the case for nanobes in the meteorite. IMO the preponderance of evidence will remain against their fossil life status (indeed all of it) unless and until similarly sized life forms are discovered on earth.

March 13, 2015 8:45 am

Those interested in Martian life, see “Mars Life?”, at http://www.oarval.org/MLphotos.htm and http://www.oarval.org/MarsLife.htm

March 13, 2015 8:52 am

The question of life on these moons always comes up.. I think it’s irrelevant whether life exists on other planets and moons in our solar system, (and it’s extremely likely they are all sterile and barren anyway) the question should be can life from earth survive on them, and if so, we should go ahead and introduce life to them as a priority..
There wont be any life without an ecosystem and ecosystems tend to be large and widespread throughout their environments, therefore detectable, If there was an alien ecosystem (unlikely) it would fight off the introduction of foreign life or adopt it as part of it’s own. it’s a waste of time, money and resources looking for microbes on other planets etc.. based on nothing more than some peoples fantasies of alien life.

Catherine Ronconi
Reply to  Sparks
March 13, 2015 9:10 am

Sampling the water plumes in fly-bys of Jupiter and Saturn’s moons or even landing on them need not cost that much more than sending probes to those gas giants in the first place. IMO it’s well worth the effort and expense.
Hypothesizing life on other bodies in the solar system isn’t a fantasy. It’s based on solid science. Life emerged on earth almost as soon as it was possible, so why not on other worlds with similar conditions, such as liquid water, energy sources and complex organic biochemical building blocks?

Reply to  Catherine Ronconi
March 13, 2015 10:13 am

Hypothesizing about life on other bodies in the solar system is as close to fantasy as you can possibly get, I’m all for sending craft to other planets and moons to look for life but not as a priority, if there was life there it’s ecosystem would be detectable, and there would be no way of knowing if any life found elsewhere throughout the solar system such as extremophiles didn’t originate from earth anyway..
I’m suggesting a more reasonable approach would be to experiment with introducing various types life from earth on other bodies where they would likely survive and monitor what happens.. And the moons around Jupiter are exposed with dangerous amounts of radiation and we scientifically understand that complex organic structures break down when exposed to it, having biochemical building blocks throughout the solar system isn’t enough to suggest that life can take hold. In my opinion space exploration of our solar system is so slow and it seems pointless sometimes, all we do is look at rocks, put a flag on it and hypothesize about stuff, and it’ll drag on and on with no direction for centuries.

Bob Boder
Reply to  Catherine Ronconi
March 13, 2015 12:10 pm

It will drag one until there is a financial return on the cost associated with it. Once we find a way to lower the cost of getting there then the race will be on.

Catherine Ronconi
Reply to  Catherine Ronconi
March 13, 2015 2:53 pm

How can it be fantastic to hypothesize life on other bodies when we know it exists on earth? There is nothing unique about our planet, although it apparently is fairly unusual to have liquid water on the surface of a planet, moon, asteroid or other celestial object.
Our unusual moon and magnetosphere might have helped provide stability for multicellular life to evolve, but even that is questionable. But in any case, microbes are more likely to exist on other celestial bodies than not.
Life as we know it requires chemical constituents, which are everywhere, an energy source or sources, also far flung, and liquid water, which now appears to be somewhat common as well, even in our own star system. This doesn’t even address the question of life as we don’t know it, such as might exist based upon liquid media other than water.

Reply to  Sparks
March 13, 2015 9:11 am

On the contrary, the extraterrestrial life question seems to be a basic quest of humanity.
And the references I gave are not fantasies. These are photographs of what appears to be fossilized microbes containing magnetite particles, just like terrestrial microbes of comparable size.

Catherine Ronconi
Reply to  Andres Valencia
March 13, 2015 9:18 am

The putative fossil microbes are much smaller than the smallest terrestrial bacteria. Nanobes of the “fossils'” scale have been hypothesized to exist on earth but remain unverified and conjectural.

Reply to  Andres Valencia
March 13, 2015 9:57 am

Thanks, Catherine Ronconi.
To be fair, I will add the Barber and Scott (PNAS 2002) abstract to my Mars Life? pages.

Catherine Ronconi
Reply to  Andres Valencia
March 13, 2015 2:54 pm

You’re welcome.

tadchem
March 13, 2015 11:03 am

I’m waiting for someone to propose moving Ganymede out of it’s orbit and into the Goldilocks Zone, possibly into an Earth-locked Lagrangian orbit – L4 or L5.

Roy A Jensen
March 13, 2015 11:20 am

Bear in mind it is the mass of a planet that holds the molecules close enough for liquid water. The temperature also has to be right. That is why Mars has never had liquid water. Mass has always been to low for the molecules to be close enough. Nautually H20 is very common. Hydrogen is the first component of the Periodic table. Oxygen is the next that there is a lot of. When viewing landscape of the world 93% of what you see by volume is Oxygen.
Related, question is where did the recipes in the DNA come from. They are very specific and some call for more then 3000 amino acid building blocks. Of course the recipes are worthless if you do not have 109 protein types to process them. And without cell walls and many other parts that is worthless too. And then there is the question of where the body plan data is stored. DNA just supplies the building blocks. It does not say where a liver is to be or the eye is to be. One of the clues to the answer to that was when they almost kill a fat cell (wiping clean the sugar codding on the out side of the cell wall, and we place it where is can restore it, we now have a stem cell. And so Dolly came to be the first cloned animal from such a cell. Life is complex and I am amazed by it. It is a lack of knowledge that allows some to believe it is. They are using blind religious faith to believe the impossible, that life is an accident.

Bob Boder
Reply to  Roy A Jensen
March 13, 2015 12:16 pm

Its blind faith one way or the other. To believe that life came from a God is to put the more complex being first. Where did God come from? Either case can be made and either could be right, but in the natural world typically complexity is achieved in steps from the less complex to the more complex. Not THE answer but a clue.

Frodo
Reply to  Bob Boder
March 13, 2015 1:18 pm

This really should stay scientific, but since you asked….
It IS faith one way or the other, but may I suggest that my worldview is perfectly logical/rational.
If God created the universe, along with all dimensions discovered by science (and yet to be discovered by science), and also created all physical laws that govern the universe at the moment of the Big Bang, it must follow that God, by definition, must exist outside of all those dimensions/laws – including and especially time, and is not at all ruled by them. This explains lot of things, like how He can listen to millions of prayers at the same time – no biggie for Him. Also how we can have a free will, even though he already knows everything we will ever. do God, to our puny minds – is eternal – He did not have a beginning, at least in the way we could ever comprehend it.. IOW, the question of how He Himself came into existence is not relevant – at least to our very limited minds/understanding. People keep trying to use the laws of the Universe to define God and explain God – he created the Universe. He exists in dimensions completely outside it (and, He’s also a huge Michigan Wolverines fan, and just a few months ago, sent His son to save the football program) And yes, that means that science is not ever going to be able to use the physical laws of the Universe to scientifically “prove” God – but, again, there is always Romans 1:20.
I love science. I love my faith. I need both. I need my faith to, as one of many examples, reject Peter Singer’s assertion that a newborn child is of less value than an adult pig – which is actually a rational conclusion of atheism (I’m worth more than a lot of sparrows – at the very least). Science is never going to help me there. I could write on this for a long time, but I’ll spare you all.
Mods – remember – He ASKED, so I answered.
Only a Michigan Man can truly understand God’s infinite ways

Bob Boder
Reply to  Bob Boder
March 13, 2015 1:54 pm

Frodo;
Your mind is so willing to accept God existence with out a beginning, why is it so difficult to accept existence with out a beginning or a God? You separate God from the power of time, let me suggest to you that existence may also not be the slave to time, no start no end but always change and it is our perception of the change that we call time.
As to what is rational to atheist I am not per say an atheist nor am I a theist but I do know the difference between a self aware individual and a pig. I value both but one much more then the other. Nor am I trying to dissuade you from what you believe that is your right just respect others right to believe differently.

Catherine Ronconi
Reply to  Bob Boder
March 13, 2015 2:47 pm

You made it unscientific as soon as you posted Meyer’s lies.
Science doesn’t require faith. It requires doubt.

Catherine Ronconi
Reply to  Roy A Jensen
March 13, 2015 5:18 pm

Life is not an accident, but the inevitable consequence of the physical laws under which our universe operates.
Mars did have liquid water on its surface but lost it, not because of its planetary mass but due to reduction in the mass of its atmosphere.
The “recipes” in DNA evolved. Thanks to genetic sequencing, we can now study the evolution of biochemical processes in detail.
Actually DNA does control where various tissues will grow. Before commenting on a subject, it’s usually best to know something about it.

Catherine Ronconi
Reply to  Catherine Ronconi
March 13, 2015 5:19 pm

Sorry. Reply should be addressed to Roy.

Catherine Ronconi
Reply to  Catherine Ronconi
March 13, 2015 5:37 pm

http://www.sciencemag.org/content/early/2015/03/04/science.aaa3630.abstract
ABSTRACT
We measured maps of atmospheric water (H2O) and its deuterated form (HDO) across the martian globe, showing strong isotopic anomalies and a significant high D/H enrichment indicative of great water loss. The maps sample the evolution of sublimation from the north polar cap, revealing that the released water has a representative D/H value enriched by a factor of about 7 relative to Earth’s ocean (VSMOW). Certain basins and orographic depressions show even higher enrichment, while high altitude regions show much lower values (1 to 3 VSMOW). Our atmospheric maps indicate that water ice in the polar reservoirs is enriched in deuterium to at least 8 VSMOW, which would mean that early Mars (4.5 billion years ago) had a global equivalent water layer at least 137 meters deep.
Since the ancient Martian ocean covered only about a third of the planet, its depth would have been three times this global equivalent.
This is but one of the numerous lines of evidence for abundant liquid water on the surface of the planet early in its history. On what basis do you, Roy, assert that Mars never had liquid water on its surface?

Mac the Knife
March 13, 2015 2:20 pm

Only a Michigan Man can truly understand God’s infinite ways ????
Pride goes before destruction, and a haughty spirit before a fall. Proverbs 16:18
Perhaps, when you understand that, you will understand the lowly stature of Michigan’s football and basketball programs.
Now, back to the posted article:
The central topic was using aurora to detect subsurface water on Ganymede…..
That is a very novel and sublime use of planetary magnetic fields and aurora!

March 13, 2015 3:06 pm

Maybe we should find a way to alter the orbits of Ganymede and/or Europa so that they “merge” with Mars. All that water and mass could make Mars habitable in a few 100-years.
Geological Engineering on a Collosal Scale. Fooy on COsub2 burial. Let us get with the BIG Picture. It’s for our great-great Grandchildren………

Eastside Eddie
Reply to  tenndon
March 15, 2015 10:24 am

I believe that was used in “The forge of God” by Greg Bear,.a classic in my opinion.

logos_wrench
March 13, 2015 4:33 pm

Maybe that is ocean where our heat is hiding.

March 14, 2015 4:33 am

this will be a great addition to the science of space
http://www.paramagneticpainthq.com

Dr. Strangelove
March 14, 2015 5:38 am

I bet there are bacteria or some worm-like creatures down there. I bet we will not find it anytime soon. Drilling into 150 km of rock is mission impossible. Here on earth we only drilled 12 km into the crust and it took 19 years of drilling! Better send Bruce Willis to that moon.

highflight56433
March 14, 2015 2:06 pm

Thank God for aliens. They plant life everywhere. 😉

DB Wood
March 16, 2015 11:12 am

I approach such reports with a dose of skepticism.
It seems to me, anything that could possibly indicate life elsewhere (even if it isn’t really a true indicator), is jumped on, much like day to day and season to season temperatures for climate change.
Everyone is so eager to find something to support the conclusion they already have, that I find theories dubious.
Planetary composition, sure involves theory and scientific approaches, but it is far from fact, and still conjecture without more observant evidence. There are a number of other mitigating factors, that could increase or decrease estimates exponentially.
I for one, think we need to stop spending so much time on the stars, and more on what we can observe, especially in reference to uncharted lands, jungles and oceans, as well as below the surface (of which) we have barely scratched the surface (ha).
Our desire to find contact or life elsewhere is meaningless, as we have plenty to find here that we still don’t know about. Sure such a perpetuated desire has led to advances in many ways, but not from new material being brought back, or new revelations upon theory as a whole, just more conjecture upon conjecture, with no hopes of falsifiable demonstrable proof of many such ideas.
The method in calculating the ocean underneath is creative, but not the first time for such a proposal. I just wish these enterprising minds would turn their focus inward.
PS: I find it odd how kneejerk reactions are to certain things here. I consider myself skeptical of all, except that my grandmother made the best apple pies, I refuse to bend on this point of fact in my life. Liar if you say different.

March 21, 2015 9:24 am

Reblogged this on gottadobetterthanthis and commented:
Ganymede, Jupiter’s largest moon, has aurora, like earth, and the aurora on Ganymede dance and wobble unexpectedly, unless one factors in under-surface water, ocean water, water with salt and minerals to give it characteristics that affect electro-magnetic characteristics; thus making the variations in the aurora different than can be explained by the atmosphere and Jupiter’s magnetic field alone.
So, is there liquid water there? Let’s assume probably at this point and wait for more evidence. Will we find life there? If there is liquid water, I expect we will find organic systems that we will have to acknowledge as living.
There is speculation of water and life on Saturn moons as well.
http://www.ft.com/cms/s/0/d8c664be-cce4-11e4-b5a5-00144feab7de.html#axzz3V2DgDB4D
“Two of the latest discoveries come from scientists working with the Cassini spacecraft, a joint project of the European and US space agencies, which has been in orbit around Saturn since 2004. One team found evidence of “hydrothermal activity” within the icy Saturnian moon Enceladus, reporting in the journal Nature that hot springs were active on its ocean floor.
“This finding is backed up by another research group using different Cassini instruments to study methane emerging from Enceladus. These eruptions of hydrocarbon gas may originate from interactions involving microbes on the moon’s ocean floor, according to a paper in Geophysical Research Letters.”
From: Planetary Science: Is there life in Jupiter and Saturn’s lunar oceans?
Clive Cookson
Here is a YouTube:

Worth the time. Good basic explanation. Its home is here:
https://www.patreon.com/scishow?ty=c
She mentions a link for downloading the mentioned software, but I don’t find it at YouTube or their site. But, Google makes things easy. http://www.topcoder.com/asteroids/asteroiddatahunter/
“if you have access to a telescope and can take photos of the sky, you can upload these photos as long as they are in .FITS format.” .FITS is new to me. Google to the rescue again. It is open, which is why, I assume, they specify it. http://en.wikipedia.org/wiki/FITS I’m surprised I never heard of it. Astronomers have been using it since I was in high school, however many decades ago that was.
Anyway, it looks like a great format, and I think the astronomers must have been pretty bullheaded to get such a useful and readable format back when computer geeks abbreviated everything to two and three letters.
Here is another take: http://www.newstatesman.com/sci-tech/2015/03/unexpectedly-watery-moons-our-solar-system-may-be-friendlier-life-we-thought
This article is about the same as the other NASA ones, but has a nice graphic of the expected Ganymede structure: http://earthsky.org/space/underground-ocean-on-jupiters-largest-moon
Perhaps there will be more detail forthcoming. In the meantime, it is looking unreasonable to suppose our earth is the only place with liquid water.

Sturgis Hooper
Reply to  Lonnie E. Schubert
March 23, 2015 2:30 pm

All the evidence suggests that liquid water is abundant in the solar system, and was even moreso three billion years ago, when it appears that Mars had an ocean and lakes.
There is even strong evidence in support of microbial mats on Mars:
http://www.astrobio.net/news-exclusive/potential-signs-ancient-life-mars-rover-photos/
The odds are that we not alone even in our own star system, let alone the galaxy and universe.

Sturgis Hooper
Reply to  Sturgis Hooper
March 23, 2015 3:07 pm

Right now though the smart money is on the little moon of Saturn Enceladus both as a likely abode of life and as a place where it would be easier to detect, thanks to its cryovolcanism:
http://www.space.com/25340-saturn-moon-enceladus-ocean-discovery.html

Reply to  Sturgis Hooper
March 23, 2015 7:26 pm

Howdy Sturgis, agreed, kinda. I’m convinced the nature of the universe, the nature of organic chemistry in particular, makes it likely that self-organized, replicative, dissipative systems arise everywhere they can. I will be surprised if we find sterile liquid water. I expect we will find systems consuming fuel in many ways most every time we find water with minerals and organics.
However, as to the galaxy, nope. We are alone. The whole of the galaxy holds no more promise than these local moons and planetesimals. Sure, self-organized, replicative, dissipative systems that we will easily recognize as living organisms, but the systems We are seem to be too hard. One in billions of trillions, alone in our neck of the woods. If any other beings capable of building and contemplating expansion beyond their home atmosphere exist, or existed, anywhere in our galaxy, they either died out before they could, or they just never figured out such things. That is, they ain’t there because they aren’t here. It really is that simple.
Energy considerations make this a certainty as far as humans are concerned. Any civilization, organization, or organism capable of producing and harnessing the power required for interstellar travel will have no secondary limitations. Not to mention the nearly insurmountable engineering and logistical requirements. We simply have no frame of reference for imagining what motivation might be behind such capability. It is limitless from our perspective.
I do think we need to stay skeptical. We are only beginning to have good evidence of liquid water. We need a lot more before we start talking about life. The reference you give is intriguing, and impetus for additional missions to Mars. Perhaps the one-way astronauts will want to study such things when they get there, assuming they get there in our lifetimes.
When I said we are alone in our neck of the woods, I’m thinking of our galaxy. In scores, perhaps several scores, of millennia, we will populate the entire habitable portions of this galaxy, given only the assumption that we go not extinct. If there are complex, intentional, thoughtful beings out there of any sort, we will find them by then, but it is simply unreasonable to assume they have capability they simply don’t use. They haven’t come because they can’t, or more likely, they aren’t there in any sense we could recognize as reasoning and sentient beings. I restrict our neck of the woods to our galaxy because we simply cannot hope to get beyond our galaxy without some seeming impossible stargate-type capability. Even that has energy problems, and even if it all proved surmountable, we could search the universe for billions of years and perhaps still find no other persons. We’d still have so much to search. It is unfathomable. Perhaps with that much, the whole of the universe, the odds were surmounted many times. We are extremely unlikely to ever know no matter how many ages we accomplish. In other words, while the odds would seem to favor other beings something like ourselves in our universe, don’t count on ever meeting them, ever.
There is this as well: http://waitbutwhy.com/2014/05/fermi-paradox.html
The main point for me is the energy. Once interstellar travel is a practical reality, even given hundreds or thousands of years for the trips, other considerations become trivial. There simply are no reasonable reasons for why they are not here other than they have never been there to begin with. So, for the WBW reference, I’m a filter proponent, and my current supposition is that the filter is somewhere before biological complexity in the sense that makes reasoning possible. It might even be in a confluence of factors internal and external. Internal such as central nervous system and opposable thumbs, for starters, and external in things like the position in the galaxy, the exact position in the Goldilocks zone, the size and position of the moon, the density and composition of the atmosphere, ad infinitum.

Sturgis Hooper
Reply to  Sturgis Hooper
March 24, 2015 12:11 pm

I should have clarified. By alone, I mean without other life of any kind. I agree that intelligent life is probably rare in any galaxy, It’s entirely possible that we’re it at the moment for the Milky Way.
But IMO microbes are probably common. Odds are that a majority of star systems outside the highly bombarded galactic core have planets or moons harboring simple life forms, IMO.
BTW, it’s becoming clear that the solar system is unusual. Jupiter is a bigger than average planet but still far too small to form a binary star. It does however have a miniature “star” system of its own. It also caused the solar system to be short of inner planets:
http://www.engadget.com/2015/03/24/thanks-for-ruining-the-solar-system-jupiter/?ncid=rss_truncated

%d bloggers like this: